复杂断块油田高分辨率层序地层学及砂体几何学特征以海塔盆地贝尔凹陷呼和诺仁油田贝301区块南屯组二段为例

摘要

Description of the geometric model of the fan delta single stage fan is the key geological technology which solving the development of Haita oilfield. Regarding high-resolution sequence stratigraphy and modern sedimentary theory as the guidance,we identify 3 long terms,4 middle terms, 6 short terms,and 53 super short terms (equivalent to single sand body)base-level cycles in N2 of Nantun Group in Bei 301 region Huhenuoren oilfield.We also establish the monosandbody rank high-resolution sequence stratigraphic framework in encrypted development zones of Haita basin for the first time.The study of sendimentary micro-facies shows underwater distributary channel and microfacies for river mouth bar which are full of favorable sandbodies mainly develop in the little accommodate space that near the turnaround serface of SSC3,SSC4,SSC5 and SSC6.The width and thickness ratio for the single underwater distributary channel is generally between 50∶1 and 200∶1 ,the average value is about 85∶1.With the decreasing of the base level,the width of underwater distributary channel is increased, and the thickness is thickened,and the width and thickness ratio is increased.With the rising of the base level,the width of underwater distributary channel becomes narrower and the thickness is decreased,and the width and thickness ratio is decreased.The distribution area and thickness of river mouth bar has a certain positive correlation.The radius and thickness ratio is between 60∶ 1 and 120∶ 1,the average value is about 90 ∶ 1. This research established the industrial drawing of monosandbody rank sendimentary micro-facies in Haita basin for the first time,described geometry characteristic of the main monosandbody and provided the geological basis for comprehensive development.%准确刻画扇三角洲单期扇体几何形态是破解海塔油田开发的关键地质技术，以高分辨率层序地层学和现代沉积学理论为指导，在海塔盆地贝尔凹陷呼和诺仁油田贝301区块南屯组二段识别出3个长期（LSC）、4个中期（MSC）、6个短期（SSC）、53个超短期（相当于单砂体）基准面旋回，首次建立了海塔盆地已加密开发区块单砂体级高分辨率层序地层格架。沉积微相研究表明，优势砂体发育的水下分流河道、河口坝微相主要发育于可容纳空间较小的 SSC3、SSC4及 SSC5与 SSC6的转换面附近。单期水下分流河道宽厚比为50∶1～200∶1，平均为85∶1；随着基准面的下降，水下分流河道的宽度增大、厚度增厚、宽厚比增大，随着基准面的上升，水下分流河道的宽度变窄、厚度减小、宽厚比减小。河口坝展布面积与其厚度有一定正相关性，一般半径与厚度的比值为60∶1～120∶1，平均为90∶1。本次研究首次实现海塔盆地单砂体级沉积微相工业化制图，精细刻画了主要砂体几何学特征，为综合挖潜提供了一定的地质依据。