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CN-122012045-A - Slurry system suitable for drilling complex rock stratum and preparation method and application thereof

CN122012045ACN 122012045 ACN122012045 ACN 122012045ACN-122012045-A

Abstract

The invention discloses a slurry system suitable for drilling complex rock formations, and a preparation method and application thereof, wherein the slurry system comprises 1-8 parts of bentonite, 0.03-0.32 part of sodium carbonate, 0.1-1 part of filtrate reducer, 0.1-0.5 part of coating inhibitor, 0.10-0.15 part of viscosity reducer and 100 parts of water, wherein 23-41g of rock slag is added into every 100mL of bentonite slurry. And (3) uniformly mixing and stirring the raw material components, and adding an alkali solution to adjust the pH value to be neutral or slightly alkaline to prepare the slurry system suitable for drilling the complex rock stratum. The slurry system can be used for preparing drilling fluid for drilling complex rock formations in Erdos areas and the like. The invention can solve the problems of large rock slag quantity, high intrusion concentration of inferior solid phase in slurry, high rheological property, high filtration loss and high mud skin quality control difficulty in the existing complex rock stratum drilling process.

Inventors

  • DING ZHENYU
  • JING GUOYE
  • LIU ZHIQIANG
  • YU JIANSHUI
  • DENG JIANMING
  • TANG ZHENG
  • ZHANG HONGFEI

Assignees

  • 天地科技股份有限公司
  • 北京中煤矿山工程有限公司

Dates

Publication Date
20260512
Application Date
20251230

Claims (10)

  1. 1. A slurry system suitable for drilling complex rock formations is characterized by comprising 1-8 parts of bentonite slurry, 0.03-0.32 part of sodium carbonate, 0.1-1 part of filtrate reducer, 0.1-0.5 part of coating inhibitor, 0.10-0.15 part of viscosity reducer and 100 parts of water, wherein 23-41g of rock slag is added into every 100mL of bentonite slurry.
  2. 2. The mud system for drilling complex rock formations according to claim 1, wherein the fluid loss additive is carboxymethyl cellulose and/or polyanionic cellulose, the coating inhibitor is polyacrylamide potassium salt KPAM and/or zwitterionic polymer strong coating agent FA367, and the viscosity reducer is viscosity reducer XY-27 and/or sodium tripolyphosphate.
  3. 3. The slurry system suitable for drilling complex rock formations according to claim 2, wherein bentonite meets the requirements in GB/T5005-2010, carboxymethyl cellulose and polyanionic cellulose meet the requirements in GB/T5005-2010, polyacrylamide potassium salt KPAM meets the requirements in SY/T5946-2019, and viscosity reducer XY-27 meets the requirements in SY/T5695-2017.
  4. 4. A mud system for drilling complex rock formations according to claim 3, wherein the carboxymethyl cellulose is low viscosity carboxymethyl cellulose CMC-LVT or high viscosity carboxymethyl cellulose CMC-HVT, the polyanionic cellulose is low viscosity polyanionic cellulose PAC-LV or high viscosity polyanionic cellulose PAC-HV, the coating inhibitor is polyacrylamide potassium salt KPAM, and the viscosity reducer is viscosity reducer XY-27.
  5. 5. A mud system for drilling complex rock formations according to claim 1, wherein the rock slag is taken from rock slag of 100-900m well depth in the area to be drilled, the in situ density of the rock slag is 2.0-3.0g/cm3, and the rock slag is sieved through a 100 mesh sieve.
  6. 6. The slurry system for drilling complex rock formations according to claim 1, wherein the bentonite slurry comprises, by weight, 3-5 parts of bentonite, 0.1-0.2 part of sodium carbonate, 0.1-0.3 part of a filtrate reducer, 0.1 part of a coating inhibitor, 0.1 part of a viscosity reducer and 100 parts of water, and the mass of sodium carbonate is 3% -4% of the mass of bentonite.
  7. 7. The mud system for drilling complex formations of claim 1, wherein the density is 1.15-1.23g/cm3, the water loss is less than or equal to 25mL/30min, the mud skin thickness is less than or equal to 1.5mm, the sand content is less than or equal to 2wt%, and the pH is 7-8.
  8. 8. A method for preparing a mud system suitable for drilling complex rock formations, comprising the steps of: (1) Weighing raw material components according to the proportion of the raw materials of a slurry system for standby, wherein the raw materials of the slurry system comprise 1-8 parts of bentonite, 0.03-0.32 part of sodium carbonate, 0.1-1 part of a filtrate reducer, 0.1-0.5 part of a coating inhibitor, 0.10-0.15 part of a viscosity reducer and 100 parts of water, and 23-41g of rock slag is added into each 100mL of bentonite slurry; (2) Mixing and stirring all the raw material components uniformly, and then standing and curing to obtain mixed slurry; (3) Adding an alkali solution into the mixed slurry to adjust the pH to be neutral or alkaline, thereby obtaining the slurry system which is suitable for drilling complex rock stratum according to any one of claims 1-7.
  9. 9. The method for preparing the slurry system suitable for drilling complex rock formations according to claim 8, wherein in the step (2), the mixing and stirring time is 20-30min, the standing and curing time is 18-30h, in the step (3), the alkali solution is 5-15% NaOH solution by mass fraction, and the pH of the slurry system is adjusted to 7-8.
  10. 10. Use of a mud system for drilling into complex rock formations, characterized in that a mud system for drilling into complex rock formations according to any of claims 1-7 is used for the preparation of drilling fluids in the region of erdos.

