燃爆强加载条件下油井破裂压力试验研究

TEST STUDY OF OIL WELL BREAKDOWN PRESSURE UNDER BLASTING LOADING

针对燃爆压裂设计中难以定量确定强动载条件下破裂压力的问题,利用"岩石动态损伤模拟试验装置"对3种抗拉强度岩心进行5种加载速率下的19组岩石冲击开裂试验;经试验验证该装置可模拟定压供给边界条件下中心一裸眼井的油藏条件,并直接对小型岩心试样中模拟井孔进行水压冲击破岩试验,且可形成153.17MPa/ms以内的加载速率,完全可以模拟燃爆压裂的实际情况。经过对试验数据回归分析,发现动/静破裂压力差值与加载速率呈现很好的对数关系,经验证该回归模型计算误差为0.95%,具有较高精度;该研究成果可为燃爆压裂设计中的最低峰值压力确定提供指导,对提高该增产措施的普适性和成功率具有一定指导意义。

Based on the problem of the quantitative description of blasting well breakdown pressure,19 experiments on rock cracking with three kinds of tensile strengths under 5 loading rates are carried out by the rock dynamic cracking simulation device.The experiments verify that the device can simulate the reservoir conditions of a center open hole with the boundary conditions of constent pressure while giving a test of rock fragmentation by water pressure impact on the small simulation hole immediately.It can offer the loading rate bellow 153.17 MPa/ms,which can simulate the real blasting fracturing condition completely.The regression analysis of experimental data shows that the difference of dynamic and static breakdown pressures with the loading rate shows a very good logarithm relationship,and the regression model presents a calculation error of 0.95%.The research results can help to ascertain minimum peak pressure in the design of detonation pressure and enhance the production of universal application and the success rate.