Horizontal well re-fracturing method for tight oil reservoir

A technology for horizontal wells and tight oil, which is applied in the field of oil recovery in oil and gas fields. It can solve the problems of small oil increase and low recovery rate, and achieve the effects of increased oil increase effect, enhanced recovery rate, and reservoir energy recovery.

Inactive Publication Date: 2018-11-13
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The invention provides a method for repeated fracturing of horizontal wells in tight oil reservoirs, so as to overcome the problems of low oil increase and low recovery after repeated fracturing in the prior art

Method used

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  • Horizontal well re-fracturing method for tight oil reservoir
  • Horizontal well re-fracturing method for tight oil reservoir
  • Horizontal well re-fracturing method for tight oil reservoir

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0076] Construction method: casing injection, general fracturing of combined layers.

[0077] Before fracturing, inject 13000m of active water according to 1.5 times of the previous liquid production volume 3 ;

[0078] Construction pressure limit: KQ70 / 65 type fracturing wellhead, casing head pressure 70, construction pressure limit 68Mpa, when the pressure reaches 65MPa, take measures to prevent the pressure from exceeding the limit pressure;

[0079] Fracturing construction: inject 2000m of fracturing fluid according to 0.23 times of the previous fluid production volume 3 . The liquid system adopts the whole slick water type fracturing fluid, the proppant adopts 40-70 mesh (52MPa) low-density ceramsite, and the total amount of proppant is 42m 3 .

[0080] The specific operation steps are as follows:

[0081] Step 1: After checking that all aspects of fracturing construction meet the quality and safety regulations, start formal construction according to the on-site comm...

example 2

[0094] Construction method: casing injection, general fracturing.

[0095] Before fracturing, inject 15,000m of active water according to the requirements of the water injection energy enhancement process 3 ;

[0096] Construction pressure limit: KQ78-65 / 105 type fracturing wellhead, casing head pressure 105MPa, construction pressure limit 85MPa, when the pressure reaches 75MPa, take measures to prevent the pressure from exceeding the limit pressure;

[0097] Fracturing construction: inject 1000m of fracturing fluid 3 . The liquid system adopts full-range slippery water type fracturing fluid, and the proppant adopts 40-70 mesh (52MPa) low-density ceramsite, with a total volume of 28m 3 ;

[0098] The specific operation steps are as follows:

[0099] Step 1: After checking that all aspects of fracturing construction meet the quality and safety regulations, start formal construction according to the on-site command instruction;

[0100] Step 2: Pressure test of ground equi...

example 3

[0111] Construction method: casing injection, general fracturing.

[0112] Before fracturing, inject 8300m of active water according to the requirements of the water injection energy enhancement process 3 ;

[0113] Construction pressure limit: KQ130 / 78-105 type fracturing wellhead, construction pressure limit 85Mpa. The pressure test of the ground high-pressure pipeline is 85Mpa. When the pressure reaches 75MPa, take measures to prevent the pressure from exceeding the pressure limit;

[0114] Fracturing construction: inject 915m of fracturing fluid 3 . The liquid system adopts full-range slippery water type fracturing fluid, and the proppant adopts 40-70 mesh (52MPa) low-density ceramsite, with a total volume of 28m 3 ;

[0115] The specific operation steps are as follows:

[0116] Step 1: After checking that all aspects of fracturing construction meet the quality and safety regulations, start formal construction according to the on-site command instructions;

[0117]...

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Abstract

The invention provides a horizontal well re-fracturing method for a tight oil reservoir. The horizontal well re-fracturing method for the tight oil reservoir comprises the steps that active water is injected into a fractured interval by using a tubing passage according to the liquid producing amount of a horizontal well; according to the liquid producing amount and the length of a well section ofthe horizontal well, fracturing fluid and fracturing fluid containing a proppant are alternately injected into the fractured interval by using a casing passage; and a wellhead is closed, when the wellhead pressure drops less than a preset value within the preset duration range, blowout and flowback are carried out. According to the horizontal well re-fracturing method, the oil production increasing effect is significantly improved.

Description

technical field [0001] The invention relates to the technical field of oil recovery in oil and gas fields, in particular to a method for repeated fracturing of horizontal wells in tight oil reservoirs. Background technique [0002] The downhole fracturing process is to use the surface high-pressure pump group to inject high-viscosity liquid into the well with a large displacement, and to suffocate high pressure near the bottom of the well. When the pressure exceeds the ground stress and the tensile strength of the rock, fractures are formed in the formation. The fracturing fluid with proppant continues to be injected into the fracture to propel the fracture forward and fill the fracture with proppant. The formed fractures expand oil and gas flow channels and improve formation permeability. [0003] With the deepening of oilfield development, there are fewer and fewer conventional reservoirs, and more and more oil and gas exploration and development in unconventional reserv...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/267
CPCE21B43/267
Inventor 刘建伟张佩玉张宁县刘海廷龚万兴蒋明潘国忠马卫东雷繁王波
Owner PETROCHINA CO LTD
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