史家湾-堡子湾地区延安组延9油层组沉积微相研究

Research on sedimentary microfacies of Yan 9 oil-bearing formation of Yan′an Formation in Shijiawan-Baoziwan area

焦滔,崔英敏,王博涛,路巍,谢耀荣,赵晓红,陈贞万,张红涛

中国石油长庆油田分公司第五采油厂，陕西 西安 710200 长庆实业集团有限公司地质工艺研究所，陕西 西安 710018 北京凯博瑞石油科技有限公司，北京 100083

史家湾￣堡子湾地区发育岩性￣构造油藏，相控砂体特征明显，该区延安组延9油层组是油气勘探开发的主要层系，但前人尚未对延9油层组沉积微相进行深入研究，严重制约了后期开发策略的制定。文中综合运用大量岩心、测井数据，对研究区岩心的颜色、岩性、沉积构造及古生物化石等沉积相标志进行研究，认为研究区延9油层组属于三角洲沉积环境下的三角洲平原亚相沉积，发育的微相类型主要有分流河道、天然堤、分流间洼地和沼泽。优势油气储集相带为分流河道，砂体平面上呈北西—南东向条带状展布，平均厚度5.8 m，宽0.5～3.0 km，局部多期河道叠加，厚度大于15 m。砂泥岩平面上相间、垂向上互层的结构有利于形成良好的岩性圈闭。

Yan 9 oil-bearing formation of Yan′an Formation in Shijiawan-Baoziwan area is the main layer series for oil and gas exploration and development. Lithologic structural reservoirs are developed in this area, and the characteristics of facies controlled sand bodies are obvious. However, the sedimentary microfacies of Yan 9 oil-bearing formation in this area have not been deeply studied by predecessors, which seriously restricts the formulation of later development strategy. In this paper, a large number of core and logging data are used to study the sedimentary facies indicators such as core color, lithology, sedimentary structure and paleontological fossils in the study area. It is considered that the Yan 9 Member in the study area belongs to the delta plain subfacies in the delta sedimentary environment, and the main microfacies are distributary channel, natural dike, inter distributary depression and swamp microfacies. The dominant oil and gas reservoir facies belt is distributary channel, and the sand body is distributed in NW-SE direction in plane, with an average thickness of 5.8 m and a width of 0.5-3.0 km. The local multi-stage channel superimposition has a thickness of more than 15 m. The structure of alternating sandstone and mudstone in plane and interbedding in vertical is favorable for forming good lithologic traps.

10.6056/dkyqt202104010