CN-121991658-A - Water-swelling elastic plugging agent for water-based drilling fluid and preparation method thereof

Abstract

The invention discloses a water-swelling elastic plugging agent for water-based drilling fluid and a preparation method thereof, wherein the plugging agent comprises, by weight, 100 parts of a polyolefin elastomer matrix material, 15-20 parts of a reinforced matrix material, 0.8-1.5 parts of a polyolefin elastomer matrix material cross-linking agent, 8-15 parts of a reinforcing agent A, 20-30 parts of a reinforcing agent B, 15-30 parts of a super absorbent resin, 15-20 parts of a plasticizer, 0.2-0.8 part of a spacer agent and 0.5-1 part of an anti-aging agent.

Inventors

• CHENG KAI
• CHEN MENGYUAN
• LIU ZHIMIN
• HE TAO
• PENG BIQIANG
• HAI BO
• XIAO FENGFENG
• WAN WEI
• LIU MING
• XIE XIANTAO

Assignees

• 中国石油天然气集团有限公司
• 中国石油集团川庆钻探工程有限公司

Dates

Publication Date

20260508

Application Date

20241105

Claims (10)

1. 1. The water-swelling elastic plugging agent for the water-based drilling fluid is characterized by comprising the following components in parts by weight: 100 parts of polyolefin elastomer matrix material; 15-20 parts of reinforced matrix material; 0.8-1.5 parts of cross-linking agent of polyolefin elastomer matrix material; 8-15 parts of reinforcing agent A; 20-30 parts of reinforcing agent B; 15-30 parts of super absorbent resin; 15-20 parts of plasticizer; 0.2 to 0.8 part of release agent; 0.5 to 1 part of anti-aging agent.
2. 2. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 1, wherein the super absorbent resin is prepared by the following steps: s1, sequentially adding a water absorption monomer, a water locking monomer and an initiator into distilled water, stirring at room temperature until the water absorption monomer, the water locking monomer and the initiator are completely dissolved, and bubbling inert gas to remove oxygen to obtain a reaction monomer solution; S2, stirring the reaction monomer solution in the step S1 under the anaerobic condition for reaction for 4-8 hours, wherein the reaction temperature is 40-70 ℃, and drying the water after the reaction and grinding to obtain the super absorbent resin.
3. 3. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 2, wherein the water-absorbing monomer is one or more of sodium acrylate, sodium methacrylate, acrylamide and methacrylamide.
4. 4. The water swelling elastic plugging agent for water-based drilling fluid according to claim 2, wherein the water-locking monomer is one or more of sodium 2-acrylamide-2-methylpropanesulfonate, sodium p-styrenesulfonate, sodium acrylate and sodium methacrylate.
5. 5. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 2, wherein the mass ratio of the water-absorbing monomer to the water-locking monomer to the initiator is 0.2-0.3:0.7-0.8:0.005-0.01, and the total concentration of the reaction monomer solution is 200 g/L-300 g/L.
6. 6. The water-swellable elastic plugging agent for water-based drilling fluids according to claim 1, wherein the polyolefin elastomer matrix material is a styrene-butadiene-styrene block copolymer (SBS), and the reinforcing matrix material is one or more of polypropylene, polystyrene and polycarbonate.
7. 7. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 1, wherein the reinforcing agent A is one or more of white carbon black, carbon black and calcium carbonate, the particle size of the reinforcing agent A is 25-50 μm, the reinforcing agent B is carbon nanotubes, the length of the carbon nanotubes is 20-25 μm, and the length-diameter ratio of the carbon nanotubes is 800:1-1000:1.
8. 8. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 1, wherein the plasticizer is one or more of paraffin oil, aromatic oil and naphthenic oil, and the cross-linking agent of the polyolefin elastomer matrix material is a peroxide cross-linking agent.
9. 9. The water-swelling elastic plugging agent for water-based drilling fluid according to claim 1, wherein the isolating agent is one or more of zinc stearate, polyvinyl alcohol and paraffin wax.
10. 10. A preparation method of the water-swelling elastic plugging agent for water-based drilling fluid is characterized by comprising the following steps of: S11, adding the polyolefin elastomer matrix material and the reinforced matrix material into a high-speed stirrer to stir at a high speed, wherein the rotating speed is 1300-1400 r/min, the temperature is 180-190 ℃, and the time is 2-3 min; S12, after stirring, sequentially adding a cross-linking agent, a reinforcing agent A, a reinforcing agent B, a super absorbent resin, a plasticizer, a release agent and an anti-aging agent into the mixture, and stirring at a high speed, wherein the rotating speed is 1300-1400 r/min, the temperature is 180-190 ℃, and the time is 12-15 min; and S13, sieving out particles with the particle size of 10 meshes to 40 meshes after stirring is finished, namely the water-swelling elastic plugging agent for the water-based drilling fluid.

