Process method for blocking top water channeling horizontal well in heavy oil reservoir

Abstract

The invention belongs to the field of oil exploitation, and discloses a process method for blocking top water channeling of a horizontal well in a heavy oil reservoir, which comprises the following steps of: confirming the position of a branch well according to a comprehensive logging actual drilling trajectory tracking map ROP, drilling data and an oil reservoir profile map of the horizontal well; 3-50 thousand standard cubic meters of nitrogen is positively injected, a front slug is formed, a water body is pushed to the far end, a branch well hole is kept unblocked, and a plugging agent is guided to enter a water channeling channel; the delayed curing plugging agent is injected into the stratum to form a main slug, large-dose injection is achieved, and a water channeling channel is effectively plugged; the inorganic curing plugging agent is injected into the stratum to form a sealing slug, and the strength of the plugging agent is enough to plug steam channeling and water channeling; drilling and grinding the horizontal well until the horizontal well is drilled and ground to the position of a branch well hole, and testing the pressure; if the test is qualified, continuing to implement the next branch borehole; drilling, grinding and washing are continuously conducted on the remaining interval of the horizontal well, and the plugging agent in the well is completely washed away; the device effectively blocks a top water channeling channel, shields top water, and improves the production effect of the horizontal well and the surrounding adjacent well.

Description

Technical Field

[0001] The invention belongs to the field of oil production and relates to a process for plugging underwater channeling wells, and in particular to a process for plugging underwater channeling horizontal wells in heavy oil reservoirs. Background Art

[0002] The Liaohe Oilfield primarily develops heavy oil. Horizontal heavy oil wells, with their advantages of long production sections, large drainage areas, and high controlled reserves, have become a key focus for increasing reserve utilization and playing a crucial role in Liaohe's current and future stable production of tens of millions of tons. Due to trajectory deviations during drilling, the actual wellbore trajectories of some horizontal wells differ from the designed wellbore trajectories. Furthermore, the presence of lateral wellbores can easily lead to the drilling of the top water layer of the production zone, allowing topwater to flow down through the lateral wellbores into the production zone, leading to flooding of the horizontal wells and surrounding adjacent wells.

[0003] Currently, ash extrusion is the common method for plugging underwater channeling in horizontal wells. However, this method suffers from a small treatment radius (slurry setting time <8 hours, treatment radius <0.5m), poor plugging effectiveness (slurry is prone to leakage), and a short plugging period. Furthermore, after ash extrusion plugging, the horizontal well cannot be opened. Therefore, a new method for plugging underwater channeling in horizontal wells is urgently needed to meet field needs. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a process for sealing horizontal wells with top water in heavy oil reservoirs, which can effectively seal branch wellbores, shield top water, and improve the production effect of horizontal wells and surrounding adjacent wells.

[0005] In order to achieve the above object, the present invention provides a process for plugging underwater channeling horizontal wells in heavy oil reservoirs, which comprises the following steps:

[0006] S1: Confirm the location of the branch wellbore based on the horizontal well's comprehensive logging drilling trajectory tracking map ROP, drilling data, reservoir profile and other information;

[0007] S2: Inject 30,000-50,000 standard cubic meters of nitrogen to form a front slug, push the water to the far end, keep the branch wellbore open, and guide the plugging agent into the water channel;

[0008] S3: Injecting the delayed curing plugging agent into the formation to form the main slug, which can achieve large-dose injection and effectively block the water channel;

[0009] The mass percentage of the solidifying plugging agent is:

[0010] Water-soluble polymer 1.5-2.8% (partially cross-linked polyacrylic acid, carboxymethyl cellulose, etc.)

[0011] Cross-linking agent: 0.2-0.5% (epoxy resin, amino resin, etc.)

[0012] Anti-filtering agent: 3-8% (dextrin, cellulose ether, etc.)

[0013] High temperature resistance agent: 1-5% (silica sol, diatomaceous earth, etc.)

[0014] Coagulant: 1-3% (ammonium persulfate, aluminum chloride, etc.)

[0015] Retarder: 0.2-1% (citric acid, acetic acid, etc.)

[0016] The rest is water.

[0017] The water-soluble polymer primarily swells in water to form a gel system. The crosslinker primarily crosslinks with the water-soluble polymer to enhance the gel's strength. The anti-filtration agent enhances the gel's resistance to filtration, preventing solid particles from filtering through it. The anti-high-temperature agent improves the gel's thermal stability. The coagulant accelerates the gel's setting speed, and the retarder controls and delays the gel's setting time.

[0018] S4: Inorganic solidifying plugging agent is injected into the formation to form a sealing segment plug. The plugging agent is strong enough to block steam and water channeling.

