Isolating fluid for composite jamming treatment, preparation method and jamming releasing method

Abstract

The invention discloses a spacer fluid for composite jamming treatment, a preparation method and a jamming freeing method, and relates to the technical field of jamming freeing agent isolation, the spacer fluid comprises 2-4% of a stabilizer, 1-2% of an emulsifier, 8-12% of a penetrant, 2-4% of calcium oxide, 0.5-1.5% of a solid defoaming agent and an oil phase. The density of the spacer fluid is 0.9-1.5 g / cm < 3 >, and the density of the spacer fluid is adjusted by adding barite powder. According to the preparation method, all the components are uniformly mixed, and the jam releasing method comprises a basic soaking jam releasing method, a second-stage injection and replacement jam releasing method and a third-stage injection and replacement jam releasing method. By adopting the specific spacer fluid, an enhanced isolation effect can be formed among the oil-based jam-freeing fluid, the hydrochloric acid jam-freeing fluid and the drilling fluid, and mixing among the oil-based jam-freeing fluid, the hydrochloric acid jam-freeing fluid and the drilling fluid is effectively reduced, so that the two-fluid jam-freeing agent effectively exerts the jam-freeing characteristic of the two-fluid jam-freeing agent; therefore, the purposes of shortening the jam releasing time, improving the jam releasing effect and reducing the drilling cost are achieved.

Description

Technical Field

[0001] This invention relates to the field of isolation technology for stuck drill bits and unsticking agents, specifically to an isolation fluid, preparation method, and unsticking method for treating composite stuck drill bits. Background Technology

[0002] The carbonate rock formations in the Sichuan-Chongqing region, such as Dongyuemiao, Jialingjiang, Qixia, and Qiongzhusi, contain multiple pressure systems and coexist high and low pressures, making differential pressure sticking a common occurrence during actual drilling operations. In particular, rock fragments frequently fall during drilling, forming hard sticking. If hard sticking is not dealt with promptly, it can easily lead to adhesive sticking, resulting in a combined sticking caused by rock fragments and differential pressure adhesion.

[0003] Current treatments for complex stuck drill bits only involve soaking in a release fluid or hydrochloric acid. While soaking in a release fluid can resolve pressure differential adhesion issues, it cannot effectively remove hard stuck drill bits. Soaking in hydrochloric acid can remove hard stuck drill bits, but its effectiveness is greatly affected by factors such as acid concentration, soaking volume, soaking time, and operating pressure. Furthermore, prolonged soaking can exacerbate well leakage, and soaking failure increases well control risks. Therefore, due to the limitations of conventional release fluids and acid solutions for treating stuck drill bits, they are no longer sufficient to meet the needs of removing complex stuck drill bits in the Sichuan-Chongqing region.

[0004] To better handle complex stuck drill bits, existing technologies have proposed a two-liquid unsticking agent using hydrochloric acid and oil-based unsticking fluid. Practical application has shown that this two-liquid unsticking agent can effectively handle complex stuck drill bits. However, in practical applications, the inventors also discovered a technical problem that cannot be effectively solved: cross-contamination between the hydrochloric acid unsticking fluid, oil-based unsticking fluid, and drilling fluid. This is especially true in large wellbores with a diameter of 311.2 mm or more, where the large contact area between the various liquids leads to increased cross-contamination, affecting not only the unsticking time and effectiveness but also prolonging troubleshooting time and increasing drilling costs. Summary of the Invention

[0005] To overcome the aforementioned problems in the prior art, this invention provides a separation fluid, a preparation method, and a method for unblocking stuck drill bits in composite treatment. This separation fluid can create an enhanced isolation effect between oil-based unblocking fluid, hydrochloric acid unblocking fluid, and drilling fluid, and effectively reduce cross-contamination between these fluids. This allows the dual-fluid unblocking agent to effectively exert its unblocking properties, thereby shortening the unblocking time, improving the unblocking effect, and reducing drilling costs.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] In a first aspect, the present invention provides a separating fluid for composite stuck drill bit treatment, comprising the following components in the following mass ratio:

[0008]

[0009]

[0010] The density of the isolation fluid is 0.9–1.5 g / cm³. 3 Furthermore, the density of the isolation fluid is adjusted by adding barite powder.

