页岩气压裂微地震监测中的裂缝成像方法

发布时间：2018-05-07 20:14

本文选题：页岩气 + 压裂裂缝　；参考：《天然气工业》2017年05期

【摘要】：微地震监测是页岩气储层水力压裂改造过程中的关键配套技术,但目前国内微地震监测技术还不能直观描绘水力压裂改造储层的裂缝网络。为此,将地面微地震层析成像和细化算法相结合,提出了一种人工压裂裂缝反演方法——细化地震发射层析成像方法 (TSET),即将图像处理中的骨架提取算法引入到地面微地震监测结果中,提取能量最强位置的骨架结构来反演压裂裂缝的位置及形态。将该方法应用于河南中牟页岩气区块MY1井的水力压裂微地震监测:(1)对原始微地震数据进行滤波,应用基于Semblance算法的地震发射层析成像(SET)技术对微地震数据进行处理,得到压裂区域储层的能量叠加结果 ;(2)采用克里格网格化将能量图插值为连续的图像,并对网格化结果进行奇异值分解降噪(SVD);(3)应用细化算法提取叠加能量图的骨架结构,得到能直观显示的水力压裂裂缝或裂缝带成像结果。结论认为:(1)水力压裂活动可以改变天然裂缝的应力状态,即激活天然裂缝并在远离作业井段部位诱发破裂,在压裂液无法到达的部位形成新的"诱发破裂裂缝";(2)当压裂裂缝与天然裂缝方向平行或近于平行时,天然裂缝对人工压裂裂缝会产生延伸诱导作用,反之则产生屏障阻隔作用。
[Abstract]:Microseismic monitoring is a key supporting technology in the process of hydraulic fracturing reconstruction of shale gas reservoir, but at present, the micro-seismic monitoring technology in China can not describe the fracture network of hydraulic fracturing reconstruction reservoir directly. Therefore, the ground micro-seismic tomography is combined with thinning algorithm. In this paper, a fracture inversion method of artificial fracturing, thinning seismic emission tomography, is proposed, which introduces skeleton extraction algorithm in image processing to ground micro-seismic monitoring results. Extract the skeleton structure of the most energy position to retrieve the fracture position and shape. The method is applied to the hydraulic fracturing microseismic monitoring of MY1 well in Zhongmu shale gas block, Henan Province. The original microseismic data are filtered. The seismic emission tomography (set) technique based on Semblance algorithm is used to process the microseismic data. The energy stacking results of reservoir in fracturing area are obtained. The Kriging grid is used to interpolate the energy map into continuous images, and the singular value decomposition (SVD) denoising method is used to reduce the noise of the grid results. The skeleton structure of the superimposed energy map is extracted by thinning algorithm. The imaging results of fracturing fracture or fracture zone can be visualized. It is concluded that hydraulic fracturing can change the stress state of natural fractures, that is, activate natural fractures and induce fractures far away from the working wells. A new "induced fracture" is formed in the unreachable part of the fracturing fluid. When the fracture is parallel to or near the direction of the natural fracture, the natural fracture will have an extension effect on the artificial fracturing fracture, otherwise it will produce barrier effect.
【作者单位】：中国矿业大学(北京)地球科学与测绘工程学院;中国石油化工股份有限公司勘探开发研究院;
【基金】：政府间国际科技创新合作重点专项“碳捕集、封存、利用的示范及新一代技术研发项目”(编号:2016YFE0102500)
【分类号】：P631.4;TE377

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