低渗透储层岩体压裂裂纹扩展机理研究

发布时间：2018-01-24 03:00

本文关键词： 水压致裂天然裂缝数值模拟流固耦合 ARAMIS测量系统　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：在石油、页岩气、煤层气开采,水压力作用下的边坡、大坝、核废料库稳定、隧道、硐室等大量岩体工程中都会涉及到工程岩体的水压致裂裂纹扩展机理。本文主要以低渗透储层岩体为主要研究载体,对有无注水情况下的裂文扩展机理进行了研究。低渗储层岩体中裂缝在水压力驱动下,其裂缝的萌生、扩展、演化,导致岩体结构的宏、细观发生改变,岩体应力场重新分布,同时岩体的渗透性能随之发生改变,渗流场随着岩体结构渗透性能的改变而重新分布。水压致裂裂纹扩展机理其实质是岩体细观结构变化导致岩体宏观结构力学特性发生改变的复杂过程,无论是从宏观还是微细观上,研究岩体的裂纹扩展机理对石油、岩体等工程起着至关重要的作用。 1)本文首先通过ARAMIS应变测量系统对岩石破裂裂纹扩展规律进行了实验研究,并获取每个阶段相关点和面的应变情况,并利用RFPA2D数值软件对实验进行了对比模拟分析,验证了RFP2D数值软件的可靠性。 2)然后在不考虑注水的条件下,依据摩尔-库伦破坏准则和岩石断裂理论,建立单预制裂隙岩石模型和双平行预制裂隙岩石模型。对不同单预制裂隙倾角的岩石试件进行研究,分析了不同单裂缝形态下岩石裂纹的萌生、扩展机制以及单裂缝形态对岩石力学特性的影响。对不同双平行预制裂隙倾角和不同岩桥倾角的岩石试件进行研究,分析了不同双平行裂缝形态下岩石裂纹的萌生、扩展机制以及双平行裂缝形态对岩石力学特性的影响,并研究了双平行裂缝倾角和岩桥倾角对多裂纹的贯通机制。 3)最后考虑岩体的液固耦合和细观损伤破裂特性,基于渗流-应力损伤耦合理论,建立含单一天然裂缝、双平行天然裂缝的低渗储层岩体数值模型,对水力裂缝激活天然裂缝的机理进行了研究。本文的研究结果对保障含节理、裂隙等初始缺陷的岩体工程稳定与安全以及石油工程开采优化等提供一定的理论依据。
[Abstract]:In oil, shale gas, coalbed methane mining, water pressure under the action of slopes, dams, nuclear waste reservoir stability, tunnels. In a large number of rock mass engineering, such as chamber, hydraulic fracturing and crack propagation mechanism of engineering rock mass will be involved. In this paper, low permeability reservoir rock mass is the main research carrier. The mechanism of crack propagation in rock mass with or without water injection is studied. The initiation, expansion and evolution of fractures in rock mass driven by water pressure result in the change of macro and meso structure of rock mass. The stress field of rock mass is redistributed and the permeability of rock mass changes. The seepage field is redistributed with the change of the permeability of rock mass structure. The mechanism of crack propagation caused by hydraulic fracturing is a complex process in which the mechanical properties of rock mass macrostructure change due to the change of meso-structure of rock mass. The study of crack growth mechanism of rock mass plays an important role in petroleum engineering and rock mass engineering. 1) in this paper, the law of crack propagation of rock fracture is studied experimentally by ARAMIS strain measurement system, and the strain of each phase is obtained. The reliability of RFP2D numerical software is verified by comparing and simulating the experiment with RFPA2D numerical software. 2) then according to the Mohr-Coulomb failure criterion and rock fracture theory without considering water injection. The single prefabricated fracture rock model and the double parallel prefabricated fracture rock model are established. The rock specimen with different prefabricated fracture inclination angle is studied and the initiation of rock crack under different single fracture morphology is analyzed. The effects of propagation mechanism and single fracture morphology on rock mechanical properties were studied. The rock specimens with different double parallel prefabricated fracture dip angles and different rock bridge inclination angles were studied. The mechanism of crack initiation and propagation and the influence of double parallel fracture morphology on rock mechanical properties are analyzed. The mechanism of double parallel fracture dip angle and rock bridge inclination angle to multiple cracks is studied. Finally, considering the liquid-solid coupling and mesoscopic damage and fracture characteristics of rock mass, a numerical model of rock mass with single natural fracture and double parallel natural fracture is established based on the coupling theory of seepage and stress damage. The mechanism of activating natural cracks by hydraulic cracks was studied. The results of this paper provide some theoretical basis for ensuring the stability and safety of rock mass engineering with initial defects such as joints and fissures, as well as the optimization of petroleum engineering exploitation.
【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】：TE311

【参考文献】