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Drilling fluid and its application in tight sandstone reservoir or fractured tight sandstone reservoir

A drilling fluid and densification technology, applied in the field of drilling fluids, can solve problems such as unsuitability of plugging layers, achieve the effects of small filtration loss at high temperature and high pressure, stabilizing reservoirs, and improving pressure bearing capacity and stability

Active Publication Date: 2022-03-29
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to overcome the problem that the sealing layer formed by the drilling fluid in the prior art is not suitable for fractured tight sandstone reservoirs, and to provide a drilling fluid and its application in tight sandstone reservoirs or fractured tight sandstone reservoirs. The drilling fluid has the characteristics of inhibiting collapse, reducing water lock damage, reducing fluid loss, improving wellbore stability, and increasing permeability recovery value for tight sandstone reservoirs or fractured tight sandstone reservoirs.

Method used

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  • Drilling fluid and its application in tight sandstone reservoir or fractured tight sandstone reservoir
  • Drilling fluid and its application in tight sandstone reservoir or fractured tight sandstone reservoir
  • Drilling fluid and its application in tight sandstone reservoir or fractured tight sandstone reservoir

Examples

Experimental program
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Effect test

Embodiment 1

[0057] According to weight percent, get 4% by weight of bentonite, 0.6% by weight of viscosifier (low-viscosity carboxymethylcellulose sodium CMC-LV), 2% by weight of high temperature and high pressure fluid loss reducer (SD201), 3% by weight of lignite Resin (SPNH), 0.3% by weight potassium polyacrylamide (KPAM), 2% by weight potassium chloride, 1.5% by weight hydrolyzed polyacrylonitrile ammonium salt (NH 4 HPAN), 4% by weight of high acid-soluble sulfonated pitch (FF-1), 2% by weight of lubricant (325 mesh graphite), 1% by weight of waterproof locking agent (SDFS-1), 10% by weight of weighting agent (limestone, 2.5 g / cm 3 ) and 69.6% by weight of water are stirred and mixed to form a density of 1.08g / cm 3 drilling fluid.

Embodiment 2

[0059] According to weight percentage, get 3% by weight of bentonite, 0.4% by weight of viscosifier (low viscosity sodium carboxymethylcellulose CMC-LV), 3% by weight of high temperature and high pressure fluid loss reducer (SD201), 2% by weight of lignite Resin (SPNH), 0.3% by weight potassium polyacrylamide (KPAM), 1.5% by weight potassium chloride, 1.5% by weight hydrolyzed polyacrylonitrile ammonium salt (NH 4 HPAN), 2% by weight of high acid-soluble sulfonated pitch (FF-1), 3% by weight of lubricant (600 mesh graphite), 0.4% by weight of waterproof locking agent (SDFS-1), 20% by weight of weighting agent (limestone, 2.5 g / cm 3 ) and 62.9% by weight of water are stirred and mixed to form a density of 1.15g / cm 3 drilling fluid.

Embodiment 3

[0061] According to weight percentage, get 2% by weight of bentonite, 0.5% by weight of viscosifier (low-viscosity carboxymethylcellulose sodium CMC-LV), 2% by weight of high temperature and high pressure fluid loss reducer (SD202), 3% by weight of lignite Resin (SPNH), 0.5% by weight potassium polyacrylamide (KPAM), 1% by weight potassium chloride, 0.5% by weight hydrolyzed polyacrylonitrile ammonium salt (NH 4 HPAN), 3% by weight of high acid-soluble sulfonated pitch (FF-1), 1% by weight of lubricant (10000 mesh graphite), 0.8% by weight of waterproof locking agent (SDFS-1), 15% by weight of weighting agent (limestone, 2.5 g / cm 3 ) and 70.7% by weight of water are stirred and mixed to form a density of 1.10g / cm 3 drilling fluid.

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Abstract

The invention relates to the field of drilling fluid used in tight sandstone reservoirs, and discloses a drilling fluid and its application in tight sandstone reservoirs or fractured tight sandstone reservoirs. Wherein, based on the total amount of the drilling fluid, the drilling fluid includes: 2-4% by weight of bentonite, 0.4-0.6% by weight of viscosifier, 4-6% by weight of fluid loss control agent, and 1.7-5% by weight of inhibitor , plugging and anti-slumping agent 1-5% by weight, lubricant 1-3% by weight, waterproof locking agent 0.4-1% by weight, dense pressure-bearing temporary plugging agent 0-4% by weight, weighting agent 0-20% by weight, water 51.4-89.5% by weight, the density of the drilling fluid is 1.05-1.15g / cm 3 . The drilling fluid prepared with the above ratio has the characteristics of inhibiting collapse, reducing water lock damage, reducing fluid loss, improving wellbore stability, and high permeability recovery value for tight sandstone reservoirs or fractured tight sandstone reservoirs. .

Description

technical field [0001] The invention relates to the field of drilling fluid used in tight sandstone reservoirs, in particular to a drilling fluid and its application in tight sandstone reservoirs or fractured tight sandstone reservoirs. Background technique [0002] In recent years, with the continuous improvement of oil and gas exploration and development, the development of tight sandstone oil and gas resources has gradually increased. China's tight sandstone oil and gas are widely distributed in large sedimentary basins such as Ordos, Sichuan, Songliao, Tuha, and Tarim, among which Ordos Basin, Sichuan The basin has achieved commercial scale mining. [0003] The tight sandstone matrix has the characteristics of low porosity and low permeability. There are different degrees of fracture development in the tight sandstone reservoirs with oil and gas production capacity. formation damage, leading to a decrease in reservoir permeability. [0004] Fractured tight sandstone re...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/14
CPCC09K8/14C09K2208/12
Inventor 邱正松陈晓华王翔暴丹钟汉毅赵欣冯永超高健
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)