CN-122011292-A - Comb type multipolymer filtrate reducer for water-based drilling fluid and preparation method thereof

CN122011292ACN 122011292 ACN122011292 ACN 122011292ACN-122011292-A

Abstract

The invention discloses a comb type multipolymer filtrate reducer for water-based drilling fluid and a preparation method thereof, belonging to the technical field of drilling fluid in petroleum industry. The filtrate reducer is of a comb-shaped structure, acrylamide is adopted as a polymer molecular main chain, anionic monomer 2-acrylamide-2-methylpropanesulfonic acid, methacrylic acid and cyclic monomer N-vinyl pyrrolidine are introduced into the main chain to form a linear polymer, and allyl polyoxyethylene ether monomer is introduced to synthesize the comb-shaped polymer, so that the comb-shaped multipolymer filtrate reducer is obtained. The comb-shaped polymer is prepared by adopting the monomers and the initiator, and the prepared filtrate reducer is resistant to saturated salt and high temperature, can ensure that drilling fluid can keep good rheological property and filtrate reducing performance in deep salt paste layers and salt layers, maintains well wall stability, carries rock debris and suspension weighting materials, and is suitable for exploration and development of deep and ultra-deep oil and gas resources.

Inventors

HAN JINGYI
ZHANG LUYANG
Xi Yongzheng
LI KUN
HUANG JIAN
Yuan Zongling
PEI YANG
DOU JIANYU
GUAN FENGYING
CAO CHENG
YAN WENHUA
GAO JUNWU
Jiang Yumiao
WANG XIANZHOU

Assignees

中国石油集团渤海钻探工程有限公司
中国石油天然气集团有限公司

Dates

Publication Date: 20260512
Application Date: 20241111

Claims (10)

1. A comb type multipolymer filtrate reducer for water-based drilling fluid is characterized in that the molecular structural formula is as follows: wherein n is a positive integer.
2. The comb-type multipolymer filtrate reducer for water-based drilling fluid according to claim 1, wherein the raw materials for preparing the effective components comprise monomers and an initiator; The monomer comprises 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, sodium methacrylate, N-vinyl pyrrolidone and allyl polyoxyethylene ether, wherein the molar ratio of the monomers is (30-40), the monomers is (50-60), the monomers is (1-5), the monomers is (1-4), and the monomers are (2-6); The number average molecular weight of the allyl polyoxyethylene ether is 400-2400.
3. The comb-type multipolymer fluid loss additive for water-based drilling fluids according to claim 2, wherein the initiator consists of potassium persulfate and sodium bisulfite in a molar ratio of 1:1.
4. A comb-type multipolymer fluid loss additive for water-based drilling fluids according to claim 2 or3, characterized in that the raw materials for preparing the active ingredients thereof further comprise a pH value regulator.
5. The comb-type multipolymer filtrate reducer for water-based drilling fluid of claim 4, wherein the pH regulator is at least one of sodium hydroxide and ammonia water.
6. A method for preparing the comb-type multipolymer filtrate reducer for water-based drilling fluid according to any one of claims 3 to 5, which is characterized by comprising the following steps in sequence: Taking 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, sodium methallylsulfonate, N-vinyl pyrrolidone and allyl polyoxyethylene ether according to a molar ratio, adding a solvent until the components are dissolved, uniformly mixing, and regulating the pH value to 7-8 to obtain a mixed solution I; heating the mixed solution I to a reaction temperature, adding an initiator and supplementing a solvent in a protective atmosphere, so that the total mass of the monomer accounts for 20% -40% of the total mass of the monomer and the solvent, and reacting for 6-10 hours to obtain a polymer solution; And drying and crushing the polymer solution to obtain the comb-type multi-polymer filtrate reducer for the water-based drilling fluid.
7. The method for preparing the comb-type multipolymer filtrate reducer for the water-based drilling fluid, which is disclosed in claim 6, is characterized in that the addition amount of the initiator is 0.3% -0.4% of the total mass of the monomer and the solvent, and sodium bisulphite in the initiator is added in a dropwise manner.
8. The method for preparing a comb-type multipolymer fluid loss additive for water-based drilling fluid according to claim 7, wherein the solvent is water.
9. The preparation method of the comb-type multipolymer filtrate reducer for the water-based drilling fluid, which is characterized in that in the dripping process of sodium bisulphite, the first 10-15 min is carried out under the condition of introducing nitrogen to protect gas, and the total use time of the dripping process is 40-50 min.
10. The preparation method of the comb-type multipolymer filtrate reducer for the water-based drilling fluid, which is characterized in that the reaction temperature is 40-60 ℃, and the drying condition is that the temperature is 80-100 ℃ and the water content is lower than 5%.

