【摘要】 通过岩芯静态酸蚀试验并结合矿物微观组构分析和岩石力学特性试验,从不同尺度和性质研究了酸液对碳酸盐岩储层岩石力学特性损伤问题及其规律,并通过压裂室内模拟试验研究了裂缝起裂和扩展演化规律以及酸液化学作用对体积缝的影响。该研究有助于指导现场储层酸压改造设计及优化技术参数,对于提高碳酸盐岩储层深度酸压增产改造技术具有重要的工程意义。试验结果表明:酸液对碳酸盐岩试样主要以表面溶蚀为主,微细观结构形成了溶蚀缝洞和微裂隙,矿物含量方解石由73.43%减至47.51%,方解石含量高且易酸化,属可压性较高储层;酸液对岩石物理力学特性劣化衰减具有明显的时间效应,酸岩反应后试样纵波波速迅速降低,岩石单轴抗压强度和弹性模量均随酸化时间增长而降低,破坏模式仍呈现拉伸劈裂破坏,但破坏方式有脆性向延性转化的趋势;碳酸盐岩水力压裂和酸化压裂的泵注压力随时间演化和声发射特征具有一定的相似性,但酸压裂缝更为复杂,裂缝表现出粗糙的溶蚀孔缝,且酸压起裂泵压明显小于水压起裂泵压。更多还原

【Abstract】 Based on systematic experiments including static dissolution tests,micro-mineral structure and composition analysis and rock mechanical tests,to make sure the rule of damage characteristics of carbonate rock with acid treatments from different scales and properties,the propagation characteristics and spatial distributions of fractures were investigate based on the fracturing chamber physics experiment,which has a crucial sense to improve the technology of stimulating and transforming in carbonate reservoirs as well as to provide effective technical parameters for the design and optimization of site operation. Results show that: samples with acid treatments arise significant change including dissolution surface and appearing seam holes,as well as a significant variation of integral shape and a sharp decreasing of quality. And the content of calcite is reduced from 73.43% to 47.51%,whose content is high and carbonate is easy to acidify and fracture. Acid treatment has obvious time effect on degradation of rock physical and mechanical properties,and velocity of longitudinal wave decreases sharply after acid treatments,and uniaxial compressive strength and elastic modulus of specimens decrease with the increasing of time of acid treatments.The uniaxial failure mode is basically tensile splitting and breaking,and bur the failure mode has a tendency of brittle transition to ductility. The pumping pressures and acoustic emission characteristics of acid fracturing have certain similarity with hydraulic fracturing,but the cracks of acid fracturing are more complicated,which show a rough corrosion crack and defects,and the pump pressure is obviously less than the pump pressure of hydraulic fracturing.更多还原