U.S. patent application number 16/675765 was filed with the patent office on 2020-11-26 for multi-functional weighting agent for drilling fluid and preparation method thereof, and water-based drilling fluid and use thereof.
This patent application is currently assigned to Southwest Petroleum University. The applicant listed for this patent is Southwest Petroleum University. Invention is credited to Yang BAI, Yan CHENG, Guancheng JIANG, Pingya LUO, Jinsheng SUN.
Application Number | 20200369936 16/675765 |
Document ID | / |
Family ID | 1000004493690 |
Filed Date | 2020-11-26 |
United States Patent
Application |
20200369936 |
Kind Code |
A1 |
BAI; Yang ; et al. |
November 26, 2020 |
Multi-Functional Weighting Agent for Drilling Fluid and Preparation
Method Thereof, and Water-Based Drilling Fluid and Use Thereof
Abstract
The invention relates to the field of drilling fluid, and
provides a multi-functional weighting agent for drilling fluid and
preparation method thereof, and water-based drilling fluid and use
thereof, wherein the multi-functional weighting agent is an
polyacrylamide/modified barium sulfate composite multi-functional
weighting agent prepared by sequentially dropwise adding acrylamide
and ammonium persulfate to a mixture of modified barium sulfate and
deionized water in a presence of an initiator.
Inventors: |
BAI; Yang; (Chengdu, CN)
; LUO; Pingya; (Chengdu, CN) ; CHENG; Yan;
(Chengdu, CN) ; SUN; Jinsheng; (Qingdao, CN)
; JIANG; Guancheng; (Beijing, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Southwest Petroleum University |
Chengdu |
|
CN |
|
|
Assignee: |
Southwest Petroleum
University
Chengdu City
CN
|
Family ID: |
1000004493690 |
Appl. No.: |
16/675765 |
Filed: |
November 6, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C08K 2003/3045 20130101;
C09K 8/12 20130101; C08L 33/26 20130101; C09K 8/03 20130101; C08K
3/30 20130101 |
International
Class: |
C09K 8/03 20060101
C09K008/03; C09K 8/12 20060101 C09K008/12 |
Foreign Application Data
Date |
Code |
Application Number |
May 20, 2019 |
CN |
201910418791.2 |
Claims
1. A multi-functional weighting agent having a composite structure,
comprising polyacrylamide, and modified barium sulfate, wherein the
modified barium sulfate and the polyacrylamide are in a ratio by
weight in a range of from about 4:5 to about 5:2.
2. The multi-functional weighting agent of claim 1, wherein the
multi-functional weighting agent is white round particles with an
average particle diameter of 8-20 and has a surface lubricating
coefficient K.sub.f within a range of 0.05-0.1 and a compressive
strength ranging from 9.times.10.sup.4 Pa to 10.times.10.sup.4
Pa.
3. The multi-functional weighting agent of claim 1, wherein the
polyacrylamide is cross-linked.
4. (canceled)
5. The multi-functional weighting agent of claim 1, wherein the
modified barium sulfate and the polyacrylamide are in a ratio by
weight being about 3:2.
6. The multi-functional weighting agent of claim 1, wherein the
modified barium sulfate comprises modified barium sulfate A,
modified barium sulfate B and modified barium sulfate C; wherein
the modified barium sulfate A has an average particle diameter of
0.05-0.45 .mu.m, the modified barium sulfate B has an average
particle diameter of 0.5-3 .mu.m, and the modified barium sulfate C
has an average particle diameter of 15-25 .mu.m.
7. The multi-functional weighting agent of claim 6, wherein a
weight ratio of the modified barium sulfate A, the modified barium
sulfate B and the modified barium sulfate C is
(0.4-0.6):(0.4-0.6):1.
8. The multi-functional weighting agent of claim 1, wherein the
modified barium sulfate has a density ranging from 4.2-4.8
g/cm.sup.3.
9. A water-based drilling fluid, comprising the multi-functional
weighting agent of claim 1; wherein the multi-functional weighting
agent is in an amount of 150-170 g, based on a total weight of 100
mL water-based drilling fluid.
10. A method for preparing the multi-functional weighting agent of
claim 1, wherein the method comprises: (1) mixing a modified barium
sulfate with deionized water to obtain a mixture; (2) heating the
mixture and adjusting a pH of the mixture at a presence of an
initiator; (3) sequentially dropwise adding acrylamide and ammonium
persulfate to step (2) for carrying out reaction; (4) washing,
drying and grinding the reaction product of step (3).
11. The method of claim 10, wherein mixing conditions in step (1)
include: stirring the mixture at a stirring rate of 300-400 r/min
for 0.2-1 h and then standing still for 3-5 h; wherein heating
conditions in step (2) comprise: a temperature within a range of
70-90.degree. C., and a pH ranging from 4-6; wherein reaction
conditions in step (3) comprise: a temperature within a range of
70-90.degree. C., and a dropping rate ranging from 0.5-6
mL/min.
12. The method of claim 10, wherein the modified barium sulfate is
used in an amount of 5-20 parts by weight, the acrylamide is used
in an amount of 5-15 parts by weight, and the ammonium persulfate
is used in an amount of 0.3-6 parts by weight, based on 100 parts
by weight of deionized water.
13. The method of claim 12, wherein the modified barium sulfate is
used in an amount of 8-15 parts by weight, the acrylamide is used
in an amount of 6-10 parts by weight, and the ammonium persulfate
is used in an amount of 0.5-5 parts by weight, based on 100 parts
by weight of deionized water.
14. The method of claim 10, wherein the modified barium sulfate
comprises modified barium sulfate A, modified barium sulfate B and
modified barium sulfate C; wherein the modified barium sulfate A
has an average particle diameter of 0.05-0.45 .mu.m, the modified
barium sulfate B has an average particle diameter of 0.5-3 .mu.m,
and the modified barium sulfate C has an average particle diameter
of 15-25 .mu.m.
15. The method of claim 16, wherein a weight ratio of the modified
barium sulfate A, the modified barium sulfate B and the modified
barium sulfate C is (0.4-0.6):(0.4-0.6):1.
16. The method of claim 10, wherein the initiator is dimethyl
azobisisobutyrate and/or sodium sulfite, in an amount of 0.1-4
parts by weight based on 100 parts by weight of deionized
water.
17. The method of claim 10, wherein the method for preparing the
modified barium sulfate comprises the following steps: (S1)
contacting an aqueous solution containing barium carbonate with
diethylenetriamine pentaacetic acid (DTPA) to form a complexing
system; (S2) dropwise adding potassium sulfate into the complexing
system to carry out reaction to produce a barium sulfate
precipitate; and (S3) washing, drying and grinding the barium
sulfate precipitate.
