阅读说明：本技术 一种胶囊暂堵压井液及其制备方法 (Capsule temporary plugging well killing fluid and preparation method thereof ) 是由 董晓焕 姜毅 朱方辉 李琼玮 李明星 刘伟 杨会丽 程碧海 张振云 于淑珍 于 2020-03-24 设计创作，主要内容包括：本发明公开了一种胶囊暂堵压井液及其制备方法,包括石蜡和暂堵压井液,石蜡包覆在暂堵压井液的外部；按质量份数计,暂堵压井液包括聚合物、交联剂、增塑剂和水配制得到；本发明通过采用转鼓喷涂法将石蜡包覆在暂堵压井液的外部,得到大尺寸胶囊暂堵压井液,实现了有效堵塞油气储层大孔径溶孔、溶洞或射孔炮眼；暂堵压井液利用无机材料与聚合物的插层作用,使大分子聚合物有效地进入无机材料层间,在交联剂作用下形成共价键结合的共混材料,从而提高了力学性能和热盐稳定性。(The invention discloses a capsule temporary plugging well killing fluid and a preparation method thereof, wherein the capsule temporary plugging well killing fluid comprises paraffin and temporary plugging well killing fluid, and the paraffin is coated outside the temporary plugging well killing fluid; the temporary plugging well killing fluid is prepared from a polymer, a cross-linking agent, a plasticizer and water in parts by mass; the invention adopts the rotary drum spraying method to coat the paraffin outside the temporary plugging kill fluid to obtain the large-size capsule temporary plugging kill fluid, thereby realizing the effective plugging of large-aperture solution holes, solution cavities or perforation blastholes of oil and gas reservoirs; the temporary plugging well killing fluid utilizes the intercalation effect of inorganic materials and polymers to ensure that macromolecular polymers effectively enter between inorganic material layers to form a blending material combined by covalent bonds under the action of a cross-linking agent, thereby improving the mechanical property and the thermal salt stability.)

1. The capsule temporary plugging well killing fluid is characterized by comprising paraffin and temporary plugging well killing fluid, wherein the paraffin is coated outside the temporary plugging well killing fluid; wherein, according to the mass portion, the temporary plugging well killing fluid comprises the following polymers: 100-120 parts of a crosslinking agent: 50-60 parts of plasticizer, 50-100 parts of water: 100 parts.

2. The temporary plugging and killing capsule fluid as claimed in claim 1, wherein the polymer is acrylamide copolymer.

3. The temporary capsule plugging control fluid of claim 1, wherein the cross-linking agent is hexamethylenetetramine cross-linking agent.

4. The temporary plugging and killing capsule fluid as claimed in claim 1, wherein the plasticizer is a micro-nano multi-layered silicate toughening material.

5. The capsule temporary plugging killing fluid of claim 1, further comprising a stabilizer and an oxygen scavenger, wherein the mass fraction of the stabilizer is 1-2 parts, and the mass fraction of the oxygen scavenger is 0.5-1.0 part.

6. The temporary plugging control fluid for capsules of claim 5, wherein the stabilizer is thiourea and the antioxidant is sodium sulfite.

7. The capsule temporary plugging control fluid of claim 5, wherein the temporary plugging control fluid is prepared from 100 parts by mass of a polymer, 50 parts by mass of a cross-linking agent, 100 parts by mass of a plasticizer, 2 parts by mass of a stabilizer, 1 part by mass of an antioxidant and 100 parts by mass of water.

8. The temporary capsule plugging and killing fluid as claimed in claim 1, wherein the paraffin wax is high-melting-point paraffin wax with a melting point of 100-115 ℃.

9. The preparation method of the capsule temporary plugging well killing fluid according to any one of claims 1 to 8, wherein, firstly, the temporary plugging well killing fluid is prepared; then, the prepared temporary plugging well killing fluid is placed in a rotary drum to be turned over, so that gel particles are turned over, petroleum ether liquid dissolved with paraffin is sprayed on the colloid particles through a spray gun head, and hot air is blown in to volatilize and recover the petroleum ether; repeatedly spraying for several times to make the capsule thickness reach 1-3mm, stopping spraying, and continuously rotating and blowing until the capsule is dried.

10. The preparation method of the capsule temporary plugging well killing fluid as claimed in claim 9, wherein the preparation of the temporary plugging well killing fluid comprises the following steps:

step 1, fully dispersing a polymer in water, and stirring to obtain a polymer solution;

step 2, adding a plasticizer into the polymer solution, and stirring until the plasticizer is uniformly distributed in the polymer solution to obtain the polymer solution with the plasticizer uniformly distributed;

and 3, adding a cross-linking agent into the polymer solution uniformly distributed with the plasticizer obtained in the step 2, and stirring uniformly to stably form a gel solution to obtain the temporary plugging well killing fluid.

