摘要
水压致裂技术作为一种绝对应力测量方法广泛地运用在原地应力测量领域,在其测量过程中影响岩石破裂值的流体力学影响因素主要是压裂液的注液速率、黏度和密度等,因此应开展流体力学影响因素的室内模拟试验,定量分析各因素对于原地应力测量准确度的影响。由于因素数量较多且该试验对于岩芯试块为破坏性试验,因此试验设计较为复杂且次数较多,全面试验或正交试验方案将严重影响试验实际操作和试验效果。本文在理论分析流体力学因素对于裂缝扩展和破裂压力影响基础上,提出一种基于混合水平均匀设计方法的水压致裂模拟试验优化方案,根据压裂液的注液速率、黏度和密度等影响因素及其参数值(水平数)构建均匀试验设计方案,利用DPS数据处理软件获取最优混合水平的均匀设计表,然后根据最优均匀设计表选择不同流体力学参数的典型点进行试验。最后将试验结果与部分全面试验结果进行对比分析,证明优化试验的岩石破裂值均处于全面试验测量区间内,印证了不同流体力学因素对于岩石破裂值的影响效应。本文中优化算法试验方案通过较少的试验次数简化了试验流程,试验次数仅为正交试验的四分之一,因此显著提高了水压致裂多影响因素模拟试验效率,对于后续建立不同流体力学影响因素的破裂压力修正公式与补偿模型提供了一种快速有效的试验方法,对原地应力进一步精确测算具有一定的积极意义。
As a kind of absolute stress measurement method,hydraulic fracturing technology is widely used in the field of in-situ stress measurement.The hydrodynamic influence factors which affect the rock fracture value during the measurement process are mainly the injection rate,viscosity and density of the fracturing fluid.Because the number of influencing factors is large and the experiment is a destructive experiment for the testing core,the experimental design is under a complex condition,and the comprehensive or orthogonal experimental method will seriously affect the experimental results.Based on the theoretical analysis of fluid mechanics influence on crack propagation and fracturing pressure,An optimization scheme for hydraulic fracturing simulation based on the mixed-level uniform design method was proposed in the paper.According to the influencing factors such as loading rate,viscosity and density of the fracturing fluid and its parameter values(number of levels),a uniform experimental design scheme was constructed.The DPS data processing software was used to obtain the table of optimal mixed-level uniform design,and then according to this table the typical points of different hydrodynamic parameters could be selected.Finally,the experimental results were compared to comprehensive experimental results.It was proved that the rock fracturing pressure value of the optimization experiment was within the comprehensive experimental measurement interval,which confirmed the influence of different fluid mechanics factors on the rock fracturing pressure value.The number of experiments in this optimization scheme is only one quarter of the orthogonal experimental scheme,therefore,the efficiency of simulation experiments of multiple factors affecting hydraulic fracturing is significantly improved.It provides a fast and effective experimental method for the subsequent establishment of the fracture pressure correction formula and compensation model for different fluid mechanics influencing factors,and it also has positive significance for accurating measurement of in-situ stress.
作者
刘一民
王成虎
王杰
张杰
LIU Yimin;WANG Chenghu;WANG Jie;ZHANG Jie(Key Lab.of Crustal Dynamics,Inst.of Crustal Dynamics,CEA,Beijing 100085,China;School of Manufacturing Sci.&Eng.,Sichuan Univ.,Chengdu 610065,China;Tianjin Branch of China Architectural Northeast Design&Research Inst.Co.Ltd.,Tianjin 300202,China)
出处
《工程科学与技术》
EI
CAS
CSCD
北大核心
2019年第6期108-114,123,共8页
Advanced Engineering Sciences
基金
国家自然科学青年基金资助项目(41804089)
中国大陆综合地球物理场观测仪器研发专项(Y201802)
关键词
水压致裂
流体力学
模拟试验
均匀设计算法
优化研究
hydraulic fracturing
fluid mechanics
simulation experiment
uniform design method
optimization research