18. The method of claim 17, wherein conditions of the contacting in
the step (S1) comprise: the temperature is 40-60.degree. C., the pH
is within a range of 5-7, and the time is 1-1.5 h; wherein
conditions of the reaction in the step (S2) comprise: a temperature
of 40-60.degree. C., a time ranging from 3-10 h, and a dropping
rate within a range of 0.5-5 mL/min.
19. The method of claim 17, wherein the diethylenetriamine
pentaacetic acid is used in an amount of 0.2-2 parts by weight, and
the potassium sulfate is used in an amount of 1-3 parts by weight,
based on 0.5-3 parts by weight of barium carbonate.
20. The method of claim 10, wherein the modified barium sulfate has
a density greater than or equal to 4.2 g/cm.sup.3, or in a range of
4.2-4.8 g/cm.sup.3.
Description
PRIORITY CLAIM & CROSS REFERENCE
[0001] The application claims priority to Chinese Application No.
201910418791.2, field on May 20, 2019, entitled "Multi-functional
weighting agent for drilling fluid and preparation method thereof,
and water-based drilling fluid and use thereof", which is
specifically and entirely incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to the technical field of drilling
fluid, and particularly relates to a multi-functional weighting
agent for drilling fluid and preparation method thereof, and
water-based drilling fluid and use thereof.
BACKGROUND
[0003] For the sake of ensuring the smooth operation in the process
of drilling oil wells, the drilling fluid must exhibit
comprehensive properties simultaneously. For example, it is
necessary to add one or more lubricants into the drilling fluid in
order to reduce the frictional resistance between the drilling tool
and the casing and the frictional resistance between the drilling
tool and the mud cake. For the sake of preventing excessive water
loss of drilling fluid and protecting the well wall in a favorable
manner, it is required to add the drilling fluid with a filtrate
reducer. In addition, it is necessary to supplement the drilling
fluid with a weighting agent and the like so as to control
formation pressure and prevent collapse of stratum.
[0004] At present, there are dozens of drilling fluid treatment
agents used in the oil drilling. It is necessary to add treatment
agents having different functions in use according to the different
on-site drilling conditions. If the mixing ratio of the treating
agents is not desirable, the expected effects will not be achieved,
or even produce an adverse effect, such as it is prone to cause the
well wall to collapse, the downward drilling process encounters
blocking or sticking. The more serious consequences may be that the
whole well is scrapped, the inputted manpower and materials are
wasted. Moreover, the simultaneous addition of a variety of
treatment agents into the drilling fluid will increase the cost of
the drilling fluid and aggrandize the labor intensity of the
workers, and it results in the complicated composition of the
drilling fluid and the increased difficulty in the maintenance and
disposal.
[0005] Therefore, it is of great significance to research and
develop a multi-functional treatment agent.
SUMMARY
[0006] To overcome the defect of the single function of the
treatment agent existing in the prior art, and the defect that the
poor synergistic effect of the treatment agents with different
functions results in collapse of the well wall, the blocking or
sticking encountered in the downward drilling process, the
scrapping of the whole well, and the wastage of inputted manpower
and materials, the present disclosure provides a multi-functional
weighting agent for drilling fluid and preparation method thereof,
and water-based drilling fluid and use thereof. The
multi-functional weighting agent adopted by the invention has
desirable weight-increasing performance due to its high sphericity
and compressive strength, low friction force and good lubricity,
and may reduce resistance in the drilling environment of high
temperature and high pressure with small filter loss and desired
application effects.
[0007] To attain the above object, in a first aspect, the present
disclosure provides a method for preparing a multi-functional
weighting agent, wherein the method comprises:
(1) mixing a modified barium sulfate with deionized water to obtain
a mixture; (2) heating the mixture and adjusting a pH of the
mixture at a presence of an initiator; (3) sequentially dropwise
adding acrylamide and ammonium persulfate to step (2) for carrying
out reaction; (4) washing, drying and grinding the reaction product
of step (3).
[0008] In a second aspect, the present disclosure provides a
multi-functional weighting agent obtained by the aforementioned
method, wherein the multi-functional weighting agent is an
polyacrylamide/modified barium sulfate composite multi-functional
weighting agent.
[0009] In a third aspect, the present disclosure provides a
water-based drilling fluid, wherein the water-based drilling fluid
contains the aforementioned multi-functional weighting agent or the
multi-functional weighting agent prepared by using the
aforementioned preparation method.
[0010] In a fourth aspect, the present disclosure provides a method
of applying the aforementioned water-based drilling fluid in the
oil drilling.
[0011] With the above technical scheme, the present disclosure
provides a multi-functional weighting agent for drilling fluid,
which may be easily prepared at a low cost, and has various
functions such as lubrication, reducing resistance, preventing
collapse, and decreasing filtrate loss, in order to reduce the
types and numbers of multi-functional weighting agents used in
preparation of the drilling fluid, reduce cost of the drilling
fluid, alleviate the labor intensity of workers, and simplify the
maintenance and disposal of the drilling fluid.
DETAILED DESCRIPTION
[0012] The terminals and any value of the ranges disclosed herein
are not limited to the precise ranges or values, such ranges or
values shall be comprehended as comprising the values adjacent to
the ranges or values. As for numerical ranges, the endpoint values
of the various ranges, the endpoint values and the individual point
value of the various ranges, and the individual point values may be
combined with one another to produce one or more new numerical
ranges, which should be deemed have been specifically disclosed
herein.
[0013] In a first aspect, the present disclosure provides a
multi-functional weighting agent for drilling fluid. In accordance
with some embodiments the multi-functional weighting agent is an
polyacrylamide/modified barium sulfate composite multi-functional
weighting agent prepared by sequentially dropwise adding acrylamide
and ammonium persulfate to a mixture of modified barium sulfate and
deionized water in a presence of an initiator.
[0014] In some embodiments, the modified barium sulfate may be used
in an amount of 5-20 parts by weight, the acrylamide may be used in
an amount of 5-15 parts by weight, and the ammonium persulfate may
be used in an amount of 0.3-6 parts by weight, based on 100 parts
by weight of deionized water.
[0015] In some embodiments, the content of each component is
strictly controlled such that the interaction between the
components allows the prepared multi-functional weighting agent to
exert an optimum effect during the drilling process, thereby
enabling the prepared drilling fluid to reduce resistance in the
drilling environment of high temperature and pressure with small
filter loss and desired application effects. In some embodiments,
it is preferably to produce optimum effects by arranging that the
dosage of modified barium sulfate is 8-15 parts by weight, the
dosage of acrylamide is 6-10 parts by weight, and the dosage of
ammonium persulfate is 0.5-5 parts by weight, based on 100 parts by
weight of deionized water.