[0011] The stabilizer is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide.

[0012] The emulsifier is sorbitan oleate.

[0013] The penetrant is one of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, or a mixture of two in any proportion.

[0014] The solid defoamer is aluminum stearate.

[0015] The oil phase is diesel oil, white oil, solvent oil, or kerosene.

[0016] Secondly, the present invention provides a method for preparing an isolation liquid, the preparation process of which is as follows: first, an oil phase is added to a mixer, then a stabilizer, an emulsifier, a penetrant, calcium oxide, a solid defoamer and barite powder are added respectively, and then the mixture is stirred at a speed of 10000 r / min for at least 10 min. After stirring evenly, a large volume of isolation liquid is obtained.

[0017] Thirdly, the present invention provides a method for unblocking based on a sealing fluid, which is a basic immersion unblocking method. The unblocking process is as follows: during the drilling process, a pre-sealing sealing fluid, a hydrochloric acid unblocking fluid, a post-sealing sealing fluid, and an oil-based unblocking fluid are pumped in sequence.

[0018] Fourthly, the present invention provides a method for unblocking based on a release fluid. This unblocking method is a two-stage injection and replacement unblocking method. The unblocking process is as follows: during the drilling process, a pre-sealing release fluid, an oil-based unblocking fluid, an intermediate release fluid, a hydrochloric acid unblocking fluid, and a post-sealing release fluid are pumped in sequence.

[0019] Fifthly, the present invention provides a method for unblocking based on a release fluid. This unblocking method is a three-stage injection and replacement unblocking method. The unblocking process is as follows: during the drilling process, a pre-sealing release fluid, an oil-based unblocking fluid, an intermediate release fluid, a hydrochloric acid unblocking fluid, another intermediate release fluid, an oil-based unblocking fluid, and a post-sealing release fluid are pumped in sequence.

[0020] The advantages of using this invention are:

[0021] 1. The isolation fluid of this invention comprises multiple components in specific proportions. The oil phase serves as the base fluid; the stabilizer provides suspension and weighting; the emulsifier ensures uniform mixing of all components; the solid defoamer eliminates air bubbles generated during preparation; the penetrant enhances compatibility with the unblocking agent; the calcium oxide reduces the impact of small amounts of water mixed into the isolation fluid on its overall performance; and barite powder adjusts the density. This invention, using the isolation fluid prepared from the aforementioned components, creates an enhanced isolation effect between the oil-based unblocking fluid, the hydrochloric acid unblocking fluid, and the drilling fluid. It also effectively reduces cross-contamination between these fluids, allowing the dual-fluid unblocking agent to effectively exert its unblocking properties. This results in advantages such as shorter unblocking time, improved unblocking effect, and reduced drilling costs.

[0022] 2. This invention is suitable for forming various forms of two-component unblocking agents, which can effectively utilize the characteristics of the two-component system, allowing for thorough mutual immersion to achieve rapid and efficient unblocking, and is conducive to promoting the technological advancement of different two-component unblocking agents.

[0023] 3. This invention relies on the role of front and rear sealing and isolation fluids to effectively isolate residual acid from drilling fluid.

[0024] 4. The sealing and isolating fluid of the present invention can form a gas-trapping plug in the annulus, which can further prevent the acidic gas generated during acid soaking from rising, and greatly reduce the pollution of drilling fluid by secondary acidic gas.

[0025] 5. The formulation of this invention is based on oil-based card unlocking solution, and has good compatibility with oil-based card unlocking solution, as well as better economy and lower cost. Attached Figure Description

[0026] Figure 1 This is a graph showing the stuck drill situation in Example 7;

[0027] Figure 2 This is a graph of the vertically moving drill string in Example 7;

[0028] Figure 3 This is a graph showing the first injection of the card in Example 7;

[0029] Figure 4 This is a graph showing the first dissolution of the card in Example 7;

[0030] Figure 5 This is a graph showing the fracture of the drill bit body in Example 7;

[0031] Figure 6 This is a graph showing the changes made to the fish head in Example 7;

[0032] Figure 7This is a graph showing the connection of the drill string in Example 7;

[0033] Figure 8 This is a graph showing the second injection of the card in Example 7;

