泌阳凹陷安棚油田深层系油气分布规律及控制因素

Study on the Distribution of Hydrocarbon and Controlling Factors of the Deep Burial Strata in Anpeng Oilfield of Biyang Sag

随着人类对油气资源需求不断增长,中浅层油气藏已基本探明和投入开发,深层系成为油气增储上产的一个新领域。国内外深层油气勘探实践证明,在深层系取得突破的关键是加强油气分布规律及控制因素认识。安棚油田位于泌阳凹陷东南部,其深层古近系核桃园组三段下亚段(Ⅴ～Ⅷ砂组)目前是河南石油勘探局的重点勘探层位。在安棚油田深层系近年的勘探成果及取得的地质认识的基础上,剖析该区油气成藏过程,并研究油气分布规律及主要控制因素。研究发现,安棚深层系油气藏主要为砂岩上倾尖灭油气藏,油气分布极不均匀,纵向上,核三Ⅴ砂组油气最为富集,Ⅵ砂组次之,Ⅶ、Ⅷ砂组最少;油气在平面上主要集中分布于鼻状构造轴部的泌185—泌252井一带。油气分布主要受沉积相、成岩作用及构造控制。平面上处于鼻状构造高部位,又处于晚成岩B期的远源水下分流河道、河口坝是最有利于油气富集的部位;纵向上,晚成岩B期的砂体有利于油气聚集,而晚成岩A3亚期的砂体不利于油气聚集。

With the increasing demand of oil and gas resource, oil and gas exploration have to expand to the deep zone. To reinforce the cognition of oil-gas distribution laws and its controlling factors is the key to achieve further in the deep zone. This article is based on the exploration achievements and geological cognition over the past years in the deep zone in Biyang sag, Anpeng oil field, and the laws of oil and gas distribution and the main controlling factors are analyzed in details. It shows that oil and gas distribution is inhomogeneous vertically. It has been found that the deep layer pool of Anpeng oil field mainly was updip wedge out trap. In Formation Hetaoyuan Ⅲ member Ⅴ sand layer is the most enriched with oil and gas, Ⅵ is less, Ⅶ and Ⅷ is the lest. In the plane, oil and gas gathers mainly along the axial lobe of nose structure near Well Bi185-Well Bi252 region. Sedimentary facies, diagenesis and structure are the main controlling factors to influence the distribution of oil and gas in this region. The site that is located on the eminence of nose structure, and far-source the underwater distributary channel and estuary bar experiencing the late dagenetic period B is the most promising for accumulation of oil and gas. Vertically, late diagenetic period B sand layer is advantageous for oil and gas gathering, while late diagenetic subperiod A3 sand layer is disadvantageous for oil and gas gathering.