[0016] In some embodiments, the modified barium sulfate may
comprise modified barium sulfate A, modified barium sulfate B and
modified barium sulfate C, which can be also called a first barium
sulfate, a second barium sulfate, and a third barium sulfate,
respectively. Preferably, the modified barium sulfate A has an
average particle diameter of 0.05-0.45 .mu.m, the modified barium
sulfate B has an average particle diameter of 0.5-3 .mu.m, and the
modified barium sulfate C has an average particle diameter of 15-25
.mu.m. In a preferable circumstance, when the weight ratio of the
content of the modified barium sulfate A, the modified barium
sulfate B and the modified barium sulfate C is
(0.4-0.6):(0.4-0.6):1, the effects are good. More preferably, when
the weight ratio of the content of the modified barium sulfate A,
the modified barium sulfate B and the modified barium sulfate C is
(0.45-0.55):(0.45-0.55):1, the effects are much better. The
multi-functional weighting agent prepared in the present disclosure
may have the functions such as lubrication, reducing resistance,
preventing collapse, reducing filtrate loss simultaneously by means
of strictly controlling the average particle diameter of modified
barium sulfate A, modified barium sulfate B and modified barium
sulfate C as well as the synergistic ratio of modified barium
sulfate A, modified barium sulfate B and modified barium sulfate
C.
[0017] In some embodiments, the initiator may be dimethyl
azobisisobutyrate and/or sodium sulfite, preferably dimethyl
azobisisobutyrate. In some embodiments, based on 100 parts by
weight of deionized water, the initiator may be used in an amount
of 0.1-4 parts by weight, more preferably 0.1-1 parts by weight. In
some embodiments, when the initiator is a mixture of dimethyl
azobisisobutyrate and sodium sulfite, the mass ratio of the
dimethyl azobisisobutyrate relative to sodium sulfite may be
(0.4-0.8):1. In addition, in some embodiments, it is desirable to
control the content of initiator, because an addition of the
initiator not only affects the polymerization rate, but also
influences the molecular mesh structure of the polymer. When the
added amount of the initiator is too small, the amount of free
radicals in the reaction system is excessively low such that the
crosslink density is low, and it is disadvantageous for forming the
three-dimensional mesh structure, and the molecular weight of the
synthesized polymer is relatively small, which indicates that the
water absorption rate is low. When the added amount of the
initiator is excessive, although it will accelerate the
polymerization rate, an excess of the initiator tends to cause a
phenomenon of implosion, which causes a decreased molecular weight
and a high crosslinking density, which is also disadvantageous for
forming a three-dimensional mesh structure and may result in a
decreased water absorption ratio. Therefore, the effects are
optimum under the conditions of the specific initiator and the
content of the initiator defined in the invention.
[0018] In some embodiments, the multi-functional weighting agent
provided in the present disclosure is a composite comprising
polyacrylamide and modified barium sulfate as described. In some
embodiments, the modified barium sulfate may comprise modified
barium sulfate A, modified barium sulfate B and modified barium
sulfate C having the particle size ranges at a ratio as described
herein. In some embodiments, polyacrylamide may have a linear or a
cross-linked structure as described above. The polyacrylamide and
the modified barium sulfate may have a content ratio as used as
specified based on the content of acrylamide and the modified
barium sulfate. A multi-functional weighting agent may have a
composite structure, comprising polyacrylamide, and modified barium
sulfate. In some embodiments, the multi-functional weighting agent
is white round particles with an average particle diameter of 8-20
.mu.m, and has a surface lubricating coefficient K.sub.f within a
range of 0.05-0.1 and a compressive strength ranging from
9.times.10.sup.4 Pa to 10.times.10.sup.4 Pa. in some embodiments,
the polyacrylamide is cross-linked. In some embodiments, the
modified barium sulfate and the polyacrylamide are in a ratio by
weight in a range of from about 4:5 to about 5:2, for example,
being about 3:2. When values are expressed as approximations, by
use of the antecedent "about," it will be understood that the
particular value forms another embodiment. As used herein, "about
X" (where X is a numerical value) preferably refers to .+-.10% of
the recited value, inclusive.
[0019] In some embodiments, the multi-functional weighting agent
may be white round particles, the average particle diameter may be
8-20 .mu.m, the surface of the multi-functional weighting agent may
have a lubricating coefficient K.sub.f within a range of 0.05-0.1
and a compressive strength ranging from 9.times.10.sup.4 Pa to
10.times.10.sup.4 Pa. Preferably, the multi-functional weighting
agent has an average particle diameter of 9-16 .mu.m, and the
surface of the multifunctional weighting agent has a lubricating
coefficient K.sub.f of 0.07-0.09 and a compressive strength of
9.5.times.10.sup.4 Pa to 10.3.times.10.sup.4 Pa. More preferably,
the compressive strength is 9.62.times.10.sup.4 Pa to
10.25.times.10.sup.4 Pa. In the present disclosure, the
multi-functional weighting agent is provided with the above
parameters, it has desirable weight-increasing performance due to
its high sphericity and uniform particle size, low friction force
and good lubricity, and may reduce resistance in the drilling
environment of high temperature and high pressure with small filter
loss and desired application effects.
[0020] In some embodiments, the method for preparing the modified
barium sulfate may comprise:
(S1) contacting an aqueous solution containing barium carbonate
with diethylenetriamine pentaacetic acid (DTPA) to form a
complexing system; (S2) dropwise adding potassium sulfate into the
complexing system to carry out reaction to produce a barium sulfate
precipitate; and (S3) washing, drying and grinding the barium
sulfate precipitate.
[0021] In some embodiments, the conditions of the contacting in the
step (S1) comprise: the temperature may be 40-60.degree. C., the pH
may be within a range of 5-7, and the time may be 1-1.5 h. In some
embodiments, formic acid may be used for adjusting the pH, and the
amount of formic acid may be 0.5-2 parts by weight based on 0.5-3
parts by weight of barium carbonate. Preferably, the amount of
formic acid is 0.5-2 parts by weight based on 2 parts by weight of
barium carbonate. Furthermore, in the step (1), the contact of the
aqueous solution containing barium carbonate with the DTPA may be
carried out under a stirring condition, for example, under the
condition of magnetic stirring, the stirring speed may be within a
range of 1,000-2,000 revolutions per minute (rpm), preferably
1,400-1,500 rpm.
[0022] In some embodiments, the conditions of the reaction in the
step (S2) comprise: the temperature may be 40-60.degree. C., the
time may be ranging from 3-10 h, and the dropping rate may be
within a range of 0.5-5 mL/min.
[0023] In some embodiments, based on 0.5-3 parts by weight of
barium carbonate, the diethylenetriamine pentaacetic acid may be
used in an amount of 0.2-2 parts by weight, and the potassium
sulfate may be used in an amount of 1-3 parts by weight.
