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Fracturing method for opening new crack through crack saturated filling sand

A fracturing and sand filling technology, applied in the fields of fluid production, earthwork drilling, wellbore/well components, etc., can solve problems such as unsatisfactory measures, changes in oil drainage area, and difficulty in achieving expansion, so as to improve the final recovery. high rate, high controllability, and the effect of expanding the degree of utilization

Pending Publication Date: 2021-06-11
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The present invention provides a fracturing method for opening new fractures by filling them with sand. The purpose is to overcome the problem that the conventional repeated fracturing technology in the prior art only extends in the low-pressure area formed by the original artificial fractures and cannot enrich the remaining oil. In the extension of the high-pressure area, the old fractures are only filled and improved to improve the conductivity in the fractures. It is difficult to achieve the purpose of expanding the drainage area and changing the original displacement system, and the effect of the measures is not satisfactory.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] A fracturing method for opening new fractures by filling fractures with sand, comprising the following steps:

[0021] 1) Inject the pre-fluid into the target area with a small displacement;

[0022] 2) Inject proppant into the opened primary fracture, and add gel breaker during the injection of proppant, so that the primary fracture is filled with sand, forming sand plugging in the fracture, and increasing the net pressure value in the fracture;

[0023] 3) Increase the injection displacement of proppant in step 2), and further increase the net pressure value in the fracture in step 2) until opening a new lateral fracture and filling the new fracture;

[0024] 4) Perform main fracturing.

[0025] Compared with conventional refracturing, this fracturing method implements sand plugging inside the primary artificial fracture, and at the same time increases the injection displacement of proppant to further increase the net pressure in the fracture, opens new lateral fract...

Embodiment 2

[0028] On the basis of embodiment 1, further, the step 1) small displacement is 0.5-2.2m 3 / min. In actual operation, 0.5-2.2m 3 The role of the small displacement per minute is to open the artificial cracks that have been formed for the first time and have a certain geometric size for the subsequent entry of sand-carrying fluid.

[0029] Further, the injection pressure of the pad fluid in step 1) is less than or equal to the fracture extension pressure of the initial fracturing. In actual operation, the injection pressure of the pad fluid is less than or equal to the fracture extension pressure of the primary fracturing, which can avoid the secondary extension of the primary artificial fracture and achieve the purpose of controlling the fracture length.

[0030] Further, the preflush is active water or slick water. In actual operation, active water or slick water is used as the front fluid to filter out the liquid quickly after opening the initial fracture, so as to quickl...

Embodiment 3

[0040] On the basis of Example 2, a fracturing experiment was carried out by using the fracturing method of the present invention to open new fractures by filling the fractures with sand for an ultra-low permeability reservoir in Changqing Oilfield, including the following steps:

[0041] 1) Use 0.5-2.2m for the target area 3 / min into the slick water, the viscosity of the slick water is 20mPa s, and the filtration rate is 1.5×10 -3 m / min 0.5 ; The injection volume of slippery water is 18m 3 ;

[0042]2) Inject proppant stepwise into the opened primary fractures according to the ratio of sand to liquid of 20%, 30%, and 40%, and add ammonium persulfate with a concentration of 0.07% during the injection of proppant (sand-carrying fluid), Fill the primary fracture with sand to form a sand plug in the fracture and increase the net pressure value in the fracture; the injection amount of the 0.07% ammonium persulfate is 7Kg, and the injection amount of the sand-carrying liquid is...

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Abstract

The invention belongs to the technical field of oilfield development downhole operation fracturing, and particularly provides a fracturing method for opening a new crack through crack saturated filling sand. A proppant is continuously injected into a primary artificial crack according to a sand-liquid ratio of 20%, 30% and 40%, and a gel breaker is added in a process of adding the proppant, so that the saturated filling sand inside the primary artificial crack is enabled to cause sand plugging in the crack; meanwhile, the net pressure in the crack is further improved by improving the construction displacement, a lateral new crack is opened, effective support is formed for the new crack, the purposes of forming a complex crack system, expanding the using degree of lateral remaining oil and improving the single well yield and the final recovery efficiency of an oil well are achieved. The technological process is simple and easy to implement, the cost is lower, and the characteristics of high on-site temporary plugging and rising amplitude controllability can greatly improve the production benefit of an oil field, and has wide application prospects in the aspects of increasing the single-well yield of lateral low-yield oil wells of ultra-low permeability reservoirs and ultra-low permeability reservoirs and improving the water drive effect of the low permeability reservoirs.

Description

technical field [0001] The invention belongs to the technical field of fracturing in downhole operations for oil field development, and in particular relates to a fracturing method for opening new fractures by filling fractures with sand. Background technique [0002] Changqing Oilfield has typical characteristics of low pressure, low permeability, and low production. With the advancement of the development process, some ultra-low permeability and ultra-low permeability reservoirs have entered the middle and late stages of development, affected by factors such as poor reservoir physical properties and the development of natural fractures. However, oilfield development is faced with the problems of high recovery degree in the main direction of fractures, and the remaining oil on the plane is mainly enriched in the lateral direction of fractures, and it is difficult to establish a lateral oil well displacement system, which makes the recovery degree in the oil drainage range co...

Claims

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Application Information

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IPC IPC(8): E21B43/267
CPCE21B43/267
Inventor 卜军张矿生薛小佳卜向前李向平康博段鹏辉顾燕凌李转红梁院科
Owner PETROCHINA CO LTD
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