Wellhead release device and slim hole injection well logging method

Abstract

The present application belongs to the field of well logging operation, and particularly relates to a wellhead releasing device and a small-bore injection well logging method. In view of the problem that the conventional isotope tracing profile logging technology cannot meet the tracing profile logging requirements of the small-bore double-layer tubing injection well, a small-diameter multi-parameter logging instrument is optimized. Firstly, a radioactive isotope tracer wellhead releasing device is developed, which releases the isotope tracer into the well sections that are not communicated with each other by using the injection pressure difference between different injection sections and installing the wellhead releasing device on the wellhead Christmas tree. Secondly, the isotope tracer anti-dispersion method is studied, and the isotope tracer parameters are optimized, so as to improve the coagulation ability of the liquid isotope tracer in long-distance migration, thereby improving the logging interpretation accuracy. Thirdly, the releasing device and the isotope tracer preparation method are applied to improve the construction process, so as to complete the logging operation and meet the application and popularization.

Description

Technical Field

[0001] This invention belongs to the field of well logging construction, specifically relating to a wellhead release device and a well logging method for small-diameter injection wells. Background Technology

[0002] To balance formation pressure and improve oil recovery, oilfield development often employs injection-production methods. A dual-layer tubing water injection process has been developed. This process uses a casing + large-diameter tubing + small-diameter tubing injection string system. Packers are used to divide the perforated oil layer into isolated sections for precise injection, achieving surface flow control and downhole segmented quantitative water injection. When using this process in 7-inch casing wells, the innermost injection tubing has an inner diameter of 51mm. Typically, a 38mm pulsed neutron oxygen-activated water flow logging tool is used to run the inner injection string. The logging task is completed by measuring the oxygen-activated water flow rate and packer setting status in the upper, middle, and lower oil layer sections. However, in 5... 1 When using this technology in a 2-inch casing well, the space within the casing is limited, and the innermost layer of the injection string is 1. 1 The inner diameter of a 2-inch tubing is 40.3 mm, and instruments with a diameter of ￠38 mm cannot pass through safely. Existing logging instruments and logging construction techniques cannot complete the logging task of small-diameter double-layer tubing injection wells. There is currently no logging construction technique for this type of well. Summary of the Invention

[0003] This invention proposes a wellhead release device and a logging method for small-diameter injection wells to solve the problem of the lack of tracer profile logging technology for small-diameter double-layer tubing injection wells in the prior art.

[0004] To achieve the above objectives, the present invention proposes the following technical solution:

[0005] A wellhead release device includes an injection sub, a high-pressure hose, and an injection sub;

[0006] The injection section is connected to one end of the high-pressure hose via the first high-pressure hose interface, and the other end of the high-pressure hose is connected to the injection section via the second high-pressure hose interface.

[0007] Preferably, the injection stub is equipped with a pressure gauge interface.

[0008] Preferably, the injection sub is connected to the pressure gauge via a pressure gauge interface.

[0009] Preferably, the filling section is provided with a filling port.

[0010] Preferably, the filling section is provided with a sealing plug, the size of which matches the size of the filling port.

[0011] A logging method for small-diameter injection wells includes the following steps:

[0012] S1: Install the wellhead release device; connect the injection sub of the wellhead release device to the injection pipeline and the four-way valve, and connect the injection sub to the tubing annulus return valve.

[0013] S2: Isotope tracer release logging in the middle oil layer;

[0014] The isotope tracer is optimized, and the optimized isotope tracer is injected into the filling section through the filling port; the tubing ring return water valve is slowly opened, and after confirming that the pressure gauge pressure is balanced, the tubing ring return water valve is fully opened;

[0015] Open the four-way valve connecting the injection pipeline. After the isotope tracer enters the oil pipe annulus, close the oil pipe annulus return water valve and the four-way valve connecting the injection pipeline.

[0016] The migration of peak values ​​of isotope gamma curves is monitored and recorded using downhole logging instruments.