Preferably, based on 2 parts by weight of barium carbonate, the
diethylenetriamine pentaacetic acid may be used in an amount of
0.2-2 parts by weight, and the potassium sulfate may be used in an
amount of 1-3 parts by weight.
[0024] In some embodiments, when there is no barium sulfate
precipitate is further formed, the barium sulfate precipitate is
washed with distilled water or absolute ethanol, and then the
barium sulfate is dried and grinded in a vacuum oven. In some
embodiments, the specific operation method and conditions of the
grinding are based on the criterion of without destroying or
substantially breaking a structure of the multi-functional
weighting agent. The skilled person in the art may select various
suitable conditions to implement the invention in accordance with
the above principle. Specifically, the grinding may be performed in
a grinder, wherein the grinding conditions include: grinding
fineness reaches 20 .mu.m or less at a revolving speed of 1,500
rpm.
[0025] In some embodiments, the modified barium sulfate has a
density greater than or equal to 4.2 g/cm.sup.3, preferably within
a range of 4.2-4.8 g/cm.sup.3.
[0026] In a second aspect, the present disclosure provides a method
for preparing the aforementioned multi-functional weighting agent,
comprising:
(1) mixing the modified barium sulfate with the deionized water to
obtain a mixture; (2) heating the mixture and adjusting the pH at a
presence of an initiator; (3) sequentially dropwise adding
acrylamide and ammonium persulfate to the step (2) for carrying out
reaction; (4) washing, drying and grinding the reaction product of
the step (3).
[0027] In some embodiments, the mixing conditions in the step (1)
include: stirring at a stirring rate of 300-400 r/min for 0.2-1 h
and then standing still for 3-5 h;
[0028] The heating conditions in the step (2) comprise: a
temperature within a range of 70-90.degree. C., and a pH ranging
from 4-6;
[0029] Preferably in the step (3), the reaction is carried out
under the conditions of ultrasonic vibration at a temperature of
70-90.degree. C. and a dropping rate of 0.5-6 mL/min; the
conditions of the ultrasonic oscillation in the invention include:
the ultrasonic frequency is 30-60 kHz.
[0030] In some embodiments, the conditions of washing, drying and
grinding in the step (3) are the same as those described above, and
will not be repeatedly described here.
[0031] In a third aspect, the present disclosure provides a
water-based drilling fluid, wherein the water-based drilling fluid
contains the aforementioned multi-functional weighting agent or the
multi-functional weighting agent prepared by using the
aforementioned preparation method.
[0032] In some embodiments, it is preferable that based on a total
weight of 100 mL water-based drilling fluid, the multi-functional
weighting agent is used in an amount of 150-170 g, preferably 160
g.
[0033] In one embodiment, based on a total weight of the
water-based drilling fluid, the water-based drilling fluid may
further comprise 4% by weight of soil slurry, 0.6% by weight of
sodium acrylate (stream pattern modifier), 4.0% by weight of
sulfo-methyl phenolic resin (filtrate reducer), 18% by weight of
organosilicon potassium humate QSAM-K (inhibitor), 3% by weight of
graphite lubricant (lubricant), and 5% by weight of natural asphalt
(e.g., RF-9). Wherein the sodium acrylate can be purchased from
Chengdu Kelong Chemical Reagent plant with the model of SA. Sodium
acrylate is a colorless or light yellow viscous liquid at room
temperature, non-toxic, weak alkaline, insoluble in organic
solvents such as ethanol and acetone, and easily soluble in water
and sodium hydroxide aqueous solution. However, with the increase
of the number of alkaline earth metal ions in aqueous solutions
such as calcium hydroxide and magnesium hydroxide, it dissolves
first and then precipitates. It can operate in alkaline and medium
concentration conditions without scaling, with a molecular weight
of about 500-3000. It can disperse microcrystalline or sediment of
calcium carbonate, calcium sulfate and other salts in water without
precipitation. The organosilicon potassium humate can be purchased
from qsam-k Minquan Yongsheng drilling aid Co., Ltd. Organosilicon
potassium humate can ionize the hydration gene with strong negative
charge in water, which has the advantages of inhibiting the
hydration expansion of clay and preventing cracks and fractures in
core. It is a good shale inhibitor, and also has the effect of
reducing the viscosity and filtration loss of drilling fluid. The
graphite RT-1 can be purchased from Wen'an Zhongde Chemical Co.,
Ltd. Graphite RT-1 contains a variety of high efficiency
surfactants, which can form a solid chemical film on the mud cake
surface, rock surface and drilling tool surface of drilling fluid,
significantly reduce the viscosity coefficient of mud cake and
improve the strength of extreme pressure film. For the water
sensitive collapse of mud and shale layer and the collapse of
broken layer, it has good embedding sealing and restraining anti
collapse effect. The natural asphalt rf-9 can be purchased from
Weifang Haorui Asphalt Technology Co., Ltd. After the adsorption of
the rock end face, through the demulsification in a certain period
of time, the asphalt particles coalesce to form a continuous
covering film to prevent the water from entering, which has the
function of seamless sealing. When the downhole temperature changes
greatly, its continuous plugging effect is still good. It has the
function of film-forming, plugging and water-proof for most of the
well sections of the long open hole well, with good plugging and
anti collapse effect.
[0034] In a fourth aspect, the present disclosure provides a use
method of the aforementioned water-based drilling fluid in the oil
drilling.
[0035] In some embodiments, the method for applying the water-based
drilling fluid in the oil drilling includes: the high-pressure
drilling fluid discharged from the drilling pump passes through the
ground high-pressure manifold, the riser, the water hose, the
faucet, the drill pipe to reach the drill bit, the drilling fluid
is ejected from a drill bit nozzle for rinsing the well bottom and
carrying the rock debris, and then flowing upward along an annular
space formed between the drill string and the well wall, and is
discharged from the pipeline after arriving at the ground and flown
into a drilling fluid pool, the whole use process of the drilling
fluid ends.
[0036] The invention will be described in detail below by means of
examples.
[0037] In the following examples and comparative examples: each of
acrylamide (AM) (grade, analytically pure), ammonium persulfate
(grade, analytically pure), barium carbonate, diethylenetriamine
pentaacetic acid (DTPA), and potassium sulfate is purchased from
Chengdu Kelong Chemical Reagent Factory in Sichuan Province of
southwest China.
[0038] Electronic balance, accuracy 0.0001 g, purchased from
Shanghai Tianping Instrument Factory in China.
[0039] Controllable constant temperature oven with the model
GZX-9240, purchased from Shanghai Boxun Industrial Co., Ltd.
[0040] Electric mixer with the model JB50-D, purchased from
Shanghai Specimen Model Factory in China.
[0041] A set of synthetic equipment, purchased from Chengdu Kelong
Chemical Reagent Factory in Sichuan Province of southwest
China.
