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Protection drilling fluid for low-pressure reservoir

A technology for reservoir protection and oil layer protection, which is applied in the field of drilling fluid, can solve the problems of ineffective prevention of formation hydration expansion, poor plugging effect, and ineffective control of drilling hydraulic pressure loss, so as to protect wellbore conditions and prevent Effect of migration and prevention of hydration expansion

Inactive Publication Date: 2013-12-18
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] However, in the prior art represented by the above-mentioned patent documents, the pressure loss water in the drilling fluid cannot be effectively controlled, and the hydration and expansion of the formation cannot be effectively prevented, so the plugging effect is poor

Method used

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  • Protection drilling fluid for low-pressure reservoir
  • Protection drilling fluid for low-pressure reservoir
  • Protection drilling fluid for low-pressure reservoir

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] The following components are used to prepare the drilling fluid for protecting reservoirs in low-pressure reservoirs above Chang 8 in Longdong Oilfield. According to the weight percentage, the weight ratio of clean water is 90.7%, the weight ratio of polyanionic cellulose (high viscosity) is 0.3%, and the weight ratio of sulfonated asphalt is 0.5%, add polyanionic cellulose (low viscosity) by weight 0.3%, add caustic soda by weight 0.2%, add hydroxypropyl starch by weight 2%, oil layer protective agent by weight 3%, white clay by weight 3%. Formation protection reservoir drilling fluid.

[0022] Polyanionic Cellulose (PAC)

[0023] PAC, divided into high viscosity (HV) and low viscosity (LV), can be used as thickener, rheology control agent, adhesive, stabilizer, protective colloid, suspending agent and water retaining agent; in the oil exploration industry Among them, PAC is a better drilling mud treatment agent and material for preparing completion fluid, with high m...

Embodiment 2

[0048] The following components are used to prepare the drilling fluid for protection of low-pressure oil reservoirs. According to the weight percentage, the weight ratio of clean water is 91.5%, the weight ratio of polyanionic cellulose (high viscosity) is 0.1%, the weight ratio of sulfonated bitumen is 0.5%, and the weight ratio of polyanionic fiber is added. The weight ratio of plain (low viscosity) is 0.2%, the weight ratio of caustic soda is 0.2%, the weight ratio of hydroxypropyl starch is 2.0%, the weight ratio of refueling layer protection agent is 2.5%, and the weight ratio of clay is 3%. drilling fluid.

Embodiment 3

[0050] The following components are used to prepare the drilling fluid for protection of low-pressure oil reservoirs. According to the weight percentage, the weight ratio of clean water is 91.2%, the weight ratio of polyanionic cellulose (high viscosity) is 0.3%, the weight ratio of sulfonated bitumen is 0.5%, and the weight ratio of polyanionic fiber is added. The weight ratio of plain (low viscosity) is 0.3%, the weight ratio of caustic soda is 0.2%, the weight ratio of hydroxypropyl starch is 1.5%, the weight ratio of refueling layer protection agent is 3.0%, and the weight ratio of white clay is 3%. drilling fluid.

[0051] In the application of Examples 2 and 3, the system also shows the effect of reducing water loss, good plugging effect and lubrication and drag reduction effect, the wellbore is stable during the drilling process, and the casing is smoothly run into the bottom of the well during the completion process.

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Abstract

The invention discloses a protection drilling fluid for a low-pressure reservoir and relates to the technical field of drilling fluids. The formula of the protection drilling fluid comprises the following components in percentage by weight: 0.1-0.3% of high-viscosity polyanionic cellulose, 0.5-1.0% of sulfonated asphalt, 0.1-0.3% of low-viscosity polyanionic cellulose, 0.1%-0.2% of caustic soda, 1-2% of fluid loss additive, 2-3% of oil layer protection agent, 2%-3% of white clay and the balance of water. The protection drilling fluid disclosed by the invention has the characteristics of good plugging effect, smooth, dense and film-like mud cake, low harm to the low-porosity, low-permeability and low-abundance reservoir, and simplicity and easiness in formulation and operation of a pulp mixing process.

Description

[0001] technical field [0002] The invention relates to the technical field of drilling fluids, in particular to a drilling fluid for protection of low-pressure oil reservoirs. Background technique [0003] The oil reservoirs in the Longdong Oilfield are typical low-permeability, low-pressure, and low-yield "three-low" reservoirs. Reservoir protection, as an effective measure to increase production in the development process of low-permeability oilfields, plays a very important role in oilfield measures to stabilize production and slow down decline. role. However, with the continuous discovery of new blocks, the increase of new development layers, and the gradual extension of development time, more and more reservoirs have the characteristics of low formation pressure, low production after production, or rapid decline in production after production. It is becoming increasingly important to minimize drilling fluid pollution during drilling, how to relieve the increasingly c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/24C09K8/035C09K8/487
Inventor 董宏伟马祥林张长庚曲波许玉生
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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