[0017] S3: Upper oil layer isotope tracer release logging;

[0018] Connect the injection sub to the casing annular return valve, and inject the optimized isotope tracer into the injection sub from the injection port; slowly open the casing annular return valve, and after confirming that the pressure gauge is balanced, fully open the casing annular return valve.

[0019] Open the four-way valve connecting the injection pipeline, and wait until the isotope tracer enters the casing annulus before closing the oil pipe annulus return water valve and the four-way valve connecting the injection pipeline.

[0020] The migration of peak values ​​in isotope gamma curves is monitored and recorded using downhole logging instruments.

[0021] Preferably, in S2, after the isotope tracer is injected into the injection stub from the injection port, the injection port is sealed with a sealing plug.

[0022] Preferably, in step S3, after the isotope tracer is injected into the injection stub from the injection port, the injection port is sealed with a sealing plug.

[0023] Preferably, in S2, the optimization process for the isotope tracer includes:

[0024] S21: In a radioactive isotope dispensing box, mix the liquid isotope, polyacrylamide, gelatin, and water, and heat and stir until completely dissolved.

[0025] S22: Based on the well logging gamma curve and the density of the well fluid, the ratio of isotope tracer, polyacrylamide, and gelatin is optimized to obtain an isotope tracer with optimal density. The advantages of this invention are:

[0026] A wellhead release device was designed, which utilizes the cooperation of injection sub and injection sub, combined with valve operation to form a water injection pressure difference, and uses the water injection pressure difference to release isotope tracers at the wellhead production tree. The device is simple to operate, safe and efficient.

[0027] A logging method for small-diameter injection wells, combining a wellhead release device and a tracer optimization method, utilizes the water injection pressure difference to release an optimized ratio of isotopic tracer at the wellhead production tree, filling the gap in engineering tracer logging technology for small-diameter double-layer tubing injection wells;

[0028] A tracer optimization method was designed. By optimizing the physical properties of the isotope tracer and combining two methods to prepare an anti-dispersion agent, the formulation parameters were optimized, which solved the dispersion problem of the isotope tracer during long-distance migration and improved the accuracy of well logging data interpretation. Attached Figure Description

[0029] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0030] Figure 1 A schematic diagram of the isotope tracer wellhead release device;

[0031] Figure 2 Daily injection volume 30m 3 Schematic diagram of gamma-ray peak widths with different gelatin ratios;

[0032] Figure 3 This is a schematic diagram of the well shaft structure;

[0033] Figure 4 This is a schematic diagram showing the release of isotopic tracers from the central oil layer.

[0034] Figure 5 Release of isotopic tracers from the upper oil layer;

[0035] Figure 6 This is a schematic diagram of a logging method for small-diameter injection wells.

[0036] In the diagram, 1 is the injection sub, 2 is the pressure gauge interface, 3 is the first high-pressure hose interface, 4 is the high-pressure hose, 5 is the second high-pressure hose interface, 6 is the injection port, 7 is the sealing plug, 8 is the injection sub, 9 is the casing annulus, 10 is the tubing annulus, 11 is the tubing annulus return water valve, 12 is the casing annulus return water valve, 13 is the Christmas tree injection line, 14 is the injection line connecting four-way valve, 15 is the upper oil layer section, 16 is the lower oil layer section, and 18 is the packer. Detailed Implementation

[0037] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0038] The following detailed description is exemplary and intended to provide further detailed explanation of the invention. Unless otherwise specified, all technical terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used in this invention is for describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention.

[0039] Example 1:

[0040] like Figure 1 The wellhead release device shown specifically includes an injection sub 1, a pressure gauge interface 2, a first high-pressure hose interface 3, a high-pressure hose 4, a second high-pressure hose interface 5, an injection port 6, a sealing plug 7, and an injection sub 8.