[0034] Figure 9 This is a graph showing the second dissolution of the card in Example 7;

[0035] Figure 10 This is a graph showing the injection of the two-component anti-card agent in Example 7;

[0036] Figure 11 The graph (a) shows the active card unlocking process in Example 7;

[0037] Figure 12 This is a graph (II) showing the active card unlocking process in Example 7. Detailed Implementation

[0038] Example 1

[0039] This embodiment provides a release fluid for composite stuck drill bit treatment, comprising the following components in the following mass ratio:

[0040]

[0041] In this embodiment, the density of the isolation fluid is 1.2 g / cm³. 3 This density is obtained by adding barite powder, at a rate of 1 m³ / m³. 3 The isolation fluid contains approximately 0.5 tons of barite powder.

[0042] Specifically, the stabilizer mentioned above is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide, which has the function of suspending and increasing the weight of the isolation liquid.

[0043] The emulsifier mentioned above is sorbitan oleate, which has the function of making the components mix evenly.

[0044] The aforementioned penetrant is a fatty alcohol polyoxyethylene ether, which enhances the compatibility with the card-unblocking agent.

[0045] The aforementioned solid defoamer is aluminum stearate, which has the function of eliminating bubbles generated during the preparation process.

[0046] The oil phase described above is kerosene.

[0047] Example 2

[0048] This embodiment provides a release fluid for composite stuck drill bit treatment, comprising the following components in the following mass ratio:

[0049]

[0050] In this embodiment, the density of the isolation fluid is 0.9 g / cm³. 3 This density is obtained by adding barite powder, at a rate of 1 m³ / m³. 3 The isolation fluid contains approximately 0.1 tons of barite powder.

[0051] Specifically, the stabilizer mentioned above is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide, which has the function of suspending and increasing the weight of the isolation liquid.

[0052] The emulsifier mentioned above is sorbitan oleate, which has the function of making the components mix evenly.

[0053] The aforementioned penetrant is an alkylphenol polyoxyethylene ether, which enhances the compatibility with the card-unblocking agent.

[0054] The aforementioned solid defoamer is aluminum stearate, which has the function of eliminating bubbles generated during the preparation process.

[0055] The oil phase described above is white oil or kerosene.

[0056] Example 3

[0057] This embodiment provides a release fluid for composite stuck drill bit treatment, comprising the following components in the following mass ratio:

[0058]

[0059] In this embodiment, the density of the isolation fluid is 1.5 g / cm³. 3 This density is obtained by adding barite powder, at a rate of 1 m³ / m³. 3 The isolation fluid contains approximately 1 ton of barite powder.

[0060] Specifically, the stabilizer mentioned above is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide, which has the function of suspending and increasing the weight of the isolation liquid.

[0061] The emulsifier mentioned above is sorbitan oleate, which has the function of making the components mix evenly.

[0062] The aforementioned penetrant is a fatty alcohol polyoxyethylene ether, which enhances the compatibility with the card-unblocking agent.

[0063] The aforementioned solid defoamer is aluminum stearate, which has the function of eliminating bubbles generated during the preparation process.

[0064] The oil phase described above is diesel oil.

[0065] Example 4

[0066] This embodiment provides a release fluid for composite stuck drill bit treatment, comprising the following components in the following mass ratio:

[0067]

[0068] In this embodiment, the density of the isolation fluid is 1.4 g / cm³. 3 This density is obtained by adding barite powder, at a rate of 1 m³ / m³. 3 The isolation fluid contains approximately 0.8 tons of barite powder.

[0069] Specifically, the stabilizer mentioned above is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide, which has the function of suspending and increasing the weight of the isolation liquid.

[0070] The emulsifier mentioned above is sorbitan oleate, which has the function of making the components mix evenly.

[0071] The above-mentioned penetrants are two types of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether mixed in any proportion, which have the function of enhancing compatibility with the card-unblocking agent.

[0072] The aforementioned solid defoamer is aluminum stearate, which has the function of eliminating bubbles generated during the preparation process.

[0073] The oil phase described above is a solvent oil.

