U.S. patent application number 13/928560 was filed with the patent office on 2014-01-09 for downhole shut-in device for pressure variation testing in gas lift wells.
The applicant listed for this patent is Instituto Mexicano Del Petroleo. Invention is credited to Rogelio ALDANA CAMARGO, Luis Arturo AMADOR ORTEGA, Fernando ASCENCIO CENDEJAS, Jorge FLORES CASTILLO, Felipe GALLEGOS CASTILLO, Enrique HERNANDEZ LECOURTOIS, Israel HERRERA CARRANZA, Miguel Angel LOPEZ LOPEZ, Emmanuel ORTEGA LOPEZ, Ivan VELAZQUEZ OVANDO, Julio Cesar ZAVALA COTA.
Application Number | 20140008075 13/928560 |
Document ID | / |
Family ID | 49877120 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140008075 |
Kind Code |
A1 |
LOPEZ LOPEZ; Miguel Angel ;
et al. |
January 9, 2014 |
Downhole shut-in device for pressure variation testing in gas lift
wells
Abstract
The device is based on the principle of downhole shut-in of oil
producing wells that do not flow to surface self-powered but
require the injection of gas to lighten the fluid column and thus
enable the well to produce. This downhole shut-in device comprises
a check valve, an anchoring system, a seal system; an untethering
system, a shock absorber and a sleeve for the protection of
pressure and temperature memory probes. The objective of the
downhole shut-in device is to obtain characteristic information of
the fluid-rock system from variations in the pressures recorded in
order to obtain the dynamic characterization of the reservoir.
Inventors: |
LOPEZ LOPEZ; Miguel Angel;
(Mexico City, MX) ; ALDANA CAMARGO; Rogelio;
(Mexico City, MX) ; FLORES CASTILLO; Jorge;
(Mexico City, MX) ; GALLEGOS CASTILLO; Felipe;
(Mexico City, MX) ; HERNANDEZ LECOURTOIS; Enrique;
(Mexico City, MX) ; HERRERA CARRANZA; Israel;
(Mexico City, MX) ; VELAZQUEZ OVANDO; Ivan;
(Mexico City, MX) ; ASCENCIO CENDEJAS; Fernando;
(Mexico City, MX) ; AMADOR ORTEGA; Luis Arturo;
(Mexico City, MX) ; ZAVALA COTA; Julio Cesar;
(Mexico City, MX) ; ORTEGA LOPEZ; Emmanuel;
(Mexico City, MX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Instituto Mexicano Del Petroleo |
Mexico City |
|
MX |
|
|
Family ID: |
49877120 |
Appl. No.: |
13/928560 |
Filed: |
June 27, 2013 |
Current U.S.
Class: |
166/316 |
Current CPC
Class: |
E21B 49/008 20130101;
E21B 34/06 20130101 |
Class at
Publication: |
166/316 |
International
Class: |
E21B 34/06 20060101
E21B034/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 29, 2012 |
MX |
MX/A/2012/007683 |
Claims
1. A downhole shut-in device for testing pressure variation in gas
lift wells, characterized in that it comprises a check valve for
pressure retaining with variable opening, which allows the flow
path of the reservoir, an anchoring system, which allows to install
the device into the production tubing, a sealing system which has
the function of sealing the well, an anchorage system, which is
composed of four lower jaws and three upper ones; an untethering
system, which allows to retrieve the device, a shock absorber,
which serves to dissipate the energy generated by shock and
vibration in the body of the device during all stages of the
operation and a jacket for memory probes, to avoid loss of
information due to operating conditions in which the reservoir may
be, even preventing damage to probe circuitry.
2. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the check valve allows
reservoir flow only from bottom to top of the closure
equipment.
3. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the check valve has a
homogeneous fluid inlet and outlet according to the fluid
composition, flow rate and downhole pressure when the well is
flowing, and at the top it has the fishing neck, which is designed
to work with a JDC pulling tool.
4. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the anchorage
bidirectional system comprises four lower jaws and three upper
ones, which allow the device to be placed on any free area of the
production tubing.
5. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the sealing mechanism
comprises three high temperature resistant seals and ensures the
tightness to prevent the well flow pass otherwise than within the
device in its operation.
6. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the shock absorber can
dissipate the energy generated by shock and vibration in the device
body during all phases of operation.
7. A downhole shut-in device for testing pressure variation in gas
lift wells, according to claim 1, wherein the probe jacket protects
memory probes from any impact occurred during the course of the
operation of the device.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a downhole shut-in device
for testing pressure variation in gas lift wells. These wells
require high pressure gas injection in order to decrease the
hydrostatic column weight, since without pressure power oil ceases
flowing. Thus, this downhole shut-in device, object of the
invention, is capable of testing pressure variation in gas lift
wells. Currently it has no precedent in the national and
international market. This invention is used in the area of field
exploitation.
