塔河地区奥陶系碳酸盐岩储层溶洞断裂定量分级技术

Quantitative Classification Technology for Karst Cave Fractures in Ordovician Carbonate Reservoirs in Tahe Area

有利缝洞带的准确预测可有效提高碳酸盐岩储层钻井的放空漏失率,达到油藏动用目的,对于断溶体内部缝洞储集体溶洞及断裂进行分级尤为重要,探索应用断裂发育模式、断裂规模分级及基于构造曲率的应力分析进行断溶体内部断裂的分类、分级研究;提出基于正演模型论证及实钻分析,应用振幅、波阻抗综合分级,并进行实钻井标定验证,形成溶洞分级标准。以塔河某研究区为例进行了应用,将该区断裂带按照规模和应力性质分为8个级别,实钻井表明拉张区储集性能明显优于挤压区。并在该研究区确定了孔洞-溶洞分级的地震属性门槛值,“串珠”位置能量比值范围在54%~62%为孔洞,能量比大于62%为溶洞。最后利用实钻井分析验证了该技术的可靠性。

The prediction accuracy of favorable fracture-cavity zones and reservoir development can be effectively improved through the quantitative classification of fracture-cavity bodies.The classification and grading of internal faults within fracture-cavity bodies were explored by applying fracture development models,fracture scale classification,and stress analysis based on structural curvature.A comprehensive classification of amplitude and wave impedance was undertaken,followed by large-sample calibration and verification with the aim of establishing a karst-cave grading standard.As an illustrative example,a specific area in Tahe was employed.The fault zone in this area was divided into eight grades based on its scale and stress properties.Indications from real drilling data show that the reservoir performance in the extension area is significantly better than that in the compression area.Additionally,the threshold value of seismic attributes for hole-cave classification was established within this study area.The specified energy ratio range of“beads-on-string”features is 54%~62%for holes,and the energy ratio exceeds 62%for karst caves.Ultimately,the reliability of this technology was confirmed through real drilling analysis.