[0074] Example 5

[0075] This embodiment provides a method for preparing the isolation liquid described in any of the embodiments 1-4. The preparation process is as follows: first, the oil phase is added to a mixer, and then stabilizer, emulsifier, penetrant, calcium oxide, solid defoamer and barite powder are added respectively. Then, the mixture is stirred at a speed of 10000 r / min for at least 10 min. After stirring evenly, a large volume of isolation liquid is obtained.

[0076] Example 6

[0077] This embodiment provides a method for unblocking the isolation fluid described in any of the embodiments 1-4. The method includes a basic immersion unblocking method, a two-stage replacement unblocking method, and a three-stage replacement unblocking method. The specific unblocking process for each method is as follows:

[0078] The basic immersion method for unsticking involves sequentially pumping in pre-sealing fluid, hydrochloric acid unsticking fluid, post-sealing fluid, and oil-based unsticking fluid during drilling. This method is primarily used for composite stuck drill bits where the upper part is hard stuck and the lower part is stuck due to pressure differential adhesion.

[0079] The two-stage injection-displacement method for unsticking involves sequentially pumping in pre-sealing fluid, oil-based unsticking fluid, intermediate sealing fluid, hydrochloric acid unsticking fluid, and post-sealing fluid during drilling. This two-stage injection-displacement method is primarily used for composite stuck drills where the lower part is hard stuck and the upper part is stuck due to pressure differential adhesion.

[0080] The three-stage injection-displacement method for unsticking drill bits involves sequentially pumping in pre-sealing fluid, oil-based unsticking fluid, intermediate sealing fluid, hydrochloric acid unsticking fluid, intermediate sealing fluid again, oil-based unsticking fluid, and post-sealing fluid. This three-stage injection-displacement method is primarily used for composite stuck drill bits where the upper part is pressure differential adhesion, the middle part is hard stuck, and the lower part is pressure differential adhesion.

[0081] Example 7

[0082] During the research of this invention, a stuck drill bit occurred during the drilling and surveying of the Qixia Formation in the Weiyuan shale gas well Wei 204H96-3. (During the surveying process, a block fell off, causing the central stabilizer to become stuck in the middle. This was not released in time, leading to subsequent stuck drill bits on the upper drill collar, the lower non-magnetic part, and the screw due to pressure differential adhesion). Two initial attempts to soak the drill bit with an unblocking agent failed. After a field test using a two-liquid unblocking agent (the three-stage injection method in Example 6), the stuck drill bit was successfully unblocked after soaking for 4 hours. The specific process is as follows:

[0083] 1. Fault Occurrence Process

[0084] On July 22, 2023, from 08:00 to 20:00, well Wei 204H96-3 was drilled to a depth of 3150.00m during the second phase of drilling; from 20:00 to 20:08, it was pulled up to a depth of 3147.09m (pump stopped for inclination measurement from 20:05 to 20:08); from 20:08 to 20:12, the drilling fluid was circulated at a flow rate of 2904-3380 L / min and a vertical pressure of 24.5-25.5 MPa. The top drive was rotated, but it was found to have stalled and the drill string was stuck; from 20:12 to 20:24, the drill string was circulated, and the drill string was moved up and down. The original suspended weight was 1500 KN, and the moving suspended weight was 900-1900 KN, with a flow rate of 2904-3380 L / min and a vertical pressure of 24.5-25.5 MPa. Figure 1 As shown, the card is not unlocked.

[0085] 2. Strategy for handling stuck drills

[0086] (1) Active shock → foaming unblocking agent → two-liquid unblocking agent.

[0087] 3. Processing procedure

[0088] 3.1 Active Shock

[0089] From 20:24 to 23:10 on July 22nd, the drill string was circulated and processed to remove stuck drill bits. The displacement was 2904-3380 L / min, the vertical pressure was 24.5-25.5 MPa, and the intermittent torque was 30000↑42000 kN.m. The drill string was moved up and down. Figure 2As shown, the suspended weight range is 500-2400KN, and the tool is not released; the drill string moves up and down, and when it is vibrated upwards, the suspended weight range is 300-2800KN, and the tool is not released; the displacement is 2904-3380L / min, and the vertical pressure is 24.5-25.5MPa. From 23:10 to 01:50 on July 23, the drill string was circulated to handle stuck drill bits, with a displacement of 3360-3368 L / min, a vertical pressure of 23.5-24.5 MPa, and a torque of 34000 kN.m. The drill string was moved up and down every 20 minutes, with a suspended weight range of 1000-1800 kN. From 01:50 to 08:00, the drill string was circulated to handle stuck drill bits, with a displacement of 3360-3368 L / min, a vertical pressure of 23.5-24.5 MPa, and a torque of 34000 kN.m. The drill string was moved up and down every hour, with a suspended weight range of 500-1800 kN (cleaning the circulation tank and preparing the unsticking agent).

