裂缝流固耦合渗流机理研究

发布时间：2018-03-11 02:37

本文选题：裂缝　切入点：精细刻画　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：裂缝性储层普遍埋藏深,钻井过程中安全密度窗口窄、井筒压力波动大,经常面临溢漏同存、井控风险大等问题。基于裂缝特征参数,测量与重构裂缝三维空间并开展裂缝流固耦合渗流研究是前述问题和进一步开展相关工程技术研究的基础。针对现场裂缝样品,进行了裂缝表面形态数学描述及裂缝空间的重构与提取、裂缝空间渗流数学模型及渗流机理研究、井筒中多物理场裂缝流固耦合分析等研究。综合利用精细面形测量、逆向重构技术,采用理论研究、实验研究、数值模拟等手段,揭示了裂缝流固耦合渗流机理,主要取得以下认识： (1)利用XSM-LC非接触式高精度测量系统获取真实裂缝表面微凸体三维数据,通过逆向工程等软件进行数据处理,进行裂缝面三维参数的精细刻画。利用获取的裂缝表面真实数据实现裂缝表面及空间三维重构。 (2)平板裂缝实验结果说明缝宽、压差和钻井液性能是影响单一理想平板裂缝内流体流速的主要敏感性因素。通过研究粗糙裂缝起伏度对裂缝渗流的影响采用粗糙度系数JRC对裂缝立方体定律进行修正,修正后的立方体定律经过验证能够较好的符合实验数据。在相同微凸体高度及进口速度下,微凸体密度越大,其压差越大。 (3)不同JRC下的裂缝渗流差异很大,裂缝流量及速度随JRC增大而减小。随着JRC的增大,裂缝起伏度增大,流体在裂缝中的渗流路径增长,流量减小。对于相同的JRC而言,随着缝宽的增加,裂缝渗流通道越大,渗流流量越大。 (4)裂缝闭合初期,其渗流能力迅速减小,随后,裂缝流体流量及速度的变化不再明显。裂缝渗流空间随着裂缝闭合逐渐减小,减小的幅度与裂缝表面形态、起伏度密切相关。 (5)压差在裂缝渗流与变形中是一个可控的重要参数。压力在缝内和基质内的传递速度差异较大,裂缝中能够快速的进行压力场的重新分布,压力场的重新分布会影响缝内流动能力。在井筒缝宽较大处,存在较大的井壁失稳风险,渗透率变化明显。在裂缝闭合区域及缝宽较小的区域存在应力集中现象。 (6)通过裂缝流固耦合渗流机理的研究,下一步需要解决工程中经常遇到的裂缝漏失问题,明确漏失规律,对其进行定量化计算；该研究是进行堵漏工艺研究、改造裂缝储层研究以及欠平衡钻井随钻储层参数分析的理论基础。
[Abstract]:The fractured reservoirs are generally buried deep, the safe density window is narrow during drilling, the wellbore pressure fluctuates greatly, and often faces problems such as the occurrence of spills and the high risk of well control, etc. Based on the fracture characteristic parameters, The measurement and reconstruction of fracture three-dimensional space and the study of fluid-solid coupling seepage flow of fracture are the basis of the above-mentioned problems and the further research of related engineering technology. The mathematical description of fracture surface morphology, reconstruction and extraction of fracture space, seepage mathematical model and seepage mechanism of fracture space, fluid-solid coupling analysis of fractures with multiple physical fields in wellbore are studied. Reverse reconstruction technology, by means of theoretical research, experimental research and numerical simulation, reveals the mechanism of fluid-solid coupling seepage of fractures. The main results are as follows:. 1) using XSM-LC non-contact high-precision measurement system to obtain 3D data of real crack surface micro-convex body, and processing the data by reverse engineering and other software. The 3D parameters of fracture surface are described in detail, and the 3D reconstruction of fracture surface and space is realized by using the obtained real data of fracture surface. 2) the experimental results of plate crack show that the crack width, Pressure difference and drilling fluid performance are the main sensitive factors affecting the flow velocity in a single ideal plate fracture. The roughness coefficient JRC is used to modify the fracture cube law by studying the effect of rough fracture fluctuation on fracture seepage. The modified cube law is proved to be in good agreement with the experimental data. At the same height and inlet velocity, the greater the density of the microconvex body, the greater the pressure difference. The flow rate and flow rate of fracture decrease with the increase of JRC. With the increase of JRC, the degree of fracture fluctuation increases, the seepage path of fluid in fracture increases, and the flow rate decreases. For the same JRC, the flow rate and the flow rate decrease with the increase of JRC, the seepage path of the fluid in the fracture increases, and the flow rate decreases with the increase of JRC. With the increase of fracture width, the larger the seepage channel, the larger the seepage flow. (4) in the early stage of fracture closure, the seepage capacity decreases rapidly, then the flow rate and velocity of fracture fluid are no longer obvious. The seepage space of fracture decreases gradually with the closure of fracture, and the decreasing amplitude is closely related to the shape and fluctuation of fracture surface. 5) pressure difference is an important and controllable parameter in fracture seepage and deformation. The velocity of pressure transfer in fracture and matrix is quite different, and the pressure field can be redistributed rapidly in fracture. The redistribution of the pressure field will affect the flow capacity in the fracture. Where the wellbore width is large, there is a greater risk of wellbore instability, and the permeability changes obviously. There is a phenomenon of stress concentration in the closed area of fracture and in the area with small fracture width. 6) through the study of fluid-solid coupling seepage mechanism of fracture, the next step is to solve the problem of crack leakage which is often encountered in engineering, make clear the law of leakage, and carry out quantitative calculation to it, the research is to study the technology of plugging leakage. The theoretical basis of reforming fractured reservoir and analyzing the parameters of underbalanced drilling while drilling reservoir.
【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】：TE312

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