MOE Key Lab of Marine Reservoir Evolution and Hydrocarbon Enrichment Mechanism,China University of
Geosciences(Beiing) MOLR Key Lab of Shale Gas Resources Survey and Strategic Evaluation,China University of
Geosciences(Beijing) China United Coalbed Methane Corporation Ltd.

为解决煤储层压裂后的裂缝展布规律无法直接观测的问题,以牛顿流体PKN模型为依据,通过分析柿庄南区块压裂施工工艺及煤储层力学特征,结合支撑剂在牛顿力学中的沉降理论,开展填砂裂缝的数值计算,进行煤储层压裂缝几何特征与支撑剂分布预测。研究表明:随着裂缝长度的延伸,流体压降导致裂缝宽度逐渐降低直至闭合,活性水压裂液不能将支撑剂带入裂缝远端,施工过程中支撑剂迅速沉降并堆积在裂缝近端,其携砂长度远小于造缝长度。建议适当增加压裂液携砂能力,降低支撑剂粒度与重度,可增加裂缝的支撑长度,提高压裂效果。

In order to solve the impossible directly observation problem of the crack distribution law after the coal reservoir fractured,taking the Newtonian fluid PKN m odel as a basis,with an analysis on the fracturing operation technique and coal reservoir dynamics features in the south block of Shizhuang,in combination with settling the ory of the proppant in the Newtonian mechanics,a numerical calculation was conducted on the sand packed cracks and a prediction was conducted on the fractured crack g eometric features of the coal reservoir and the proppant distribution. The study showed that with the crack length expanded,the fluid pressure drop would cause that the cra ck width steadily reduced until close and the activated hydraulic fracturing liquid would not bring the proppant to a far terminal of the crack. During the construction process, the proppant would be rapidly settled down and the sand travel length would be less than the crack length.The paper proposed that the sand holding capacity by the fractur ing liquid properly increased and the particle size and weight of the proppant reduced could increase the support length of the crack and improve the fracturing effect.

国家科技重大专项资助项目(2011ZX05060；2011ZX05034-003)；