Description

Comb type multipolymer filtrate reducer for water-based drilling fluid and preparation method thereof Technical Field The invention belongs to the technical field of drilling fluid in petroleum industry, relates to preparation of a fluid loss additive for water-based drilling fluid, and in particular relates to a comb-type multipolymer fluid loss additive for water-based drilling fluid and a preparation method thereof. Background Along with the gradual development of oil and gas resources to develop into deep layers, the possibility of drilling into salt paste layers and brine layers is also continuously increased. When drilling a salt paste layer and a salt layer, the pollution of drilling fluid is very easy to cause, the filtration reducing performance and the rheological property of the drilling fluid are obviously deteriorated, the capability of the drilling fluid for maintaining the stability of a well wall, carrying rock debris and suspending weighting materials is seriously affected, and even underground accidents are caused. At present, most of temperature-resistant and salt-resistant filtrate loss reducing agents used at home and abroad are realized by introducing special functional groups into vinyl monomers through polymer modification or copolymerization, and the product has unsatisfactory filtrate loss reducing effect in saturated salt environments polluted by salt paste layers and salt layers, and has far away from excellent filtrate loss reducing capability under low salinity conditions. Besides the filtrate reducer, the Chinese patent application CN117384321A discloses a comb-type zwitterionic polymer filtrate reducer and a preparation method thereof, and the zwitterionic polymer filtrate reducer with zero net charge is obtained by adopting a zwitterionic monomer, however, the salt resistance of the product only reaches 4 percent at 200 ℃, and the salt resistance of the filtrate reducer is improved to a certain extent, but the filtrate reducer is still not ideal under the high-temperature condition and the high-salt condition. Disclosure of Invention In order to solve the defects in the prior art, the invention aims to provide a comb type multipolymer filtrate reducer for water-based drilling fluid, which adopts acrylamide as a polymer molecular main chain, introduces anionic monomer 2-acrylamide-2-methylpropanesulfonic acid, methacrylic acid and cyclic monomer N-vinyl pyrrolidine on the main chain to form a linear polymer, and introduces allyl polyoxyethylene ether monomer on the linear polymer to synthesize the comb type polymer, thereby improving the viscosity increasing, temperature resisting and salt resisting capabilities while ensuring the water loss reducing effect of the polymer. The invention also aims to provide a preparation method of the comb-type multipolymer filtrate reducer for the water-based drilling fluid. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: a comb type multipolymer filtrate reducer for water-based drilling fluid has a molecular structural formula as follows: wherein n is a positive integer. As one limitation of the invention, the raw materials for preparing the effective component comprise monomers and an initiator; the monomer comprises 2-acrylamido-2-methylpropanesulfonic Acid (AMPS), acrylamide (AM), sodium Methacrylate (SMAS), N-vinyl pyrrolidone (NVP) and Allyl Polyoxyethylene Ether (APEG) with the molar ratio of (30-40), (50-60), (1-4) and (2-6); The number average molecular weight of the allyl polyoxyethylene ether is 400-2400. As a further definition of the invention, the initiator consists of potassium persulfate and sodium bisulfite in a molar ratio of 1:1. As a still further limitation of the present invention, the raw materials for preparing the active ingredient thereof further comprise a pH regulator. As a still further limitation of the present invention, the pH adjustor is at least one of sodium hydroxide and ammonia water. The invention also provides a preparation method of the comb type multipolymer filtrate reducer for the water-based drilling fluid, which comprises the following steps of taking 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, sodium methallyl sulfonate, N-vinyl pyrrolidone and allyl polyoxyethylene ether according to a molar ratio, adding a solvent until the components are dissolved, uniformly mixing, and adjusting the pH value to 7-8 to obtain a mixed solution I; heating the mixed solution I to a reaction temperature, adding an initiator and supplementing a solvent in a protective atmosphere, so that the total mass of the monomer accounts for 20% -40% of the total mass of the monomer and the solvent, and reacting for 6-10 hours to obtain a polymer solution; And drying and crushing the polymer solution to obtain the comb-type multi-polymer filtrate reducer for the water-based drilling fluid. Further, the protective atmosphere is a nitrogen atmosphere. As one limitati