CN-121991663-A - Self-repairing well wall stabilizer, preparation method thereof and drilling fluid

CN121991663ACN 121991663 ACN121991663 ACN 121991663ACN-121991663-A

Abstract

The invention provides a self-repairing well wall stabilizer which comprises 2.0-2.5 wt% of a cross-linking agent, 0.6-1.2 wt% of an early strength agent, 28-32 wt% of an organosilicon microcapsule, 15-18 wt% of a silicate microcapsule and 48-52 wt% of chitosan. The invention also provides a preparation method of the self-repairing well wall stabilizer and a drilling fluid containing the self-repairing well wall stabilizer. The self-repairing well wall stabilizer provided by the invention has the advantages that the organic silicon microcapsule and the silicate microcapsule are mixed with the cross-linking agent and the early strength agent and then are packaged in the chitosan shell, so that multiple capsules are formed, the plugging capability is stronger, the temperature resistance can reach 180 ℃, and the self-repairing well wall stabilizer can be directly added into drilling fluid for use.

Inventors

LAN QIANG
ZHANG YANAN
WANG JUN
ZHU CHUANMING
LI LEI
YANG DAWEI

Assignees

中石化石油工程技术服务股份有限公司
中石化胜利石油工程有限公司
中石化胜利石油工程有限公司钻井液技术服务中心
山东胜工石油科技有限公司

Dates

Publication Date: 20260508
Application Date: 20241101

Claims (10)

