Film formation drilling fluid applicable to coal-bed gas well and preparation method thereof

A coalbed methane well and drilling fluid technology, applied in the field of sandstone formation operations, can solve the problems of reservoir damage, plugging and film formation, etc., to reduce electrical and surface energy, prevent wellbore instability, The effect of reducing fluid loss

Inactive Publication Date: 2014-01-22
CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the patent still has the following problems: the main component of the film-forming agent in the film-forming drilling fluid is silicate, and the silicate is strongly alkaline (generally, the pH is above 10), and the coal rock in the coalbed methane reservoir section has a strong alkali Sensitivity, if the pH is too high, the permeability of coal and rock will decrease and damage the reservoir; the main mechanism of action of silicate is that its silanol group reacts with calcium and magnesium ions in formation water or clay minerals in fractures to form silanol

Method used

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  • Film formation drilling fluid applicable to coal-bed gas well and preparation method thereof

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Effect test

Embodiment 1

[0045] A film-forming drilling fluid suitable for coalbed gas wells, comprising the following components in mass percentage:

[0046] 4% pre-hydrated soil slurry;

[0047] Viscosity enhancer 0.1%;

[0048] Film former 2.0%;

[0049] Coating flocculant 0.1%;

[0050] Plugging agent 0.2%;

[0051] Stoppage agent 1.0%;

[0052] Alkalinity regulator 0.05%;

[0053] The balance is water.

[0054] A preferred implementation of this example is that the viscosity-increasing agent is prepared from hydroxyethyl cellulose HEC and carboxymethyl cellulose CMC in a mass ratio of 2:1. This is a preferred mode, but not limited thereto.

[0055] In this embodiment, the film-forming agent is prepared from polyvinyl alcohol (PVA) and at least one of sodium formate, potassium formate, potassium organosilicate or KCL in any proportion.

[0056] Yet another preferred implementation of this embodiment is that the coating flocculant is prepared from potassium polyacrylate (K-PAM) and cationic...

Embodiment 2

[0062] This embodiment is basically the same as the above-mentioned embodiment, the main difference is:

[0063] A film-forming drilling fluid suitable for coalbed gas wells, consisting of the following components in mass percentage:

[0064] Pre-hydrated Huaban soil slurry 10.0%

[0065] Viscosity enhancer 0.3%;

[0066] Film former 5.0%;

[0067] Coating flocculant 0.3%;

[0068] Plugging agent 5.0%;

[0069] Stoppage agent 10.0%

[0070] Alkalinity regulator 0.2%;

[0071] The balance is water.

[0072] In this embodiment, the viscosity-increasing agent is carboxymethylcellulose CMC or polyanionic cellulose PAC-H.

[0073] In this embodiment, the film-forming agent is prepared from sodium formate and polyvinyl alcohol in a mass ratio of 2:1.

[0074] In this example, the coating flocculant is prepared from potassium polyacrylate (K-PAM) and cationic polyacrylamide (CPAM) in a mass ratio of 1:1.

[0075] In this embodiment, the plugging agent is prepared from 325-m...

Embodiment 3

[0079] This embodiment is basically the same as the above-mentioned embodiment, the main difference is:

[0080] A film-forming drilling fluid suitable for coalbed gas wells, consisting of the following components in mass percentage:

[0081] 6.0% pre-hydrated soil slurry;

[0082] Viscosity enhancer 0.2%;

[0083] Film former 3.0%;

[0084] Coating flocculant 0.2%;

[0085] Plugging agent 3.0%;

[0086] Alkalinity regulator 0.1%;

[0087] The balance is water.

[0088] In this embodiment, the film-forming agent is prepared from polyvinyl alcohol (PVA), potassium organosilicate and KCL in any proportion.

[0089] In this example, the coating flocculant is prepared from potassium polyacrylate (K-PAM) and cationic polyacrylamide (CPAM) according to the mass ratio of 1:1.5.

[0090] The plugging agent is prepared from one or more of 325-mesh calcium carbonate, 1250-mesh ultra-fine calcium carbonate or sulfonated asphalt in any proportion.

[0091] The leak-stopping agent ...

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Abstract

The invention discloses a film formation drilling fluid applicable to a coal-bed gas well and a preparation method thereof. The film formation drilling fluid comprises the following components in percentage by mass: 0.1-0.3% of tackifying agent, 2.0-5.0% of film forming agent, 0.1-0.3% of coated flocculant, 0.2-5.0% of blocking agent, 1.0-10.0% of plugging agent, 0.05-0.2% of alkalinity regulator and the balance of water. By adopting the film formation drilling fluid disclosed by the invention, a low-permeability blocking layer can be quickly formed at the coal pore throat so as to prevent the fluid or solid phase from entering the coal bed, effectively prevent and slow down fluid loss and prevent the easily-hydrated substances in the coal cleat and crack from expanding, dispersing and polluting the reservoir stratum.

Description

technical field [0001] The invention relates to a film-forming drilling fluid suitable for coalbed methane wells and a preparation method thereof, which is applicable to coalbed methane wells and formation sections with large voids and high permeability, and also suitable for sandstones with high permeability in reservoir sections Strata work. Background technique [0002] my country's coalbed methane resources are very rich, but the exploration and development of coalbed methane in my country is still in its infancy. With the continuous deepening of coalbed methane development, the problems of coalbed wellbore stability and coalbed reservoir protection during drilling have become increasingly prominent, which seriously restricts the large-scale development and commissioning of coalbed methane. If a downhole complex accident occurs when drilling in coal and rock sections, it will not only delay the progress of the project but also cause significant economic losses. [0003...

Claims

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Application Information

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IPC IPC(8): C09K8/24
CPCC09K8/10C09K8/12C09K8/206C09K8/24
Inventor 林海陈磊张振活黎金明凡帆郑玉辉董海东蒋振伟涂海海董宏伟张宇郝超刘婷婷赵向阳崔贵涛陈龙
Owner CHINA NAT PETROLEUM CORP CHUANQING DRILLING ENG CO LTD
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