Acid fracturing method

A technology of acid fracturing and fracturing, which is applied in the field of oil or shale gas exploitation. It can solve problems such as difficult rock surface morphology, rapid collapse of protrusions, and decreased conductivity, so as to reduce temperature, increase the length of acid-etched fractures, The effect of increasing stability

Active Publication Date: 2021-04-13
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, no matter which technology or liquid is used, it is difficult to control the surface morphology of the rock after fracturing, and all the non-uniform etched walls are formed, and these non-uniform etched walls mostly present point-like unevenness, and some There will be grooves or small pit-shaped bumps. Under the condition of high closure stress, there will be obvious stress concentration on the wall surface, which will cause the protrusion to collapse rapidly due to excessive force, resulting in crack closure or blockage. Rapid decline or loss, rapid decline in production capacity

Method used

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Effect test

Embodiment 1

[0059] Acid fracturing is performed through the following process:

[0060] (1) Evaluation of key reservoir parameters

[0061] Including physical properties, rock mechanical parameters, three-dimensional in-situ stress, development of natural fractures, etc., methods such as seismic, well logging, mud logging, and pilot well core laboratory testing and analysis can be used.

[0062] (2) Determination of well completion method

[0063] If the open hole completion method is used to complete the well, the open hole sliding sleeve segmental fracturing method can be used, or the casing completion method can be used, and the bridge plug perforation technology can be used for segmental fracturing construction.

[0064] (3) Optimization of fracture parameters

[0065] On the basis of geological modeling in step (1), use commercial software such as ECLIPSE, which has the simulation function of acid fracturing with dual-media or triple-media simulation function, to set artificial fra...

Embodiment 2

[0085] A deep carbonate reservoir in the Tarim Basin was exploited by using the acidizing fracturing process as in Example 1. The well depth of the carbonate reservoir is 6,500 meters. 3 / min displacement injection 240m 3 The viscosity of the fracturing fluid is 100mPa.s, and then the fracturing fluid is 3m 3 / min displacement, use 1-3mPa.s slick water to carry 40-60 purpose shielding and protecting agent into 3 slugs, and the injection concentration of shielding and protecting agent is 200-500kg / m 3 , the displacement of the injected displacement fluid is 6m 3 / min, the displacement fluid used is slick water. The total liquid volume of the shielding agent is 4m 3 , the replacement fluid volume is 4m 3 , alternately for 3 times, after the construction of this stage, stop the pump for 15 minutes. Then sequentially use 3m 3 / min displacement injection 10mPa.s acid 60m 3 , 4m 3 / min displacement injection 30mPa.s acid liquid 60m 3 , 6m 3 / min displacement injection 50m...

Embodiment 3

[0088] The acid fracturing process as in Example 1 is used to exploit a certain deep carbonate reservoir. The well depth is 7480 meters. 3 / min displacement injection 300m 3 Fracturing fluid with a viscosity of 100mPa.s, and then 8m 3 / min of displacement with slippery water to carry 40-60 mesh first shielding agent and inject 3 slugs. The injection concentration of the first shielding agent is 400kg / m 3 , carried by slick water with a viscosity of 3mPa.s, the replacement fluid is the same slick water, and the total liquid volume at this stage is 42m 3 , where the first slug, carrying fluid is 5m 3 , the replacement fluid is 5m 3 ;Second slug with 6m of carrier fluid 3 , the replacement fluid is 8m 3 ; the third slug, the carrier fluid is 8m 3 , the displacement fluid is 10m 3 ; equal time intervals between each slug. After the construction at this stage, stop the pump for 20 minutes.

[0089] Then sequentially use 4m 3 / min displacement injection 15mPa.s acid solut...

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Abstract

The invention discloses a novel acid fracturing method. The method comprises the steps that crack forming is conducted through first fracturing fluid; and a carrying fluid containing a first shielding protective agent and a displacement fluid is alternately added into the obtained cracks, then acid liquid etching is conducted, and finally a fracturing composition containing a second fracturing fluid and a second shielding protective agent is added. According to the novel acid fracturing method, the long-time stable flow conductivity of the fracturing cracks is effectively improved, and the method can be used for efficient and stable mining of deep carbonate reservoirs.

Description

technical field [0001] The invention belongs to the field of petroleum or shale gas exploitation, in particular to an acidizing fracturing method. Background technique [0002] The acid fracturing method is to use acid liquid as fracturing fluid under the fracture pressure higher than the formation, and carry out fracturing without proppant. During the acid fracturing process, the wall surface of the crack is eroded into an uneven surface by the dissolution of the acid liquid, so that the wall surface of the crack will not be completely closed after the pump is stopped and the pressure is relieved. Compared with fracturing that relies entirely on the physical action of proppant, it has higher flow conductivity and higher productivity. [0003] This method has been efficiently and widely used in general carbonate reservoirs, but at present, more and more deep carbonate reservoirs are discovered, such as Tahe Oilfield of Sinopec, whose burial depth is generally above 5000m. ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/26E21B43/267E21B43/22
CPCE21B43/26E21B43/267E21B43/16
Inventor 蒋廷学周珺曾义金王宝峰孙同成贾文峰罗攀登
Owner CHINA PETROLEUM & CHEM CORP
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