Apparatus and method for mechanical sealing evaluation of cement sheath in large-scale fracturing

A mechanical seal and cement sheath technology, applied in the field of testing and experimental devices, can solve the problems of inability to compare the performance of cement sheaths, quantitative analysis, etc.

Active Publication Date: 2019-07-05
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Existing literature reports use the simulated wellbore to carry out qualitative analysis of the sealing performance of the cement sheath, without actual field simulation and stress-strain measurement. Therefore, the existing technology cannot obtain the results of quantitative analysis and relevant data support, so it is impossible to analyze different Therefore, it is impossible to provide experimental tests and data basis for the selection of cement slurry system

Method used

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  • Apparatus and method for mechanical sealing evaluation of cement sheath in large-scale fracturing
  • Apparatus and method for mechanical sealing evaluation of cement sheath in large-scale fracturing

Examples

Experimental program
Comparison scheme
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example 1

[0043] The test temperature was slowly raised from room temperature to 85°C within 24 hours, and 2MPa gas was injected into the bottom annulus to maintain gas stability, and the circumferential stress of the cement sheath was measured to be 0.52MPa. The temperature was slowly raised to 120°C within 48 hours, the pressure at the top of the annulus was 1.9MPa, the peak circumferential stress of the cement ring was 2.3MPa, and the seal of the cement ring failed. Confirm that the cement sheath has failed due to thermal expansion, and record the relevant data.

example 2

[0045] The test temperature was 23°C, and the gas pressure was 2MPa injected into the bottom of the cement sheath. The inner cylinder of the annulus model is pressurized by a liquid booster pump, and the pressurization rate is 10MPa / 10min. When the internal pressure is 30MPa, the circumferential stress of the cement sheath is 1.4MPa, the top pressure is 0MPa, and the acoustic wave detection instrument does not detect the sound signal. When the internal pressure of the model was 61.5MPa, the measured circumferential stress decreased from 2.3MPa to 0MPa, the bubble detector showed a clear peak, the sound wave detected a clear peak, and the pressure at the top of the model was 1.8MPa. It was confirmed that the internal pressure overload caused tensile failure of the cement sheath, resulting in the failure of the cement sheath seal.

Embodiment 3

[0047] The experimental temperature increased slowly from 23 °C, and the maximum temperature did not exceed 85 °C. The bottom of the cement sheath was injected with a gas pressure of 2 MPa, and the inner cylinder of the annulus model was pressurized by a liquid booster pump, and the experimental pressure was pressurized at a rate of 10 MPa / 10min. When the internal pressure is 30MPa, the circumferential stress of the cement sheath is measured to be 1.7MPa, the top pressure is 0MPa, and no sound signal is detected by the acoustic wave detection instrument. When the internal pressure of the model was 55MPa, the measured circumferential stress decreased from 2.3MPa to 0MPa, the bubble detector showed a clear peak, the sound wave detected a clear peak, and the pressure at the top of the model was 1.8MPa.

[0048] After comparing the data of the above three examples with the cement sheath without experiment, it can be seen that the change of temperature and pressure causes the seali...

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Abstract

The invention discloses a device and method for mechanical property evaluation and mechanical sealing evaluation of a cement ring when large fracturing is performed. The device comprises a to-be-measured cement ring, an inner cylinder sleeving an inner surface of the cement ring, an outer cylinder sleeving an outer surface of the cement ring, a pressure-adjustment mechanism connected with the inner cylinder to adjust a pressure acting on an inner wall of the cement ring, a temperature control mechanism connected with the cement ring and controlling temperature of the cement ring, and a detection assembly for detecting a stress state, a stress size and mechanical sealing performance of the cement ring. The device can test mechanical properties and mechanical sealing performance of the cement ring well, and a data support is provided for selection of a cement slurry system when large hydrofracture of, especially, an unconventional reservoir layer occurs.

Description

technical field [0001] The invention relates to a test experiment device, in particular to a device and method for evaluating the mechanical sealing performance of a cement sheath during large-scale fracturing, especially for large-scale hydraulic fracturing conditions. Background technique [0002] In recent years, the development of unconventional oil and gas has become a hot spot in the development of the domestic oil industry. Since unconventional oil and gas (especially shale oil, shale gas, tight sandstone oil, tight sandstone gas, etc.) belong to low-porosity and low-permeability reservoirs, large-scale hydraulic fracturing is required. Large-scale hydraulic fracturing requires high mechanical properties of cement sheath, such as elasticity and toughness of cement sheath, and requires effective isolation between sections. Therefore, it is necessary to simulate staged fracturing to evaluate the mechanical properties and mechanical sealing properties of cement sheaths,...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): G01M13/005G01M3/04
Inventor陶谦周仕明杨红歧汪晓静
OwnerCHINA PETROLEUM & CHEM CORP