地震沉积学在薄储层岩性油藏勘探中的应用

APPLICATION OF SEISMIC SEDIMENTOLOGY IN THE EXPLORATION OF THE LITHOLOGICAL OIL RESEROVIRS IN THE THIN LAYER

松辽盆地扶余油层中央坳陷区发育大面积岩性油藏,储层主要为薄层河道砂,岩性圈闭的有效识别是勘探部署的瓶颈。为了解决扶余油层薄砂岩储层岩性圈闭识别难题,应用地震沉积学研究方法,形成了高频层序地层格架建立、细分层沉积微相划分、地震资料保幅处理、精细地震解释、大比例尺沉积微相制图、岩性圈闭识别与评价等6项关键技术。通过建立层序地层格架,划分沉积微相,井震结合砂体预测,研究大比例尺沉积微相,认清了扶余油层沉积演化与砂体展布特征,有效地识别了岩性圈闭,大幅提升了钻探成功率,新发现石油储量1亿吨。应用实践证明,地震沉积学是薄砂岩储层岩性油藏勘探的有效方法。

Large-area lithologic oil reservoirs are well developed in the Central Depression of Fuyu oil layers in Songliao Basin,the thin channel sandstones are the main reservoirs,the effective identification of the lithologic trap is the bottleneck of the exploratory arrangement. In order to solve the problem of identifying the lithologic trap in the thin sandstone reservoir of Fuyu oil layers,with the help of seismic sedimentology studying method,six key techniques were developed： high-frequency sequence stratigraphic framework establishment,separated layer＇s sedimentary microfacies classification,seismic amplitude preservation and processing,fine seismic interpretation,large-scale sedimentary microfacies mapping and lithologic trap identification and evaluation. Through the established sequence stratigraphic framework,the further classified sedimentary microfacies and the predicted sandbodies by means of the well-seismic integration,and moreover the studied large-scale sedimentary microfacies,the characteristics of the sedimentary evolution and the sandstone distribution were made clear,the lithologic trap was effectively identified,the drilling success ratio was increased to a great deal,the new discovered oil reserves were up to100 million tons. The practice shows that the seismic sedimentology is the effective approach to explore the thin sandstone reservoir of the lithologic oil reservoir.