Acid fracturing test method for fracture-vug type carbonate rock test piece

A carbonate rock, acid fracturing technology, applied in the direction of applying stable tension/pressure to test material strength, measuring devices, instruments, etc., can solve problems that limit the research progress of carbonate rock acid fracturing tests

Pending Publication Date: 2021-11-16
INST OF ROCK AND SOIL MECHANICS - CHINESE ACAD OF SCI
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AI-Extracted Technical Summary

Problems solved by technology

The natural fractures and caves contained in carbonate rocks often have strong randomness, and it is difficult to find multiple identical fract...
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Abstract

The invention discloses an acid fracturing test method for a fracture-vug type carbonate rock test piece. The method comprises the following steps of: forming a fracture-vug type carbonate rock spliced body by utilizing the fracture-vug type carbonate rock test piece; forming a test sample by using the fractured-vug type carbonate rock spliced body; building an acid fracturing test system; placing the test sample in the acid fracturing test system; setting working parameters of the acid fracturing test system; and monitoring a test result of the acid fracturing test system. According to the acid fracturing test method for the fracture-vug type carbonate rock test piece, the interaction condition of an acid fracturing crack and a natural fracture-vug body can be effectively simulated, and parameter optimization is carried out on a carbonate oil and gas reservoir site acid fracturing construction process; and the acid fracturing process of the carbonate reservoir is reduced to the maximum extent, so that guidance is provided for the acid fracturing process.

Application Domain

Material strength using tensile/compressive forces

Technology Topic

Carbonate rockNatural fracture +4

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  • Acid fracturing test method for fracture-vug type carbonate rock test piece
  • Acid fracturing test method for fracture-vug type carbonate rock test piece
  • Acid fracturing test method for fracture-vug type carbonate rock test piece

Examples

  • Experimental program(2)
  • Effect test(1)

Example Embodiment

[0131] Example 1
[0132] like Figure 2-4, in the embodiment of the present application, the regular-shaped carbonate rock block is divided into several smaller divided blocks 1 by means of splitting, and drilling or partial knocking is performed on the dividing surface 3 of the divided block 1 Drill artificial holes 2 to simulate hydrochloric rock salt caves. The plurality of divided blocks 1 are re-spliced ​​and fixed according to the initial position. The produced splicing cracks 5 simulate natural cracks, and the remaining splicing cracks 5 are filled with slaked lime slurry to form a CaCO2-based crack filling layer 6. Wait for the slaked lime to solidify. The junction formed a complete fracture-cavity carbonate splicing body. The fracture-cavity carbonate rock spliced ​​body is placed in the center of the mold, and the remaining space of the mold is poured with cement slurry to form a cement outer body 7, and the specimen is formed by curing for more than 7 days. After the cement outer body 7 is solidified, cured and formed, the artificial wellbore 4 is consolidated inside the rock by means of integral drilling and refilling of the formed fracture-cavity carbonate rock specimen. When the acid fracturing test is carried out, the formed fracture-cavity carbonate rock sample needs to be put into the triaxial fracturing test machine, the triaxial stress σ1-σ2-σ3 is applied to the sample, and the injection line 9 is connected to the injection pipe. The fluid pump 8 and the artificial wellbore 4 are turned on, and the fluid injection pump 8 is turned on to inject the acid fracturing fluid into the specimen, and observe the circulation and acid corrosion of the acid fluid inside the fracture-cavity specimen. The acid fracturing construction process is tested and optimized by changing the type and concentration of acid liquid, adjusting the in-situ stress, and adjusting the density of spliced ​​fractures 5, artificial holes 2 and fracture filling layers 6, etc.

Example Embodiment

[0133] Example 2
[0134] like Figure 5-7 , in the embodiment of the present application, the regular-shaped carbonate rock block is divided into several smaller divided blocks 1 by means of plane cutting, and drilling or partial knocking is performed on the dividing surface 3 of the divided block 1 Drill artificial holes 2 to simulate hydrochloric rock salt caves. The plurality of divided blocks 1 are re-spliced ​​and fixed according to the initial position. The produced splicing cracks 5 simulate natural cracks, and the remaining splicing cracks 5 are filled with slaked lime slurry to form a CaCO2-based crack filling layer 6. Wait for the slaked lime to solidify. The junction formed a complete fracture-cavity carbonate splicing body. The fracture-cavity carbonate rock spliced ​​body is placed in the center of the mold, and the remaining space of the mold is poured with cement slurry to form a cement outer body 7, and the specimen is formed by curing for more than 7 days. After the cement outer body 7 is solidified, cured and formed, the artificial wellbore 4 is consolidated inside the rock by means of integral drilling and refilling of the formed fracture-cavity carbonate rock specimen. When the acid fracturing test is carried out, the formed fracture-cavity carbonate rock sample needs to be put into the triaxial fracturing test machine, the triaxial stress σ1-σ2-σ3 is applied to the sample, and the injection line 9 is connected to the injection pipe. The fluid pump 8 and the artificial wellbore 4 are turned on, and the fluid injection pump 8 is turned on to inject the acid fracturing fluid into the specimen, and observe the circulation and acid corrosion of the acid fluid inside the fracture-cavity specimen. The acid fracturing construction process is tested and optimized by changing the type and concentration of acid liquid, adjusting the in-situ stress, and adjusting the density of spliced ​​fractures 5, artificial holes 2 and fracture filling layers 6, etc.
[0135] The present application provides an acid fracturing test method for fracture-cavity carbonate rock specimens, which can effectively simulate the interaction between acid fracturing fractures and natural fracture-cavity bodies, and provides an on-site acid fracturing construction process for carbonate oil and gas reservoirs. Carry out parameter optimization; reduce the acid fracturing process of carbonate reservoirs to the maximum extent, so as to provide guidance for the process of acid fracturing.

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