Research Of Sedimentary Facies And Sedimentary Microfacies Of The First Member Of Shahejie Formation In Shennan-yuke Area

Shennan-yuke region lies in the southeast of Shenxian sag, in the south of the region is hengshui-sunhu fracture, the north is near jiuchengbei fracture and liucun low bulge, the west is near baisongzhuang hollow tank belt, the east is connect with Raoyang sag, which is a complex trap with the bulge and the hollow hoiding in sunhu and jiuchengbei fracture, and is a continental fault basin whose development controlled by complex fracture system. The area has low conversion rate with significant resources exploration potential. Over the past years the region is the key study area in exploration and devlepment of oil and gas. In the early Esl, Shennan-yuke region experienced a wide lake invasion, formed the main hydrocarbon source rock, the formation of Esl is the study formation. Because of the complicated geological conditions in the area, with crushed tectonic, many fault and small fault blocks, the reservoir horizontal change fast and the heterogeneity is serious, which bring difficulties for the rolling development of the oilfield. In addition, the study area have many characteristics, such as fast water appearance, short water-free oil production period, fast water rising, fast dropping speed of reservoir pressure, fast production decline and so on, which seriously affected the region’s capacity building. So more precise sedimentary facies and sedimentary microfacies research results is urgently needed to guide predictting the reservoir and developping the advantageous areas in order to improve the yield and production efficiency.Combined with the regional geology sedimentary background and the study results of predecessors’, making full use of the data of coring, seismic, logging, well logging and testing, under the instruction of the theory of structural geology, seismic stratigraphy, sequence stratigraphy, sedimentology, logging geology, reservoir geology, petroleum geology, combining geophysical, geological with geochemical as the method, using the research idea of "by the single well and wells to plane to space distribution", to study sedimentary facies and microfacies of Esl, then analyze the characteristics of its distribution, study the relationship between sand body distribution with the sedimentary facies, clear the sedimentary system and establish the sedimentary model.The specific research steps as follows:on the basis of horizon definition and unifield stratification of Es1 in studied area, studied the source of sediments and the characteritics of sedimentary facies, make clear the sedimentary facies type of studied area. Then make sedimentology research on the coring wells and cutting logging data of studied area, divided sedimentary microfacies. On the basis of this, though the calibration of different sedimentary microfacies in the corresponding logging curves, determine logging curve characteristics of all kinds of sedimentary microfacies, establish the logging-sedimentary microfacies model for quantitative interpretation in studied area so as to study the sedimentary facies of wells without coring. Though the identification of sedimentary microfacies in different wells to determine the sedimentary system types reflected by the drilling. On the basis of studying sedimentary system of wells, compare sedimentary system of different wells, make clear the characteristics of sedimentary microfacies. Though the variation of the sedimentary microfacies in vertical and horizontal upward, summarized the evolution rule of sedimentary microfacies, in the end established the combining form of sedimentary facies in space.From the analysis, this paper mainly come to some conclusions:First, under the guidance of the principle and method of the high resolution sequence stratigraphy, according to the seismic data indentified the system interface of Esl, combine the data of coring, well logging, logging and seismic, subdivided the formation Esl into four oil groups, setting up the framework of isochronous genesis stratigraphic.Second, using a variety of provenance analysis methods such as debris combination characteristics, particle size distribution, formation thickness, clastic composition, heavy mineral analysis, sandstone thickness and sand ratio, a conclusion from comprehensive analysis is that the provenance direction of the formation Esl is mainly from the northwest of shennan and yuke area, and the southwest of shennan area.Third, it found from the restored of ancient landform that the ancient terrain is complicated with big ups and downs. The ancient landscape pattern is"north and south wing is asymmetric, north and south has zoning characteristics, south slow north steep, north and south has zonality".Forth, making use of the core observation result and logging data, making a statistical analysis of the major facies marks (color) in the studied area, judging it as underwater sedimentary environment.Fifth, the type of sedimentary facies in shennan area is braided river delta facies, most developed the delta front subfacies, microfacies types are underwater distributary channel, river mouth dam, far sand bar, sheet sand, distributary bay. The yuke area mainly developed meandering river delta facies with delta front subfacies most developed, the microfacies types are underwater distributary channel, river mouth dam, far sand bar, sheet sand and distributary bay. Local lake facies developed coastal and shallow lake and half deep lake facies, the microfacies types are beach sand, mud and turbidite.