BACKGROUND OF THE INVENTION
[0002] According to the history of the country's hydrocarbon
production, in recent years we have observed that oil production
has been declining. To stop this we require development and/or
improvement of current techniques specifically focused on oil
extraction. Exploitation of mature fields or low pressure ones
requires generating strategies to incorporate new technologies and
design scenarios, planning, operation, maintenance, monitoring,
control and optimization of production systems throughout the
production life. Therefore, there is the need for the use of
advanced technologies for the acquisition of downhole information.
One technique for acquiring such information is the pressure
variation testing.
[0003] Pressure variation tests are to generate and record pressure
variation downhole of one or more wells for a period of time. These
downhole pressure variations are generated by modifying injection
or production conditions of the wells.
[0004] The purpose of testing pressure variations is to obtain
characteristic information from the fluid-rock system
(petrophysical properties of the reservoir). From the pressure
variations recorded, we can obtain the dynamic characterization of
the reservoir in order to establish the optimum exploitation
system.
[0005] Techniques for generating pressure disturbance are based
primarily on surface operations such as opening and /or closing the
well, fluid injection, variation in throttle, etc. The echometer is
the device that collects information in this type of operation.
When performing these surface operations there arise
technical-mechanic issues, undesired physical phenomena, impacts to
surface facilities, among others. These problems affect the quality
of information and cannot be filtered by the echometer, reducing
then the reliability of the same. The shortcomings of the echometer
are that production rigging must not present accessories that alter
the behavior of the sound wave, and it is only applied in liquid
wells.
[0006] Therefore, the Systems and Tools for Information Acquisition
from Wells (SHAIP for its acronym in Spanish) group of the
Instituto Mexicano del Petroleo (Mexican Petroleum Institute), set
itself the task of developing a device that can generate pressure
disturbances inside a gas injection well comprising the following
characteristics: installation close to the producing reservoir; use
in wells with gas present; diminishing or eliminating storage
effects of the well with short times of interruption of production;
not being affected by rigging accessories of production; and that
the recorded information be reliable. Based on these
characteristics, we obtain the downhole shut-in device for pressure
variation testing in gas lift wells.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] In order to provide a clear and accurate description of the
functionality of the downhole shut-in device of the present
invention, reference is made to the accompanying figures.
[0008] FIG. 1 shows the general components of the downhole shut-in
device for pressure variation testing in gas lift wells.
[0009] FIG. 2 shows the typical curve obtained by processing the
information retrieved from the downhole shut-in device.
[0010] FIG. 3 shows the plotted results of the pressure variation
test obtained in Well Coyotes 461 of PEMEX.
DETAILED DESCRIPTION OF THE INVENTION
[0011] Below is a detailed description of our invention, for which
reference is made to the accompanying descriptive figures.
[0012] FIG. 1 shows the device, object of the invention, which is
constituted by a retaining pressure check valve with variable
opening (1), which permits passage of the flow in the reservoir; an
anchoring system (2) that installs the device inside the production
tubing, a sealing system (3) which serves to seal the wellbore;
untethering system (4), to retrieve the device, a shock absorber
(5), which has the function of dissipating the energy generated by
shock and vibration in the device body, through all stages of the
operation, which can damage the memory probe set pressure and
temperature, and a jacket for the memory probes (6) to prevent loss
of information because the operating conditions in the reservoir,
avoiding also damages to probe circuitry. This downhole shut-in
device for testing pressure variation in gas lift wells is placed
downstream of the operation valve, just at the lower end of the
production tubing, and is mainly used to generate pressure
variations in gas lift wells through a pressure check valve with
variable opening, which allows only the flow from below upwards of
the closing equipment and opens when the differential pressure
(lower initial pressure and higher flow pressure) is greater on
magnitude than the calibration pressure of the valve after opening
the well and injecting the gas for pneumatic pumping.
[0013] The present invention is based on the principle of downhole
shut-in of oil producing wells that do not flow to the surface
self-powered, but require the injection of gas to lighten the fluid
column and thus enable the well to produce. At the beginning, only
the fluids into the production tubing will be moved with pneumatic
gas injection pumping until the differential pressure between the
inferior initial pressure (P1 initial) and the superior pressure
due to flow (P2 flow) is greater on magnitude than the calibration
pressure of the valve (P3 spring), the pressure check valve with
variable opening (FIG. 1) which will open and begin the drawdown
pressure stage in downhole (FIG. 2).
P.sub.3 Spring<PInitial-P.sub.2 Flow
[0014] After closing the well and stopping the pneumatic gas
injection pumping, the downhole pressure will seek to achieve the
pressure P1 initial and the flow will increase to fulfill the
following inequality for the check valve closure:
P.sub.3 spring<P.sub.1flow-P.sub.2 flow
[0015] Once the valve is closed, downhole pressure increment will
start due to the reservoir response without the effects of the
fluid stored in the well (FIG. 2).
