Optimization of reservoir stimulation scheme based on fine fracture evaluation and mechanical activity analysis and its application in Bozi block

doi:10.3969/j.issn.1672-7703.2017.06.006

Abstract

Abstract: The fractured tight sandstone reservoir in the Kuqa foreland basin is ultra-deep with ultra-high pressure. To obtain economic productivity from the reservoir, it is essential to stimulate the potential of natural fractures with appropriate strategy. Based on the fine fracture evaluation and logging interpretation, the mechanical activity of natural fractures is studied, and accordingly the reservoir stimulation treatment is optimized. Through numerical simulation and theoretical analysis, it is found that the effectiveness of natural fractures, in addition to the dip angle and dip direction, has a significant effect on the mechanical activity of fractures during the treatment, and the calculation method of the shear activation pressure of the fracture is given. The effectiveness of fractures is evaluated comprehensively in respect of mud loss events, quantitative analysis of imaging logging parameters, core analysis, R/S scale-variable analysis and so on, and the classification criteria for such reservoir fractures is put forward. According to the analysis on mechanical activity of natural fractures, the customized stimulation strategies are proposed. To be specific, different fracturing strategies, such as volumetric acid fracturing, fracture network fracturing and large-scale sand fracturing, can be employed for three types of reservoirs with different fracture development features. In this way, the reservoir stimulation scheme is improved. The improved scheme has been satisfactorily applied in the Bozi block in the western Kuqa basin. As a result, the actual production is significantly higher compared with adjacent wells. This scheme facilitates theoretically and technically the effective production of nearly 100 billion cubic meters of reserves in the block.

Key words: integration method, fracture effectiveness, mechanical activity, fracturing strategy, Bozhi block

CLC Number:

TE357.1

Zhang Yang, Wang Zhenlan, Fan Wentong, Zheng Zijun, Li Wei, Yu Yinhua, Teng Qi. Optimization of reservoir stimulation scheme based on fine fracture evaluation and mechanical activity analysis and its application in Bozi block[J]. China Petroleum Exploration, 2017, 22(6): 47-58.

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