页岩储层水平井分段压裂裂缝延伸模拟研究

发布时间：2018-04-02 06:41

本文选题：页岩储层　切入点：天然裂缝　出处：《西南石油大学》2015年硕士论文

【摘要】：页岩气作为一种非常规油气资源,目前已成为我国天然气开发的重点。受到页岩储层低孔超低渗透物性特征的影响,页岩气的经济开采必须依靠水平钻井和压裂改造才能实现。在对含有天然裂缝且脆性较强的页岩储层进行压裂时,水力裂缝必然沟通或扩展天然裂缝,通过不断延伸与更多远井天然裂缝进一步相交,最终在储层中形成大规模、不规则的复杂裂缝网络。准确的预测复杂缝网的波及范围是页岩气藏水力压裂优化设计的关键环节。论文基于流体力学、弹性力学和渗流力学的相关理论知识,建立了裂缝内压降方程、连续性方程和裂缝变形方程,考虑了水力裂缝与天然裂缝相交作用模式,建立了复杂裂缝网络模型；对缝网模型进行了差分求解,同时分析了地层参数与施工参数对改造体积的影响。论文主要内容包括以下几方面： (1)根据水力裂缝与天然裂缝相交过程中可能出现的各种破裂方式,基于弹性力学和岩石力学相关理论,建立了相应破裂模式下的裂缝相交作用准则,利用所建立的准则对相交点处可能发生的破裂情况进行了全面的分析和计算。该准则为研究水力裂缝相交天然裂缝后的延伸路径提供了手段。 (2)基于渗流力学、弹性力学和流体力学基础理论,建立了由裂缝系统中的液体流动方程、物质平衡方程、连续性方程和裂缝变形方程控制的复杂网络裂缝延伸模型；通过有限差分数值计算方法并应用VB语言编制了缝网波及体积模拟计算程序。 (3)通过编制的计算程序,对影响缝网波及体积的地质因素和工程因素进行了敏感性分析。结果表明以更大的液量、较低的压裂液黏度和排量施工,可以获得更大的储层改造体积；在相同的施工条件下,具有高弹性模量、低水平应力差的储层,获得的改造体积更大；天然裂缝密度越大的储层,改造体积越小。此外,根据裂缝交点处的裂缝宽度数据,获得了整个波及范围内的缝宽分布云图。
[Abstract]:Shale gas, as an unconventional oil and gas resource, has become the focus of natural gas development in China.The economic exploitation of shale gas depends on horizontal drilling and fracturing under the influence of the physical properties of low porosity and ultra-low permeability in shale reservoir.When fracturing shale reservoirs with natural fractures and strong brittleness, hydraulic fractures must communicate or expand natural fractures, and further intersect with more natural fractures in remote wells, and finally form a large scale in the reservoir.Irregular network of complex cracks.Accurate prediction of complex fracture network is the key to the optimal design of hydraulic fracturing in shale gas reservoir.Based on the theoretical knowledge of fluid mechanics, elastic mechanics and seepage mechanics, the pressure drop equation, continuity equation and fracture deformation equation are established, and the interaction mode between hydraulic fracture and natural fracture is considered.The complex fracture network model is established, the difference solution of the fracture mesh model is carried out, and the influence of formation parameters and construction parameters on the reconstruction volume is analyzed.The main contents of this paper are as follows:1) according to various fracture modes that may occur in the process of intersecting hydraulic fracture with natural fracture, based on the theory of elastic mechanics and rock mechanics, the criterion of fracture intersecting under the corresponding fracture mode is established.By using the established criterion, the possible fracture at the intersection point is analyzed and calculated.This criterion provides a means for studying the extension path of hydraulic fracture intersecting natural fracture.2) based on the basic theories of seepage mechanics, elastic mechanics and fluid mechanics, a complex network crack extension model controlled by fluid flow equation, mass balance equation, continuity equation and fracture deformation equation is established.Based on the finite difference numerical method and VB language, a computer program for the simulation of slit network and its volume is developed.3) the sensitivity analysis of geological and engineering factors which affect the swept volume of seams is carried out through the calculation program.The results show that with larger fluid volume, lower fracturing fluid viscosity and displacement, larger reservoir reconstruction volume can be obtained, and under the same construction conditions, the reservoir with high elastic modulus and low horizontal stress difference can obtain larger reconstruction volume.The larger the density of natural fractures, the smaller the reconstruction volume.In addition, according to the data of fracture width at the intersection of fractures, the distribution of crack width in the whole sweep range is obtained.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.1

【参考文献】