[0016] The present invention operates by downhole shut-in to
minimize storage effect within the well and duration of the
variation pressure tests.
Operation of the Parts Constituting the Invention
[0017] 1. Check Valve:
[0018] Non-return or check valve with variable opening that will
isolate the bottom of the well as this area does not have a high
enough pressure to overcome the pressure of the upper zone; it has
a fluid homogeneous inlet and outlet according to the fluid
composition, flow velocity and downhole pressure when well is
flowing. At the top has a fishing neck, which is designed to work
with JDC type pulling tool. [0019] 2. Anchorage System:
[0020] Bidirectional anchoring system comprises four lower jaws and
three upper ones that allow the device to be placed on any free
area of the production tubing. The system is activated by falling
impacts. [0021] 3. Seal System:
[0022] This system comprises three seals made of high-strength
polymer to the temperature and chemical attack. These seals
insulate the top of the lower zone of the well to ensure the flow
path through the interior of the device. Actuation occurs when the
falling impacts activate the anchoring system, whereupon
compression occurs on the seals, so that they reduce theft length
and increase theft diameter. [0023] 4. Untethering System:
[0024] Untethering system comprises bolts made of high tensile
strength but low shear strength. Its function is to maintain the
anchorage of the tool until the time to be retrieved upon. [0025]
5. Shock Absorber:
[0026] The shock absorber has the function of dissipating the
energy generated by shock and vibrations in the body of the device
during all stages of the operation, which can damage the memory
probe set. Its principle is based on the combination of the
spring-damper. [0027] 6. Probes Jackets,
[0028] Produced in high strength steel, they will have the purpose
of protecting memory probes from any impact effects occurring
during development of the device operation.
EXAMPLES
Application in Well Coyotes 461 PEMEX.
[0029] The results obtained in the pressure variation test in Well
Coyotes 461 made with the "downhole shut-in device for testing
pressure variation in aft lift wells IMP" and high resolution
memory probes at 955 m depth are presented. The shut-in period was
carried out with downhole shut-in, allowing a clear definition of
the response of a hydraulically fractured well and we were able to
identify the different flow periods in a Reservoir-Hydraulic
Fracture-Well system.
[0030] Well Coyotes-461 produces at an interval of 993 to 1040 m,
that belongs to the body of sand Sim.sub.--50, of Chicontepec
formation. The well is located in the central part of the field
Coyotes. It is located NW of Paleocanal Chicontepec within the
study area called Sector 3.
[0031] Analysis determined that the well has a finite conductivity
fracture with a length of 88 m, which represent 61% of the
programmed (144 m) and a conductivity of 10.4.times.10.sup.-3
Darcy/ft which is well below of estimated (2855 mD-ft) by Byron
Jackson Company (BJ).
[0032] The well was producing with a rate of 16-20 bpd and a head
pressure of 4-6 kg/cm2. Based on this, we asked the production area
of Activo Cerro Azul, belonging to Poza Rica-Altamira, a portable
separator installed to measure the volume of gas and liquid before
closing the well, With the well closed, and using slickline the
well was calibrated with a printing block of 2 5/16 going down
"free" to 1060 m, subsequently the accessory "collar stop" was
descended and anchored at 960 m.
[0033] Two pressure and temperature high resolution probes were
programmed and the device of downhole shut-in was assembled with
check valve and the two probes connected to their respective
battery. The trial period took place after starting the pneumatic
gas injection pumping, producing gas and liquid toward liquids dam
and subsequently carry it to portable separator for
measurement.
[0034] Once the probe was retrieved and pressure information
obtained, we proceeded to perform the analysis. FIG. 3 shows the
total time spent on the test of pressure variation (pressure trend,
pressure increase curve and decrease curve). The buildup test shows
a trend fairly good, almost perfect, without distortion or
abnormalities during development. This is because the downhole
shut-in was effective and there was no leakage through the seals
and the interior of the check valve calibrated to 1/3 of downhole
pressure. The literature mentions that the buildup curves are the
most representative due to full control of the flow rate because
the well is closed, so that the flow rate is zero as long as there
are no leaks.
From This Test it was Concluded That:
[0035] A.) The drawdown pressure was successfully performed by the
lightening of the hydrostatic column, through the gas injection
through the annular space and the corresponding opening of the
check valve calibrated previously
[0036] B) The shut-in downhole, which was conducted stopping the
gas injection through the annular space and the corresponding
closure of the precalibrated check valve. Through buildup test,
which allowed reducing storage effects, it have gotten a clear
definition of the response of a finite conductivity in a
"Reservoir-hydraulic fracture-Well" system.
* * * * *