Search

CN-121991647-A - Reservoir drilling fluid and preparation method thereof

CN121991647ACN 121991647 ACN121991647 ACN 121991647ACN-121991647-A

Abstract

The invention discloses a reservoir drilling fluid and a preparation method thereof, belonging to the technical field of oilfield chemical preparation, wherein the reservoir drilling fluid comprises, by weight, 50-80 parts of water, 3-5 parts of a flocculating agent, 2-8 parts of a polyamine inhibitor, 2-4 parts of an antiscaling agent, 1-3 parts of graphite, 4-6 parts of a mixed auxiliary agent and 1-3 parts of xanthan gum; S1, preparing alkyl glycoside and pH adjusting solution with concentration of 0.8-1.2% according to a mass ratio of 1:2, mixing the alkyl glycoside and the pH adjusting solution, stirring the mixture at a temperature of 45-55 ℃ for 20-35 min, and then adding calcium formate to stir to obtain a primary mixture. Through preparing a mixed auxiliary agent prepared by mixing substances such as alkyl glycoside, sodium nitro humate and the like, the drilling fluid finished product can effectively reduce the damage of a coal bed gas reservoir caused by solid phase invasion, prevent mineral hydration, promote desorption of the coal bed gas on the surface of coal rock, and simultaneously maintain the stability of the coal bed.

Inventors

  • ZHANG XIAOPING
  • ZHAO LEI
  • JIA JUN
  • WEI HAIFANG
  • FAN FAN
  • CHEN LEI
  • LIU WEI
  • WANG JINGGUANG
  • LIANG HAIJUN
  • GUO KANG

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
20241104

Claims (12)

  1. 1. The reservoir drilling fluid is characterized by comprising, by weight, 50-80 parts of water, 3-5 parts of a flocculating agent, 2-8 parts of a polyamine inhibitor, 2-4 parts of an antiscaling agent, 1-3 parts of graphite, 4-6 parts of a mixing auxiliary agent and 1-3 parts of xanthan gum; The preparation method of the mixed auxiliary agent comprises the following method steps: Step S1, preparing alkyl glycoside and pH adjusting solution with the concentration of 0.8-1.2% according to the mass ratio of 1:2, mixing the alkyl glycoside and the pH adjusting solution, stirring the mixture at the temperature of 45-55 ℃ for 20-35 min at the rotating speed of 220-300 r/min, and then adding calcium formate for stirring to obtain a primary mixture; s2, adding 2-3% of sodium nitro humate into the initial mixture, heating to 75-90 ℃ and stirring for 15-20 min, wherein the rotation speed is 180-240 r/min during stirring, adding triethanolamine, stirring for 30-50 min under the environment of 55-60 ℃ and the rotation speed is 260-320 r/min during stirring, and obtaining a mixed matrix; and S3, taking magnesium chloride, petroleum sodium sulfonate and a mixed matrix according to a mass ratio of 1:2:7, placing the magnesium chloride, the petroleum sodium sulfonate and the mixed matrix into a stirrer for heating and mixing treatment, and obtaining a mixed preparation finished product after mixing.
  2. 2. The reservoir drilling fluid of claim 1, wherein in the step S1, the added mass of calcium formate is 1.5-2% of the total mass of the alkyl glycoside and the pH adjusting solution.
  3. 3. The reservoir drilling fluid of claim 1, wherein in the step S2, the addition mass of triethanolamine is 1.5-2.2% of the total mass of the primary mixture and the nitro humic acid.
  4. 4. The reservoir drilling fluid of claim 1, wherein in the step S3, the stirring time of magnesium chloride, sodium petroleum sulfonate and the mixed matrix is controlled to be 12-15 min, the rotating speed is 160-320 r/min during stirring, and the heating temperature is controlled to be 80-95 ℃.
  5. 5. The reservoir drilling fluid of claim 1, wherein the flocculant is one or more of polymeric ferric sulfate, polyaluminum chloride PAC, magnesium aluminum silicate, polyacrylamide, sodium polyacrylate, chitosan, and cationic melamine polymer.
  6. 6. The reservoir drilling fluid of claim 1, wherein the polyamine inhibitor is one or more of polyethylenimine, polyetheramine, alkyl diamine, and quaternary ammonium salt polyamine.
  7. 7. The reservoir drilling fluid of claim 1, wherein the pH adjusting solution is one or more of sodium hydroxide, potassium hydroxide and ammonia.
  8. 8. The reservoir drilling fluid of claim 1, wherein the scale inhibitor is prepared by compounding amino trimethylene phosphonic acid, hydrolyzed polymaleic anhydride and hydroxyethylidene diphosphonic acid according to a ratio of 1:1.8:1.5.
  9. 9. A reservoir drilling fluid as defined in claim 1, wherein the water is deionized water from which impurities in ionic form have been removed.
  10. 10. A method of preparing a reservoir drilling fluid according to any one of claims 1 to 9, comprising the steps of: Step one, preparing raw materials according to parts by weight, adding water into a stirring kettle, and then adding an amine inhibitor, calcium formate, an antiscaling agent and graphite into the stirring kettle, and uniformly stirring, wherein potassium chloride is supplemented during the stirring to obtain a mixture; Injecting a mixing auxiliary agent into the stirring kettle, adding a flocculating agent and xanthan gum at the same time, heating the stirring kettle to fully stir, and obtaining a reservoir drilling fluid finished product; And thirdly, placing the drilling fluid finished product into a sealed barrel for packaging and storing.
  11. 11. The method for preparing a reservoir drilling fluid according to claim 10, wherein in the first step, the addition mass of potassium chloride is 0.8-1.2% of the water mass.
  12. 12. The method for preparing reservoir drilling fluid according to claim 11, wherein in the second step, the heating temperature of the stirring kettle is controlled to be 55-70 ℃, the stirring time is 20-35 min, and the rotating speed during stirring is 210-250 r/min.