[0090] 3.2 First soaking with anti-card agent

[0091] From 08:00 to 14:00 on July 23, the density decreased by 1.83 g / cm³. 3 Prepare unsticking agent; vertical pressure: 13.0~23.5MPa; displacement: 2460~3360L / min; 14:00~17:15 connect to the ground shock absorber and plug valve, move the drill string up and down (prepared with unsticking agent); 17:15~17:35 inject at a density of 1.38g / cm³. 3 Unblocking agent 21m 3 ,like Figure 3 As shown; the displacement density was 1.78 g / cm³ from 17:35 to 17:55. 3 Drilling fluid 22.3m 3 From 17:55 to 19:30, the vibratory impactor was activated 14 times, with an impact tonnage of 25-150T and an intermittent torque of 30KN·m, moving the drill string up and down; from 19:30 to 20:10, the vibratory impactor was emptied from the ground; from 20:10 to 23:30, the intermittent torque of 40KN·m was applied, moving the drill string up and down, with a suspended weight range of 30-170t. After every 30 minutes of movement, the torque was released, and the vibratory impactor was activated 10 times. 23:30~00:30 Connect the new ground shock device; 00:30~03:30 Intermittently hold the torque at 30KN·m, move the drill string up and down, with a suspended weight range of 30-170t. After every 30 minutes of movement, release the torque and start the ground shock device to strike 10 times; 03:30~08:00 Intermittently hold the torque at 30KN·m, move the drill string up and down, with a suspended weight range of 30-170t. After every 30 minutes of movement, release the torque and start the drilling shock device to strike 10 times.

[0092] July 24, 2023, 08:00-08:40: Surface shock device removed; 08:40-15:00: Intermittently maintain torque of 40-45 KN.m, move drill string up and down, suspended weight range 30-220t, each time the shock device is started, it strikes down 3 times and up once; 15:00-17:20: Intermittently maintain torque of 40 KN.m, move drill string up and down, suspended weight range 30-200t, each time the shock device is started, it strikes down 5 times and up once; 17:20-19:00: Circulate and remove stuck material, such as... Figure 4 As shown; stand pressure: 6.9~18.0MPa, displacement 1740~2850L / min; 19:00~20:09 circulate drilling fluid, move drill string up and down, suspended weight range 30-280t, start the drilling shock absorber to strike 10 times, pull up to well depth 3140.95m, and find that the suspended weight decreased from 1722KN↓263KN; 20:09~21:00 check the surface equipment and drill string, and find that the drill pipe broke in the middle of the body, as Figure 5 As shown; 2 drill pipes with a diameter of 139.7mm each + half a pipe = 24.96m were pulled out (the well depth at the top of the fish is 13.29m), and the total length of the fish that fell was 3136.71m.

[0093] Fishing structure: 311.2mm PDC drill bit × 0.28m + 244.5mm 1.25° bent screw 308 support × 9.45m + 228mm return screw × 0.57m + 228.6mm non-magnetic screw × 9.26m + 228.6mm directional joint × 0.97m + 306mm centralizer × 1.28m + 731×630 adapter × 0.48m + 9 drill collars × 79.64m + 203.2mm tremie drill × 9.60m + DS631×DS520 adapter × 0.47m + 6 heavy-duty drill pipes × 56.39m + 309 drill pipes × 2964.54m + half a pipe × 3.78m = 3136.71m.

