海陆过渡相页岩气藏不稳定渗流数学模型  

AN UNSTABLE POROUS FLOW MODEL OF MARINE-CONTINENTAL TRANSITIONAL SHALE GAS RESERVOIR

作　　者：陈志明 王佳楠 廖新维[1] 曾联波[1] 赵鹏飞 Yu Wei Chen Zhiming;Wang Jianan;Liao Xinwei;Zeng Lianbo;Zhao Pengfei;Yu Wei(State Key Laboratory of Petroleum Resources and Prospecting,China University of Petroleum(Beijing),Beijing 102249,China;The University of Texas at Austin,Austin,7X78712,USA)

机构地区：[1]中国石油大学(北京)油气资源与探测国家重点实验室,北京102249 [2]美国德州大学奥斯汀分校,美国奥斯汀78712

出　　处：《力学学报》2021年第8期2257-2266,共10页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金(52074322,U762210,52004299);北京市自然科学基金(3204052)资助项目。

摘　　要：海陆过渡相页岩常与煤层和砂岩呈互层状产出,储层连续性较差、横向变化快、非均质性强,水力压裂技术是其获得经济产量的关键手段.然而,目前缺乏有效的海陆过渡相页岩气藏不稳定渗流数学模型,对其渗流特征分析及储层参数评价不利.针对这一问题,首先建立海陆过渡相页岩气藏压裂直井渗流数学模型,其次采用径向复合模型来反映强非均质性,采用Langmuir等温吸附方程来描述气体的解吸和吸附,分别采用双重孔隙模型和边界元模型模拟天然裂缝和水力裂缝,建立并求解径向非均质的页岩气藏压裂直井不稳定渗流数学模型,分析海陆过渡相页岩气藏不稳定渗流特征,并进行数值模拟验证和模型分析应用.分析结果表明,海陆过渡相页岩气藏不稳定渗流特征包括流动早期阶段、双线性流、线性流、内区径向流、页岩气解吸、内外过渡段、外区径向流及边界控制阶段.将本模型应用在海陆过渡相页岩气试井过程中,实际资料拟合效果较好,其研究成果可为同类页岩气藏的压裂评价提供一些理论支撑,具有较好应用前景.Marine-continent transitional shale is often interbedded with coal seams and sandstone. The reservoir has poor continuity, rapid lateral change, and high heterogeneity. Hydraulic fracturing technology is the key method to obtain economic production. However, there is currently a lack of effective unstable porous flow model of Marinecontinent shale gas reservoirs. In response to this problem, considering the characteristics of shale gas adsorption/desorption, diffusion, fractures, and shale heterogeneity, a heterogeneous shale gas mathematical model was established and solved by using boundary element method. First, a vertically fractured well model in MCT shale-gas reservoir is built. Second, Radial composite model is used to reflect the high heterogeneity, and Langmuir isothermal adsorption curve is applied to describe the gas adsorption/desorption and diffusion. Dual-porosity model, boundary element model, and Pedrosa’s substitution are respectively used to simulate the natural fractures, hydraulic fractures,and effect of stress-sensitive permeability The analysis results show that the unstable flow characteristics in Marinecontinent transitional shale gas reservoir include flow early stage, bilinear flow, linear flow, inner radial flow, shale gas desorption, transition section, outer radial flow and boundary-dominated flow stage. This model has been applied in the process of well testing of Marine and continental transitional shale gas in Ordos Basin, and the actual effect is good.The research results can provide some theoretical support for the fracturing evaluation of similar shale gas reservoirs,and it has a good application prospect.

关 键 词：海陆过渡相 页岩气藏 渗流模型 参数反演 鄂尔多斯盆地 

分 类 号：TE319[石油与天然气工程—油气田开发工程]