Marine facies natural gas hydrate storage compound drilling fluid

A drilling fluid and natural gas technology, applied in the field of natural gas hydrate exploitation, can solve problems such as temperature and pressure conditions damage, formation collapse pressure increase, well wall easy collapse and fracturing, etc., to reduce and prevent repeated fragmentation, and reduce formation leakage The degree of avoiding the effect of severely expanding the aperture

Inactive Publication Date: 2018-07-06
DALIAN DONGYOU RUIJIA PETROLEUM TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] (1) When drilling in natural gas hydrate formations, due to the release of formation stress near the well wall and bottom of the reservoir, the formation pressure will decrease; and the drill bit will cut rock, and the friction between the bottom drilling tool and the well wall and core will generate a large amount of Thermal energy destroys the temperature and pressure conditions for the stable existence of hydrates; thus triggering the decomposition of hydrates, resulting in instability of the well wall and adverse effects on drilling operations
[0004] (2) The invasion of drilling fluid and the decomposition of hydrates will lead to the increase of formation pore pressure in different degrees, and the increase of pore pressure will increase the density of drilling fluid required to maintain the stability of the wellbore wall, which not only seriously affects the penetration rate, but also increases the pressure of the wellbore wall. Seepage increases the pore pressure around the well, thereby further reducing the stability of the well wall and forming a vicious circle
Moreover, the decomposition of hydrates will also increase the permeability of the formation, and the drilling fluid will seep into the well wall to generate osmotic pressure, which will increase the collapse pressure of the formation and reduce the fracture pressure, making the well wall more likely to collapse and fracture, reducing the stability of the well wall
[0006] (4) For subsea natural gas hydrate storage, during the drilling process of natural gas hydrate storage, the decomposition of gas hydrate will rapidly increase the ultra-static pore pressure in the storage soil, which may cause submarine landslides or instability of the subsea foundation, which may lead to Cause damage to drilling holes, drilling platforms, submarine pipelines and other facilities
The above drilling fluids all have certain effects on the drilling of natural gas hydrate reservoirs, but none of them consider the use of compound hydrate inhibitors

Method used

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  • Marine facies natural gas hydrate storage compound drilling fluid

Examples

Experimental program
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Effect test

Embodiment 1

[0036] Embodiment 1, the contents of each component in the drilling fluid are: the mass ratio of sodium formate is 2.8%, the mass ratio of sodium chloride is 4.5%, the mass ratio of methanol is 4.5%, the mass ratio of ethylene glycol is 14%, and the mass ratio of potassium chloride is 14%. 4.5%, low viscosity carboxymethylcellulose LV-CMC mass ratio of 1.8%, potassium humate mass ratio of 1.8%, xanthan gum mass ratio of 0.4%, polyvinyl caprolactam mass ratio of 0.8%, propylene glycol The mass ratio of phenylene ether is 0.8%, the mass ratio of tetra-n-hexyltrimethylammonium bromide is 0.8%, and the remaining components are prepared water.

Embodiment 2

[0037] Embodiment two, the contents of each component in the drilling fluid are: the mass ratio of sodium formate is 3%, the mass ratio of sodium chloride is 5%, the mass ratio of methanol is 5%, the mass ratio of ethylene glycol is 15%, and the mass ratio of potassium chloride is 5%. 5%, low-viscosity carboxymethylcellulose LV-CMC mass ratio of 2%, potassium humate mass ratio of 2%, xanthan gum mass ratio of 0.5%, polyvinyl caprolactam mass ratio of 1%, propylene glycol The mass ratio of phenylene ether is 1%, the mass ratio of tetra-n-hexyltrimethylammonium bromide is 1%, and the remaining components are prepared water.

Embodiment 3

[0038] Embodiment three, the contents of each component in the drilling fluid are: the mass ratio of sodium formate is 3.2%, the mass ratio of sodium chloride is 5.5%, the mass ratio of methanol is 5.5%, the mass ratio of ethylene glycol is 16%, and the mass ratio of potassium chloride is 16%. 5.5%, low viscosity carboxymethyl cellulose LV-CMC mass ratio is 2.2%, potassium humate mass ratio is 2.2%, xanthan gum mass ratio is 0.6%, polyvinyl caprolactam mass ratio is 1.2%, propylene glycol The mass ratio of phenylene ether is 1.2%, the mass ratio of tetra-n-hexyltrimethylammonium bromide is 1.2%, and the remaining components are prepared water.

[0039] The drilling fluid configuration methods of the above-mentioned examples 1, 2, and 3 are conventional drilling fluid configuration methods, and are evaluated by the following experimental methods:

[0040] 1 Evaluation of drilling fluid shale hydration inhibition

[0041] Inhibition evaluation experiment is an important part of...

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Abstract

The invention discloses marine facies natural gas hydrate storage compound drilling fluid and relates to the field of exploitation of natural gas hydrate. The drilling fluid is prepared from the following components: sodium formate, sodium chloride, methyl alcohol, ethylene glycol, potassium chloride, low viscosity carboxymethyl cellulose (LV-CMC), potassium humate, xanthan gum, polyvinyl caprolactam, propylene glycol phenyl ether, tetrahexamethyltrimethylammonium bromide and prepared water; the drilling fluid can be used for marine facies natural gas hydrate storage drilling and has the effects of no solid phase and low temperature resistance. By adding a kinetic inhibitor and a synergist for compounding, the drilling fluid has a stronger hydrate formation inhibition effect; in addition,the drilling fluid components have little damage to the environment; the drilling fluid has the advantages of high efficiency, environment friendliness, low-priced and easily-obtained raw materials and the like.

Description

technical field [0001] The invention relates to a compound drilling fluid for marine natural gas hydrate storage, in particular to the field of natural gas hydrate exploitation. Background technique [0002] Natural gas hydrates are mainly distributed in the deep-water areas of the continental margins and the permafrost areas on land, and the former accounts for the vast majority of the discovered quantities. Natural gas hydrate is one of the potential alternative energy sources, and the research on natural gas hydrate is a hot spot in contemporary earth science and energy industry development research. There are a large amount of natural gas hydrates in seabed sediments. Drilling is an essential means to explore and develop natural gas hydrates at a certain depth underground. The phase equilibrium property of gas hydrate determines that drilling in this type of formation is very different from drilling in general oil and gas formations, and it also leads to more complex in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/12
CPCC09K8/12C09K2208/12C09K2208/22
Inventor 张晓丽袁鹏飞宋鑫王培龙李天民鲍春雷龚鑫晶李海洋黄岩
Owner DALIAN DONGYOU RUIJIA PETROLEUM TECH CO LTD
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