[0094] 3.3 Salvaging drilling tools and reducing density

[0095] From 21:00 to 21:40 on July 24th, the damaged drill pipe was removed, and the fishing tools were assembled. From 21:40 to 22:10, the drill string was lowered to a depth of 10m, and the pump was turned on to probe for the top of the fish. The pump was used at 62 strokes. The drill string was lowered to a depth of 13.29m, and the top of the fish was found. The suspended weight was 300KN - 250KN. The torque was set at 45KN.m. Repeated attempts to create a connection were made, but the fishing attempt was unsuccessful. From 22:10 to 23:50, the fishing tools were inspected and repaired. From 23:50 to 00:00 on July 25th, the drill string was lowered to a depth of 13.29m to probe for the top of the fish. The rotation speed was 15r / min, and the suspended weight was 300KN - 250KN. From 00:00 to 01:00, the torque was set at 48KN.m. Repeated attempts to create a connection were made. The drilling pressure was 50KN, the rotation speed was 10-20r / min, and the suspended weight increased to 1450KN. The fish was captured. The suspended weight was reversed at 700KN. Figure 6 As shown; retrieve the fish; from 01:00 to 02:00, drill down for coupling, gradually setting the torque to 48KN.m, the suspended weight from 700KN to 1450KN, gradually starting the pump, pump pressure from 2.4MPa to 20.5MPa, coupling successful, as shown. Figure 7 As shown; density decreased cyclically from 02:00 to 08:00, density 1.78↓1.75 g / cm³ 3 The torque of the moving drill bit is 40 kN.m every 30 minutes, the suspended weight range is 30-180 t, the vertical pressure is 19.8~20.5 MPa, and the displacement is 2700~2780 L / min.

[0096] 3.4 Second soaking with anti-card agent

[0097] July 25th, 08:00–16:40: Circulation (preparation of unsticking agent), drilling tool movement every 30 minutes, suspended weight range 50-200t, vertical pressure: 7.6–18.6MPa, displacement 1617–2804L / min; 16:40–17:05: Injection density 1.40g / cm³ 3 Unblocking agent 21.0m 3 ,like Figure 8 As shown; the displacement density was 1.73 g / cm³ from 17:05 to 17:15. 3 Drilling fluid 22.9m 3 ; 17:15~18:40 Intermittently apply a torque of 40KN·m, moving up and down once every 10-15 minutes, with a suspended weight range of 35-200t; 18:40~20:00 Inspect the equipment (wire rope, brake, slide rail); 20:00~08:00 on July 26th Intermittently apply a torque of 40KN·m, vibrating once every 10 minutes, with a suspended weight range of 35-200t.

[0098] On July 26th, from 08:00 to 10:00, intermittently apply a torque of 40 kN·m, with a vibration every 10 minutes; the suspended weight range is 35-200 t. From 10:00 to 19:00, reverse the main rope. From 19:00 to 21:20, circulate and remove the stuck agent. Figure 9 As shown, adjust the mud properties: vertical pressure: 12.7~20.1MPa, discharge rate: 1920~2980L / min.

[0099] 3.5 Immersion in two-component anti-card solution

[0100] From 21:20 to 21:30 on July 26, a 700-type fracturing truck was used to inject 2.5m of pre-positioning sealing fluid. 3 ; Pumping density 1.52 g / cm³ from 21:30 to 21:35 3 Card release solution 5ml 3 Vertical pressure 6.3–6.7 MPa, displacement 1675–1690 L / min; 2.0 m³ of spacer fluid was injected using a 700-type fracturing truck from 21:35 to 21:40. 3 Displacement 250-400 L / min; 21:40-22:25, inject 16m³ of 24% hydrochloric acid using a 700-type fracturing truck. 3 Displacement 250-400 L / min; 22:25-22:30, inject 2.0 m³ of spacer fluid using a 700-type fracturing truck. 3 ; Pumping density 1.52 g / cm³ from 22:30 to 20:40 3 Oil-based card unlocking solution 12ml 3 Vertical pressure 19.2–20.4 MPa, displacement 1720–1833 L / min; 22:40–22:45, inject 1.5 m of post-fracturing sealing fluid using a 700-type fracturing truck. 3 ; 9.6m of well slurry was pumped in between 22:45 and 23:00 3 ,like Figure 10 As shown, the vertical pressure was 20.5–22.5 MPa, and the displacement was 1889–1901 L / min; from 23:00 to 03:00 on July 27th, the torque was intermittently applied at 40 kN.m, with a suspended weight range of 40–180 kN, and the drill string was moved up and down every 5 minutes; the torque was released, and the suspended weight range was 40–200 kN; from 03:00 to 03:15, the drill string was lifted, and the suspended weight was reduced to 2800 × 1478 kN, successfully freeing the drill string. Figure 11 , 12 As shown.

