Water-based drilling fluid suitable for high well temperature and low formation pressure coefficient

A technology of formation pressure coefficient and water-based drilling fluid, which is applied in drilling compositions, chemical instruments and methods, etc., can solve the problems of low-density drilling fluid sticking and cutting difficult to maintain, insufficient plugging ability, easy to collapse, etc. Achieve long-term stability, low unit cost, and low environmental impact

Inactive Publication Date: 2016-10-26
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low pressure coefficient of the formation in the Dengying Formation, the formation is broken, easy to collapse, easy to leak, and because the conventional polysulfide drilling fluid is not capable of preventing collapse and plugging, when the well collapse occurs during drilling, increasing the drilling fluid density stabilizes the well wall and induces serious lost circulation , leaks and collapses coexist, the processing is complicated and takes a lot of time, and some wells are forced to complete drilling ahead of schedule
Conventional polysulfonate drilling fluids have the following disadvantages: ① Some treatment agents are easy to degrade under high temperature conditions, and it is difficult to maintain low-density drilling fluid viscosity and shear, resulting in excessive scouring and instability of the well wall; ② Insufficient plugging capacity can only be supported by increasing the drilling fluid density. wall
But there are also issues with hydrolytic and oxidative stability, low temperature fluidity, and foaming

Method used

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  • Water-based drilling fluid suitable for high well temperature and low formation pressure coefficient
  • Water-based drilling fluid suitable for high well temperature and low formation pressure coefficient
  • Water-based drilling fluid suitable for high well temperature and low formation pressure coefficient

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Embodiment 1

[0025] As a preferred embodiment of the present invention, it discloses a water-based drilling fluid suitable for high well temperature and low formation pressure coefficient, which consists of clear water, viscosifier, fluid loss reducer, plugging agent, stabilizer, pH Conditioner and weighting agent are prepared according to the ratio of parts by weight, clear water: viscosifier: fluid loss reducer: plugging agent: stabilizer: pH regulator: weighting agent = 100:10~15:15~25:9 ~15:1~2:0.5~1:35~60.

[0026] The tackifier is OCMA bentonite.

[0027] The fluid loss reducer is composed of 8-10 parts by weight of sulfonated phenolic resin SMP, 3-5 parts by weight of high temperature and salt-resistant fluid loss reducer RSTF, and 2-3 parts by weight of modified natural resin compound JNJS -220 blended.

[0028] The plugging agent is prepared by mixing 1-2 parts by weight of shale inhibitor SOLTEX, 2-3 parts by weight of modified resin bitumen YH-150, and 1-2 parts by weight of p...

Embodiment approach

[0036] As a best embodiment of the present invention, its preparation method is as follows: take clear water, viscosifier, fluid loss reducer, plugging agent, lubricant, pH regulator and weighting agent.

[0037] The specific ratio is: 400ml water, 48g OCMA soil, 60g SMP, 18g RSTF, 12g JNJS-220, 8g SOLTEX, 24g YH-150, 4g TYRF-1, 4g AB201, 3.2g caustic soda Weighted to 1.2g / cm 3 . After being fully stirred and mixed at 11000r / min, it was aged in a roller furnace at 130°C for 16 hours.

[0038] The measurement of basic performance parameters at 55°C is shown in Table 1:

[0039]

[0040] refer to figure 1 , The high-temperature and high-pressure filtration loss decreased significantly after 5 minutes and gradually decreased to zero after 40 minutes, achieving a good immediate plugging effect. Take out the formed filter cake, replace the drilling fluid with clean water and put it into the prepared high-performance drilling fluid high-temperature and high-pressure filter ca...

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Abstract

The invention discloses water-based drilling fluid suitable for high well temperature and a low formation pressure coefficient. The water-based drilling fluid is prepared by, by weight, 100 parts of clear water, 10-15 parts of tackifier, 15-25 parts of filtrate reducer, 9-15 parts of blocking agent, 1-2 parts of stabilizer, 0.5-1 part of pH regulating agent and 35-60 parts of weighting agent. The water-based drilling fluid has the advantages that the environment hazard of oil-based drilling fluid can be avoided, and the water-based drilling fluid has features of efficient sealing, multi-phase lubricating, composite inhibiting and weak gelling and is applicable to a long horizontal well with high well temperature (temperature resistance 150-180 DEG C) and low easy-to-collapse and formation pressure coefficient (below 1.4g / cm<3>).

Description

technical field [0001] The invention relates to the technical field of oil and gas drilling, in particular to a high-performance water-based drilling fluid suitable for shale gas horizontal wells. Background technique [0002] With the success of large-scale commercial development of shale gas in the United States, my country is also paying more and more attention to the exploitation and utilization of shale gas. From the Sinian to the Middle Triassic, my country has a wide range of developed marine deposits, with a distribution area of ​​more than 200 square kilometers and a cumulative maximum stratum thickness of more than 10Km. According to reliable exploration data, the shale gas in the Lower Cambrian Qiongzhusi Formation in the southern Sichuan Basin alone is 7.14-14.6×1012m 3 , which is 1-2 times of the existing conventional natural gas resources in the entire Sichuan Basin. Therefore, the development of shale gas has both broad application prospects and high strateg...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/24
CPCC09K8/24C09K2208/34
Inventor 谢显涛覃勇黄平蒋羿黎邓宇万伟
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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