四川盆地元坝气田长兴组礁滩相超深薄储层水平井轨迹优化技术与应用

Trajectory optimization technology of horizontal wells and application in ultra-deep thin reef-shoal reservoir of Changxing Formation in Yuanba gas field,Sichuan Basin

元坝气田上二叠统长兴组礁滩相气藏的开发过程中,多种因素引起目的层深度的变化以及储层非均质性,给水平井施工中准确钻遇目标地质体带来了极大困难。为了提高优质储层钻遇率,笔者根据前期生物礁储层分布规律研究成果,结合随钻地质、测井和物探等资料,分析礁体分布地质模式,通过储层深度精确预测、岩性识别、储层评价和地层水识别等技术的结合,建立水平井轨迹优化调整技术,进而确立具底水、多礁体、薄互层和较厚礁体等多种储层水平井轨迹。该技术在元坝气田开发过程中广泛应用,水平井储层钻遇率达82.1%,在提高产能上取得显著效果,测试井平均无阻流量292×10^(4)m^(3)/d,实现了动用储量最大化、多穿优质储层。

During the development of reef-shoal reservoir of Upper Permian Changxing Formation in the Yuanba gas field,the variation of the depth of target layer caused by various factors and reservoir heterogeneity have brought great difficulties to the accurate drilling of the target geological bodies in the horizontal wells.In order to successfully drilling into the high-quality reservoirs,the authors analyze the geological pattern of reef reservoir distribution according to the previous research results of biohermal reservoir distribution law,combined with the geological data from drilling,logging and geophysics,and then establish the horizontal well trajectory optimization and control technology through the combination of accurate prediction of reservoir depth,lithology identification,reservoir evaluation,and formation water identification,etc.Furthermore,the horizontal well trajectories in various reservoirs with bottom water,multi reefs,thin interbeds and thicker reefs are established.This technology has been widely used in the development of Yuanba gas field.The reservoir drilling encounter rate of horizontal wells is 82.1%,which has achieved remarkable results in improving productivity,and the average open flow rate of the test well reaches 292×10^(4) m^(3)/d.This technology maximizes the producing reserves and enables more penetration of high-quality reservoirs.