Description

Water-swelling elastic plugging agent for water-based drilling fluid and preparation method thereof Technical Field The invention relates to the technical field of oil and gas drilling leakage control and blocking, in particular to a water-swelling elastic plugging agent for water-based drilling fluid and a preparation method thereof. Background The stratum structure of the current ChoYu area is extremely complex, which brings serious challenges to drilling work. Because of geological features such as cracks, pores and karst cave in the stratum, the drilling fluid may leak into the stratum, so that the pressure of the well bore is reduced, and the safety and efficiency of drilling are influenced. The lost circulation not only can prolong the drilling period and increase the cost, but also can cause serious conditions such as collapse of a well bore, unstable stratum and the like. In addition, lost circulation can also bring potential pollution risks to groundwater resources and cause adverse effects to the environment. The conventional plugging materials are not enough in bearing capacity and can not effectively plug the formation crack pores, the plugging materials with certain deformability, such as cement paste or gel plugging agents, are difficult to control the cementing solidification time or are diluted quickly under the well, the plugging materials are lost under the action of high temperature and high pressure, the complete solidified body cannot be formed, and the high-temperature fluid loss and cement paste plugging still have the defects in construction safety, pollution resistance and the like. The existing elastic plugging agent, like polymer gel, has the advantages of improving the temperature resistance and the pressure bearing capacity, and has the problems of more plugging times, low plugging success rate and the like when treating the well leakage treatment of complex stratum such as the same spraying and leaking layer, a multi-pressure system and the like, and the polyolefin elastomer plugging agent has no expansion characteristic, is easy to slip after entering the leaking layer and cannot play a good supporting and plugging role. Therefore, the water-swelling elastic plugging agent for the water-based drilling fluid meets the current plugging requirement of the drilling fluid. Through literature search, no research on water-swelling elastic plugging agents for water-based drilling fluids is found, and the plugging agents are still in the blank period of research at present. The invention patent application with the publication number of CN117431040A discloses a gel slug plugging agent for oil-based drilling fluid and application thereof, wherein the gel slug plugging agent comprises 30-60 parts by weight of thermoplastic lipophilic polymer, 30-60 parts by weight of rigid particles, 10-30 parts by weight of flexible fibers and the like, and the thermoplastic lipophilic polymer is formed by mixing an amorphous lipophilic material, a crystalline lipophilic material and a reinforcing agent. After the lipophilic polymer contained in the gel slug plugging agent for the oil-based drilling fluid is pumped into a leakage layer, a slug with strong viscosity can be formed under the action of the formation temperature and the oil-based drilling fluid, the compounded rigid particles and flexible fibers can plug the hole seams of the formation on one hand, and the pressure bearing capacity of the gel slug is improved by the synergistic effect of the gel slug plugging agent and the lipophilic polymer on the other hand, the formed slug plugging agent can effectively plug the leakage layer of the oil-based drilling fluid and isolate the oil-based drilling fluid from the formation fluid, so that the effective plugging of the formation with the overflow and leakage is realized. The invention also provides a preparation method of the gel slug plugging agent for the oil-based drilling fluid. However, the plugging agent is used for oil-based drilling fluid, can not be suitable for plugging of water-based drilling fluid, is formed by physical mixing, and can have the problems of non-uniform components, fluctuation in performance, poor long-term stability and poor functional cooperativity. Disclosure of Invention The invention aims to provide the water-swelling elastic plugging agent for the water-based drilling fluid and the preparation method thereof, and the plugging agent has simple preparation process, is beneficial to industrial production, is convenient for preparing plugging slurry on site, can realize good plugging effect and provides an effective technical means for lost circulation treatment. In order to achieve the above object, the present invention has the following technical scheme: The water-swelling elastic plugging agent for the water-based drilling fluid comprises the following components in parts by weight: 100 parts of polyolefin elastomer matrix material; 15-20 parts of reinforced matrix