Technical Field

The invention belongs to the technical field of well repair leakage prevention and reservoir protection of natural gas wells, and particularly relates to a capsule temporary plugging well killing fluid and a preparation method thereof.

Background

The ancient gas layer in Changqing gas field is mainly formed by dissolving holes, intercrystalline holes and intergranular dissolving holes, and then formed by casting mould holes, intercrystalline micropores and microcracks, low permeability is mainly formed by local middle and high permeability areas, the difference between layers is obvious, the heterogeneous degree is serious, the matrix permeability is 0.001-6.368mD, generally less than 5mD, and the permeability of corrosion-hole dolomite with cracks is 1.0-100mD or even larger. At present, the stratum pressure coefficient is generally in the range of 0.3-0.8, the pressure coefficient span range is large, and the geological condition is complex; in the well repairing process, the positive pressure difference is too large, so that the well killing fluid is seriously leaked, and the gas well is difficult to recover and even stops producing.

At present, temporary plugging well killing fluid systems researched at home and abroad are generally high in pertinence and mainly comprise temporary plugging technologies such as super absorbent resin particles (solidified water), low-density foam, gel and the like; the super absorbent resin particle temporary plugging kill-job technique has harsh use conditions and higher operation cost; in addition, the super absorbent resin particles temporarily block the gas layer with large span range of pressure coefficient, are easy to transfer and float due to pressure fluctuation in the underground, seriously affect the air tightness and cause potential safety hazard; the low-density foam temporary plugging kill-job technology is complex in process, and the low-density foam has short stable period and cannot meet the requirement of overhaul operation; the gel temporary plugging control fluid has better application potential in the aspect of repairing and temporarily plugging, not only has the viscosity of liquid, but also has the hardness of solid, but the reported gel temporary plugging control fluid has to be improved in high temperature resistance, plugging of large-aperture karst caves, perforation blastholes and flowback plugging removal performance; therefore, the development of a low-damage and low-cost temporary plugging kill fluid technology for karst cave, fractured and vuggy fracture-cavity carbonate reservoirs is urgently needed.

Disclosure of Invention

Aiming at the problems in the prior art, the capsule temporary plugging well killing fluid and the preparation method thereof provided by the invention have the advantages that the rotary drum spraying method is utilized, paraffin is sprayed for multiple times to coat the temporary plugging well killing fluid, and a large-size capsule temporary plugging well killing fluid system is obtained, so that a large-aperture solution cavity and a perforation blast hole of a carbonate reservoir are effectively plugged.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the invention provides a capsule temporary plugging well killing fluid, which comprises paraffin and temporary plugging well killing fluid, wherein the paraffin is coated outside the temporary plugging well killing fluid; wherein, according to the mass portion, the temporary plugging well killing fluid comprises the following polymers: 100-120 parts of a crosslinking agent: 50-60 parts of plasticizer, 50-100 parts of water: 100 parts.

Further, the polymer is acrylamide copolymer.

Further, a hexamethylene tetramine crosslinking agent is adopted as the crosslinking agent.

Furthermore, the plasticizer adopts a micro-nano multi-layer silicate toughening material.

Further, the composite material also comprises a stabilizer and an oxygen scavenger, wherein the mass fraction of the stabilizer is 1-2 parts, and the mass fraction of the oxygen scavenger is 0.5-1.0 part.

Further, thiourea is used as a stabilizer, and sodium sulfite is used as an antioxidant.

Furthermore, the temporary plugging well killing fluid is prepared from 100 parts of polymer, 50 parts of cross-linking agent, 100 parts of plasticizer, 2 parts of stabilizer, 1 part of antioxidant and 100 parts of water in parts by mass.

Further, the paraffin wax adopts high-melting-point paraffin wax with the melting point of 100-115 ℃.

The invention also provides a preparation method of the capsule temporary plugging well killing fluid, which comprises the following steps of firstly, preparing the temporary plugging well killing fluid; then, the prepared temporary plugging well killing fluid is placed in a rotary drum to be turned over, so that gel particles are turned over, petroleum ether liquid dissolved with paraffin is sprayed on the colloid particles through a spray gun head, and hot air is blown in to volatilize and recover the petroleum ether; repeatedly spraying for several times to make the capsule thickness reach 1-3mm, stopping spraying, and continuously rotating and blowing until the capsule is dried.