[0041] The injection sub 1 is equipped with a pressure gauge interface 2 for connecting a pressure gauge; one end of the injection sub 1 is connected to the injection pipeline of the tree injection pipeline 13 and a four-way valve 14, and the other end is equipped with a first high-pressure hose interface 3; the injection sub 8 is equipped with an injection port 6, which is annular, and a sealing plug 7 is adapted to the injection port 6 to seal the injection port 6; one end of the injection sub 8 is connected to the annulus return water valve on the oil well section where the isotope tracer needs to be released, and the other end is equipped with a second high-pressure hose interface 5; the inside of the injection sub 8 is designed to be conical, serving as an isotope tracer buffer chamber.

[0042] The high-pressure hose 4 is connected to the injection section 1 and the filling section 8 through the first high-pressure hose interface 3 and the second high-pressure hose interface 5. The hose connection method can meet the connection requirements of different angles and lengths on site.

[0043] Example 2:

[0044] A tracer optimization method, comprising the following steps:

[0045] In the process of preparing anti-diffusion isotope tracers in the workshop, liquid isotopes are mixed with polyacrylamide and gelatin in a radioactive isotope dispensing box with a measured amount of water. The mixture is heated and stirred until completely dissolved. The proportions of each substance in the mixed solution are optimized to achieve the best peak value and symmetry in the well logging gamma curve, and to obtain the optimal ratio in terms of density and aggregation performance. The mixture is then dispensed into a metering vessel and rapidly cooled to solidify as a whole. The isotope tracers are prepared, stored, and transported under protective conditions.

[0046] Daily injection volume 30m 3 Variations in gamma peak width with different gelatin ratios, such as Figure 2 As shown, the curve with the best gamma-ray peak value and symmetry was obtained.

[0047] Example 3:

[0048] like Figure 6 The following are the steps of a logging method for a small-diameter injection well:

[0049] Install wellhead release device:

[0050] Well structure such as Figure 3 As shown in the figure, 9 is the casing annulus, 10 is the tubing annulus, 11 is the tubing annulus return water valve, 12 is the casing annulus return water valve, 13 is the Christmas tree injection line, 14 is the injection line connecting four-way valve, 15 is the upper oil layer section, 16 is the lower oil layer section, and 18 is the packer. The injection sub 1 of the wellhead release device is connected to the injection line connecting four-way valve 14 of the Christmas tree injection line 13. The injection sub 8 is connected to the tubing annulus return water valve 11 on the tubing annulus 10. The high-pressure hose 4 connects the injection sub 1 and the injection sub 8 through the first high-pressure hose interface 3 and the second high-pressure hose interface 5. The result is shown in Figure 4.

[0051] Isotope tracer release logging in the middle oil layer:

[0052] The isotope tracer was optimized according to Example 2, and the optimized tracer was injected from the injection port 6 into the buffer cavity of the injection sub 8, and the injection port 6 was sealed with the sealing plug 7.

[0053] Slowly open the tubing annulus return water valve 11 connected to injection sub 8. After confirming that the pressure gauge is balanced, fully open the valve. Then open the injection line connection four-way valve 14 on the wellhead injection line 13 connected to injection sub 1. Use the injection pressure difference to complete the release of isotope tracer in tubing annulus 10. Wait for the isotope tracer to enter tubing annulus 10. Close the tubing annulus return water valve 11 and the injection line connection four-way valve 14. The wellhead returns to normal water injection status.

[0054] Downhole logging instruments monitored and recorded the migration of peak values ​​of isotope gamma curves, and completed the acquisition of tracer flow data for 16 sections of the middle oil layer.

[0055] Upper oil layer isotope tracer release logging:

[0056] like Figure 5 As shown, the filling section 8 is connected to the casing annulus return valve 12 of the casing annulus 9, and the optimized tracer is injected into the buffer chamber of the filling section 8 from the filling port 6. The filling port 6 is then sealed with the sealing plug 7.

