Water-based clay-free drilling fluid and application of drilling fluid to polar region frozen soil stratigraphical drilling

A drilling fluid and clay-free technology, which is applied in the direction of drilling compositions, chemical instruments and methods, etc., can solve problems such as viscosity increase, and achieve good mud shale expansion, high environmental protection requirements, and good lubricity effects

Active Publication Date: 2020-02-18
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to overcome the defects in the prior art that the viscosity of the drilling fluid increases greatly with the decrease of the temperature, which leads to flow obstacles and cause drilling engineering problems, and takes into account the unique environmental characteristics of ultra-low temperature and coexistence of ice and water in the polar permafrost stratum, and provides a Environment-friendly water-based clay-free drilling fluid and its application in polar permafrost drilling, the water-based clay-free drilling fluid can be used in polar permafrost drilling

Method used

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  • Water-based clay-free drilling fluid and application of drilling fluid to polar region frozen soil stratigraphical drilling
  • Water-based clay-free drilling fluid and application of drilling fluid to polar region frozen soil stratigraphical drilling
  • Water-based clay-free drilling fluid and application of drilling fluid to polar region frozen soil stratigraphical drilling

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preparation example Construction

[0034] According to the present invention, the modified starch can be obtained by preparation, wherein the preparation method comprises: the modified starch is made of corn starch, 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and acrylamide (AM ) a zwitterionic modified starch fluid loss reducer obtained after copolymerization; wherein, the conditions of the copolymerization include: the initiator is 0.3% ammonium persulfate, the reaction temperature is 50°C, and the reaction time is 8h.

[0035] According to the present invention, the polyanion cellulose is a low-viscosity polyanion cellulose, the VP value is less than 1 when the water addition amount is 4ppd, and the API filtration loss is less than 10mL. In the present invention, it can be purchased from Hebei Hengju Chemical Co., Ltd., the model is LV-PAC.

[0036] According to the present invention, the blocking agent is selected from one or more of ultrafine calcium carbonate, graphite and nano microspheres; preferab...

Embodiment 1

[0049] This example is to illustrate the water-based clay-free drilling fluid of the present invention.

[0050] Prepared water-based clay-free drilling fluid, which contains:

[0051] 80 parts by weight of water, 45 parts by weight of ultra-low temperature base fluid, 0.3 parts by weight of viscosifier, 0.6 parts by weight of fluid loss control agent, 2 parts by weight of plugging agent, and 2 parts by weight of lubricant.

[0052] Wherein, the ultra-low temperature base fluid is mixed with sodium chloride and ethylene glycol at a mass ratio of 5:4, and the freezing point of the ultra-low temperature base fluid is -29°C; and, at normal temperature, the ultra-low temperature base fluid The thermal conductivity is 0.49W / m K;

[0053] Wherein, the tackifier is xanthan gum;

[0054] Wherein, the fluid loss reducer is formed by mixing hydroxyethyl cellulose and modified starch according to a mass ratio of 1:1;

[0055] Wherein, the plugging agent is an average particle diameter...

Embodiment 2

[0058] This example is to illustrate the water-based clay-free drilling fluid of the present invention.

[0059] Prepared water-based clay-free drilling fluid, which contains:

[0060] 85 parts by weight of water, 48 parts by weight of ultra-low temperature base fluid, 0.3 parts by weight of viscosifier, 0.7 parts by weight of fluid loss reducer, 2 parts by weight of plugging agent, and 2 parts by weight of lubricant.

[0061] Wherein, the ultra-low temperature base fluid is mixed with sodium chloride and ethylene glycol at a mass ratio of 1:1, and the freezing point of the ultra-low temperature base fluid is -28°C; and, at normal temperature, the ultra-low temperature base fluid The thermal conductivity is 0.48W / m K;

[0062] Wherein, the tackifier is xanthan gum;

[0063] Wherein, the fluid loss reducer is formed by mixing hydroxyethyl cellulose and modified starch according to the mass ratio of 3:4;

[0064] Wherein, the plugging agent is an average particle diameter of ...

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Abstract

The invention relates to the field of drilling fluids for petroleum, natural gas and natural gas hydrate drilling and discloses a water-based clay-free drilling fluid and application of the drilling fluid to polar region frozen soil stratigraphical drilling. The drilling fluid comprises an ultralow-temperature base liquid, a tackifier, a filtrate reducer, a blocking agent, a lubricating agent andwater, wherein the ultralow-temperature base liquid is composed of inorganic salt and alcohol, the solidifying point of the ultralow-temperature base liquid is lower than or equal to -28 DEG C, and the heat conduction coefficient is smaller than 0.5W/m.K. The water-based clay-free drilling fluid has good rheological properties, filtration properties, low heat conduction characteristics, well wallstability and environment-friendliness even under the condition of -25 DEG C and can be applied to polar region frozen soil stratigraphical drilling.

Description

technical field [0001] The invention relates to the field of drilling fluid for oil, natural gas and natural gas hydrate drilling, in particular to a water-based clay-free drilling fluid and its application in drilling in polar frozen ground formations. Background technique [0002] The oil reserves in the polar regions are extremely rich. According to survey data from Russia and other countries, the crude oil reserves in the Arctic region alone are about 400×10 8 m 3 (250 billion barrels), which is equivalent to 25% of the current global proven crude oil reserves, and natural gas reserves are about 80×10 12 m 3 , accounting for 41% of global natural gas reserves. Compared with conventional land and ocean drilling, due to the harsh conditions such as the special geographical environment of the polar region and extremely low ambient temperature, it has brought great challenges to drilling development equipment and technology. As the blood of drilling engineering, drilling...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/12
CPCC09K8/12C09K2208/10C09K2208/12C09K2208/22C09K2208/34
Inventor 邱正松张玉彬陈曾伟钟汉毅赵欣慕佳兴
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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