塔里木盆地库车坳陷超深层现今地应力对储层品质的影响及实践应用

Effects and practical applications of present-day in-situ stress on reservoir quality in ultra-deep layers of Kuqa Depression,Tarim Basin

塔里木盆地库车坳陷油气资源埋藏深度大,储层非均质性强、井间产能差异大。现今地应力对储层品质具有重要影响和控制,但当前研究方法存在不足。为了革新储层评价的理论认识与技术方法,从地应力角度出发,基于岩石测试和测井数据,结合区域演化和构造变形综合分析,开展系统的地质力学研究,并提出了量化表征应力集中的参数,实现有利区带的优选。结果表明:(1)现今地应力及其控制下的裂缝渗透性是决定超深层产能的重要因素,低应力和裂缝活动性好的位置是有利优选区,要避免以井壁连续崩落为特征的局部应力集中区这类不利位置;(2)“强应力”由地应力和岩石强度之间“博弈”导致,根据二者平衡关系确定的应力集中参数有效表征了“强应力”的分布,将地应力影响下的相关参数纳入储层品质评价提高了储层分级的精度;(3)宜充分利用大斜度井有多穿有利区、多垂直穿裂缝的多重优势,解决复杂问题,提高勘探开发效率。

There is an important relationship between in-situ stress and reservoir quality,in order to innovate the theoretical understanding and technical methods of reservoir evaluation from the perspective of in-situ stress.Based on the rock mechanical test and logging data,combined with regional evolution and structural deformation,this study carried out systematic geomechanics research,and proposed the quantitative characterization of stress concentration parameters,so as to realize the optimization of favorable zones. The results show that the in-situ stress and the fracture permeability under its control are important factors to determine the productivity in ultra-deep reservoir. The favorable location with low stress and good fracture activity should be selected,and the unfavorable location such as local stress concentration area characterized by continuous borehole breakouts should be avoided. The strong stress is caused by the imbalance between in-situ stress and rock strength. The stress concentration parameters determined according to the equilibrium relationship effectively characterize the distribution of strong stress. The accuracy of reservoir classification is improved by incorporating the relevant parameters under the influence of in-situ stress into the evaluation method of reservoir quality. It is necessary to make full use of the multiple advantages of highly deviated wells with multiple favorable areas and multiple vertical fractures to solve complex problems and improve the efficiency of exploration and development.