岩石脆性实验及压裂缝高度与宽度测井预测

Research on Rock Brittleness Experiment and Logging Prediction of Hydraulic Fracture Height & Width

随着长庆油田勘探开发的不断深入,低孔低渗储层已成为主要勘探开发对象,几乎所有井的储层都要经过压裂改造才有产能。储层压裂改造的规模需要考虑岩石脆性剖面变化特征,其脆性系数从岩石力学的角度间接反映了储层被压开的难易程度。以长庆油田姬塬地区延长组地层为例,通过岩芯三轴脆性实验数据(杨氏弹性模量和泊松比)得到岩石脆性系数,并用其校正测井计算的岩石脆性系数,由此建立连续的岩石脆性系数剖面。在此基础上,推导并建立了岩石脆性系数与最小水平地应力的定量关系式,实现了基于岩石脆性系数的储层压裂缝高度与宽度的定量预测、将此方法应用于工区多口油井的压裂改造工程中,取得了良好的效果,值得推广应用。

With the development of Changing Oilfield exploration and exploitation, low porosity and permeability reservoir has become a major object of exploration and development. The reservoirs of almost all wells go through fracturing transformation before they have the capacity. The brittle rock sectional variation should be considered in reservoir fracturing, as brittleness coefficient indirectly reflects the degree for difficulty of the reservoir pressure to open from rock mechanics angle. Taking the Yanchang reservoir of Changing Oilfield in Jiyuan area for example, we get the rock brittleness coefficient and calculate the dynamic rock brittleness coefficient of calibration logging with the core of triaxial test data （Young＇s modulus and Poisson＇s ratio）, by this we establish the continuous rock brittle coefficient of profile. Quantitative relationship between the rock brittle- ness coefficient B and minimum horizontal stress S h is established, and quantitative prediction of fracture height and width is realized based on reservoir rock brittleness coefficient. Application of this method to the work area wells fracturing renovation project generated good results, which proves its worth of wide application.