Abstract：

The development of unconventional shale oil and gas is of great significance for ensuring China's energy security. In the process of shale oil and gas hydraulic fracturing in China, casing deformation is very serious, which restricts the development of shale oil and gas in China. After fracturing operation in Dagang Guandong Shale Oil Block, the casing deformation rate was 66%. After analyzed the fault data of the Guandong shale oil block, it was found that the casing deformation area had a high overlap with the well trajectory and fault intersection, which indicated that the casing deformation is closely related to the fault slip during fracturing. The deformation area of the casing was measured by the MIT (The Multi Finger Imaging Tool) tool, and the obtained data were inversed based on the SolidWorks software to obtain the deformed casing 3D model. The analysis results of the deformation characteristics of the model showed that the deformation characteristics of the casing are strongly related to the movement direction of the fault and the direction of observation, and it does not always show the classic S-shaped deformation characteristics. The casing in this area is mainly squeezed by the strike slip fault moving in the horizontal direction, so the casing section can be observed to be compressed and expanded in the vertical fault dislocation direction. To study the influence of fault shearing on the casing, a formation-cement sheath-casing model (containing fault) was established by using Abaqus software, and the fault slip was simulated by controlling the displacement boundary conditions, and the sensitivity analysis of geo stress changes of casing caused by different fault dip angles and strike were carried out. The research results showed that: (1) The deformation characteristics of the casing are related to the observation direction. When the observing direction paralleled to the fault movement direction, the compression expansion characteristics could be observed; When the observing direction perpendicular to the fault movement direction, the S-shaped shear deformation characteristics could be observed; (2) The profile of the casing in the deformation area under the influence of fault squeeze will be elliptical, and the squeezed direction is consistent with the short axis direction of the section; (3) the larger the dip angle of a horizontally moving fault, the smaller the displacement when the casing reaches the ultimate strength; under the geo stress condition of the block, with the fault strikes 45°, the displacement of the casing reaches the ultimate strength is minimum. The research results provided a basis for determining whether the casing deformation is caused by fault slip.

Key words：Guandong oil field; shale oil; hydraulic fracturing; casing deformation; MIT measurement; fault slip

Received： 2020-06-19

Corresponding Authors： dengjingen@cup.edu.cn

Cite this article：闫伟, 王孔阳, 邓金根, 唐庆, 步宏光, 檀朝东, 阴启武, 秦飞翔. 断层错动型套管变形特征分析——以大港官东页岩油为例. 石油科 学通报, 2022, 04: 543-554 YAN Wei, WANG Kongyang, DENG Jingen, TANG Qing, BU Hongguang, TAN Chongdong, YIN Qiwu, QIN Feixiang. Analysis on the deformation characteristics of casing caused by fault slip-A case study of Dagang Guandong shale oil. Petroleum Science Bulletin, 2022, 04: 543-554.

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