Description

Slurry system suitable for drilling complex rock stratum and preparation method and application thereof Technical Field The invention relates to the technical field of drilling. In particular to a mud system suitable for complex rock stratum drilling, a preparation method and application thereof. Background Because the dwarfism stratum in the western region contains a large amount of mudstone, the mudstone is characterized in that the original rock has certain strength and hardness, and is rapidly mudized when meeting water after being broken by a drill bit cutter. The slurry making capability of part of the well section is extremely strong, so that the viscosity and specific gravity of slurry in a well bore are rapidly increased, the value exceeding the drilling requirement is exceeded, the drilling construction efficiency is affected, and the viscosity reduction treatment is required to be continuously carried out. The most effective method is to dilute the slurry by adding water, but the slurry cannot be directly discharged outside due to the environmental protection at present, and solid-liquid separation treatment is needed. The sodium tripolyphosphate is adopted as the viscosity reducer on site, so that the viscosity of the slurry can be reduced within a certain time, and the solid phase of the slurry can be reduced by using a mechanical mode, but the sodium tripolyphosphate can cause other performance fluctuation of the slurry, and the treatment capacity of the mechanical solid control device is insufficient, so that the requirement of site construction is difficult to meet. The stratum drilled in the construction of the Erdos area is complex and changeable, the stratum is penetrated by a drill bit, and the stratum near the well wall loses mechanical balance, so that accidents such as scattering, collapse, rock-soil accumulation, diameter expansion or diameter reduction of the wall of the well can occur. When drilling is carried out on clay layers or silt layers with strong hydration, if the viscosity of slurry is too high and the length of the slurry is too fast, the drill bit can be wrapped, the drilling is blocked when the treatment is improper, the drilling tool cannot be lifted to rotate and cannot be blocked completely, and hundreds of meters of drilling tools are buried underground, so that engineering is scrapped. In a formation having a strong crevice property, mud leakage occurs to different extents. Therefore, in the process of vertical well drilling in the Erdos area, the problems of large rock slag quantity, high intrusion concentration of poor solid phase in slurry and large rheological property, filtration loss and mud skin quality control difficulty are faced, and a slurry system for drilling a complex stratum still needs to be further studied. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a slurry system suitable for drilling a large-diameter ultra-deep vertical well of a water-rich complex rock stratum, and a preparation method and application thereof, so as to solve the problems of large rock slag quantity, high intrusion concentration of inferior solid phase in slurry, and large rheological property, filtration loss and mud skin quality control difficulty in the conventional complex rock stratum drilling process. In order to solve the technical problems, the invention provides the following technical scheme: A slurry system suitable for drilling complex rock stratum is composed of bentonite slurry and rock slag, wherein 23-41g of rock slag is added into every 100mL of bentonite slurry, and the bentonite slurry is composed of 1-8 parts by weight of bentonite, 0.03-0.32 part by weight of sodium carbonate, 0.1-1 part by weight of filtrate reducer, 0.1-0.5 part by weight of coating inhibitor, 0.10-0.15 part by weight of viscosity reducer and 100 parts by weight of water. The fluid loss additive is carboxymethyl cellulose and/or polyanion cellulose, the coating inhibitor is polyacrylamide potassium salt KPAM and/or zwitterionic polymer strong coating agent FA367, and the viscosity reducer is viscosity reducer XY-27 and/or sodium tripolyphosphate. The mud system suitable for drilling complex rock stratum is characterized in that bentonite meets the requirements of GB/T5005-2010, carboxymethyl cellulose and polyanion cellulose meet the requirements of GB/T5005-2010, polyacrylamide potassium salt KPAM meets the requirements of SY/T5946-2019, and viscosity reducer XY-27 meets the requirements of SY/T5695-2017. The slurry system suitable for drilling complex rock stratum is characterized in that the carboxymethyl cellulose is low-viscosity carboxymethyl cellulose CMC-LVT or high-viscosity carboxymethyl cellulose CMC-HVT, the polyanion cellulose is low-viscosity polyanion cellulose PAC-LV or high-viscosity polyanion cellulose PAC-HV, the coating inhibitor is polyacrylamide potassium salt KPAM, and the viscosity reducer is viscosity reducer XY