A multi-stage seated continuous pressure measurement well testing tool and its testing method

Abstract

The present invention discloses a multi-stage seated continuous pressure testing well tractor barrel and its testing method. This device is applicable to the field of pressure testing of oilfield stratified injection wells. The device includes, from top to bottom, a tractor barrel fishing head, a tractor barrel sealing section, a lower hanging short joint, a lower hanging tractor barrel, a matching length short joint, a shock absorption short joint, and a tractor barrel bottom plug. The tractor barrel can internally fix and shock absorb the well testing pressure gauge. The tractor barrel can be lengthened. Its positioning step and sealing section can be seated and sealed in the working barrel of the water distributor of the injection well, locally sealing the layer, and conducting the formation pressure at the corresponding position to the well testing tractor barrel through the pressure transmission hole. The outer diameter size of the well testing tractor barrel is divided into multiple levels, and it can be successively lowered into the well by wireline operation to achieve continuous stratified pressure testing of oilfield injection wells. The present invention solves the disadvantages of the traditional wireline suspension testing of the pressure gauge in the wellbore, and eliminates the workload and construction cost brought by the wireline operation to adjust the water nozzle of the downhole water distributor and cooperate with the stratified pressure testing by changing layers back and forth.

Description

Technical Field

[0001] The invention belongs to the field of pressure well testing of stratified water injection wells in oil fields, and in particular relates to a multi-stage sitting continuous pressure well testing drag tube and a testing method thereof. Background Art

[0002] The Bohai Oilfield's stratified water injection string is composed of multiple water distributor mandrels and their corresponding internal water distributors to achieve stratified water injection at different depths. Currently, during the segmented pressure testing of its injection wells, it is necessary to use a steel wire operation to salvage the water distributor corresponding to the layer to be tested, open the water nozzle on the ground and return it to the original well. The water distributors corresponding to the remaining non-test layers are also salvaged step by step, closed the water nozzle on the ground and returned to the original well step by step. After the wellbore pressure stabilizes, the steel wire is suspended to suspend the well test pressure gauge to record the pressure and temperature data of the target layer. For individual pressure tests of several layers, this needs to be repeated in sequence, that is, the water distributor needs to be dropped back and forth by steel wire operations to change layers to achieve stratified pressure testing of offshore oilfield water injection wells. This requires many steel wire operations, a long construction period, high operating costs, and the pressure measurement data is seriously affected by the wellbore effect. Summary of the Invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a multi-stage seated continuous pressure test well drag. The present invention solves the existing problem of needing to use wireline operations to cast the water distributor back and forth to change layers to achieve stratified pressure testing of offshore oil field water injection wells, many wireline operations, long construction period, high operation cost, and the pressure test data being seriously affected by the wellbore effect. The well test drag of the present invention can fix the well test pressure gauge inside it and achieve sealing. The well test drag divided into multiple levels of size is sequentially cast into the corresponding water distributor working cylinder in the well through wireline operations, and the pressure and temperature parameters of the corresponding formation are directly measured and recorded through the pressure transmission holes, eliminating the workload and construction cost caused by wireline operations to adjust the water nozzle of the downhole water distributor back and forth to change layers, and the well test process is not affected by the wellbore storage effect.

[0004] The present invention is achieved through the following technical solutions:

[0005] A multi-stage sitting continuous pressure testing well drag tube comprises a drag tube fishing head, a drag tube sealing section, a lower hanging short section, a lower hanging type drag tube, a lengthened short section, a shock absorbing short section and a drag tube bottom plug connected end to end in sequence;

[0006] The top of the drag drum salvage head is provided with an internal salvage structure for cooperating with the salvage tool, with a blind plate installed inside and a diameter-changing step formed at the lower end;

[0007] A pressure transmission hole is provided on the wall of the sealing section of the drag cylinder;

[0008] A shock-absorbing groove is formed in the under-hanging drag drum, and a rubber ring matching the outer diameter of the pressure gauge is installed in the shock-absorbing groove;

[0009] A limiting step is formed inside the shock-absorbing sub, shock-absorbing springs are installed on both sides of the limiting step, the central rod passes through the middle of the shock-absorbing springs and the limiting step and is fixed to the locking cap, and a centralizer that is in clearance fit with the matching length sub is installed at the top of the central rod.

[0010] In the above technical solution, packing glands are respectively arranged at the joints of the barrel sealing section with the barrel fishing head and the barrel wall of the lower hanging sub. O-ring seals are arranged at the joints of adjacent subs of the well testing barrel (including the barrel fishing head, the barrel sealing section, the lower hanging sub, the lower hanging type barrel, the matching length sub, the shock-absorbing sub and the barrel bottom plug).

