摘要
页岩气井的产能主要取决于支撑剂充填层裂缝和储层剪切滑移形成的自支撑裂缝提供的导流能力,目前对页岩自支撑裂缝导流能力变化规律和影响机理的认识仍不够充分,采用分形理论方法,引入裂缝开度分形维数和迂曲度分形维数对裂缝空间进行定量表征,建立了考虑闭合应力作用的自支撑裂缝导流能力数学模型。开展自支撑裂缝导流能力实验,结果显示初期裂缝导流能力可达30~50 D·cm,在40 MPa的闭合压力下仍可保持在1 D·cm以上;理论模型预测的结果与实验测试结果基本吻合;模型敏感性分析表明,裂缝开度分形维数与导流能力呈正相关关系;迂曲度分形维数与导流能力呈负相关关系。利用此方法可实现自支撑裂缝导流能力的快速、准确预测,为合理预测气井产能提供支撑。
The production capacity of shale gas wells primarily depends on the conductivity of the proppant filling layer fracture and the self-supporting fracture formed by the shear slip of the reservoir. Currently, our understanding of the variation law and mechanism that influences the self-supporting fracture conductivity of shale is insufficient. The fractal theory method was used to introduce the fractal dimensions of fracture aperture and tortuosity to characterize the fracture space quantitatively, and a mathematical model of self-supporting fracture conductivity was established that considers the effect of closure stress. An experiment of self-supporting fracture conductivity was conducted. The results show that the initial fracture conductivity reached 30~50 D·cm and could be maintained above 1 D·cm under a closure pressure of 40 MPa. The theoretical model prediction results agree well with the experimental test results. The sensitivity analysis shows that the fractal dimension of fracture aperture is positively correlated with the conductivity, while the fractal dimension of tortuosity is negatively correlated with the conductivity. The proposed method can quickly and accurately predict the self-supporting fracture conductivity of shale and provide support for rational prediction of gas well productivity.
作者
曹海涛
关小旭
李晓平
赵勇
余小群
CAO Haitao;GUAN Xiaoxu;LI Xiaoping;ZHAO Yong;YU Xiaoqun(Postdoctoral Research Station, Southwest Oil and Gas Branch, SINOPEC, Chengdu, Sichuan 610041, China;Postdoctoral Research Station, Southwest Petroleum University, Chengdu, Sichuan 610500, China;Exploration and Production Research Institute, Southwest Oil & Gas Company, SINOPEC, Chengdu, Sichuan 610041, China;National Science Park, Southwest Petroleum University, Chengdu, Sichuan 610500, China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, Sichuan 610500, China)
出处
《西南石油大学学报（自然科学版）》
CAS
CSCD
北大核心
2019年第5期134-141,共8页
Journal of Southwest Petroleum University(Science & Technology Edition)
基金
国家科技重大专项(2017ZX05036003-006)
中国石化科技攻关项目(P18058-1)
关键词
分形
导流能力
闭合应力
页岩气
自支撑裂缝
fractal
conductivity
closure stress
shale gas
self-supporting fracture