[0042] Particle size test is completed by laser particle sizer
1a-950a2, which analyzes particle size by diffraction of particles
or spatial distribution (scattering spectrum) of scattered light.
Using furanhofer diffraction and Mie scattering theory, the test
process is not affected by many factors such as temperature change,
medium viscosity, sample density and surface state. As long as the
sample to be tested is evenly displayed in the laser beam, namely
Accurate test results can be obtained.
Preparation Example 1
[0043] The preparation example serves to illustrate the preparation
method of the modified barium sulfate of the invention, the
preparation method comprises the following steps:
(S1) Dissolving 2 parts by weight of barium carbonate with an
average particle size of 0.3 .mu.m, 2 .mu.m and 20 .mu.m fully in
deionized water, heating the solution to 50.degree. C., adding a
formic acid solution to adjust the pH to 7, and then adding 1 part
by weight of diethylenetriamine pentaacetic acid, stirring the
solution under a stirring condition of 1,450 rpm for 1.2 h,
reacting sufficiently to form a complexing system; (S2) Slowly
adding 2 parts by weight of potassium sulfate solution to the S1
complexing system at a dropping rate of 3 mL/min, and reacting at a
constant temperature for 5 h to form the barium sulfate
precipitate; (S3) When there is no barium sulfate precipitate is
further formed, washing and separating the barium sulfate
precipitate with distilled water sufficiently, drying the barium
sulfate in a vacuum oven, and then grinding the barium sulfate.
[0044] As a result, the modified barium sulfate A, modified barium
sulfate B and modified barium sulfate C were obtained, wherein the
modified barium sulfate A has an average particle diameter of 0.3
.mu.m, the modified barium sulfate B has an average particle
diameter of 2 .mu.m, the modified barium sulfate C has an average
particle diameter of 20 .mu.m.
Preparation Example 2
[0045] This preparation example serves to illustrate the
preparation method of the modified barium sulfate of the invention,
the preparation method comprises the following steps:
(S1) Dissolving 0.5 parts by weight of barium carbonate with an
average particle size of 0.05 .mu.m, 0.5 .mu.m and 15 .mu.m fully
in deionized water, heating the solution to 40.degree. C., adding a
formic acid solution to adjust the pH to 5, and then adding 0.2
part by weight of diethylenetriamine pentaacetic acid, stirring the
solution under a stirring condition of 1,450 rpm for 1 h, reacting
sufficiently to form a complexing system; (S2) Slowly adding 1
parts by weight of potassium sulfate solution to the 51 complexing
system at a dropping rate of 0.5 mL/min, and reacting at a constant
temperature for 3 h to form the barium sulfate precipitate; (S3)
When there is no barium sulfate precipitate is further formed,
washing and separating the barium sulfate precipitate with
distilled water sufficiently, drying the barium sulfate in a vacuum
oven, and then grinding the barium sulfate. As a result, the
modified barium sulfate A, modified barium sulfate B and modified
barium sulfate C were obtained, wherein the modified barium sulfate
A has an average particle diameter of 0.05 .mu.m, the modified
barium sulfate B has an average particle diameter of 0.5 .mu.m, the
modified barium sulfate C has an average particle diameter of 1.5
.mu.m.
Preparation Example 3
[0046] This preparation example serves to illustrate the
preparation method of the modified barium sulfate of the invention,
the preparation method comprises the following steps:
(S1) Dissolving 3 parts by weight of barium carbonate with an
average particle size of 0.45 .mu.m, 3 .mu.m and 25 .mu.m fully in
deionized water, heating the solution to 60.degree. C., adding a
formic acid solution to adjust the pH to 6, and then adding 2 part
by weight of diethylenetriamine pentaacetic acid, stirring the
solution under a stirring condition of 1,450 rpm for 1.5 h,
reacting sufficiently to form a complexing system; (S2) Slowly
adding 3 parts by weight of potassium sulfate solution to the 51
complexing system at a dropping rate of 5 mL/min, and reacting at a
constant temperature for 10 h to form the barium sulfate
precipitate; (S3) When there is no barium sulfate precipitate is
further formed, washing and separating the barium sulfate
precipitate with distilled water sufficiently, drying the barium
sulfate in a vacuum oven, and then grinding the barium sulfate.
[0047] As a result, the modified barium sulfate A, modified barium
sulfate B and modified barium sulfate C were obtained, wherein the
modified barium sulfate A has an average particle diameter of 0.45
.mu.m, the modified barium sulfate B has an average particle
diameter of 3 .mu.m, the modified barium sulfate C has an average
particle diameter of 25 .mu.m.
Example 1
[0048] The example aims to illustrate the multi-functional
weighting agent of the invention and a method of preparing the
same, the preparation method comprises:
(1) Adding 8 parts by weight of modified barium sulfate powder into
a three-necked flask with 100 parts by weight of deionized water,
stirring the solution at a stirring rate of 350 r/min for 0.2 h,
and then standing still for 3 h; wherein the modified barium
sulfate prepared in the Preparation Example 2 is used. That is, the
modified barium sulfate A has an average particle diameter of 0.05
.mu.m, the modified barium sulfate B has an average particle
diameter of 0.5 jam, the modified barium sulfate C has an average
particle diameter of 15 .mu.m. The weight ratio of an amount of the
modified barium sulfate A, the modified barium sulfate B and the
modified barium sulfate C is 0.4:0.4:1, and the modified barium
sulfate has a density of 4.2 g/cm.sup.3; (2) Placing the
three-necked flask in a water bath kettle, heating it to 70.degree.
C., adding formic acid and adjusting pH to 4, and adding 0.2 parts
by weight of dimethyl azobisisobutyrate as an initiator under a
protective nitrogen atmosphere; (3) Initially adding 5 parts by
weight of acrylamide under the conditions of the ultrasonic
vibration (30 KHz) and a dropping rate of 0.5 mL/min, performing a
constant temperature reaction for 3 h and then adding 0.3 parts by
weight of ammonium persulfate until the completion of reaction; (4)
Washing the product with absolute ethanol, drying it in a vacuum
oven for 2 h, grinding and pulverizing the product.
[0049] As a result, a multi-functional weighting agent for drilling
fluid labeled as S1 was obtained, and its parameters are shown in
Table 1.
[0050] 160 g of the multi-functional weighting agent was added to
100 mL of water-based drilling fluid, and its performance
evaluation experimental data is as shown in Table 2.