[0011] In the above technical solution, drain holes are formed on the barrel wall of the barrel fishing head.

[0012] In the above technical solution, the number of the pressure transmission holes is greater than or equal to 2.

[0013] In the above technical solution, the pressure transmission holes have internal threads.

[0014] In the above technical solution, the matching length sub is a single metal barrel or is composed of multiple subs connected end to end.

[0015] In the above technical solution, a spare installation groove is formed inside the barrel bottom plug.

[0016] A testing method for a multi-stage sitting type continuous pressure measurement well testing barrel is carried out according to the following steps:

[0017] Step 1: Ensure that there is no water distributor in the injection well borehole or fish out the downhole water distributor in advance through wire operation.

[0018] Step 2: According to the law that there are multiple injection working barrels at different depths in the injection well for layered water injection into each sand control section, and the inner diameter size decreases successively from deep to shallow in the well borehole, for the different outer diameter sizes of the multi-stage sitting type continuous pressure measurement well testing barrels, each well testing barrel is successively defined as the first stage, the second stage, the third stage... from thick to thin.

[0019] Step 3: Keep all the pressure transmission holes in the middle of the sealing section of the well testing barrel open. Hang the internal fishing structure at the top of the first-stage barrel fishing head under the wire operation fishing tool, and lower it (with a pressure gauge installed inside) into the water injection pipe string by wire operation. When the well testing barrel reaches a position 10 meters above the water injection working barrel, conduct a hook load test, record the wire tension reading, quickly lower the well testing barrel, and rely on the impact force of the wire operation tool string downward to position it by the stepped diameter change at the outer bottom of the barrel fishing head, so that the well testing barrel is seated in the lowest water injection working barrel in the water injection pipe string. The shock absorption device in the barrel ensures the integrity of the electronic pressure gauge during the lowering process. Test the hook load again at the same position, and judge whether the well testing barrel has become disengaged based on the change in the wire tension reading, then retrieve the wire tool string;

[0020] Similarly, hang the internal fishing structure at the top of the second-stage well testing barrel fishing head under the wire operation fishing tool, and lower it (with a pressure gauge installed inside) into the water injection pipe string by wire operation. Seat it in the second-to-last water injection working barrel in the water injection pipe string. After it becomes disengaged, retrieve the wire. Repeat the process in sequence to successively lower well testing barrels of other size grades into the corresponding water injection working barrels in the pipe string, and wait for 12 hours to balance the pressure between the inner cavity of the barrel and the formation pressure.

[0021] Step 4: After the pressure measurement is completed, use wire operation to successively fish and retrieve all the well testing barrels in the well. Take out the internal well testing pressure gauge on the ground and playback the test data, and conduct data processing to obtain the pressure at the middle position of the perforated oil layer corresponding to each sand control section.

[0022] The advantages and beneficial effects of the present invention are as follows:

[0023] 1. After the well testing barrel is inserted into the working barrel of the water distributor, it isolates the water injection pipe string, locally seals the layer of the well testing barrel, directly senses the true formation pressure, and the formation fluid does not release into the pipe string. There is no need to balance the entire wellbore, and the test data is not affected by the wellbore storage effect, improving the accuracy of well testing pressure measurement.

[0024] 2. There is no additional impact on the wellbore pressure during the process of lowering the pressure gauge suspended by wire or coiled tubing.

[0025] 3. The layered pressure measurement operation cycle of the water injection well is shortened to one-third of the conventional wire operation layered pressure measurement operation cycle, eliminating the 24-hour pressure recovery time between each layer of testing and the workload caused by repeatedly fishing and replacing the water nozzle of the water distributor to change layers. The segmented test is completed at one time, improving the operation efficiency, reducing the operation cost, and minimizing the operation risk. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a schematic structural diagram of the present invention.

[0027] Wherein: 1 is the drag barrel fishing head, 1-1 is the stepped diameter change, 1-2 is the drain hole, 2 is the drag barrel sealing section, 3 is the lower hanging short joint, 4 is the lower hanging drag barrel, 5 is the matching length short joint, 6 is the shock absorption short joint, 7 is the drag barrel bottom plug, 7-1 is the spare installation groove, 8 is the sealing packing, 9 is the pressure transmission hole, 10 is the O-ring seal, 11 is the shock absorption groove, 12 is the centralizing block, 13 is the limiting step, 14 is the central rod, 15 is the shock absorption spring, and 16 is the locking nut.