[0019] The mass percentage of the inorganic solidifying plugging agent is:

[0020] Aluminosilicate: 5-15%,

[0021] Gelling material: 2-5% (polyacrylamide, acrylic resin, polyacrylic acid, etc.),

[0022] Cross-linking agent: 3-8% (epoxy resin, amino resin, polyurethane, etc.),

[0023] Filler: 5-10% (fly ash, silica powder, calcium powder, etc.),

[0024] Thickener: 2-5% (glycidyl acrylate, vinyl acetate, etc.),

[0025] High temperature resistance agent: 2-6% (silica sol, ceramic microspheres, etc.),

[0026] Coagulant: 1-3% (ammonium nitrate, calcium chloride, etc.)

[0027] Retarder: 0.5-2% (sodium acetate, citric acid, etc.)

[0028] The rest is water.

[0029] This formula uses aluminosilicate as the primary filler, polyacrylamide as the gelling material to form the gel network structure, epoxy resin as a crosslinking agent to enhance structural strength, fly ash as an auxiliary filler to adjust performance, acrylic acid glycidyl ether as a thickener to increase the consistency of the plugging agent, silica sol to improve the plugging agent's high-temperature resistance, and ammonium nitrate and sodium acetate as a coagulant and retarder, respectively, to control gelation time. This formula can form an inorganic curing gel plugging agent that is resistant to high temperatures and has high strength.

[0030] S5: Drill the horizontal well until the branch wellbore is reached and perform pressure testing;

[0031] S6: If the test is qualified, continue to S5 for the next branch wellbore; if the test is unqualified, re-implement S3-S5 until all branch wellbore pressure tests are qualified;

[0032] S7: Continue drilling, grinding and flushing the remaining layers of the horizontal well to completely flush out the plugging agent in the well;

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] This invention provides a method for plugging topwater channeling in horizontal wells in heavy oil reservoirs. By implementing a combined plugging process, it effectively blocks topwater channeling, shields the topwater, and improves the production performance of the horizontal well and surrounding adjacent wells. This process offers advantages such as simple construction, a large treatment radius, good plugging effectiveness, and a long-term effectiveness. DETAILED DESCRIPTION

[0035] The present invention is implemented in the following examples. Unless otherwise specified, the experimental methods used in the present invention are conventional methods, and the experimental equipment, materials, reagents, etc. used can be obtained from commercial channels.

[0036] Example 1

[0037] For example, well Du 813-H2107 normally produced 18.1 tons of liquid and 10.7 tons of oil per day, with a water cut of 40.9%. After water production, the well's daily liquid production dropped to 28.9 tons, oil production to 0.5 tons, and water cut to 98.3%. Three neighboring wells, Du 813-40-55, Du 813-41-56, and Du 813-H217, were also affected, with daily oil production dropping by 33.7 tons and water cut rising by 37%. The annual production of the four wells in this well group was affected by 16,000 tons. This demonstrates that after this horizontal well was flooded, not only was normal production at the well itself halted, resulting in essentially ineffective water production, but the three other wells within the group were also affected by the water production, significantly reducing their daily oil production.

[0038] Investigation and analysis revealed that the well was experiencing topwater channeling due to trajectory deviation during drilling. To address this issue, a combined water plugging process was implemented on Well Du 813-H2107 to block topwater channeling.

[0039] 1. By analyzing the wellbore trajectory map and logging data of Du 813-H2107 well, it was confirmed that there was a branch wellbore at the 816th meter.

[0040] 2. 40,000 standard cubic meters of nitrogen are being injected into the Du 813-H2107 well to form a slug, push water to the far end, and keep the branch wellbore unobstructed.

[0041] 3. Prepare for a 500m run 3 Delayed curing plugging agent, mass percentage composition is:

[0042] (1) Water-soluble polymer: 2%

[0043] (2) Cross-linking agent: 0.3%

[0044] (3) Anti-filter agent: 5%

[0045] (4) Anti-high temperature agent: 3%

[0046] (5) Coagulant: 2%

[0047] (6) Retarder: 0.5%

[0048] (7) Water: balance

[0049] The plugging agent is slowly injected into the formation to form a main segment plug to block the water channel. The specific configuration method is:

[0050] (1) Prepare a certain volume of water, add a stirring device, and start stirring slowly;

[0051] (2) dissolving the anti-filtration agent, anti-high temperature agent, coagulant and retarder in water in sequence;

[0052] (3) Add the water-soluble polymer and continue stirring until it is completely dissolved; finally, add the cross-linking agent and control the stirring speed to ensure thorough mixing;

[0053] (4) The prepared plugging agent is allowed to stand for 20 minutes and then injected into the well after quality inspection.

