Segmented acidifying method for low-pressure blocking horizontal well of ultra-low permeability oil deposit

A horizontal well, ultra-low permeability technology, applied in chemical instruments and methods, earthwork drilling, wellbore/well components, etc., can solve the problems of short validity period, short validity period of daily liquid production decline, difficulty in establishing an effective displacement system, etc. To achieve the effect of convenient and simple construction and short cycle

Inactive Publication Date: 2019-12-03
PETROCHINA CO LTD
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  • Summary
  • Abstract
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  • Application Information

AI Technical Summary

Benefits of technology

This technology allows for better control over acidifying treatments during drilling operations while also reducing environmental impact compared with traditional methods like bullseye or nitrogen gas flooding techniques. It achieves this through multiple stages of treatment that involve different types of fluids such as oils, acids, proppants, etc., along with various tools used on top of them.

Problems solved by technology

This patented technical problem addressed in this patents relates to studying methods used during drilling operations when treatments aimed towards reducing flow restrictions can cause damage to oil producing formations such as shale gas deposits that have been developed through hydrocracking processes. These treatment techniques involve injecting acids into specific areas within the hydrocarbon bearing rock layers near fault zones where there may be significant amounts of unconventional resources like bitumen from which crude oil cannot easily escape without being forced downhole. However, these conventional ways require high pump pressures and long periods before they work effectively. Existing solutions involving chemical agents also suffer issues related to their effectiveness over longer times.

Method used

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  • Segmented acidifying method for low-pressure blocking horizontal well of ultra-low permeability oil deposit

Examples

Experimental program
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Effect test

Embodiment 1

[0028] A method for staged acidizing of low-pressure plugged horizontal wells in ultra-low permeability reservoirs, comprising the following steps:

[0029] S1. According to the reservoir characteristics of ultra-low permeability reservoirs, select the type of horizontal well pattern, specifically five-point area well pattern or seven-point area well pattern;

[0030] S2. According to the well pattern of the horizontal well selected in step S1, design the structure of the multi-stage sliding sleeve acidizing string, then connect the multi-stage sliding sleeve acidizing string, and lower the connected multi-stage sliding sleeve acidizing string into the wellbore of the horizontal well until design location;

[0031] S3. According to the pattern of horizontal wells selected in step S1, design the corresponding number of acidizing construction layers, and deploy the operation mode of each layer;

[0032] S4. Carry out acidizing operation or joint operation of acidizing and reple...

Embodiment 2

[0037] On the basis of Example 1, in the step S2, the multi-stage sliding sleeve acidizing string includes a check valve, an injector, a first-stage sliding sleeve seat, and a first-stage K344 packer that are sequentially connected from the bottom of the well to the wellhead. Device, first-level sliding sleeve injector, first-level chamfering tool tubing, second-level sliding sleeve seat, second-level K344 packer, second-level sliding sleeve injector, second-level chamfering tool tubing... n-level sliding sleeve seat, N-level K344 packer, n-level sliding sleeve injector, n-level chamfering tool tubing, n-level K344 packer, n-level chamfering tool tubing and tool tubing.

[0038] Furthermore, the multi-stage sliding sleeve acidizing string of the five-point area well pattern includes a check valve, an injector, a first-stage sliding sleeve seat, a first-stage K344 packer, and a first-stage sliding sleeve connected sequentially from the bottom of the well to the wellhead. Sleeve...

Embodiment 3

[0041]On the basis of Example 1, further, in the step S3, when the selected horizontal well pattern is a five-point area well pattern, the number of acidizing construction layers of the five-point area well pattern is designed to have 4 sections, wherein 1, The acidizing operation is carried out in the 4th section, and the combined operation of acidizing and replenishing energy is carried out in the 2nd and 3rd sections; when the selected horizontal well pattern is a seven-point area well pattern, the number of acidizing construction sections of the seven-point area well pattern is designed to be 5 sections, of which 2 1, 4 sections carry out combined operation of acidification and supplementary energy, and 1, 3, 5 sections carry out acidizing operation.

[0042] Furthermore, the acid liquid used in the acidizing operation is organic earth acid, and the pumping volume is 30-40 m 3 , with a displacement of 1.0-2.0 m 3 / min, the liquid used in the energy replenishment operation...

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Abstract

The invention belongs to the technical field of segmented acidification of horizontal wells of oil fields, and in particular relates to a segmented acidifying method for a low-pressure blocking horizontal well of an ultra-low permeability oil deposit. For the blocking horizontal well, the holding level of formation pressure kept smaller than 80%, with a five-point or seven-point area well patternof the horizontal well of the ultra-low permeability oil deposit, immovable strings of the horizontal well are segmentally acidified by combining a K344 packer, a sliding sleeve ejector, a sliding sleeve ball seat and the like by adopting multi-stage sliding sleeve acidifying strings. A displacement fracturing fluid is injected to a segment without a corresponding water injection well to supplement stratum energy during segmented acidification, and blowout for backflushing and production restoration are carried out in 1-2 days after closing the well and diffusing after acidification. The segmented acidification and energy supplementation of the horizontal well are integrated to achieve a purpose of same layer displacement, so that a segmented acidifying effect of the horizontal well is further improved.

Description

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Claims

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Application Information

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Owner PETROCHINA CO LTD
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