[0028] For those of ordinary skill in the art, without creative efforts, other relevant drawings can be obtained based on the above drawings. Specific implementation manners

[0029] In order to enable the personnel in the technical field to better understand the solution of the present invention, the technical solution of the present invention will be further described below in conjunction with specific embodiments.

[0030] Embodiment

[0031] A multi-stage sitting type continuous pressure measurement well testing drag barrel is serially connected from top to bottom by a drag barrel fishing head 1, a drag barrel sealing section 2, a lower hanging short joint 3, a lower hanging drag barrel 4, a matching length short joint 5, a shock absorption short joint 6, and a drag barrel bottom plug 7. Both ends of the drag barrel assembly are axially sealed, and it has a well testing pressure gauge fixing and shock absorption mechanism inside. The outside of the drag barrel has a positioning step, a sealing section, and a pressure transmission hole. Radial sealing is achieved between each short joint through an O-ring seal.

[0032] The top of the drag barrel fishing head 1 has an internal fishing structure for cooperating with a fishing tool, and has a blind plate inside. There is a stepped diameter change 1-1 at the bottom outside. The middle of the drag barrel sealing section 2 is provided with a plurality of pressure transmission holes 9 with internal threads. The upper and lower parts are installed with insert-type sealing packings 8, which are connected and limitedly fixed to the bottom of the drag barrel fishing head 1 and the top of the lower hanging short joint 3. Its assembly is inserted and sealed with the working barrel of the water distributor in the injection well and sits on it. The lower hanging short joint, the lower hanging drag barrel, the matching length short joint, the shock absorption short joint, and the drag barrel bottom plug are serially connected from top to bottom, and the inner and outer diameters are the same. The overall length of the well testing drag barrel can be adjusted by connecting multiple matching length short joints. There is an annular shock absorption groove 11 inside the lower hanging drag barrel 4, and radial shock absorption of the well testing pressure gauge inside the drag barrel is achieved through an embedded combination with a rubber ring of corresponding size. The shock absorption short joint 6 is internally provided with a limiting step 13, and shock absorption springs are installed on both sides of it. After passing the central rod through the middle of the shock absorption spring and the limiting step, it is fixed with a locking nut 16. The position of the centralizing block at the top of the central rod has a clearance fit with the inner cavity of the drag barrel, and the fixation with the well testing pressure gauge can be achieved.

[0033] When in use, according to the different inner diameters of the working barrels of the water distributors to be pressure measured, several groups (generally 5 groups) of the above-mentioned well testing drag barrels with the same structure but gradually increasing outer diameters are prepared. The stepped diameter change sizes between each group of well testing drag barrels remain unchanged, and the drag barrel fishing head and the various components connected in series below are proportionally reduced.

[0034] Assembly of well testing drag tube:

[0035] 1. Install damping springs 15 on both sides of the limit step 13 inside the damping sub 6. Pass the center rod 14 between the damping spring 15 and the limit step 13 and secure it with the locking cap 16. The position of the straightening block 12 on the top of the center rod matches the clearance of the inner cavity of the drag tube to achieve fixation with the well test pressure gauge.

[0036] 2. According to the length of the well test pressure gauge and the number of downholes, consider the extension length of the short section 5 so that the overall length of the well test tube can be adjusted to accommodate the required pressure gauge.

[0037] 3. The annular shock-absorbing groove 11 left inside the lower-hanging drag drum 4 is embedded with a rubber ring of corresponding size (the inner diameter of the selected rubber ring should be sufficient to allow the well test pressure gauge to pass through it).

[0038] 4. The upper and lower parts of the drag drum sealing section 2 are installed with sleeve-type sealing packing 8, which are connected and fixed in position through the bottom of the drag drum fishing head 1 and the top of the lower hanging short section 3.

[0039] 5. The drag drum fishing head 1, the drag drum sealing section 2, the lower hanging short section 3, the lower hanging drum 4, the auxiliary length short section 5, the shock absorbing short section 6, and the drum bottom plug 7 are connected in series from top to bottom. The shock absorbing short section 6 realizes axial vibration reduction of the well test pressure gauge inside the drag drum, and the lower hanging drum 4 realizes radial vibration reduction of the well test pressure gauge inside the drag drum.

[0040] Well testing tube sealing test:

[0041] The multiple pressure transmission holes 9 with internal threads opened in the middle of the drag tube sealing section 2 are blocked, leaving only one hole for connecting to the pressure test device. A pressure test is performed to verify the axial sealing formed by the internal blind plate of the drag tube fishing head 1 and the drag tube bottom plug 7 before the drag tube is lowered into the well, as well as the radial sealing achieved by the O-rings 10 between the short sections.

