库车坳陷裂缝性致密砂岩储层有效性评价方法

Effective Evaluation Methods for Fractured Tight Sandstone Reservoirs in Kuqa Depression

塔里木盆地库车坳陷多成因裂缝发育为储层提供了有效的储集空间和渗流通道,储层基质岩块孔隙小,是典型的裂缝性致密砂岩储层。面对埋藏深、岩性复杂的致密砂岩储层,孔隙度与渗透率低、喉道细、连通性差、非均质强的问题使得储层有效性评价面临不确定性。单井在物性和裂缝定性评价发育相当的情况下,测试产能差别大,迫切需要开展测井评价攻关研究。从孔隙度、裂缝参数、地应力等方面展开分析,对影响裂缝性致密砂岩储层品质的因素进行系统分析总结。选取孔隙度、裂缝孔隙度、裂缝宽度以及裂缝走向与最大水平主应力夹角等参数,利用测试资料刻画砂岩储层品质,通过调整主控因素相关系数对储层质量进行区分,建立储层品质因子,形成一套利用储层品质因子识别储层有效性的方法。该方法在新井解释评价中取得了较好的效果,为后期的解释评价提供技术支撑。

The multi-genetic fracture in Kuqa depression of Tarim basin provide effective reservoir space and permeability pathways for the reservoir,and the matrix rock blocks have small porosity,making it a typical fractured tight sandstone reservoir.Faced with the problems of low porosity and permeability,fine throats,poor connectivity,and strong heterogeneity in the deeply buried,complex tight sandstone reservoir,the effective reservoir evaluation is faced with uncertainty.In the case where the single well has similar petrophysical and fracture qualitative evaluation,the test production capacity is different,and there is an urgent need to conduct a well test evaluation research.By analyzing the factors affecting the quality of fractured tight sandstone reservoirs from the perspectives of porosity,fracture parameters,and stress,a systematic analysis and summary of the influencing factors is carried out.Selecting parameters such as porosity,fracture porosity,fracture width,and the angle between the maximum horizontal principal stress and the fracture strike direction,the sandstone reservoir quality is depicted using test data,and the reservoir quality is differentiated by adjusting the main control factor correlation coefficient.A reservoir quality factor is established,and a method of identifying reservoir effectiveness using reservoir quality factor is formed.This method has achieved good results in new well interpretation and evaluation,providing technical support for subsequent interpretation and evaluation.