1. The self-repairing well wall stabilizer is characterized by comprising 2.0-2.5 wt% of cross-linking agent, 0.6-1.2 wt% of early strength agent, 28-32 wt% of organosilicon microcapsule, 15-18 wt% of silicate microcapsule and 48-52 wt% of chitosan.
2. The borehole wall stabilizer according to claim 1, wherein the organosilicon microcapsule comprises tetramethyl divinyl disiloxane, polydimethylsiloxane, polydiethylsiloxane, organic solvent, furfuryl mercaptan, photosensitizer and urea-formaldehyde resin; preferably, the mass ratio of the tetramethyl divinyl disiloxane to the polydimethylsiloxane to the polydiethyl siloxane is 1-1.5:1:1-1.8; Preferably, the mass ratio of the polydimethylsiloxane to the organic solvent is 1:3-5.5; preferably, the ratio of the addition amount of furfuryl mercaptan to the mass of polydimethylsiloxane is 1:3-6; Preferably, the ratio of the addition amount of the photosensitizer to the mass of the polydimethylsiloxane is 1:1.5-3; preferably, the ratio of the adding amount of the urea-formaldehyde resin to the mass of the polydimethylsiloxane is 6.5-10:1.
3. The stabilizer according to claim 2, wherein the polydimethylsiloxane has a structural formula shown in formula (I), ((CH 3 ) 2 SiO)n(I) In the formula (I), n is 6-15, preferably 6-9, and/or The structural formula of the polydiethylsiloxane is shown as a formula (II), ((C 2 H 5 ) 2 SiO)m(II) In the formula (II), m is 3≤m≤12, preferably 5≤m≤8, and/or The photosensitizer is at least one selected from benzoin, benzoin dimethyl ether, benzoin diethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzophenone, 2, 4-dihydroxybenzophenone and Mi ketone, and/or The structural formula of the urea-formaldehyde resin is shown as a formula (III), (CH 2 N(CH 3 )CON(CH 3 )CH 2 )x,(III) In the formula (III), x is 5000 to 10000, preferably 6000 to 7200, and/or The organic solvent is at least one selected from tetrahydrofuran, N-methyl pyrrolidone, dimethyl sulfoxide and ethylene glycol butyl ether.
4. A borehole wall stabilizer according to claim 2 or 3, wherein the preparation method of the organosilicon microcapsule comprises the following steps: S1, adding tetramethyl divinyl disiloxane, polydimethylsiloxane and polydiethyl siloxane into an organic solvent to perform a first prepolymerization reaction; S2, adding furfuryl mercaptan and a photosensitizer, and carrying out photopolymerization under ultraviolet light; s3, adding urea-formaldehyde resin, performing a first reaction at a first temperature, and then performing a curing granulation reaction at a second temperature; s4, removing residual organic solvent in the mixture obtained by the solidification and granulation reaction to obtain a product; Preferably, the conditions of the first prepolymerization reaction comprise that the temperature is 60-80 ℃, the stirring speed is 800-1200 rpm, and the time is 30-50 min; Preferably, the photopolymerization reaction conditions comprise that under the irradiation of ultraviolet rays, the temperature is 60-80 ℃, the stirring speed is 100-300 rpm, the time is 30-50 min, the wavelength of ultraviolet rays is 300-500 nm, and the power is 3000-5000W; Preferably, the first reaction conditions comprise a first temperature of 160-200 ℃, a stirring speed of 4800-5200 rpm and a stirring time of 30-50 min; Preferably, the conditions of the solidification and granulation reaction comprise that the second temperature is 60-80 ℃, the stirring speed is 80-120 rpm, and the time is 30-50 min.
5. The borehole wall stabilizer according to any one of claims 1 to 4, wherein the silicate microcapsule comprises silicate, inorganic base, alginate, first solvent, second solvent and curing agent, Preferably, the mass ratio of silicate to inorganic base is 8-12.5:1; preferably, the mass ratio of the inorganic base to the first solvent is 1:6.5-10; Preferably, the ratio of the adding amount of the alginate to the mass of the inorganic base is 12-18.5:1; preferably, the ratio of the addition amount of the second solvent to the mass of the inorganic base is 6.5-10:1; preferably, the ratio of the adding amount of the curing agent to the mass of the inorganic base is 1-1.8:1; Preferably, the silicate is one of sodium silicate, potassium silicate and potassium sodium silicate, more preferably sodium silicate, and has a structural formula shown in formula (IV), Na 2 O·ySiO 2 ,(IV) In the formula (IV), y is more than or equal to 1.5 and less than or equal to 3.0; Preferably, the inorganic base is one of NaOH and KOH, more preferably NaOH; Preferably, the alginate is one of sodium alginate and potassium alginate, more preferably sodium alginate, more preferably kelp of brown algae, or a byproduct of extracting iodine and mannitol from gulfweed; Preferably, the solidifying agent is selected from at least one of calcium chloride, calcium bromide and calcium nitrate; Preferably, the first solvent and the second solvent are the same or different and are each independently selected from water and ethanol.
6. The borehole wall stabilizer as claimed in claim 5, wherein the preparation method of the silicate microcapsule comprises the following steps: S10, adding silicate and inorganic base into a first solvent to perform a second prepolymerization reaction; s20, adding alginate and a second solvent to perform a second reaction; s30, adding a curing agent to perform a curing reaction; S40, after the curing reaction is finished, taking out the microcapsule product, washing and removing the residual solvent; preferably, the conditions of the second prepolymerization reaction comprise the temperature of 80-100 ℃, the stirring speed of 2800-3200 rpm and the time of 30-50 min; Preferably, the conditions of the second reaction comprise the temperature of 80-100 ℃, the stirring speed of 2800-3200 rpm and the time of 20-30 min; preferably, the curing reaction conditions comprise a temperature of 30-50 ℃, a stirring speed of 100-300 rpm and a time of 30-50 min.
7. The borehole wall stabilizer as claimed in any one of claims 1 to 6, wherein the crosslinking agent is at least one selected from the group consisting of 2-ethyl-4-methylimidazole, 2-phenylimidazole, 2-isopropylimidazole, and/or The early strength agent is at least one selected from sodium nitrite, triethanolamine and urea, and/or The chitosan is deacetylated chitin.
8. A borehole wall stabilizer as claimed in any one of claims 1 to 7 wherein the borehole wall stabilizer is for a drilling fluid.
9. The method for preparing the self-repairing borehole wall stabilizer as claimed in any one of claims 1 to 8, which is characterized by comprising the following steps: S100, adding a cross-linking agent and an early strength agent for a third reaction; s200, adding the organosilicon microcapsule and the silicate microcapsule to perform a fourth reaction; s300, adding chitosan, and performing a fifth reaction; S400, after the reaction is finished, filtering, and collecting a product to wash and remove residual solvent; Preferably, the mass ratio of the cross-linking agent to the early strength agent is 2-3:1; Preferably, the conditions of the third reaction comprise the temperature of 80-100 ℃, the stirring speed of 2800-3200 rpm and the time of 30-50 min; Preferably, the mass ratio of the organic silicon microcapsule to the early strength agent is 25-40:1; preferably, the mass ratio of the silicate microcapsule to the early strength agent is 15-20:1; preferably, the fourth reaction condition comprises the temperature of 80-100 ℃, the stirring speed of 2800-3200 rpm and the stirring time of 30-50 min; preferably, the mass ratio of the chitosan to the early strength agent is 40-65:1; preferably, the fifth reaction condition comprises a temperature of 80-100 ℃, a stirring speed of 100-500 rpm and a time of 20-30 min.
10. A drilling fluid, which is characterized by comprising the self-repairing borehole wall stabilizer according to any one of claims 1 to 8 or the self-repairing borehole wall stabilizer prepared by the preparation method according to claim 9, preferably, the self-repairing borehole wall stabilizer is added in an amount of 2.0% -5.0% of the mass of the drilling fluid.

