吉木萨尔凹陷芦草沟组致密油储层沉积相分析

利用岩芯、薄片、录井和测井等资料，在识别各级次基面旋回界面类型及特征的基础上，将准噶尔盆地吉木萨尔凹陷芦草沟组划分为1个长期旋回，6个中期旋回，44个短期旋回，建立高分辨率层序地层对比格架。在总结地球化学、岩性、沉积构造、电性特征的基础上，综合分析古生物化石、测井等资料，以识别沉积相标志为主，进行单井、连井及平面沉积相分析。研究结果认为，吉木萨尔凹陷芦草沟组为咸化湖泊-三角洲沉积体系，岩性复杂多变，在机械、化学、生物等沉积作用共同影响下，形成由细粒碎屑岩、泥岩、碳酸盐岩构成的混积岩层。芦草沟组发育上、下两个致密油甜点体，上甜点体（SSC37-SSC42）为咸化湖相沉积，微相类型以滩坝为主；下甜点体（SSC6-SSC17）以三角洲前缘沉积为主，微相类型为席状砂、远砂坝等。利用开发试验区及水平井部署区的井多、井密的有利条件，对沉积相边界进行控制，从而实现平面微相的精细刻画，研究表明芦草沟组优质甜点以滩坝主体微相为主，主要集中发育在凹陷中心低隆起处。

Depositional Facies Analysis on Tight Reservoir of Lucaogou Formation in Jimsar Sag,Junggar Basin

Using cores,thin section,log and well log data,based on the identification of every base types and characteristics of the cycle interface,the Permian Lucaogou Formation strata in Jimsar sag are divided into 1 long-term cycles,6 medium-term cycles and 44 short-term cycles,the high resolution sequence stratigraphy correlation framework is established.On the basis of summarizing the geochemistry,lithology,sedimentary structure and electrical characteristics,comprehensive analysis of fossils and logging data to identify the sedimentary facies marks,single well,well connected and plane sedimentary facies analysis,the Permian Lucaogou Formation strata are mainly salified-lake facies,locally delta facies deposit,with the complex lithology formed by mechanical deposition,chemical deposition,and the deposition of fine clastic rocks,mud and carbonate rocks which are deposited under the influence of the deposition.Lucaogou Formation developed two tight oil body sweet spot,the upper body is a kind of salty lacustrine carbonate rocks,the types of micro facies in shallow lake dam;The inferior dessert is mainly based on the delta front to the former delta subfacies.Micro facies type is sheet sand and far sand dam.At the same time,the advantage of horizontal continuous change of reservoir in the area of the study area and the level of the well is to be revealed by the reservoir,control of planar micro facies boundary in tight oil reservoir,thus more accurately reflect the plane distribution characteristics of tight oil reservoir.Research shows that the quality of Lucaogou Formation near to the sweet spot is beach bar microfacies mainly developed in the center of the sag at low uplift.