[0057] Slowly open the casing annulus return water valve 12 connected to injection sub 8. After confirming that the pressure gauge is balanced, fully open the valve. Then open the injection line connection four-way valve 14 on the wellhead injection line 13 connected to injection sub 1. Use the injection pressure difference to complete the release of isotope tracer in casing annulus 9. Wait for the isotope tracer to enter casing annulus 9. Close the tubing annulus return water valve 12 and the injection line connection four-way valve 14. The wellhead will return to normal water injection status.

[0058] Downhole logging instruments monitor and record the migration of peak values ​​of isotope gamma curves, and complete the acquisition of tracer flow data for the upper oil layer section 15.

[0059] Example 4:

[0060] In well Jin 2-B5-xxx, to improve the effectiveness of water injection, a double-layer tubing string injection technique was used. The outer diameter of the casing was 139.7 mm (5). 1 / 2), Outer layer large-diameter tubing: outer diameter 88.9mm, inner diameter 75.9mm; Inner layer small-diameter tubing: outer diameter 48.3mm, inner diameter 40.3mm. The entire well section is divided into three levels of water injection: Level 1 (oil-casing annulus): upper oil layer section 1340.6~1376.6m, 2 perforated layers; Level 2 (tubing annulus): middle oil layer section 1387.1~1418.0m, 3 perforated layers; Level 3 (inner tubing): lower oil layer section 1427.3~1461.0m, 8 perforated layers. The actual daily water injection volume is: daily injection volume of Level 1, Level 2, and Level 3 water injection sections are 20, 20, and 20 m3 / d respectively, and the water injection pressure is 16, 16, and 18 MPa respectively.

[0061] Logging Requirements: Well logging interpretation and analysis of water absorption in each oil layer within each injection well section. Based on well condition analysis: Inner layer small-diameter tubing: outer diameter 48.3mm, inner diameter 40.3mm. Instrument entry channel diameter is 40.3mm. The instrument diameter must be below 30mm for safe passage; therefore, a 26mm diameter magnetic positioning + gamma + well temperature + pressure multi-parameter logging tool is selected, employing a small-diameter double-layer tubing injection well tracer profile logging method.

[0062] The isotope tracer was optimized according to the embodiment, dispensed into a metering vessel, and rapidly cooled to condense as a whole. The isotope tracer was prepared, stored, and transported under protective conditions.

[0063] At the construction site, a 26mm magnetic positioning + gamma + well temperature + pressure multi-parameter logging tool was used, and conventional isotope tracer logging methods were employed to complete the data acquisition for the 17 water injection zones in the lower oil layer section. Figure 3The installation process of the isotope tracer wellhead release device and the logging procedure for isotope tracer release in the middle oil layer involves connecting the injection sub 1 of the isotope tracer wellhead release device to the injection line of the Christmas tree injection line 13 via a four-way valve 14. The filling sub 8 is connected to the tubing annulus return water valve 11 of the tubing annulus injection line 10. A high-pressure hose 4 connects the injection sub 1 and the filling sub 8. The prepared isotope tracer is placed into the buffer chamber of the filling sub 8 through the filling port 6, and the filling port 6 is sealed with a sealing plug 7. The tubing annulus return water valve 11 connected to the filling sub 8 is slowly opened. After confirming that the pressure gauge is balanced, the tubing annulus return water valve 11 is fully opened. Then, open the four-way valve 14 connected to the injection subsection 1, and use the injection pressure difference to release the isotope tracer into the tubing annulus. Wait for the isotope tracer to enter the tubing annulus, then close the tubing annulus return water valve 11 and the four-way valve 14 connecting the injection line, restoring the Christmas tree to normal water injection status. Downhole, a ￠26mm multi-parameter logging tool is used to monitor and record the peak migration velocity direction of the isotope tracer gamma curve in the oil layer section, providing data for interpretation and completing the acquisition of tracer flow rate data for the central oil layer.

