多尺度页岩气藏水平井压裂产能模拟研究

发布时间：2018-02-21 02:14

本文关键词： 孔隙尺度分布微观流动天然裂缝流动模型产能模型　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着油气勘探领域技术的不断进步和发展,非常规页岩气已经成为常规油气的重要接替资源,目前已经在北美取得了成功的商业开发,产量呈现爆炸式增长,2014年美国年产量达到了2700×108m3。研究表明我国页岩气资源丰富,地质储量占世界总储量的22%,但目前还处于开发初期阶段,开展页岩气开发的相关研究对提升我国自主开发页岩气水平具有重要作用。与传统气藏不同,页岩储层孔隙尺度从几到几百纳米,气体流动形态复杂,可能包含黏性流、滑移流、过渡流及分子流的复杂多流态特征。同时受页岩储层低孔低渗物性影响,必须对页岩储层进行水平井分段压裂改造才能达到经济产能。受页岩压裂改造过程中裂缝扩展特征影响,水力压裂形成的裂缝网络体系包括远井区域自支撑的剪切缝和近井区域支撑剂铺置的支撑缝。基于以上页岩压裂水平井的介质特征和流体在多尺度介质下的渗流特征,考虑扩散、吸附、解吸、滑移等渗流影响,开展了页岩气在纳米孔隙中气体流动行为的研究,基于微观和宏观流动特性,考虑自支撑和支撑缝展布状态,建立了页岩储层水平井压裂产能模型,并进行了产能模拟研究,得到了以下重要研究成果： (1)考虑页岩储层低孔、低渗的特点,建立了考虑纳米尺度页岩储层的微观流动模型,该模型基于表观渗透率定义,结合不同流态的作用效应,建立了基于黏性流、滑移流、过渡流和分子自由流的表观渗透率计算统一方程。 (2)基于页岩基质系统微观流动,考虑支撑缝与自支撑缝的影响,以及页岩吸附解吸现象,建立了纳米尺度页岩气藏水平井二维单相模型,对该数学模型进行数值求解,利用Visual Basic6.0程序语言编制了页岩产能数值计算程序。 (3)采用所编制的纳米尺度页岩气藏水平井压裂产能模型计算程序全面分析了影响页岩气藏水平井压裂后产能的相关参数,包括水力裂缝条数、水力裂缝导流能力、水力裂缝长度、地层渗透率、孔隙半径、井底流压、Langmuir体积以及Langmuir压力。
[Abstract]:With the continuous progress and development of oil and gas exploration technology, unconventional shale gas has become an important replacement resource for conventional oil and gas, and has been successfully developed in North America. In 2014, the annual output of the United States reached 2700 脳 108m3.The study shows that China is rich in shale gas resources, with geological reserves accounting for 22% of the world's total reserves, but at present it is still in the early stage of development. The research on shale gas development plays an important role in improving the level of shale gas development in China. Unlike traditional gas reservoirs, the pore size of shale reservoirs ranges from several to several hundred nanometers, and the gas flow forms are complex, which may include viscous flow and slip flow. The complex multi-flow characteristics of transition flow and molecular flow are also affected by the physical properties of shale reservoir with low porosity and low permeability. In order to achieve economic productivity, the shale reservoir must be fracturing in horizontal wells by stages, which is influenced by the fracture propagation characteristics in the process of shale fracturing. The fracture network system formed by hydraulic fracturing includes the self-supporting shear fractures in the far well region and the proppant supported fractures in the near well area. Based on the medium characteristics of the shale fracturing horizontal wells and the percolation characteristics of the fluids in the multi-scale media, Considering the influence of diffusion, adsorption, desorption and slip, the gas flow behavior of shale gas in nano-pores was studied. Based on the microscopic and macroscopic flow characteristics, the self-supporting and supporting fracture distribution state was considered. The fracturing productivity model of shale reservoir horizontal well is established, and the productivity simulation is carried out. The following important research results are obtained:. 1) considering the characteristics of low porosity and low permeability in shale reservoir, a microscopic flow model considering nano-scale shale reservoir is established. The model is based on the definition of apparent permeability and combined with the effect of different flow states, which is based on viscous flow and slip flow. The unified equation of apparent permeability calculation for transition flow and free molecular flow is presented. Based on the microcosmic flow of shale matrix system, considering the influence of supporting fracture and self-supporting fracture, and the phenomenon of shale adsorption and desorption, a two-dimensional single-phase model of horizontal well of nano-scale shale gas reservoir is established, and the mathematical model is solved numerically. A numerical calculation program for shale productivity is developed by using Visual Basic6.0 program language. The related parameters affecting the productivity of horizontal well fracturing of shale gas reservoir after fracturing, including the number of hydraulic fractures and the hydraulic fracture conductivity, are analyzed comprehensively by using the program compiled by the authors for the calculation of horizontal well fracturing productivity model of nano-scale shale gas reservoir. Hydraulic fracture length, formation permeability, pore radius, bottom hole flow pressure, Langmuir volume and Langmuir pressure.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357

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