控缝高压裂技术研究及应用

THE RESEARCH AND APPLICATION OF FRACTURE HEIGHT CONTROL TECHNIQUES

准噶尔盆地玛湖凹陷北斜坡三叠系百口泉组储层物性差,主力油层百二段厚度一般大于30m,油气显示及主要富集部位位于储层上部。由于纵向上无高应力遮挡层,常规水力压裂易导致裂缝高度向下部延伸,裂缝高度不易控制,加之支撑剂沉降,常导致顶部油气富集段支撑剂铺置效果差,压裂效果不理想。在对国内外控缝高压裂技术调研基础上,确立了适用于百口泉组的控缝高压裂技术优化条件。现场实验和回归分析方法研究表明,泥质隔层、压裂液粘度、二次加砂工艺、压裂参数对压裂缝高具有较好的控制作用,通过优化可降低支撑缝高10%～20%。该技术在百口泉组取得了较好的现场应用效果。

In this paper the status quo of the fracture height controlled technologies are investigated,besides,main-stream technologies which include mudstone interlayer,artificial interlayer,variable displacement and mechanism are sorted out.The characteristics of the reservoir in northern slope of Triassic Baikouquan formation of Mahu sag of Junggar basin are analyzed.The permeability of Baikouquan reservoir is poor and the thickness of the main reservoir is greater than30m,the main oil and gas shows in the top,no high stress shielding layer vertical,conventional hydraulic fracturing is easy to cause the fracture height extension and the fracture height is not easy to control,proppant sinking is easy to cause top good layer's laying effect poor,In this paper a set of suitable for the reservoir fracture height controlled technologies are developed.Through experiments and regression analysis,the study result shows that the mudstone barriers,viscosity of fracturing fluid,secondary sand fracturing and fracture parameters have the advantages of high good control effect,and made good application effect at the scene.Compared to conventional techniques,propped fracture height was reduced from10%to20%.