[0064] After the middle oil layer test is completed, the injection sub 8 is connected to the casing annulus return water valve 12 of the tubing annulus 9 to carry out the isotope tracer release and data acquisition work of the upper oil layer well section 15. The specific steps are shown in Example 3.

[0065] An optimized isotope tracer was released at the wellhead using an isotope wellhead release device to collect water absorption profile data. The interpretation results of the water absorption profile are shown in Table 1.

[0066] Table 1. Interpretation of water absorption profile of well Jin 2-B5-xxx

[0067]

[0068]

[0069] Table 1 shows that in the first-level water injection zone, the lower part of layer 6 is the main water-absorbing zone, the upper parts of layers 5 and 6 are secondary water-absorbing zones, and the lower part of layer 5 is a weakly water-absorbing zone. In the second-level water injection zone, the upper part of layer 10 is the main water-absorbing zone, the lower part of layer 10 and layer 11 are secondary water-absorbing zones, and layer 12 does not absorb water. In the third-level water injection zone, layers 21-23 are the main water-absorbing zones (further subdivision is not possible due to instrument obstruction in this zone), layer 18 is a secondary water-absorbing zone, and layers 16-20 do not absorb water. The interpretation results of the water absorption profile are basically consistent with the oil layer porosity and permeability data and the production dynamics, providing data support for adjusting the next development measures.

[0070] The isotope tracer wellhead release device is simple to operate, safe, and efficient. Research and optimization of the isotope tracer formulation effectively solves the dispersion problem during migration, improves the accuracy of logging data interpretation, and makes the logging process feasible.

[0071] As is known from common technical knowledge, this invention can be implemented through other embodiments that do not depart from its spirit or essential characteristics. Therefore, the disclosed embodiments described above are merely illustrative in all respects and are not the only ones. All modifications within the scope of this invention or its equivalents are included in this invention.

