复杂缝网页岩压裂水平井多区耦合产能分析

发布时间：2018-11-26 19:48

【摘要】：针对页岩储层水平井压裂开发中复杂缝网形态、纳微米孔隙—复杂缝网—井筒多尺度渗流规律认识不清等问题,开展了针对性的研究:(1)通过巴西劈裂实验,诱导压裂缝的产生;(2)通过X射线CT扫描,观测岩样内部压裂缝形态,测得压裂缝开度;(3)结合压裂缝形态描述和气体在基质—复杂缝网—井筒中的渗流机理,在多尺度统一渗流模型的基础上,建立考虑扩散、滑移及解吸的水平井单段压裂改造产能方程;(4)考虑多级压裂区干扰及水平井筒压降,建立页岩储层多级压裂水平井产能预测模型。研究结果表明:(1)压裂缝形态为复杂网状缝;(2)测得压裂缝开度为4.25~453.00μm,平均为112.00μm;(3)不同缝网形态下页岩气表现出不同非线性渗流规律;(4)随着重改造区裂缝密度、重/弱改造裂缝分布范围的增大,产气量逐渐增加,压裂段间缝网渗流区域发生干扰,产气量增加幅度减小;(5)模拟水平井筒长1 500 m、重度改造区缝网半长100 m时,压裂10级产能效果最好。结论认为,需要合理地控制压裂程度、优化裂缝参数,才能为页岩气压裂优化设计等提供技术支撑。
[Abstract]:Aiming at the problems of complex fracture pattern in horizontal well fracturing development of shale reservoir and unclear understanding of multi-scale percolation law of nano micron pore and complex fracture network-wellbore, the following researches have been carried out: (1) through Brazilian splitting experiment, Induces the production of compressive cracks; (2) through X-ray CT scanning, the fracture morphology in rock samples is observed and the fracture opening is measured. (3) based on the description of fracturing shape and the percolation mechanism of gas in matrix, complex fracture net and wellbore, the productivity equation of single section fracturing reconstruction of horizontal well considering diffusion, slip and desorption is established on the basis of multi-scale unified percolation model. (4) considering the interference of multistage fracturing area and the horizontal wellbore pressure drop, the productivity prediction model of multistage fracturing horizontal well in shale reservoir is established. The results show that: (1) the shape of compressive fracture is complex mesh, (2) the crack opening is 4.25 ~ 453.00 渭 m with an average of 112.00 渭 m, (3) shale gas shows different nonlinear seepage law under different fracture pattern; (4) with the increase of the fracture density, the distribution range of the heavy / weak reconstruction fracture increases, the gas production increases gradually, the percolation zone of the fracture network between the fracturing sections is disturbed, and the increase amplitude of the gas production decreases; (5) when the horizontal wellbore is 1 500 m long and the fracture net half length is 100 m in the heavily reformed area, the 10 grade fracturing productivity is the best. The conclusion is that it is necessary to control the fracturing degree reasonably and optimize the fracture parameters in order to provide technical support for the optimal design of shale pressure fracture.
【作者单位】：北京科技大学土木与资源工程学院;北京科技大学应用力学研究所;
【基金】：国家重点基础研究发展计划(973计划)项目“页岩气多场耦合非线性渗流理论研究”(编号:2013CB228002)
【分类号】：TE377

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