正宁—宜君地区长6油层组沉积相研究

发布时间：2019-02-21 10:30

【摘要】：正宁-宜君地区长6油层组石油资源丰富,但是深入勘探与其地质研究程度低的矛盾却日益凸现,表现为由于地质认识的不统一,尤其是沉积相及砂体展布问题仍存在着诸多争议,给油气的进一步勘探开发带来困难。本文以沉积学理论为指导,综合运用沉积岩石学、石油地质学、测井地质学等学科的多种技术方法,通过露头剖面、钻井岩心、录井和测井资料,以地层划分为基础,明确物源方向,重点识别沉积相类型,深入开展沉积相和砂体展布规律的研究。在地层划分与对比中,通过标志层控制和旋回对比的方法,结合厚度原则,将研究区长6油层组地层细分为长61、长62、长63三个小层,层顶构造呈现东南高西北低的特点,3-4个近北西-南东向的鼻状隆起继承性明显。根据古流向、轻重矿物和岩屑分析及古陆分布特征,综合认为研究区长6油层组主要受来自南部物源的控制,西南物源对研究区的影响次之。推测南部物源来自秦岭造山带,西南物源来自陇西古陆。依据岩心描述、露头剖面,结合岩石类型、结构特征、沉积构造及古生物特征等,认为研究区长6发育三角洲-湖泊-重力流沉积体系,首次在研究区识别出砂质碎屑流沉积。底模构造(槽模、沟模),变形构造(重荷模、火焰状构造、砂球构造、砂侵蘑菇),撕裂状泥砾片和不完整的鲍马序列这些代表着深水重力流沉积的典型构造在研究区广泛发育。通过进一步研究,划分为砂质碎屑流、浊积、(半)深湖、三角洲前缘四类亚相沉积,进一步可分为七类微相,并详细分析了各个微相的主要特征。通过单井测井相分析和连井剖面对比,编制了不同时期的沉积相及砂体平面展布图。研究表明沉积相控制着砂体的展布规律,长61、长62、长63亚期沉积环境具有良好的继承性,砂体展布格局基本相同,大致呈北东-南西向展布,从长63期到长61期,砂体规模逐步缩小,砂体连片性变差。
[Abstract]:The oil resources of Chang-6 formation in Zhengning-Yijun area are abundant, but the contradiction between deep exploration and low degree of geological research is becoming more and more prominent, which is due to the inconsistency of geological knowledge. Especially, the distribution of sedimentary facies and sand bodies is still controversial, which brings difficulties to the further exploration and development of oil and gas. Guided by the theory of sedimentology, this paper synthetically applies various technical methods of sedimentary petrology, petroleum geology, logging geology and so on, based on stratigraphic division through outcrop profile, drilling core, logging and logging data. The distribution of sedimentary facies and sand body is studied in detail by defining the direction of the source, identifying the types of sedimentary facies and studying deeply the distribution of sedimentary facies and sand body. In stratigraphic division and correlation, the strata of Chang 6 oil formation in the study area are subdivided into three sub-layers, Chang 61, Chang 62 and Chang 63, by means of the method of marker layer control and cyclic correlation, combined with the thickness principle. The top structure of the formation shows the characteristics of high, northwest and low southeast. The succession of 3-4 nasal uplift near NW-E direction is obvious. According to the paleodirection, the analysis of heavy and heavy minerals and lithosphere and the distribution characteristics of paleocontinent, it is considered that the Chang 6 oil formation in the study area is mainly controlled by the southern provenance, followed by the influence of the southwest provenance on the study area. It is inferred that the southern provenance comes from the Qinling orogenic belt, and the southwest provenance comes from the Longxi ancient land. Based on the core description, outcrop profile, rock types, structural characteristics, sedimentary structures and paleontological characteristics, it is considered that the depositional system of delta-lacustry-gravity flow was developed in Chang6 area, and the sandy clastic flow deposits were identified for the first time in the study area. Bottom mold structure (groove mold, groove mold), deformation structure (heavy load model, flame structure, sand ball structure, sand invasion mushroom), The tearing debris and incomplete Baumar sequences, which represent the typical structures of deep water gravity flow deposition, are widely developed in the study area. Through further study, it can be divided into four subfacies: sand clastic flow, turbidite, (half) deep lake and delta front, which can be further divided into seven types of microfacies, and the main characteristics of each microfacies are analyzed in detail. Based on the single well logging facies analysis and the correlation of continuous well profiles, the sedimentary facies and sand body plane distribution diagrams in different periods have been compiled. The results show that the sedimentary facies control the distribution of sand bodies. The sedimentary environments of Chang 61, Chang 62 and Chang 63 have good inheritance, and the distribution pattern of sand bodies is basically the same, which is roughly NE-NW distribution, from Chang63 to Chang61. The scale of sand body gradually shrinks and the continuity of sand body becomes worse.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】