U.S. patent application number 13/880974 was filed with the patent office on 2013-09-19 for method for continuous formation core sampling.
This patent application is currently assigned to REELWELL AS. The applicant listed for this patent is Jostein Aleksandersen, Ove Hole. Invention is credited to Jostein Aleksandersen, Ove Hole.
Application Number | 20130240267 13/880974 |
Document ID | / |
Family ID | 44937361 |
Filed Date | 2013-09-19 |
United States Patent
Application |
20130240267 |
Kind Code |
A1 |
Aleksandersen; Jostein ; et
al. |
September 19, 2013 |
METHOD FOR CONTINUOUS FORMATION CORE SAMPLING
Abstract
The present invention regards a method for performing core
sampling during drilling of wells, comprising the steps of
providing a dual bore drill pipe with drill bit in the end in the
well bore, providing means to introduce a drill liquid into an
annular space of the drill pipe and return it together with drill
cuttings to the surface through centrally arranged return line in
the dual bore drill pipe, removing larger cuttings at outlet of
return pipe, and perform core testing on these cuttings, knowing
where the cuttings come from in the well. The invention also
regards a device for performing the invention.
Inventors: |
Aleksandersen; Jostein;
(Randaberg, NO) ; Hole; Ove; (Hafrsfjord,
NO) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Aleksandersen; Jostein
Hole; Ove |
Randaberg
Hafrsfjord |
|
NO
NO |
|
|
Assignee: |
REELWELL AS
Roeyneberg
NO
|
Family ID: |
44937361 |
Appl. No.: |
13/880974 |
Filed: |
November 15, 2011 |
PCT Filed: |
November 15, 2011 |
PCT NO: |
PCT/EP11/70102 |
371 Date: |
April 22, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61413496 |
Nov 15, 2010 |
|
|
|
Current U.S.
Class: |
175/60 ;
175/250 |
Current CPC
Class: |
E21B 25/00 20130101;
E21B 21/12 20130101 |
Class at
Publication: |
175/60 ;
175/250 |
International
Class: |
E21B 21/12 20060101
E21B021/12 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 15, 2010 |
IE |
S20100726 |
Claims
1. A method for performing core sampling during drilling of wells,
comprising: providing a dual bore drill pipe with a drill bit at an
end thereof in a well bore, providing means to introduce a drilling
liquid into an annular space of the drill pipe and return the
drilling liquid together with drill cuttings to the surface through
a centrally arranged return pipe in the dual bore drill pipe,
removing cuttings at an outlet of the return pipe, and performing
core testing on the removed cuttings.
2. The method of claim 1, wherein the drilling liquid is introduced
into the annular space at a velocity of more than 1 meter per
second.
3. The method of claim 1, wherein the cuttings are removed
continuously or at intervals.
4. The method of claim 3, wherein cuttings of a given size range
are removed for testing.
5. The method of claim 1, wherein the return pipe is provided with
an equal inner diameter between the two ends of the return
pipe.
6. The method of claim 1, wherein the drilling liquid is lighter
than conventional drilling mud and makes less contamination of the
removed cuttings.
7. The method of claim 1, wherein a flow of the drilling liquid in
the dual bore drill pipe is set up in the drill pipe before the
drilling liquid is guided to the drill bit.
8. A device for performing core sampling during drilling of wells,
comprising: a dual bore drill pipe with a drill bit on one end,
means for providing a drilling liquid to flow down the drill pipe
in an annulus of the drill pipe and return through a return pipe
centrally arranged in the drill pipe, a cuttings sample arrangement
at an outlet of the return pipe, wherein the return pipe is formed
with an equal inner diameter between the two ends thereof.
9. The device of claim 8, wherein a cross over element is arranged
between the drill bit and the dual bore drill pipe.
10. The device of claim 8, wherein the sample arrangement is
configured to remove cutting samples of a given size range
continuously or at intervals.
11. The device of claim 8, wherein the drill bit is a reverse
circulation bit.
12. The method of claim 1, further comprising separating out
cuttings that are within a given size range and that traveled
substantially the same velocity through the return pipe from the
removed cuttings.
13. The method of claim 12, wherein the core testing is performed
on the separated out cuttings.
Description
FIELD
[0001] The present invention regards a method for providing samples
for testing of earth formation core knowing the location where the
cuttings come from.
BACKGROUND
[0002] Generally there is a need for testing of the earth formation
related to hydrocarbon exploration in order to determine the
likelihood of finding such hydrocarbons. One solution for providing
this is to provide core samples from the well, and then to perform
tests on these core samples. There are several ways to obtain core
samples; special drill bits which are used to take out core
samples, for instance as described in US2009/0283326. There are
developed different containers and methods for getting samples into
the containers and removing the material from the containers, for
instance as described in US2010084193 (Livingstone). There are also
several methods for core taking while drilling, for instance as
described in CN2690572 and U.S. Pat. No. 3,871,486, where the last
of these describe a system for continuous drilling of a well bore
and coring involving the use of a rotatable percussion drill having
a central barrel, the drill being operated by air circulated
through a dual concentric drill pipe and a swivel at the top of the
drill pipe, the air, in major part, flowing upwardly through the
bore annulus, outside the drill pipe to remove cuttings and other
material from the annulus, and a minor part of the air flows
upwardly in the central core tube of the drill pipe from the centre
of the drill to carry uncontaminated core samples from the bottom
of the bore hole. In U.S. Pat. No. 3,871,486 there is also
described a system where one has used dual concentric drill pipes,
with return fluid with cuttings through centre, which experienced
problems.
