The Research Of Sedimentary Microfacies In The GⅢ And GⅣ Reservoir Of Qijia Area And Reservoir Control Effect

With the application of the theory of high resolution sequence stratigraphy and sedimentology including the datas about lithology, mineralogy, biological stratigraphy, geochemistry and geophysics material, Gaotaizi reserviors in Qijia area are studied based on of high resolution sequence stratigraphy theory.We identified two kinds of sequence boundary.One is the falling and rising conversion surfaces of the reference plane of delta diversion plain and shore shallow lake,the other is the top of the delta front reverse cycle and the maximum lake is coincident with the sequence boundary.We subdivided the Gaotaizi reservior group into 2 Grade Ⅳ, 5 Grade Ⅴ and detailed division of stratigraphic unit,they are G Ⅲ up,G Ⅲ down, G Ⅳ up, G Ⅳmiddle, G Ⅳ down.Qijia is large sill-like delta syestem,and the sand in the delta front sheet is much developed. The sand distribution range is controled by river distributary chunnel, mouth bar,frontal sheet.The sand for river distributary and mouth bar have a large thickness and poor continuity, but the sheet sand have a stability and good continuity. The frontal sand bodies of delta and loch beach barrier sand have been recognized as the favorable ones for oil- gas reservoir forming in this area.It’s the first time to compile the sedimentary microfacies map with much work area well shock combined in large scale, which can depict sedimentary microfacies boundary, and make the sedimentary microfacies map more practical significance. The further development of the 3d seismic sedimentary interpretation technology and large scale sedimentary microfacies mapping technology in three dimensional area, which have effective guidance to the exploration and deployment.