The Studing On The Sand Body Characteristics Of Donghetang Formation In Central Uplift In Tarim Basin

In this paper, I used sedimentology, sequence stratigraphy, facies and reservoir geology ancient geography and other subjects theory as a guide, and this paper is focus on Devonian donghetang formation of Central uplift belt in Tarim Basin as the research. On the basis of referring to the local regional tectonic setting, Combining macroscopic analysis with microscopic research, according to the evolution of stratigraphic-sedimentary evolution- the characteristics of sandbody as research ideas, Using the method of combining field geological data collection and indoor mirror observation to divide the sedimentary facies of the single well which is more than 170 in the central uplift zone, and making a comparison of 170 single wells, I have established the pictures of sedimentary facies of the central uplift zone. And then, to study the characteristics of the types of sedimentary facies and sedimentary phase plane distribution and vertical evolution of DongHeTang formation depositional stage which is in the sequence stratigraphic framework, on the basis of above all, this paper analyzed the sand body characteristics of donghetang formation more in-depth.Based on the analysis of evolution characteristics of regional tectonic,This paper established the division scheme of Donghetang Formation, and made a comparative study on different regional strata, The study area which belongs to KEPINGTAGE group is divided into 3 lithologic section, and discussing the Donghetang Formation, this paper judges geological age of the Donghetang formation belongs to Devonian.Making full use of previous information, Combining with the basin outcrop, drilling core data, logging data and laboratory test data, based on the study of sedimentary facies marks. According to the rock assemblage, sedimentary structure, profile character and evolution sequence, this paper studied the types and characteristics of sedimentary facies in the study area which is Devonian donghetang formation, and identified the shore facies, continental shelf facies, delta facies, these three sedimentary facies types. And the shore facies is further divided into two sub phases, the foreshore and shoreface,then the pre-littoral facies can be divided into two microfacies, sandy front and gravel,and the next, the paper analyzed the Donghetang Formation in different sub sedimentary period of sedimentary facies distribution, to establish the sand bodies' sedimentary model which is deposited at the different time-same phase of donghetangformation shore.Combining with research results in two aspects of formation and deposition, deeply analysising of characteristics of donghetangformation reservoir, the paper has studied the reservoir type, reservoir space characteristics and reservoir characteristics of Donghe sandstone. And described the formation processes of lithologic traps in the sequence evolution of the littoral sand bodies.Studing on the development characteristics of lithologic trap of Donghe sandstone, The transgression of the reservoir sand body is composed of foreshore and nearshore sand conglomerate, sandstone. The maximum flooding period is composed by Shoreface mud or continental shelf facies mudstone,and the maximum flooding period can make up the good reservoir-cap combination vertically. The slope belt is the surface of the shore and the land, which is favorable reservoir zone. It has formed formation of stratigraphic lithologic block between the slope zone and sand body, The transition from the front to the near shore had been become fine sandstone laterally, and it composit the occlusion of phsical property variation.