SUMMARY
[0003] The aim with the present invention is to provide a system
which is alleviated of at least some of the problems with known
systems.
[0004] This is achieved with a system as described in the
independent claims with additional favourable features given in the
dependent claims or the following description.
[0005] There is provided a method for performing core sampling
during drilling of hydrocarbon wells knowing the location where the
cuttings comes from. According to the invention the method
comprises the steps of providing a dual bore drill pipe with a
drill bit at the end in the well bore, providing means to introduce
a drill liquid into an annular space of the drill pipe and return
the drill liquid together with drill cuttings to the surface
through a centrally arranged return pipe in the dual bore drill
pipe, removing larger cuttings at an outlet of return pipe, and
perform core testing on these cuttings.
[0006] The dual bore drill pipe will be a concentric dual bore
drill pipe but it is not necessary to have them concentrically
arranged. It might also be possible to have the two pipes arranged
side by side. The main issue is to provide a return pipe with a
relatively large cross section, given the available cross section
within the well bore. The drill bit may be a reverse circulation
drill bit or it may be a conventional drill bit, but then with a
cross-over arrangement between the drill bit and the dual bore
drill string. Preferably the solution has a conventional drill
bit.
[0007] According to an aspect the method may comprise adding
drilling liquid at velocities of more than 1 meter per second
measured at a flow control unit, typically located at the drill
floor, by comparing volume pumped into the well per second and
volume extracted out of the well per second (using Coreolismeter),
measured as a main velocity at inlet of annulus at surface by
calculations. Preferably the velocity of the drilling liquid
through the drill string is around 1 to 3 meter per second. With
such a velocity the possibility of having insufficient cuttings
removal becomes negligible, and therefore it no longer represents a
risk factor. Further, due to the speed for the flow the cuttings
are transported to surface in minutes, with the extraction location
known, providing a unique way of analyzing the formation properties
while drilling providing valuable formation properties
information.
[0008] According to an aspect the method may also comprise removing
larger cuttings continuously or at intervals. By removing larger
cutting continuously one will have a good picture of the properties
of the earth formation. As one then also has a full representation
of the larger cuttings one has a full picture representing all
levels of the formations in the well. There is also the possibility
of taking out the larger cuttings at intervals, where these
intervals are recorded together with the samples taken at the
intervals. Such a configuration of the sample takings will also
give a good representation of the conditions in the well. With both
systems one may also record wellbore ID in relation to the samples,
to know wherefrom the samples are in the well bore. One also has
the possibility of adding markers in the drilling liquid to
establish the wellbore ID.
[0009] According to another aspect the method may comprise the step
of removing cuttings of a given size range for testing. By limiting
the cuttings to a given size range there is even less questions in
relation to wherefrom in the well the cuttings are from, as these
will all experience more or less the same lift from the drilling
liquid out of the well bore. The cutting will travel with more or
less the same velocity through the return pipe and thereby the
determination of the position wherefrom the cuttings are from, is
even more certain. There is also the possibility of separating out
cuttings above a given size for testing. This may be done by for
instance separating out all cutting which in one direction is
larger than 1 cm, or alternatively separating out cuttings which
are 1 cm times 1 cm, measured in perpendicular directions or
cuttings which are from 0.5 cm.sup.3 or 1 cm.sup.3 and larger.
Another possibility is to take out all cutting in the range 1
cm.sup.3 to 2 cm.sup.3. It is also possible to set these limits at
other values as for instance 1.5 cm or even 2 cm, 0.7 m.sup.3.
Another possibility is to separate out all cuttings. A further
possibility is to have a manual selection of cutting as they will
land on a cuttings-chute in the mud handling system, for further
testing of the properties of the formation.
[0010] According to another aspect the method may comprise
providing a return pipe with an equal inner diameter between the
two ends of the return pipe. By having the return pipe with an
equal inner diameter, or a mainly equal inner diameter as there of
course will be some variation, it limits the possibility of
damaging the cuttings in their travel through the return pipe. By
equal inner diameter, one should understand that there may be some
variations in the diameter, the main issues is to not have elements
extending in to the return pipe or obstructions in the return pipe
or with other words to have a mainly smooth inner surface.
[0011] According to another aspect the method may comprise
providing a light drill liquid that has a lower density than
traditional drill mud and minimises the contamination of the
cutting samples. This is to get a better reading of the conditions
in the well, with the core samples taken from the cutting.