Claims

1. A small- bore injection well water intake profile logging method, characterized by, The small-diameter injection well is 5. 1 The well has a 2-inch casing with an outer casing diameter of 139.7 mm. The outer large-diameter tubing has an outer diameter of 88.9 mm and an inner diameter of 75.9 mm, while the inner small-diameter tubing has an outer diameter of 48.3 mm and an inner diameter of 40.3 mm. The small-diameter injection well uses a double-layer tubing system consisting of casing, large-diameter tubing, and small-diameter tubing. A packer separates the perforated oil layer into three non-communicating sections: an upper section, a middle section, and a lower section. The upper section corresponds to the casing annulus, the middle section to the tubing annulus, and the lower section to the inner small-diameter tubing. The water intake profile logging method for the small-diameter injection well includes: S1, based on the inner diameter of the inner small-diameter tubing being 40.3mm and the logging tool diameter needing to be below 30mm for safe passage, a 26mm diameter magnetic positioning, gamma, well temperature and pressure multi-parameter logging tool is selected and lowered into the well along the inner small-diameter tubing; S2, Preparation of Anti-Diffusion Isotope Tracer: In a radioactive isotope dispensing box, mix liquid isotope, polyacrylamide, gelatin, and water, and heat and stir until completely dissolved; based on the well logging gamma curve and the density of the well fluid, optimize the ratio of liquid isotope, polyacrylamide, and gelatin to ensure that the peak value and symmetry of the well logging gamma curve meet the well logging interpretation requirements, and obtain an isotope tracer with matching density and dispersion performance; dispense the optimized isotope tracer into a metering vessel and rapidly cool to solidify as a whole; S3, using conventional isotope tracer logging methods, and using the 26mm diameter magnetic positioning, gamma, well temperature and pressure multi-parameter logging tool to complete the data acquisition of the lower oil layer section; S4, Install the wellhead release device: Connect the injection sub of the wellhead release device to the injection line on the Christmas tree injection line via a four-way valve, and connect the injection sub and the filling sub through a high-pressure hose. The filling sub has an isotope tracer buffer chamber. When logging in the middle oil layer section, connect the filling sub to the tubing annulus return water valve. When logging in the upper oil layer section, connect the filling sub to the casing annulus return water valve. S5, Isotope tracer release logging in the middle oil layer: The isotope tracer prepared in step S2 is placed into the isotope tracer buffer chamber of the injection sub through the injection port, and the injection port is sealed with a sealing plug; the tubing annulus return water valve connected to the injection sub is slowly opened, and after confirming that the pressure gauge is balanced, the tubing annulus return water valve is fully opened; then the injection line connecting four-way valve connected to the injection sub is opened, and the tubing annulus isotope tracer is released using the injection pressure difference; after the isotope tracer enters the tubing annulus, the tubing annulus return water valve and the injection line connecting four-way valve are closed, so that the Christmas tree returns to normal water injection state; the 26mm diameter magnetic positioning, gamma, well temperature and pressure multi-parameter logging instrument is run into the well along the inner small-diameter tubing to monitor and record the migration speed, direction and state of the peak value of the isotope tracer gamma curve in the middle oil layer section, and the data acquisition of the middle oil layer section is completed; S6, Upper oil layer isotope tracer release logging: After the middle oil layer test is completed, connect the injection sub to the casing annulus return valve. Place the isotope tracer prepared in step S2 into the isotope tracer buffer chamber of the injection sub through the injection port, and seal the injection port with a sealing plug. Slowly open the casing annulus return valve, and after confirming pressure balance on the pressure gauge, fully open the casing annulus return valve. Then open the four-way valve connected to the injection line connected to the injection sub, and use water injection... The pressure difference completes the release of isotope tracer in the casing annulus; after waiting for the isotope tracer to enter the casing annulus, the casing annulus return water valve and the four-way valve connecting the injection pipeline are closed to restore the Christmas tree to normal water injection state; by using the 26mm diameter magnetic positioning, gamma, well temperature and pressure multi-parameter logging instrument lowered into the well along the inner small-diameter tubing, the migration speed, direction and state of the peak value of the isotope tracer gamma curve in the upper oil layer section are monitored and recorded to complete the data acquisition of the upper oil layer section; S7. Based on the data of the lower oil layer well section, the middle oil layer well section, and the upper oil layer well section, the water absorption profile is interpreted to obtain the water absorption situation of each oil layer in each water injection section.

2. The slim hole injection well water entry profile logging method of claim 1, wherein, The wellhead release device includes an injection sub, a high-pressure hose, and a filling sub. One end of the injection sub is connected to a four-way valve on the injection line of the wellhead injection line, and the other end of the injection sub is provided with a first high-pressure hose interface. One end of the filling sub is connected to an annulus return valve on the oil well section where the isotope tracer needs to be released, and the other end of the filling sub is provided with a second high-pressure hose interface. The high-pressure hose connects the injection sub and the filling sub through the first high-pressure hose interface and the second high-pressure hose interface.

3. The slim hole injection well water entry profile logging method of claim 2, wherein, The injection section is provided with a pressure gauge interface, and the injection section is connected to a pressure gauge through the pressure gauge interface; the filling section is provided with an annular filling port, and the sealing plug is adapted to the filling port to seal the filling port; the interior of the filling section has a conical structure and forms the isotope tracer buffer cavity.

4. The slim-hole injection well water influx profile logging method of claim 1, wherein, In step S2, the isotope tracer is prepared, stored, and transported under protective conditions.

5. The slim-hole injection well water influx profile logging method of claim 1, wherein, The data for the lower oil layer, the middle oil layer, and the upper oil layer all include the migration velocity, direction, and state of the peak values ​​of the isotope tracer gamma curves.

6. The slim-hole injection well water influx profile logging method of claim 1, wherein, In step S7, the main water-absorbing section, secondary water-absorbing section, weakly water-absorbing section, or non-water-absorbing section of each oil layer in each water injection section is determined based on the interpretation results of the water absorption profile.

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