Further, when preparing the temporary plugging well killing fluid, the method comprises the following steps:

step 1, fully dispersing a polymer in water, and stirring to obtain a polymer solution;

step 2, adding a plasticizer into the polymer solution, and stirring until the plasticizer is uniformly distributed in the polymer solution to obtain the polymer solution with the plasticizer uniformly distributed;

and 3, adding a cross-linking agent into the polymer solution uniformly distributed with the plasticizer obtained in the step 2, and stirring uniformly to stably form a gel solution to obtain the temporary plugging well killing fluid.

Compared with the prior art, the invention has the beneficial effects that:

the capsule temporary plugging well killing fluid is prepared by coating the temporary plugging well killing fluid with paraffin, so that the large-size capsule temporary plugging well killing fluid is obtained, and the effect of effectively plugging large-aperture solution holes, solution cavities or perforation blastholes of an oil-gas reservoir is realized.

Furthermore, the polymer adopts acrylamide copolymer, the bond of the molecular main chain of the molecular structure of the acrylamide copolymer is selected from the molecular bonds with larger bond energy such as 'C-C', 'C-N' and 'C-S', etc., the damage of high temperature to the molecular structure is effectively avoided, and simultaneously, the intercalation effect of inorganic materials and macromolecular polymers is utilized to ensure that the macromolecular polymers effectively enter between the layers of inorganic nano materials to form a blending material combined by covalent bonds under the action of a cross-linking agent, thereby improving the mechanical property and the thermal salt stability.

Furthermore, the cross-linking agent is a phenol-formaldehyde cross-linking agent formed by phenol/formaldehyde and phenol derivatives thereof with a wide temperature suitable range, and an antioxidant of aromatic amine and derivatives thereof capable of eliminating free radicals is added, so that the high-temperature stability of the well control fluid is improved.

Furthermore, the plasticizer adopts a multi-layer silicate material, and forms a blending material combined by covalent bonds under the action of a cross-linking agent by utilizing the intercalation of an inorganic material and a macromolecular polymer, so that the mechanical property and the heat salt stability of the temporary plugging control fluid are improved.

Furthermore, by adding a stabilizer into the temporary plugging well killing fluid, the mechanical property and the heat salt stability of the temporary plugging well killing fluid are improved; the stabilizing agent adopts thiourea, which mainly plays roles of deoxidizing and sterilizing, and ensures the high-temperature stability of the medicament.

Furthermore, the antioxidant capable of eliminating free radicals and aromatic amine and derivatives thereof are added to serve as a high-temperature stabilizer to improve the high-temperature stability of the well control fluid.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

The capsule temporary plugging well killing fluid comprises paraffin and temporary plugging well killing fluid, wherein the paraffin adopts commercially available industrial grade high-melting-point paraffin, the melting point of the paraffin is 100-; spraying for many times by using a rotary drum spraying method to ensure that paraffin is coated outside the temporary plugging kill fluid to obtain a large-size capsule temporary plugging kill fluid system with the size diameter of more than 12mm, thereby realizing effective plugging of large-aperture solution caverns and perforation blastholes of carbonate reservoirs;

the temporary plugging well killing fluid comprises, by mass, 120 parts of polymer, 50-60 parts of cross-linking agent, 50-100 parts of plasticizer, 1-2 parts of stabilizer, 0.5-1 part of antioxidant and 100 parts of water;

the invention also provides a preparation method of the capsule temporary plugging well killing fluid, which comprises the following steps:

at normal temperature, firstly dispersing a polymer in water, and stirring until the polymer is fully dispersed to obtain a polymer solution; then adding a plasticizer into the polymer solution, and stirring until the plasticizer is uniformly distributed in the polymer solution to obtain the polymer solution with the plasticizer uniformly distributed; adding a cross-linking agent into the polymer solution with the plasticizer uniformly distributed, and stirring until the cross-linking agent is uniformly dispersed to obtain a mixed solution; secondly, adding a stabilizer and a deoxidant into the mixed solution, and after uniformly stirring, stably forming a gel solution to obtain a temporary plugging well killing fluid; next, placing the temporary plugging kill fluid into a rotary drum sprayer to turn over, spraying petroleum ether dissolved with paraffin into the temporary plugging kill fluid in the rotary drum sprayer by adopting a spray gun head, mixing the paraffin and the petroleum ether according to the mass ratio of 2:1, and blowing hot air into the temporary plugging kill fluid to volatilize and recover the petroleum ether; and repeating the spraying for many times until the thickness of the paraffin coated outside the temporary plugging well killing fluid reaches 1-3mm, and screening to obtain the capsule temporary plugging well killing fluid with the required size.