Example 2
[0051] The example aims to illustrate the multi-functional
weighting agent of the invention and a method of preparing the
same, the preparation method comprises:
(1) Adding 11 parts by weight of modified barium sulfate powder
into a three-necked flask with 100 parts by weight of deionized
water, stirring the solution at a stirring rate of 300 r/min for
0.5 h, and then standing still for 3 h; wherein the modified barium
sulfate prepared in the Preparation Example 1 is used. That is, the
modified barium sulfate A has an average particle diameter of 0.3
.mu.m, the modified barium sulfate B has an average particle
diameter of 2 .mu.m, the modified barium sulfate C has an average
particle diameter of 20 .mu.m. The weight ratio of an amount of the
modified barium sulfate A, the modified barium sulfate B and the
modified barium sulfate C is 0.5:0.5:1, and the modified barium
sulfate has a density of 4.3 g/cm.sup.3; (2) Placing the
three-necked flask in a water bath kettle, heating it to 80.degree.
C., adding formic acid and adjusting pH to 5, and adding 0.5 parts
by weight of dimethyl azobisisobutyrate as an initiator under a
protective nitrogen atmosphere; (3) Initially adding 8 parts by
weight of acrylamide under the conditions of the ultrasonic
vibration (45 KHz) and a dropping rate of 3 mL/min, performing a
constant temperature reaction for 3 h and then adding 2 parts by
weight of ammonium persulfate until the completion of reaction; (4)
Washing the product with absolute ethanol, drying it in a vacuum
oven for 3 h, grinding and pulverizing the product.
[0052] As a result, a multi-functional weighting agent for drilling
fluid labeled as S2 was obtained, and its parameters are shown in
Table 1.
[0053] 160 g of the multi-functional weighting agent was added to
100 mL of water-based drilling fluid, and its performance
evaluation experimental data is as shown in Table 2.
Example 3
[0054] The example aims to illustrate the multi-functional
weighting agent of the invention and a method of preparing the
same, the preparation method comprises:
(1) Adding 15 parts by weight of modified barium sulfate powder
into a three-necked flask with 100 parts by weight of deionized
water, stirring the solution at a stirring rate of 400 r/min for 1
h, and then standing still for 5 h; wherein the modified barium
sulfate prepared in the Preparation Example 3 is used. That is, the
modified barium sulfate A has an average particle diameter of 0.45
.mu.m, the modified barium sulfate B has an average particle
diameter of 3 .mu.m, the modified barium sulfate C has an average
particle diameter of 25 .mu.m. The weight ratio of an amount of the
modified barium sulfate A, the modified barium sulfate B and the
modified barium sulfate C is 0.6:0.6:1, and the modified barium
sulfate has a density of 4.5 g/cm.sup.3; (2) Placing the
three-necked flask in a water bath kettle, heating it to 90.degree.
C., adding formic acid and adjusting pH to 6, and adding 1 parts by
weight of dimethyl azobisisobutyrate as an initiator under a
protective nitrogen atmosphere; wherein the mass ratio of dimethyl
azobisisobutyrate to sodium sulfite is 0.6:1; (3) Initially adding
10 parts by weight of acrylamide under the conditions of the
ultrasonic vibration (60 KHz) and a dropping rate of 6 mL/min,
performing a constant temperature reaction for 3 h and then adding
4 parts by weight of ammonium persulfate until the completion of
reaction; (4) Washing the product with absolute ethanol, drying it
in a vacuum oven for 5 h, grinding and pulverizing the product.
[0055] As a result, a multi-functional weighting agent for drilling
fluid labeled as S3 was obtained, and its parameters are shown in
Table 1.
[0056] 160 g of the multi-functional weighting agent was added to
100 mL of water-based drilling fluid, and its performance
evaluation experimental data is as shown in Table 2.
Example 4
[0057] The example aims to illustrate the multi-functional
weighting agent of the invention and a method of preparing the
same, the preparation method comprises:
(1) Adding 6 parts by weight of modified barium sulfate powder into
a three-necked flask with 100 parts by weight of deionized water,
stirring the solution at a stirring rate of 320 r/min for 0.2 h,
and then standing still for 3 h; wherein the modified barium
sulfate prepared in the Preparation Example 2 is used. That is, the
modified barium sulfate A has an average particle diameter of 0.05
.mu.m, the modified barium sulfate B has an average particle
diameter of 0.5 jam, the modified barium sulfate C has an average
particle diameter of 15 .mu.m. The weight ratio of an amount of the
modified barium sulfate A, the modified barium sulfate B and the
modified barium sulfate C is 0.45:0.45:1, and the modified barium
sulfate has a density of 4.5 g/cm.sup.3; (2) Placing the
three-necked flask in a water bath kettle, heating it to 70.degree.
C., adding formic acid and adjusting pH to 4, and adding 0.1 parts
by weight of dimethyl azobisisobutyrate as an initiator under a
protective nitrogen atmosphere; (3) Initially adding 5 parts by
weight of acrylamide under the conditions of the ultrasonic
vibration (45 KHz) and a dropping rate of 2.5 mL/min, performing a
constant temperature reaction for 3 h and then adding 3 parts by
weight of ammonium persulfate until the completion of reaction; (4)
Washing the product with absolute ethanol, drying it in a vacuum
oven for 2 h, grinding and pulverizing the product.
[0058] As a result, a multi-functional weighting agent for drilling
fluid labeled as S4 was obtained, and its parameters are shown in
Table 1.
[0059] 160 g of the multi-functional weighting agent was added to
100 mL of water-based drilling fluid, and its performance
evaluation experimental data is as shown in Table 2.
Example 5
[0060] The example aims to illustrate the multi-functional
weighting agent of the invention and a method of preparing the
same, the preparation method comprises:
(1) Adding 20 parts by weight of modified barium sulfate powder
into a three-necked flask with 100 parts by weight of deionized
water, stirring the solution at a stirring rate of 380 r/min for 1
h, and then standing still for 3 h; wherein the modified barium
sulfate prepared in the Preparation Example 3 is used. That is, the
modified barium sulfate A has an average particle diameter of 0.45
.mu.m, the modified barium sulfate B has an average particle
diameter of 3 .mu.m, the modified barium sulfate C has an average
particle diameter of 25 .mu.m. The weight ratio of an amount of the
modified barium sulfate A, the modified barium sulfate B and the
modified barium sulfate C is 0.55:0.55:1, and the modified barium
sulfate has a density of 4.1 g/cm.sup.3; (2) Placing the
three-necked flask in a water bath kettle, heating it to 90.degree.
C., adding formic acid and adjusting pH to 6, and adding 0.5 parts
by weight of dimethyl azobisisobutyrate as an initiator under a
protective nitrogen atmosphere; (3) Initially adding 15 parts by
weight of acrylamide under the conditions of the ultrasonic
vibration (45 KHz) and a dropping rate of 3 mL/min, performing a
constant temperature reaction for 3 h and then adding 5 parts by
weight of ammonium persulfate until the completion of reaction; (4)
Washing the product with absolute ethanol, drying it in a vacuum
oven for 5 h, grinding and pulverizing the product.
[0061] As a result, a multi-functional weighting agent for drilling
fluid labeled as S5 was obtained, and its parameters are shown in
Table 1.
