辽西凹陷热河台油气层油气分布规律

辽河坳陷西部凹陷双台子油田是由下第三系渐新统沙河街组二段的兴隆台油气层和沙河街组三段上部的热河台油气层所构成的复式油气藏。热河台油气层整体属于深水湖底扇沉积成因，对该油气层研究和认识不足制约了勘探工作发展。通过对储层岩性、含油性、物性、电性关系的研究，确定了该油气层下限标准为细砂岩、油斑，含油饱和度40%，孔隙度8%及电阻率16 Ω·m。重点分析了中子伽马测井、声波时差测井交会识别气层的方法，依据新标准重新解释了双台子68 口井，将原解释结论中30.2%的水层改判为油气层，新发现油气层多是热河台油气层上部的低阻油气层。研究结果表明：该油气层在纵向上有两套油气单元；平面上油气主要分布在断裂背斜的轴线附近，构造控油作用明显；紧邻生油洼陷和东西向断裂切割是造就双台子断裂背斜构造带复式油气成藏的主因。该油气层上部层段的低阻气层仍有较大勘探潜力。

HYDROCARBON DISTRIBUTION PATTERNS IN REHETAI RESERVOIR OF SHUANGTAIZI OILFIELD, WESTERN LIAOHE DEPRESSION

Shuangtaizi oilfield in the western Liaohe depression is a composite pool composed of Xinglongtai reservoir in the 2nd member and Rehetai reservoir in the 3rd member of the Oligocene Shahejie Fm of Eogene. Rehetai reservoir is, as a whole, of deep sublacustrine fan facies and the poor understandings of this reservoir constrain petroleum exploration in the study area. Based on study of the relationship among lithology, oil bearing property, physical property and electric property of the reservoir, criteria for identifying the lower limits of this reservoir are determined, i.e. fine sandstone, oil patch, oil saturation of 40%, porosity of 8% and resistivity of 16 Ω·m. According to the new criteria, neutron gamma logs and acoustic logs of 68 wells are reinterpreted in Shuangtaizi oilfield. Out of the water layers previously interpreted, 30.2% are identified to be oil/gas layers and the newly identified oil/gas layers mostly have low resistivity. Two units are recognized vertically in this reservoir and the hydrocarbons mainly occur along the axial line of the faulted anticline, indicating the significant control of structures on hydrocarbon distribution. The proximity to the hydrocarbon kitchen and the cutting of EW trending faults are the main causes of the composite reservoirs in the Shuangtaizi faulted anticlinal structural zone. The upper interval with low resistivity in this reservoir still has great potential for gas exploration.