The Sedimentary Environment And Single Sand Body Research Of Quantou-4Formation Of JF229Well Areas At Yongping Oilfield In The Southern Songliao Basin

Yongping oilfield is located at the north of Denglouku anticline in thesouth-east uplift area of Songliao basin, and JF229well areas are situated in thecentral-southern part of Yongping oilfield dome structure. Under the guidance ofhigh resolution stratigraphy and sedimentology theory, the papers provide a detailedstratigraphic division of Quantou-4formation in the study area, and discuss asystematic study on the sedimentary features of Quantou-4formation. Meanwhile,under dense well pattern conditions, the dissection of the study area identified asingle sand body makes clear the spatial distribution characteristics of sand.Conclusions are drawn as follows:(1) In the study area, there are16contrast sections, under the fully consideringabout the lithology and electric property combination characteristics and thecharacteristics of the cycle, the papers find the maker bed and summarize thecharacteristics of each time unit. As a result, the Quantou-4formation has beenvertically divided into four groups and12small layers. Among them,4small layersin I sand group,3small layers in Ⅱ sand group,2small layers in Ⅲ sand groupand3small layers in Ⅳ sand group. The thickness of the small layers in the studyarea changes little with the steady sedimentary.(2) Summarizes the characteristics of the shallow water delta of the study area:developed in the early depression basin; the basement sank stably and the palaeoto-pography was gentle and smooth slope; large scale sand body distribution; the lakewater was shallow and lake level changed obviously; the finer grain size; plenty of sedimentary structures formed by strong hydropower; moderate maturity ofcomposition and texture; the alternate distribution of wide purple and grayish greenmudstone, development of pyrite; The main study area developed underwaterdistributary channel, underwater distributary bay, underwater natural levee and sheetsand microfacies with few mouth bars.(3) The characteristics and formation conditions of the clay and calciummezzanine developed in the study area were analyzed, and these are used to divide asingle sand body on a vertical. The papers sum up the relationship between the typeof channel sand body on a plane to split channel, and describe the sand body featuresof major reservoirs.(4) The scale of the complex channel in the shallow water delta was large, butthe thickness and width of the single-channel sand were small, the width from200to600m, the average thickness was3to6m. The channel sand body swung frequentlyin a small layer of single-period.