Description

Reservoir drilling fluid and preparation method thereof Technical Field The invention relates to the technical field of oilfield chemical preparation, in particular to reservoir drilling fluid and a preparation method thereof. Background Coal bed gas is unconventional natural gas, takes methane as a main component in a coal bed, takes the surface of coal matrix particles as a main component, and is hydrocarbon gas partially dissociated in coal pores or dissolved in coal bed water, is a semi-produced mineral resource of coal, and is increasingly valued along with the new requirements of China on the diversified development of energy sources, and the exploitation of the coal bed gas is gradually expanded in scale. The coal bed rich in coalbed methane in China is special and has the characteristic of low pore and low permeability, the main exploitation mode is mainly a horizontal well, and in order to ensure the requirements of safety, high quality, high efficiency and rapidness of drilling production operation, a drilling fluid which is a chemical agent is needed, so that the bottom of a well can be cleaned, the bottom of the well can be kept clean, meanwhile, repeated cutting of a drill bit can be avoided, abrasion is reduced, and the operation efficiency is improved. The coal bed rich in coalbed methane in China is special and has the characteristic of low pore and low permeability, the main exploitation mode is mainly a horizontal well, and in order to ensure the requirements of safety, high quality, high efficiency and rapidness of drilling production operation, a drilling fluid which is a chemical agent is needed, so that the bottom of a well can be cleaned, the bottom of the well can be kept clean, meanwhile, repeated cutting of a drill bit can be avoided, abrasion is reduced, and the operation efficiency is improved. However, in the actual drilling process, after the working fluid invades the reservoir, solid phase particles and stratum particles in part of drilling fluid can move to block pore throats, so that the permeability of the reservoir is greatly reduced, the recovery ratio of oil gas is affected, most of the current drilling fluid is clear water drilling fluid, the current drilling fluid has the advantages of low cost, no solid phase and the like, and can meet the operation requirements of horizontal well drilling engineering, but the drilling fluid of the type easily causes the expansion of clay minerals of the coal bed, affects the seepage channel of the coal bed gas, and meanwhile, the drilling fluid of the type is easy to combine with the coal bed water to form a scale, and has weak flocculation capability due to high hydration rate. Therefore, in order to ensure smooth exploitation of the coalbed methane, protect the stability of a coalbed methane reservoir and improve the yield of coalbed methane exploitation, the invention provides a novel reservoir drilling fluid and a preparation method thereof so as to meet the requirements of safe exploitation and production of the coalbed methane. Disclosure of Invention The invention aims to solve the problems in the prior art, provides a reservoir drilling fluid and a preparation method thereof, and solves the problems that the existing drilling fluid product is easy to cause expansion of clay minerals of a coal bed, influences a seepage channel of the coal bed gas, is easy to combine with the coal bed water to form scaling and has weaker flocculation capability in actual use. The invention aims at realizing the following technical scheme: the reservoir drilling fluid comprises, by weight, 50-80 parts of water, 3-5 parts of a flocculating agent, 2-8 parts of a polyamine inhibitor, 2-4 parts of an antiscaling agent, 1-3 parts of graphite, 4-6 parts of a mixing auxiliary agent and 1-3 parts of xanthan gum; The preparation method of the mixed auxiliary agent comprises the following method steps: Step S1, preparing alkyl glycoside and pH adjusting solution with the concentration of 0.8-1.2% according to the mass ratio of 1:2, mixing the alkyl glycoside and the pH adjusting solution, stirring the mixture at the temperature of 45-55 ℃ for 20-35 min at the rotating speed of 220-300 r/min, and then adding calcium formate for stirring to obtain a primary mixture; s2, adding 2-3% of sodium nitro humate into the initial mixture, heating to 75-90 ℃ and stirring for 15-20 min, wherein the rotation speed is 180-240 r/min during stirring, adding triethanolamine, stirring for 30-50 min under the environment of 55-60 ℃ and the rotation speed is 260-320 r/min during stirring, and obtaining a mixed matrix; and S3, taking magnesium chloride, petroleum sodium sulfonate and a mixed matrix according to a mass ratio of 1:2:7, placing the magnesium chloride, the petroleum sodium sulfonate and the mixed matrix into a stirrer for heating and mixing treatment, and obtaining a mixed preparation finished product after mixing. Preferably, in the step S1, the added mass of the