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Blocking removal construction process for removing barium strontium calcium compound scale pollution

A construction process and a technology for removing blockages, which are used in drilling compositions, cleaning tools, wellbore/well components, etc., which can solve the difficulty of increasing scale removal, corroding oil casings, and ineffective removal of pollution, etc. question

Inactive Publication Date: 2018-05-08
CNPC BOHAI DRILLING ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Most domestic oil fields need to use barite to increase the density during drilling and well completion, and the main components of barite are barium sulfate, strontium sulfate, and calcium sulfate. These are inorganic scales that cannot be removed by conventional pickling. Some oil reservoirs contain barium sulfate, strontium sulfate and calcium sulfate, which undoubtedly increases the difficulty of descaling
Although pickling or strong oxidants can be used to dissolve or oxidize a part of the complex scale near the wellbore, the downhole blockage is very complicated, generally it is the complex scale formed by the accumulation of inorganic scale and organic polymer scale, so the method of pickling and dissolution The effect is not ideal
Although some blockages can be removed by using invisible acid completion fluid, the acid (hydrochloric acid, spit acid, etc.) does not react with sulfate scales such as barium sulfate, strontium sulfate, and calcium sulfate, so the pollution cannot be effectively removed
In addition, pickling will also corrode the oil casing after completing the deblocking work of dealing with complex scale

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] The acidified layer of Well XX-1# in an oilfield in a certain area is the 300-313# layer of Liuyiyi Ⅳ Oil Group, and the target formation is pebbly fine sandstone: argillaceous cement, loose, and the cuttings are loose sand. Because the impurities in the layer continuously accumulate near the wellbore oil layer and the impurities around the wellbore pollute the low-permeability layer, resulting in low water absorption and high injection pressure, the plugging removal construction technology for removing barium-strontium-calcium composite scale pollution is used for plugging removal construction. The specific construction steps are as follows:

[0020] S1, use 10m 3 Descaling and blocking solution at 0.5m 3 / min displacement, 15MPa pump pressure for reverse replacement;

[0021] S2, use 20m 3 0.5m 3 / min displacement, 15MPa pump pressure for reverse replacement;

[0022] S3. After the clean water in step S2 is completely replaced, stop the pump and soak for 24 hours;

[0023] S...

Embodiment 2

[0029] The 2# well of XX Oilfield in a certain area is a water injection well. In order to better produce, I want to take acidification measures for this well. However, because the impurities contained in the layer continue to accumulate near the wellbore oil layer, the impurities around the wellbore pollute the low permeability layer. As a result, the water absorption capacity is low and the injection pressure is high. Therefore, the blocking removal construction technology for removing barium-strontium-calcium composite scale pollution is used to remove the blockage near the well to improve its water injection capacity. The specific construction steps are as follows:

[0030] S1, use 10m 3 Descaling and blocking solution at 0.5m 3 / min displacement, 15MPa pump pressure for reverse replacement;

[0031] S2, use 20m 3 0.5m 3 / min displacement, 15MPa pump pressure for reverse replacement;

[0032] S3. After the clean water in step S2 is completely replaced, stop the pump and soak for...

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PUM

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Abstract

The invention discloses a blocking removal construction process for removing barium strontium calcium compound scale pollution. The process includes the steps: scale removal and blocking removal reverse replacement; clear water reverse replacement; soaking and dissolving; clear water positive extruding; scale removal and blocking removal liquid positive extruding; clear water reverse extruding. According to the process, blocking of near-well-bore areas is removed, pollution caused by inorganic scales such as barium sulfate, strontium sulfate and calcium sulfate with difficultly-dissolved acidis effectively removed by the aid of a non-acid blocking removal liquid system, oil and gas recovery efficiency is improved, blocking of formation pore throat channels can be effectively removed, water injection rate is increased, water injection pressure is reduced, and a foundation is laid for subsequent improvement of oil and gas recovery efficiency.

Description

Technical field [0001] The invention relates to the technical field of oil and gas field environmental protection, in particular to a plugging removal construction process for removing barium-strontium-calcium composite scale pollution. Background technique [0002] In most domestic oilfields, during the drilling and completion process, barite is needed to increase the density. The main components of barite are barium sulfate, strontium sulfate, and calcium sulfate. These are inorganic scales that cannot be removed by conventional pickling. Some oil reservoirs contain barium sulfate, strontium sulfate, and calcium sulfate, which undoubtedly increases the difficulty of descaling. Although the use of pickling or strong oxidizers can dissolve or oxidize part of the composite scale near the well, the downhole blockage is very complicated, and is generally a composite scale formed by the accumulation of inorganic scale and organic polymer scale, so pickling and dissolution methods are...

Claims

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Application Information

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IPC IPC(8): E21B37/06C09K8/528
CPCE21B37/06C09K8/528
Inventor 刘音黄其任秋军姜有才王瑞泓王晓磊刘位杨东海高秀君张伟辉
Owner CNPC BOHAI DRILLING ENG
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