[0042] Downhole pressure test of well test tube: Follow the steps below:

[0043] Step 1: Ensure that there is no water distributor in the water injection well or salvage the water distributor in the well in advance by wireline operation;

[0044] Step 2: Based on the rule that multiple water injection mandrels exist at different depths in the injection well, water is injected into each sand control section in layers. The inner diameter decreases from deep to shallow in the wellbore. Based on the different outer diameters of the multi-stage seated continuous pressure test wellbore, each wellbore is defined as level one, level two, level three, etc., from coarse to fine.

[0045] Step 3: Keep all the pressure transmission holes in the middle of the sealing section of the well testing barrel open. Hang the internal fishing structure at the top of the first-stage barrel fishing head under the wireline operation fishing tool, and lower it (with a pressure gauge installed inside) into the injection string by wireline operation. When the well testing barrel reaches a position 10 meters above the injection working barrel, conduct a hook load test, record the wire tension reading, quickly lower the well testing barrel, and rely on the impact force of the wireline operation tool string downward to position it by the stepped diameter change at the outer bottom of the barrel fishing head, so that the well testing barrel is seated in the lowermost injection working barrel of the injection string. The shock absorption device inside the barrel ensures the integrity of the electronic pressure gauge during the lowering process. Test the hook load again at the same position, and judge whether the well testing barrel has become disengaged by the change in the wire tension reading, then retrieve the wire tool string;

[0046] Similarly, hang the internal fishing structure at the top of the second-stage well testing barrel fishing head under the wireline operation fishing tool, and lower it (with a pressure gauge installed inside) into the injection string by wireline operation. Seat it in the second-to-last injection working barrel in the injection string. After it becomes disengaged, retrieve the wire. Repeat the process in sequence to successively lower well testing barrels of other size grades into the corresponding injection working barrels in the string, and wait for 12 hours to balance the pressure between the barrel inner cavity and the formation pressure.

[0047] Step 4: After the pressure measurement is completed, use wireline operation to successively fish and retrieve all the well testing barrels in the well. Take out the internal well testing pressure gauge on the ground and playback the test data, and conduct data processing to obtain the pressure at the middle position of the perforated oil layer corresponding to each sand control section.

[0048] (1) Calculate the vertical depth d1 corresponding to each measuring point D1 (the measured depth of the pressure gauge in the well testing barrel in the well). Consult the well deviation data table in the well completion summary of this well to obtain the measured depth and vertical depth data (DX1, dX1) and (DX2, dx2) of the two points closest to this point. Then the vertical depth of the measuring point d1 = dX1 + (dx2 - dX1)(D1 - DX1) / (DX2 - DX1);

[0049] (2) Obtain the vertical depth d2 at the middle of the perforated oil layer of each sand control section. By consulting the perforation data table of this well, obtain the vertical top depth and vertical bottom depth of the perforated layer corresponding to this sand control section. Then the vertical depth at the middle of the perforated oil layer d2 = (vertical top depth + vertical bottom depth) / 2;

[0050] (3) Obtain the pressure P2 corresponding to the vertical depth d2 at the middle of the perforated oil layer of each sand control section. Read the pressure P1 corresponding to each measured depth D1 from the pressure gauge test data, and use the formula: P2 = (d2 - d1) / 100 + P1 (Note: The pressure gradient of the water column per 100 meters in the wellbore is known to be 1). The P2 obtained after completing the above steps is the pressure at the middle of the perforated oil layer corresponding to this sand control section.

[0051] Comparative Example

[0052] Conventional wireline operation layer-changing type sectional pressure test:

[0053] Currently, during the sectional pressure test of an injection well, it is necessary to fish out and remove the water distributor corresponding to the layer to be tested through wireline operation, open the water nozzle on the ground and then lower it back into the original well, and also successively fish out the water distributors corresponding to the remaining non-test layers, close the water nozzle on the ground and then successively lower them back into the original well. After waiting for the wellbore pressure to stabilize (to be balanced with the formation pressure to be measured), a wireline suspended well testing pressure gauge is used to record the pressure and temperature data of the target layer. For the individual pressure tests of several layers, this process needs to be repeated successively, that is, it is necessary to realize the layer-by-layer pressure test of the injection well in an offshore oilfield by repeatedly fishing and changing layers of the water distributor through wireline operation.