Description

Self-repairing well wall stabilizer, preparation method thereof and drilling fluid Technical Field The invention belongs to the technical field of drilling fluid additives, and particularly relates to a self-repairing well wall stabilizer, a preparation method and application thereof, in particular to a slow-release type high-viscosity self-repairing well wall stabilizer, and a preparation method and application thereof. Background Along with the current increasing demand for oil and gas, the complexity of the well bore hole drilled by people in the oil and gas exploration and development process is higher, and particularly the probability of drilling a well section meeting complex shale is higher, and the probability of generating complex accidents is also higher. The loss caused by complex accidents of the shale section in the drilling process accounts for more than 70% of the total loss. Thus, how to ensure well wall stabilization during shale section drilling is a great focus of current safety drilling, and most treatments developed are conducted for this interval. The conventional well wall stabilizer mainly inhibits hydration and dispersion of shale and comprises an amino inhibitor, a quaternary ammonium salt clay stabilizer, an inorganic salt inhibitor and the like. Subsequently, new borehole wall stabilizers, mostly synthetic multipolymers, have been developed. Recently, people start to turn the eyes to nanoparticles to block shale pores, most of researches are limited to indoor places due to the fact that the performance influence factors of the nanoparticles are more, and few researches go to the site. Jiang Guancheng et al (bionic drilling fluid theory and technique, oil industry Press) propose a method of adopting chemical bionics to chemically react on the well wall to generate a shell-like coating layer, thereby improving the stability of the well wall. Disclosure of Invention The invention aims to solve the defect of poor coating effect of the current water-based drilling fluid borehole wall stabilizer, and provides a slow-release high-viscosity self-repairing borehole wall stabilizer, a preparation method thereof and a drilling fluid, wherein the self-repairing borehole wall stabilizer comprises organosilicon microcapsules and silicate microcapsules as raw materials, under the conditions of high temperature and high pressure (the temperature is 150-250 ℃ and the pressure is 40-100 MPa), the organic silicon and sodium silicate are released and react with the cross-linking agent and the early strength agent quickly to form an inorganic polymer with extremely high viscosity, and the inorganic polymer is coated on a well wall to repair the well wall and improve the stability of the well wall. For the purposes of the first aspect, the invention provides a self-repairing borehole wall stabilizer, which comprises 2.0-2.5 wt% of cross-linking agent, 0.6-1.2 wt% of early strength agent, 28-32 wt% of organosilicon microcapsule, 15-18 wt% of silicate microcapsule and 48-52 wt% of chitosan. In the self-repairing well wall stabilizer, the organosilicon microcapsules and the silicate microcapsules are mixed with the cross-linking agent and the early strength agent and then packaged in the chitosan shell, so that multiple capsules are formed, the plugging capability is stronger, the temperature resistance can reach 180 ℃, and the self-repairing well wall stabilizer can be directly added into drilling fluid for use. In the self-repairing borehole wall stabilizer, a plurality of silica bonds exist at the edge of an organosilicon microcapsule, the organosilicon microcapsule can be combined with exposed silica bonds in shale components in a stratum to form a strong adhesive force, so that a good coating effect is achieved, the outer end of silicate in a silicate microcapsule also contains a plurality of silica bonds, the silica bonds can be combined with silica bonds on the borehole wall and firmly adsorbed on the borehole wall, meanwhile, because the silica bonds exist in an organosilicon polymer and silicate at the same time, strong interaction exists between the organosilicon polymer and sodium silicate, a high-strength coating layer can be formed under the action of a crosslinking agent, and an early strength agent is added on the basis, so that the solidification of an organic polymer can be accelerated. As a specific embodiment of the invention, the raw materials of the organosilicon microcapsule comprise tetramethyl divinyl disiloxane, polydimethylsiloxane, polydiethyl siloxane, organic solvent, furfuryl mercaptan, photosensitizer and urea-formaldehyde resin. In the organic silicon microcapsule, a plurality of silicon bonds exist in tetramethyl divinyl disiloxane, polydimethylsiloxane and polydiethyl siloxane, and can be combined with exposed silicon bonds in shale components in stratum to form stronger adhesive force, so that a better coating effect is achieved. As a specific embodiment of the inventio