高渗松软地层水力压裂缝宽预测新模型  

NEW MODEL OF PREDICTING THE WIDTHS OF HYDRAULIC FRACTURES IN HIGH PERMEABILITY LOOSE FORMATION

作　　者：胡永全[1] 王腾飞[1] 赵金洲[1] 田继东[1] 石孝志[2] 甘升平[2] 

机构地区：[1]西南石油学院"油气藏地质及开发工程"国家重点实验室 [2]四川石油管理局

出　　处：《天然气工业》2005年第6期65-66,共2页Natural Gas Industry

基　　金：国家863项目"石油勘探开发分布式集成应用系统"成果(编号:863-306-ZT04-03)。~~

摘　　要：对高渗透松软地层进行水力压裂施工时,由于地层胶结程度差,强度低,压裂液对弱胶结裂缝壁面的切向应力就会破坏裂缝壁面的稳定性,使附着在裂缝壁面上的砂粒由静止变为运动,并随压裂液的注入而向缝端后移,形成冲刷裂缝;同时,砂粒在水力冲刷作用下的后移有利于“端部脱砂”产生,而“端部脱砂”的形成又加剧了水力冲刷作用强度,这种相互作用控制着缝宽的大小,影响着“端部脱砂”压裂施工的成败,因而具有很强的研究价值。现有的缝宽模型都以弹性理论为基础,并没有考虑该水力冲刷现象,因而不能准确地预测缝宽,文中综合考虑岩石力学、流体力学、压裂液性质以及压裂施工等理论,对该冲刷缝形成机理进行了分析,建立了一种新的针对垂直裂缝的水力冲刷缝宽预测模型,并编制了相应的计算程序,最后根据一些实际参数对该模型进行了分析验证。During the course of hydraulic fracturing in high permeability loose formation, the stability of fracture face will be destroyed by the shearing stress of fracturing fluid because of the formation’s poor cementation and low strength, thus causing the sand grains attached to the fracture face to be moved back to the fracture tip with fracturing fluid injection to form scour fractures. Meanwhile, the back-moving of sand grains by the action of hydraulic scour is favourable to the formation of “Tip-screen-out” (TSO), which can also strengthen the hydraulic scour on the contrary. Such an interaction will control the size of fracture width and the efficiency of TSO-fracturing, thus having important value to scientific research. The existent fracture width prediction models are based on elastic theory, by which the fracture width can’t be exactly predicted, because the hydraulic scour phenomenon couldn’t be considered. In the paper, in consideration of rock mechanics, fluid mechanics, fracturing fluid property and fracturing operation conditions, the mechanism of forming scour fractures is analyzed; a new model of predicting the widths of hydraulic scour fractures (aiming at vertical fractures) is set up; the relevant calculation program is worked out; and the model is analyzed and checked up according to some actual data finally.

关 键 词：高渗透松软地层 水力压裂 缝宽模型 弹性理论 水力冲刷现象 

分 类 号：TE357.1[石油与天然气工程—油气田开发工程]