[0054] For the operation efficiency analysis of the layer-by-layer pressure test of an injection well, taking the example of having 5 levels of injection working barrels in the well, the comparison of two testing methods is as follows:

[0055]

[0056]

[0057]

[0058] The above is an exemplary description of the present invention. It should be noted that without departing from the core of the present invention, any simple deformation, modification or equivalent replacement that can be made by those skilled in the art without creative labor falls within the protection scope of the present invention.

Claims

1. A testing method for a multi-stage sitting continuous pressure measurement well logging tool, characterized in that, The following steps are carried out: Step 1: Ensure that there is no water distributor in the injection wellbore or fish out the downhole water distributor in advance through wireline operation. Step 2: According to the law that there are multiple injection working barrels at different depths in the injection well for stratified water injection into each sand control section, and the inner diameter size decreases successively from deep to shallow in the wellbore, for the different outer diameter sizes of the multi-stage seated continuous pressure measurement and well testing drag barrels, multiple well testing drag barrels are successively defined as multiple size levels from thick to thin. Step 3: Keep all the pressure transmission holes in the middle of the sealing section of the well testing drag barrel open. Hang the internal fishing structure at the top of the first-stage drag barrel fishing head under the wireline operation fishing tool, and lower it into the injection pipe string through wireline operation. When the well testing drag barrel reaches a position 10 meters above the injection working barrel, conduct a hook load test, record the wire tension reading, quickly lower the well testing drag barrel, and rely on the impact force of the wireline operation tool string downward to position it on the basis of the stepped diameter change at the outer bottom of the drag barrel fishing head, so that the well testing drag barrel is seated in the lowest injection working barrel in the injection pipe string. During the lowering process, the shock absorption device in the drag barrel ensures the integrity of the electronic pressure gauge; conduct a hook load test again at the same position. Judge whether the well testing drag barrel has become disengaged through the change of the wire tension reading, and retrieve the wire tool string. Similarly, hang the internal fishing structure at the top of the second-stage well testing drag barrel fishing head under the wireline operation fishing tool, and lower it into the injection pipe string through wireline operation. Seat it in the second-to-last injection working barrel in the injection pipe string. After it becomes disengaged, retrieve the wire. Repeat the process in turn to successively put the well testing drag barrels of other size levels into the corresponding injection working barrels in the pipe string, and wait for 12 hours to ensure the pressure balance between the inner cavity of the drag barrel and the formation pressure. Step 4: After the pressure measurement is completed, successively fish out and retrieve all the well testing drag barrels in the well through wireline operation, take out the internal well testing pressure gauge on the ground and playback the test data, and conduct data processing to obtain the pressure at the middle position of the perforated oil layer corresponding to each sand control section.

2. The testing method of a multi-stage seated continuous pressure measurement well testing tool according to claim 1, characterized in that: The multi-stage seated continuous pressure measurement and well testing drag barrel includes a drag barrel fishing head, a drag barrel sealing section, a lower hanging short joint, a lower hanging drag barrel, a matching length short joint, a shock absorption short joint and a drag barrel bottom plug that are successively connected end to end. The top of the drag barrel fishing head is provided with an internal fishing structure for cooperating with the fishing tool, and a blind plate is installed inside, and a stepped diameter change is formed at the lower end; pressure transmission holes are arranged on the barrel wall of the drag barrel sealing section; a shock absorption groove is formed in the lower hanging drag barrel, and a rubber ring matching the outer diameter of the pressure gauge is installed in the shock absorption groove; a limiting step is formed inside the shock absorption short joint, shock absorption springs are installed on both sides of the limiting step, the central rod passes through the middle of the shock absorption spring and the limiting step and is fixed to the locking cap, and a centralizing block with a clearance fit with the matching length short joint is installed at the top of the central rod.

3. The testing method of a multi-stage seated continuous pressure measurement well testing tool according to claim 1, characterized in that: Sealing packing is respectively arranged at the connections between the barrel wall of the drag barrel sealing section and the drag barrel fishing head and the lower hanging short joint.

4. The testing method of a multi-stage sitting type continuous pressure measuring well logging tool according to claim 1, characterized in that: O-ring seals are arranged at the connections between adjacent short joints of the well testing drag barrel.

5. The testing method of a multi-stage seated continuous pressure measurement well testing string according to claim 1, characterized in that: The number of the pressure transmission holes is greater than or equal to 2.

6. The testing method of a multi-stage seated continuous pressure measurement well testing tool according to claim 1, characterized in that: The matching length short joint is a single metal barrel or composed of multiple short joints connected end to end. A spare installation groove is formed inside the drag barrel bottom plug.

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