Study On Sedimentary Characteristics Of Asmari Formation In Iraq A Oilfield

The Iraq’s A oil field is developed by the CNOOC and the government of Iraq. It was once stopped producing oil because of the Iraq war and the restoration of production is needed after the war.so it is important to study the sedimentary characteristics. This article is based on sedimentology,sequence stratigraphy,sedimentary petrology and geophysical logging theory,classifies the formation and builds the stratigraphic framework. Relying on the core data,thin section datalogging data,test material and research results,forms a set of sedimentary facies identification. On this basis,completing16wells’Sedimentary facies division and follow the single well-combine well-surface routine to recognize and divide the sedimentary facies and study the distribution of the sedimentary facies. The results achieved are as follows:(1)Relying on the basis of core data and logging data classifies the formation of16wells in the study area.The Asmari formation is divided into A,B,C three oil groups and A1,A2,A3,B1,B2,B3,B4,C eight layers. Established the sedimentary framework in the study area. There are three kinds of rock in A oil field from bottom to top,A oil group is mainly dolomite, B oil formation is mainly limestone,C oil group is mainly sandstone and mudstone.(2) Relying on the core and slice observation,forms a set of sedimentary facies identification including lithology,colors feature,structural feature,sedimentary structures, palaeontology characteristics and logging facies deposition.(3) According to the identifications of sedimentary facies and previous studies,analysis of the sedimentary environment of the study area,summarize that the Asmari formation of the research area changes from the continental shelf to open platform to restricted platform depositional environment. And divided into6subfacies:continental shelf,tempestite,semi restricted lagoon,intraplatform restricted lagoon.and clastic tidal flat. On the basis of the previous study we establish the sedimentary model and a single vertical sedimentary sequence,then study the distribution of the sedimentary facies.(4) According to the layer data and the single well sedimentary facies data, the3D sedimentary facies visualization models were developed, by use of the deterministic modeling method to add the geologist’s thoughts into3D model.