[0062] 160 g of the multi-functional weighting agent was added to
100 mL of water-based drilling fluid, and its performance
evaluation experimental data is as shown in Table 2.
Comparative Example 1
[0063] A multi-functional weighting agent is prepared in the
substantially identical manner as in Example 1, except for the
following differences:
(1) Adding 21 parts by weight of the modified barium sulfate powder
into a three-necked flask containing an appropriate amount of
deionized water, stirring the solution for 1 h and then standing
still for 3 h; wherein the modified barium sulfate prepared in
Preparation Example 2 is used. That is, the modified barium sulfate
A has an average particle diameter of 0.05 .mu.m, the modified
barium sulfate B has an average particle diameter of 0.5 .mu.m, the
modified barium sulfate C has an average particle diameter of 15
.mu.m; wherein the weight ratio of an amount of the modified barium
sulfate A, the modified barium sulfate B and the modified barium
sulfate C is 0.3:0.3:1; (2) Placing the three-necked flask in a
water bath kettle, heating it to 70.degree. C., adding formic acid
and adjusting pH to 4, and adding 0.1 parts by weight of dimethyl
azobisisobutyrate as an initiator under a protective nitrogen
atmosphere; (3) Slowly adding 5 parts by weight of acrylamide under
the ultrasonic vibration (45 KHz), performing a constant
temperature reaction for 3 h and then adding 0.1 parts by weight of
ammonium persulfate until the completion of reaction; (4) Washing
the product with absolute ethanol, drying it in a vacuum oven for 2
h, grinding and pulverizing the product.
[0064] As a result, a treatment agent for drilling fluid labeled as
DS1 was obtained, and its parameters are shown in Table 1.
[0065] 160 g of the treatment agent was added to 100 mL of
water-based drilling fluid, and its performance evaluation
experimental data is as shown in Table 2.
Comparative Example 2
[0066] A multi-functional weighting agent is prepared in the
substantially identical manner as in Example 1, except for the
following differences:
(1) Adding 3 parts by weight of the modified barium sulfate powder
into a three-necked flask containing an appropriate amount of
deionized water, stirring the solution for 1 h and then standing
still for 3 h; wherein the modified barium sulfate A has an average
particle diameter of 0.5 .mu.m, the modified barium sulfate B has
an average particle diameter of 3 .mu.m, the modified barium
sulfate C has an average particle diameter of 26 .mu.m; wherein the
weight ratio of an amount of the modified barium sulfate A, the
modified barium sulfate B and the modified barium sulfate C is
0.7:0.7:1; (2) Placing the three-necked flask in a water bath
kettle, heating it to 70.degree. C., adding formic acid and
adjusting pH to 4, and adding 4 parts by weight of dimethyl
azobisisobutyrate as an initiator under a protective nitrogen
atmosphere; (3) Slowly adding 16 parts by weight of acrylamide
under the ultrasonic vibration, performing a constant temperature
reaction for 3 h and then adding 3 parts by weight of ammonium
persulfate until the completion of reaction; (4) Washing the
product with absolute ethanol, drying it in a vacuum oven for 2 h,
grinding and pulverizing the product.
[0067] As a result, a treatment agent for drilling fluid labeled as
DS2 was obtained, and its parameters are shown in Table 1.
[0068] 160 g of the treatment agent was added to 100 mL of
water-based drilling fluid, and the performance evaluation
experimental data is as shown in Table 2.
Comparative Example 3
[0069] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the modified barium sulfate only includes
the modified barium sulfate A, the consequently produced treating
agent is labeled as DS3, and its parameters are as shown in Table
1. In addition, 120 g of the treatment agent was added into 100 mL
of water-based drilling fluid, and its performance evaluation
experimental data is as shown in Table 2.
Comparative Example 4
[0070] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the modified barium sulfate merely includes
the modified barium sulfate A and the modified barium sulfate B,
and the consequently produced treating agent is labeled as DS4, and
its parameters are as shown in Table 1. In addition, 180 g of the
treatment agent was added into 100 mL of water-based drilling
fluid, and its performance evaluation experimental data is as shown
in Table 2.
Comparative Example 5
[0071] The ordinary barite was used as the treating agent with a
label DS5. The parameters of ordinary barite are as shown in Table
1. Moreover, 160 g of ordinary barite was added into 100 mL of
water-based drilling fluid, and its performance evaluation
experimental data is as shown in Table 2.
Comparative Example 6
[0072] The treatment agent is composed of 15 g lubricant graphite
glass microspheres, 25 g filtrate reducer lignite resin, 120 g
weighting agent barite, and the treatment agent is labeled as DS6;
the parameters of the treatment agent are as shown in Table 1. In
addition, 160 g of the treatment agent was added into 100 mL of
water-based drilling fluid, and its performance evaluation
experimental data is shown in Table 2.
Comparative Example 7
[0073] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the modified barium sulfate powder is
replaced with the ordinary barite, and the consequently produced
treating agent is labeled as DS7, the parameters of the treating
agent are as shown in Table 1. In addition, 160 g of the treating
agent was added into 100 mL of a water-based drilling fluid,
wherein the ordinary barite has an average particle diameter of
18.24-19 .mu.m, a density of 4.28 g/cm.sup.3, and a specific
surface area of 0.48 m.sup.2/g, the particles are relatively large
and the particles present a blocky structure.
[0074] The performance evaluation experimental data is as shown in
Table 2; the parameters of the treatment agent are as shown in
Table 1.
Comparative Example 8
[0075] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the modified barium sulfate A has a particle
diameter of 0.04 .mu.m, the modified barium sulfate B has a
particle diameter of 4 .mu.m, and the modified barium sulfate C has
a particle size of 12 .mu.m; the consequently produced treating
agent is labeled as DS8, and the parameters of the treating agent
are as shown in Table 1. In addition, 160 g of the treatment agent
was added into 100 mL of water-based drilling fluid, and its
performance evaluation experimental data is as shown in Table
2.
Comparative Example 9
[0076] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the modified barium sulfate A has a particle
diameter of 5 .mu.m, the modified barium sulfate B has a particle
diameter of 0.3 .mu.m, and the modified barium sulfate C has a
particle size of 30 .mu.m; the consequently produced treating agent
is labeled as DS9, and the parameters of the treating agent are as
shown in Table 1. In addition, 160 g of the treatment agent was
added into 100 mL of water-based drilling fluid, and its
performance evaluation experimental data is as shown in Table
2.
Comparative Example 10
[0077] A multi-functional weighting agent was prepared in the
substantially identical manner as in Example 1, except for the
following differences: the density of the modified barium sulfate
was 4 g/cm.sup.3, the consequently produced treating agent is
labeled as DS10, and the parameters of the treating agent are as
shown in Table 1. In addition, 160 g of the treatment agent was
added into 100 mL of water-based drilling fluid, and its
performance evaluation experimental data is as shown in Table
2.