[0054] 4. Prepare for the 100m 3 Inorganic solidifying plugging agent, mass percentage composition is:

[0055] (1) Aluminosilicate: 10%

[0056] (2) Cementitious material: 3%

[0057] (3) Cross-linking agent: 5%

[0058] (4) Filler: 8%

[0059] (5) Thickener: 3%

[0060] (6) Anti-high temperature agent: 4%

[0061] (7) Coagulant: 2%

[0062] (8) Retarder: 1%

[0063] (9) Water: Remainder

[0064] Inject the plugging agent into the formation to form a sealing segment plug. The specific configuration method is:

[0065] (1) Prepare a certain volume of water and place it in a stirring container;

[0066] (2) Dissolve the filler, high temperature resistance agent and thickener into water in sequence and stir;

[0067] (3) Add the gelling material and coagulant and continue to stir rapidly for 5 minutes to fully dissolve;

[0068] (4) Reduce the stirring speed and slowly add the crosslinking agent to ensure uniform mixing;

[0069] (5) Finally, add the retarder and stir evenly at a low speed;

[0070] (6) After stirring, the plugging agent can be used after standing for 30 minutes.

[0071] 5. Use the drill bit to drill the Du 813-H2107 well until it reaches the branch wellbore position at 816 meters.

[0072] 6. Conduct pressure test on branch wellbore location and the result is qualified.

[0073] 7. Continue drilling and cleaning the remaining layers of Well Du 813-H2107 to completely flush out the plugging agent.

[0074] Through the above steps, the topwater channeling plugging process was successfully implemented in Well Du 813-H2107. Following the measures, the well's daily liquid production reached 20.1 tons, daily oil production reached 10.1 tons, and a water cut of 49.8%. Simultaneously, three neighboring wells—Du 813-40-55, Du 813-41-56, and Du 813-H217—increased their daily oil production by 29.9 tons and reduced their water cut by 35.9%, effectively improving the well group's development performance.

[0075] The above is a schematic description of the present invention and its embodiments. This description is not restrictive and only illustrates one embodiment of the present invention. The actual structure is not limited thereto. Therefore, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without creatively designing them, they shall fall within the scope of protection of the present invention.

Claims

1. A process for plugging underwater channeling horizontal wells in heavy oil reservoirs, characterized in that: The following steps are involved: S1: Confirm the location of the branch wellbore based on the horizontal well's comprehensive logging drilling trajectory tracking map ROP, drilling data, and reservoir profile; S2: Inject 30,000-50,000 standard cubic meters of nitrogen to form a front slug, push the water to the far end, keep the branch wellbore open, and guide the plugging agent into the water channel; S3: Injecting the delayed curing plugging agent into the formation to form the main slug, which can achieve large-dose injection and effectively block the water channel; S4: Inorganic solidifying plugging agent is injected into the formation to form a sealing segment plug. The plugging agent is strong enough to block steam and water channeling. S5: Drill the horizontal well until the branch wellbore is reached and perform pressure testing; S6: If the test is qualified, continue to S5 for the next branch wellbore; if the test is unqualified, re-implement S3-S5 until all branch wellbore pressure tests are qualified; S7: Continue drilling, grinding and flushing the remaining layers of the horizontal well to completely flush out the plugging agent in the well.

2. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 1 is characterized in that: The mass percentage of the solidifying plugging agent is: water-soluble polymer 1.5-2.8%, cross-linking agent: 0.2-0.5%, anti-filtration agent: 3-8%, anti-high temperature agent: 1-5%, coagulant: 1-3%, retarder: 0.2-1%, and the rest is water.

3. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 2, characterized in that: Water-soluble polymers include partially cross-linked polyacrylic acid and carboxymethyl cellulose.

4. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 2, characterized in that: Crosslinking agents include epoxy resins and amino resins.

5. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 2, characterized in that: Anti-filtering agents include dextrin and cellulose ether.

6. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 2, characterized in that: High temperature resistant agents include silica sol and diatomaceous earth; coagulants include ammonium persulfate and aluminum chloride; retarders include citric acid and acetic acid.

7. The process for sealing underwater channeling horizontal wells in heavy oil reservoirs according to claim 1, characterized in that: The mass percentage of the inorganic solidifying plugging agent is: Aluminosilicate: 5-15%, gelling material: 2-5%, cross-linking agent: 3-8%, filler: 5-10%, thickener: 2-5%, high temperature resistance agent: 2-6%, coagulant: 1-3%, retarder: 0.5-2%, and the rest is water.

8. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 7, characterized in that: Gelling materials include polyacrylamide, acrylic resin, and polyacrylic acid.

9. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 7, characterized in that: Crosslinking agents include epoxy resins, amino resins, and polyurethanes.

10. The process for plugging underwater channeling horizontal wells in heavy oil reservoirs according to claim 7, characterized in that: Fillers include fly ash, silica powder, and calcium powder; thickeners include acrylic acid glycidyl ether and vinyl acetate; high-temperature resistant agents include silica sol and ceramic microspheres; coagulants include ammonium nitrate and calcium chloride; and retarders include sodium acetate and citric acid.