[0101] As can be seen from the above process, the present invention can effectively utilize the characteristics of the two-component card-unlocking agent, allowing them to fully soak into each other, thus achieving the purpose of rapid and efficient card unlocking.

[0102] Comparative Example 1

[0103] This comparative example, with the stabilizer removed, conducted high-temperature rheological tests on the isolation fluids of Examples 1-4. The experimental results showed that, except for the isolation fluid system of Example 1 which was normal, the isolation fluid systems of Examples 2-4 all exhibited stratification and were not homogeneous, making them unusable.

[0104] Comparative Example 2

[0105] This comparative example, with the emulsifier removed, conducted indoor compatibility evaluation experiments and pollution evaluation experiments on the isolation solutions of Examples 1-4, respectively.

[0106] The results of the compatibility evaluation test in the laboratory showed that the isolation fluid systems in Examples 1-4 were not homogeneous and all exhibited phase separation, making them unsuitable for application.

[0107] The pollution assessment experiment used potassium polysulfone drilling fluid and isolation fluid for pollution assessment. The experimental data are shown in the table below:

[0108]

[0109] The experimental results show that the isolation fluid system in Example 1 has good fluidity under different pollution ratios and its effect is the best, while the isolation fluid systems in Examples 2-4 are slightly inferior.

[0110] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All features or steps in the disclosed methods or processes may be combined in any way, except for mutually exclusive features and / or steps.

Claims

1. A separating fluid for handling composite stuck drill bits, characterized in that, The components include the following mass ratios: The density of the isolation fluid is 0.9–1.5 g / cm³. 3 Furthermore, the density of the isolation fluid is adjusted by adding barite powder.

2. The isolation fluid for composite stuck drill bit treatment according to claim 1, characterized in that: The stabilizer is an organic clay formed by modifying bentonite with hexadecyltrimethylammonium bromide.

3. The isolation fluid for composite stuck drill bit treatment according to claim 1, characterized in that: The emulsifier is sorbitan oleate.

4. The isolation fluid for composite stuck drill bit treatment according to claim 1, characterized in that: The penetrant is one of fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether, or a mixture of two in any proportion.

5. The isolation fluid for composite stuck drill bit treatment according to claim 1, characterized in that: The solid defoamer is aluminum stearate.

6. The isolation fluid for composite stuck drill bit treatment according to claim 1, characterized in that: The oil phase is diesel oil, white oil, solvent oil, or kerosene.

7. A method for preparing the isolation liquid according to any one of claims 1-6, characterized in that, The preparation process is as follows: first, add the oil phase into the mixer, then add the stabilizer, emulsifier, penetrant, calcium oxide, solid defoamer and barite powder respectively, and then stir at a speed of 10000r / min for at least 10min. After stirring evenly, a large volume of isolation liquid is obtained.

8. A method for releasing the isolation liquid according to any one of claims 1-6, wherein the method is a basic immersion release method, characterized in that, The unblocking process is as follows: during drilling, pre-sealing isolation fluid, hydrochloric acid unblocking fluid, post-sealing isolation fluid, and oil-based unblocking fluid are pumped in sequence.

9. A method for releasing the isolation fluid according to any one of claims 1-6, wherein the method is a two-stage injection-displacement method, characterized in that, The unblocking process is as follows: during drilling, pre-sealing fluid, oil-based unblocking fluid, intermediate sealing fluid, hydrochloric acid unblocking fluid, and post-sealing fluid are pumped in sequence.

10. A method for releasing the isolation fluid according to any one of claims 1-6, wherein the method is a three-stage injection-displacement method, characterized in that, The unblocking process is as follows: during drilling, the pre-sealing fluid, oil-based unblocking fluid, intermediate sealing fluid, hydrochloric acid unblocking fluid, intermediate sealing fluid, oil-based unblocking fluid, and post-sealing fluid are pumped in sequence.

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