[0012] According to another aspect the method may comprise the step
of establishing a flow of drilling liquid in the dual bore drill
pipe before the drilling liquid is guided to the drill equipment as
such. This may be achieved by having a three way valve down in the
drill pipe close to the drilling equipment. The three way valve
will initially allow a fluid flowing from the annulus and into the
central bore above the drilling equipment and when drilling starts
shuts this flow passage and opens the passages in the annulus down
to the drilling equipment and from the drilling equipment and up to
the central bore. This will give a better start of the drilling
sequence and a better removal of the cutting at the start of the
drilling sequence. This will also provide a better tracking of
where the cuttings are taken from in the well.
[0013] The invention also regards a device for performing core
sampling during drilling of oil wells. According to the invention
the device comprising a dual bore drill pipe with a drill bit on
one end, means for providing a drilling liquid to flow down the
drill pipe in an annulus and return through a central pipe, a
cuttings sample arrangement at outlet of return pipe, wherein the
return pipe is formed with an equal inner diameter between the two
ends.
[0014] According to an aspect the drill bit may be, and preferably
is, a conventional drill bit where there is arranged a cross over
element between the drill bit and the dual bore drill pipe.
Alternatively there may be a reverse circulation drill bit attached
to an end of the dual bore drill pipe.
[0015] According to another aspect the sample arrangement may be
configured to remove cutting samples of a given size range
continuously or at intervals. This may be done by having a filter
arrangement at the outlet of the return pipe, or a separation
device, which for instance may separate or filter out any cutting
above a given size or within a given size range. The main issue is
to provide samples of cuttings large enough for performing core
testing on the samples. And by limiting them to a given size range
one also have an increased certainty of wherefrom in the well they
are from.
BRIEF DESCRIPTION OF DRAWINGS
[0016] FIG. 1 shows a system for continuous formation core
sampling.
[0017] FIG. 2 is a comparison of cuttings from a conventional
drilling method and a method for continuous formation core sampling
according to an embodiment of the invention.
DETAILED DESCRIPTION
[0018] The invention will now be explained with reference to an
attached schematic drawing showing the principles of the invention
FIG. 1, and a picture comparing cuttings provided with the present
invention compared with conventional drilling, FIG. 2.
[0019] In FIG. 1 there is schematically shown the principles of the
invention in one possible embodiment. There is provided a dual bore
drill string 1 with an outer pipe 2 arranged around an inner pipe
3, thereby forming an annulus 4 for drilling fluid and a central
bore 5 for the return of drilling fluid out of the well. The outer
pipe 2 and inner pipe 3 are arranged concentrically and may be
ordinary drill pipes or coiled pipes. At one end of the drill
string 1 there is a drill bit 8, drilling a well bore 9 into the
ground. The well bore 9 has one part which is not cased and one
part covered with a set casing 10. The dual bore drill pipe 1 is
connected to a conventional drill bit 8 through a cross over
assembly 7, guiding an annular flow in the drill pipe 1 to a
central flow in the drill bit 8 and an annular flow around the
drill bit 8 into the central flow passage or central bore 5 of the
drill pipe. Alternatively there may be connected a reverse flow
drilling bit to the drill pipe, then there is no need for a cross
over assembly between the drill bit and the drill pipe. There is
further in the drill pipe 1 also arranged a valve device 6, which
regulated the flow through and between the annulus 4 and the
central bore 5. The valve device 6 may be arranged to be a blow out
preventer, BOP, for both the central bore 5 and annulus 4 and it
may also provide for a controlled fluid passage between the annulus
4 and the central bore 5. The drill pipe 1 is further bringing a
casing element 11 to be set in the well when a new section of well
is drilled. The top of the bore hole is closed by a rotating
control device 12, and there is provided a BOP at the top of the
well bore as well. The opposite end of the dual bore pipe 1
compared with the drill bit 8, is provided with a top drive adapter
13, that is also guiding drilling fluid into and out of the drill
pipe 1. There is in relation to this provided a flow control unit
14 and a system 15 for treating the drilling fluid as it returns
from the well to prepare it to be used in the well again. In
relation to this there is according to the invention arranged a
sample arrangement 16, separating out cuttings for core
testing.
[0020] The drill bit 8 in this embodiment is also assisted in its
progression by the system with the piston 17 and fluid added in an
annular space formed between the drill pipe 1 and the part of the
well with the set casing 10. This annular space is closed in by the
drill pipe 1, the set casing 10, the piston 8 and a top assembly
10. With adding pressure to this annular space with an upper
annulus control unit 18 the drill bit 8 is pushed towards the
bottom of the well 9. The present invention will work also in a
system without the progression system with piston 17 and control
unit 18.
[0021] With a system according to the invention there will at the
outlet of the central bore 5 be cuttings which are much larger
compared with conventional cutting, as typically shown in the
picture of FIG. 2, where cuttings from conventional drilling is
shown on the left of the picture and cuttings from drilling with a
system as described above is shown in the right on the picture.
[0022] The invention has now been explained with reference to a
non-limiting embodiment. A skilled person will understand that
there may be made alterations and modifications to the explained
embodiments which are within the scope of the invention as defined
in the claims. The method and device may also be used for other
kinds of well other than hydrocarbon well, where there is need for
getting information about the formation into which one is
drilling.
* * * * *