苏里格气田下奥陶统马家沟组马五4亚段沉积相研究

Study on sedimentary facies of Ma54 Sub-Member, Majiagou Formation, Lower Ordovician in Ordos Basin

以苏里格气田东区南部下奥陶统马家沟在马五4亚段为研究对象．采用“点-线-面”工作思路与优势相法，对研究区马五4期沉积微相特征进行了研究，研究结果表明，马五4亚段沉积期主要发育了一套以碳酸盐岩、泥岩和膏岩沉积为主的蒸发潮坪相，亚相类型主要有潮间带和潮上带亚相，结合岩心相与其反映的沉积构造，进一步识别出8个次级亚相和14种微相。马五4亚段沉积期自下而上具有水体变浅的特征。从西北到东南水体逐渐变深．依次发育了潮上泥云坪、潮上云坪、潮上灰云坪3个南西-北东向条带状展布的沉积亚相带。潮间带于研究区西南部及东北偏东方向楔入，水体从北东和南西方向侵入，并最终建立了研究区的沉积模式。研究目标是通过对苏里格气田下古生界已有的钻井取心资料、测井资料、试气资料以及生产动态资料的综合分析与研究，精细刻画下古生界马五4亚段沉积相特征，为苏里格气田下古气藏的开发提供技术支持。

Taking the Ma54 Sub-Member, Majiagou Formation, Lower Ordovician in southern Sulige Gasfield as an object of study, the characteristics of the sedimentary microfacies of the research area in the Ma54 stage has been studied by adopting a working idea and advantaged-facies method of ＂ point- line-plane＂. The results indicate that there was mainly a set of evaporated tidal-flat facies which took carbonate rock, mudstone and gypsolyte deposition as the main developed in the Ma54 period. The subfacies types are intertidal zone and epilittoral or supratidal zones. Eight secondary subfacies and fourteen microfacies can be further identified by combining with core facies and the reflected sedimentary structures. The water-body becomes shallow from bottom to top in the Ma54 sub-Member sedi- mentary stage. The water-body is gradually deeper and deeper from northwest to southeast. And there were three banded distribution of sedimentary subfacies tracts from south-west to north-east, that is, supratidal argillaceous dolomite fiat, supratidal dolomite flat, and supratidal limestone flat, sequentially developed in this area. The intertidal zone wedged in the southwest and the east-northeast direc- tion, and the water intruded from the north east and the south west direction. A sedimentary model of the study area is finally estab- lished. The research goal is to make fine description of the sedimentary characteristics of the Lower Paleozoic Ma54 sub-Member through comprehensive analysis and researches on the existing drilling and core data, logging, gas testing and production performance data of the Lower Paleozoic in the Sulige gasfield, so as to provide technical support to the development of the Lower Paleozoic gas reservoirs.