高速通道压裂裂缝的高导流能力分析及其影响因素研究  

Theoretical analysis of high flow conductivity of a fracture induced in Hi Way fracturing

作　　者：严侠[1] 黄朝琴[1] 辛艳萍[2] 姚军[1] 李阳[3] 巩亮[4] 

机构地区：[1]中国石油大学(华东)石油工程学院,青岛266580 [2]中国石油大学胜利学院油气工程学院,东营257061 [3]中国石化油田勘探开发事业部,北京100029 [4]中国石油大学(华东)储运与建筑工程学院能源与动力工程系,青岛266580

出　　处：《物理学报》2015年第13期251-261,共11页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2011CB201004);国家自然科学基金(批准号:51404292;51234007);山东省自然科学基金(批准号:ZR2014EEQ010);中央高校基本科研业务费专项资金(批准号:14CX06091A;14CX05027A;13CX05007A;13CX05017A;13CX02052A)资助的课题~~

摘　　要：高速通道压裂是近年在非常规致密油气资源开采中出现的新工艺,已在世界范围内推广实施,并取得了良好的增产效果.该技术可使支撑剂在人工压裂缝中形成簇团式分布,从而形成油气高速流动通道,提高裂缝的导流能力.但目前对于高速通道压裂裂缝高导流能力的形成机理及其影响因素尚不清楚.对此,本文从流体力学理论出发,首先将高速通道压裂裂缝内形成的支撑剂簇团视为渗流区域,簇团间的大通道视为自由流动区域;然后基于Darcy-Brinkman方程建立了裂缝内的流动数学模型,采用均匀化理论对该流动数学模型进行了尺度升级,推导得到了高速通道压裂裂缝的渗透率,揭示了其高导流能力的形成机理;并以此为基础,分析了不同支撑剂簇团形状、大小以及分布方式等因素对其导流能力的影响,可为高速通道压裂工艺参数设计与优化提供基础.HiWay （or channel） fracturing has been a new technology for development of unconventional oil and gas resources in recent years. It has been carried out more than 4000 times worldwide, and obtained good performance in oil and gas recovery. HiWay fracturing improves the flow conductivity of fractures by constructing inhomogeneous distributions of proppant and stable, open flow channel in hydraulic fractures. However, the mechanism and impact factors of high flow conductivity of HiWay fractures are not very clear. To the best of our knowledge, there are no relevant research reports available for such analysis. In this paper, it is first assumed that the fluid flow in proppant clusters follows the Darcy’s law and the flow in the channels with proppant clusters is laminar viscous flow, which can be described using Stokes equation. However, the coupling of Darcy-Stokes equations is di？cult, and some untrivial interface conditions at the interface between the porous and free-flow regions should be introduced, this will increase greater complexity in numerical computation. As an alternative approach, the Darcy-Brinkman equation is often used for this coupling flow problem, which provides a unified equation with continuous variable coe？cients in the two different flow regions. Therefore, there is not necessary to introduce specific interface conditions any more. In this work, we first applied the Darcy-Brinkman equation to model the fluid flow in hydraulic fractures, and then the upscaling of Darcy-Brinkman equation is conducted to evaluate the equivalent permeability of a fracture by using homogenization theory and finite element numerical simulation. Finally, various impact factors of flow conductivity of a hydraulic fracture, such as the cluster shape, cluster distribution, cluster size, etc., are analyzed based on the equivalent permeability. Results show that the permeability of a hydraulic fracture is considerably greater than thst of proppant cluster when the free-flow region is well connected in the fra

关 键 词：高速通道压裂 裂缝导流能力 均匀化理论 渗流-自由流耦合 

分 类 号：O357.3[理学—流体力学]