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Preparation method of mud for salt formation drilling

A technology for mud and salt layers, applied in drilling compositions, chemical instruments and methods, etc., can solve problems such as dissolving wellbore, melting wellbore, affecting drilling speed, etc., so as to restrain shrinkage and reduce the probability of stuck pipe accident Effect

Inactive Publication Date: 2016-02-03
成都棕通石油配件有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

If the drilling fluid density is too high, it can inhibit the shrinkage of the wellbore, but it will affect the drilling speed and increase the drilling cost; the unsuitable salt saturation may dissolve the wellbore, resulting in a belly hole or insufficient melting resulting in a shrinkage of the wellbore
[0003] The current mud cannot fundamentally solve the technical problems of salt layer drilling

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] A method for preparing mud for drilling in salt formations, comprising the following steps:

[0016] a. Base slurry preparation: prepare a bentonite aqueous solution with a mass concentration of 4%, and pre-hydrate for 24 hours to obtain the base slurry;

[0017] b. Add sulfonated pitch to the base slurry obtained in step a, and mix well to obtain mixture A;

[0018] c. Adjust the mixture A obtained in step b to pH=10.5 with sodium hydroxide, then add gypsum, sulfomethyl phenolic resin, sodium humate, sodium carboxymethylcellulose and SPAN-80 in sequence, and stir well to obtain mixture B;

[0019] D, sodium chloride is added in the mixture B that step c obtains, obtains the mixture C that chlorine ion concentration is greater than 180,000 ppm;

[0020] e. Add iron titanate to the mixture C obtained in step d, and adjust the density to be greater than 1.25g / cm 3 , to obtain the mud for drilling in the salt layer.

Embodiment 2

[0022] A method for preparing mud for drilling in salt formations, comprising the following steps:

[0023] a. Base slurry preparation: prepare a bentonite aqueous solution with a mass concentration of 4%, and pre-hydrate for 24 hours to obtain the base slurry;

[0024] b. Add sulfonated pitch to the base slurry obtained in step a, and mix well to obtain mixture A;

[0025] c. Adjust the mixture A obtained in step b to pH=11 with sodium hydroxide, then add gypsum, sulfomethyl phenolic resin, sodium humate, sodium carboxymethylcellulose and SPAN-80 in sequence, and stir well to obtain mixture B;

[0026] D, add sodium chloride in the mixture B that step c obtains, obtain the mixture C that chlorine ion concentration is 190,000 ppm;

[0027] e. Add iron titanate to the mixture C obtained in step d to adjust the density to 1.3g / cm 3 , to obtain the mud for drilling in the salt layer.

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PUM

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Abstract

The present invention provides a preparation method of mud for salt formation drilling in oil drilling and production, and belongs to the field of oil drilling engineering. In order to solve the problem that current ordinary mud cannot meet the complex situations of salt drilling, the invention provides the preparation method of mud for salt formation drilling. The method comprises: preparing base mud, adding sulfonated asphalt into the base mud to obtain a mixture, and adding sodium hydroxide into the mixture to adjust pH of the mixture to 10.5-11; adding gypsum, sulfur methyl phenol resin, humic acid sodium, sodium carboxymethyl cellulose and SPAN-80 successively into the mixture; using sodium chloride to adjust concentration of chloride ion of the mixture to be greater than 180,000 ppm; and finally using iron titanate to adjust density of the mixture to be greater than 1.25g / cm<3> to obtain the finished product. According to the preparation method provided by the invention, choice of feedstocks and adjustment of an adding sequence of the feedstocks, the prepared mud can not only inhibit contraction of the wellbore, but also avoid the influence on drilling speed, thereby reducing an incident probability of sticking of tool during salt drilling, and being capable of wide application to salt drilling.

Description

technical field [0001] The invention belongs to the field of oil field drilling engineering, and in particular relates to a method for preparing mud used for drilling in salt layers in oil drilling. Background technique [0002] During the drilling process, encountering salt formations will bring great risks to drilling, and the occurrence of stuck pipe accidents will seriously affect the smooth progress of drilling, and even cause the wellbore to be scrapped. The main reason is that after the formation is drilled, the original stress balance of the salt rock is destroyed, which makes the salt rock around the borehole wall move to the center of the borehole diameter. In actual engineering, undersaturated brine drilling fluid and appropriate drilling fluid density are usually used to drill through the salt layer well. Reasonable drilling fluid density and salt saturation are often determined empirically or qualitatively. If the drilling fluid density is too high, it can res...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/24
Inventor 吴兵张宇肖剑锋
Owner 成都棕通石油配件有限公司