Test Example 1
[0078] Density Testing of Water-Based Drilling Fluids.
[0079] The densities of water-based drilling fluids containing the
multi-functional weighting agents S1-S5 and DS1-DS10 were tested by
using a drilling fluid densitometer.
[0080] Specifically, the method includes the following steps:
(1) First, calibrating the instrument; (2) Adding the configured
multi-functional weighting agents S1-S5 and DS1-DS10 to the
experimental instrument, respectively, covering the cup lid and
ensuring that some drilling fluid exudes from the small hole of the
cup lid and tightly pressing the cup lid.
[0081] The results are as shown in Table 2.
Test Example 2
[0082] Filter Loss Testing of Water-Based Drilling Fluids.
[0083] The GLS42-2A high temperature and high pressure (HTHP)
filter press was used for testing the filtrate loss condition of
water-based drilling fluids containing multi-functional weighting
agents S1-S5 and DS1-DS10, respectively.
[0084] The specific operations are as follows:
(1) Putting the configured multi-functional weighting agents S1-S5
and DS1-DS10 into a slurry cup, and the liquid surface should not
be higher than 1/2 of the upper end of the cup; (2) Closing the
upper end air valve and lower end air valve of the cup, placing the
slurry cup into a heating sleeve, and inserting a thermometer into
the thermometer hole; (3) Pressurizing, recording the milliliter
number FLAN of filtrate volume under a variety of temperatures and
pressures.
[0085] The results are shown in Table 2.
Test Example 3
[0086] Lubrication coefficient test for water-based drilling
fluids.
[0087] The lubricating coefficient K.sub.f of the multi-functional
weighting agents S1-S5 and DS1-DS10 was tested by the NR-1 drilling
fluid lubricity determinator, respectively.
[0088] The specific operations are as follows:
(1) Loading the drilling fluid to be tested into a sample cup; (2)
Starting a motor under a non-loaded circumstance and running the
motor until a pointer of the amperemeter is stable; (3) Slowly
pressurizing to 50 lbs with a torque wrench, running for 5 minutes
until the amperemeter pointer is stable, recording the amperemeter
reading and multiplying the reading with 0.01, the product is the
lubrication coefficient value of the drilling fluid being
tested.
[0089] The results are as shown in Table 2.
Test Example 4
[0090] The sphericity of the multi-functional weighting agents
S1-S5 and DS1-DS10 was tested with reference to the sphericity and
roundness comparison chart in the Chinese national standard
Q/SY125-2007-- China National Petroleum Corporation Enterprise
Standard .
[0091] The specific operations are as follows:
30-40 particles were randomly selected from the samples to be
tested, and observed under an electron microscope. The sphericity
of each particle in the sample was determined according to the
plate, and the average sphericity of this batch of sample is
finally calculated.
[0092] The results are shown in Table 2.
TABLE-US-00001 TABLE 1 Multi- Average functional particle weighting
diameter Spherity Compressive agent (.mu.m) (%) strength (Pa)
K.sub.f S1 15 0.92 9.62 .times. 10.sup.4 0.08 S2 16 0.93 10.25
.times. 10.sup.4 0.07 S3 11 0.91 9.82 .times. 10.sup.4 0.08 S4 9
0.89 9.73 .times. 10.sup.4 0.09 S5 13 0.90 9.68 .times. 10.sup.4
0.09 DS1 15 0.76 5.21 .times. 10.sup.4 0.13 DS2 12 0.69 6.62
.times. 10.sup.4 0.15 DS3 11 0.54 4.69 .times. 10.sup.4 0.21 DS4 17
0.72 6.36 .times. 10.sup.4 0.23 DS5 19 0.63 4.47 .times. 10.sup.4
0.32 DS6 16 0.59 3.68 .times. 10.sup.4 0.35 DS7 19 0.64 4.89
.times. 10.sup.4 0.36 DS8 12 0.58 5.31 .times. 10.sup.4 0.29 DS9 9
0.71 3.56 .times. 10.sup.4 0.34 DS10 14 0.53 5.65 .times. 10.sup.4
0.27
[0093] It is illustrated in Table 1 that the multi-functional
weighting agents prepared in the Examples S1-S5 have high
sphericity, uniform particle size, high compressive strength, small
lubricating coefficient, low friction force, good lubricity and
desirable weighting performance. The treatment agents prepared by
Comparative Examples DS1-DS10 have low sphericity, uneven particle
size, low compressive strength and large lubricating coefficient.
It demonstrates that the multi-functional weighting agents of the
invention have desired performance and can meet the field
application requirements of the drilling fluid.
TABLE-US-00002 TABLE 2 Multi-functional Added .rho. (g/ FL.sub.API
weighting agent amount (g) cm.sup.3) (mL) K.sub.f-1 S1 160 g 1.21
22.3 0.15 S2 160 g 1.23 21.5 0.12 S3 160 g 1.28 22.7 0.13 S4 160 g
1.26 25.4 0.16 S5 160 g 1.25 24.2 0.13 DS1 160 g 1.35 32.6 0.56 DS2
160 g 1.36 33.5 0.45 DS3 120 g 1.28 36.2 0.82 DS4 180 g 1.24 31.9
0.66 DS5 160 g 1.29 32.8 0.45 DS6 160 g 1.33 36.3 0.59 DS7 160 g
1.24 39.2 0.52 DS8 160 g 1.36 29.8 0.64 DS9 160 g 1.35 27.3 0.58
DS10 160 g 1.23 28.2 0.69
[0094] As illustrated in Table 2, the water-based drilling fluids
comprising the multi-functional weighting agents prepared in
Examples S1-S5 have a density ranging from 1.21-1.28 g/cm.sup.3, a
filter loss between 21.5-25.4 mL, and a lubricating coefficient
K.sub.f-1 less than 0.2; while the water-based drilling fluid
comprising the treatment agents prepared by the Comparative
Examples DS1-DS10 have a density ranging from 1.23-1.36 g/cm.sup.3,
a filter loss between 27.3-39.2 mL, and a lubrication coefficient
K.sub.f greater than or equal to 0.4.
[0095] Therefore, Table 2 demonstrates that the multi-functional
weighting agents of the invention can reduce resistance in the
drilling environment of high temperature and high pressure with
small filter loss and desired application effects.
[0096] While the invention is described above in detail in some
preferred embodiments, the invention is not limited to those
embodiments. Various simple variations, including combinations of
the technical features in any other appropriate way, can be made to
the technical scheme of the invention within the scope of the
technical concept of the invention, but such variations and
combinations shall be deemed as disclosed content in the invention
and falling in the protection scope of the invention.
* * * * *