A stepwise sand adding method for shale gas fracturing

A pressure and step technology, applied in the direction of earthwork drilling, wellbore/well components, production fluid, etc., can solve the problems of increasing construction procedures and engineering costs, sand plugging, affecting the effect of reservoir transformation, etc., to achieve the improvement of liquid sand carrying Efficiency, Increased Net Pressure, Enhanced Effects

Inactive Publication Date: 2019-03-05
重庆矿产资源开发有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0002] In the fracturing of shale gas reservoirs, the slug-type sand-adding process is often used, that is, pumping a sand-adding slug, and then pumping a liquid slug, so that the sand ratio gradually increases. The sand slug has a constant sand addition ratio, and the critical point of sand addition cannot be predicted, which may easily cause sand plugging, increase subsequent construction procedures and engineering costs, and affect the effect of reservoir stimulation

Method used

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  • A stepwise sand adding method for shale gas fracturing
  • A stepwise sand adding method for shale gas fracturing
  • A stepwise sand adding method for shale gas fracturing

Examples

Experimental program
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Embodiment 1

[0017] Table 1 uses the stepwise sand injection pumping procedure (overview) for fracturing a certain shale gas well as a specific description.

[0018] This embodiment includes the following steps:

[0019] (1) Pumping pre-fluid: use surface high-pressure pumping equipment to pump 120 cubic meters (6 wellbore volumes) of pre-fluid into the wellbore, and the liquid enters the formation to create fractures.

[0020] (2) Pump the first sand-adding slug, and after the pre-fluid enters the formation to create fractures, start to add proppant quartz sand to the fracturing fluid to fill the fractures, with 40 cubic meters (2 wellbore volumes) of sand fluid As a sand-adding slug, 62.5% of the volume before the first sand-adding slug is added with sand at a ratio of 1%, and the sand ratio is constant. After the first sand-added slug, 37.5% of the volume is added with sand at a ratio of 2%.

[0021] (3) Pump the first liquid slug, use 35 cubic meters (1.7 wellbore volume) of fracturin...

Embodiment 2

[0029] In this embodiment, the stepwise sand addition method for fracturing is shown in the table below, and the pumping procedure is as follows:

[0030]

[0031] The well is a shale gas horizontal well in the southeastern area of ​​Chongqing. Through the stepped sanding fracturing process, the subsequent sanding space of the wellbore passing through different formations can be effectively predicted, the sand-carrying efficiency of the liquid is improved, and the potential of different formations is initially explored. The critical sanding point provides a reliable basis for subsequent drilling trajectory design and fracturing scheme design. At the same time, at the second sanding slug, the construction pressure is stable and basically remains unchanged, indicating that the formation has good sanding properties and increases Up to 3 different sand ratios, gradually increasing in increments of 1%, increase the sand volume and liquid sand-carrying efficiency in fracturing sti...

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Abstract

The invention relates to a shale gas fracturing stepping sand-adding method which comprises the following steps: (1) pumping a prepared fluid into a shaft and causing the fluid enter into ground gaps; (2) pumping a first sand-adding section plug and performing the stepping sand adding; (3) pumping a first fluid section plug, and if the pressure shows as diagonal rising, confirming that the pressure change is mild and the sand ratio has a rising potential, and then skipping to the step (4), and if the pressure shows as the sand ratio rising unsuitable for the present stage, further pumping the fracturing fluid for forming gaps and then skipping to the step (1); (4) pumping a second sand-adding section plug and performing the stepping sand adding; (5) pumping a second fluid section plug and observing the pressure variation trend of the sand-adding section plug at different sand ratios after entering into the stratum; and (6) repeating the steps (4)-(5) for 15-20 times till meeting the requirement for designed fracturing sand-adding volume, completing the sand adding in each stage, and lastly, pumping the displacing liquid and completing the whole fracturing construction task. According to the invention, the stepping sand-adding method is adopted for effectively preventing reservoir sand blocking, reducing the construction risk and guaranteeing the smooth construction.

Description

technical field [0001] The invention relates to the technical field of shale gas exploration and development fracturing engineering, in particular to a stepwise sand adding method for shale gas fracturing. Background technique [0002] In the fracturing of shale gas reservoirs, the slug-type sand-adding process is often used, that is, pumping a sand-adding slug, and then pumping a liquid slug, so that the sand ratio gradually increases. The sand slug has a constant sand addition ratio, and the critical point of sand addition cannot be predicted, which may easily cause sand plugging, increase subsequent construction procedures and engineering costs, and affect the effect of reservoir stimulation. Contents of the invention [0003] In order to overcome the above-mentioned defects in the prior art, the object of the present invention is to provide a stepwise sanding method for shale gas fracturing, which can effectively prevent reservoir sand plugging and reduce construction ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/267
CPCE21B43/267
Inventor 姚光华王晓泉董卫军廖金华邓洪军宜伟谭秀华熊鑫张宇周游
Owner 重庆矿产资源开发有限公司
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