Research On Sedimentary Microfacies And Petroleum Enrichment Pattern Of Fuyu Formation In Zhaozhou Field

The Fuyu formation in Zhao zhou field is recognized as one of the important hydrocarbon exploration targets of San zhao depression which is administered by the Eighth Oil Production Plant. Currently there have been 2 test areas to invest in developing and seen a good hydrocarbon potential. But for the difficulty of predicting reservoir sedimentary characters and sand exhibition, it is hard to expand the development zone and to layout wells. In the paper, taking sedimentology as a guide, uing cores, well logs and three-dimensional seismic data, doing research on the provenance system, sedimentary characteristics, sedimentary facies and oil-water distribution pattern, we have sep up an microfacies-oil control model of the study area. And 16 hydrocarbon tagets have been depicted.Using heavy mineral data in and around the study area, the change of the stratigraphic thickness and anatomy to the dense well network in development zone, analyzing the provenance direction of Fuyu formation to Zhao zhou field in San zhao depression, the conclusion is that it is in the southwest. The Fuyu formation was divided into 17 layers,35 sedimentary time units according to 140 logs , well net contrasts and well-well contrasts . On this basis, distinguish each facies of 140 wells. Then synthesized provenance direction, sedimentary microfacies figures of Fâ… and Fâ…¡i n plane have been draw. Fâ… 11~Fâ… 3 2 develop delta front subfacies. Fâ… 4 1~Fâ…¡5 2 develop delta plain subfacies. Then we knew that the sand bodies develop well in the west of Zhaozhou field in plane, while Fâ… 7 1~Fâ…¡1 3 vertically.By the use of statistical data, the relationship between oil accumulation and distribution and the sedimentary microfacies in Zhao zhou field has been analyzed. According to the interpretation data in Zhao zhou field, count the numbers and the thicknesses in each layer in profile, which the conclusion is that the oil mainly exists in Fâ… 6 2, Fâ… 7 3, Fâ… 7 2 and Fâ…¡1 1. In plane, the Zhao zhou field is divided into three areas: the First Zone, the Second Zone and the Third Zone, which is according to the well density level. The maximum of densities is at the First Zone. There are two developing area: Zhou 201 and Zhou 211. The density value of the Second Zone is in the middle of them all. The more the well density is, the bigger the precision of the oil distribution map. So it is the First Zone which is the most credible. Oil accumulates the most in First Zone. By counting the type of the oil-bearing microfacies by layers, we fount that the oil mainly accumulate in the underwater channels and sheets in the delta front subfacies, while the channels in the delta plain subfacies. The relationship between the numbers of the mainly oil-bearing microfacies and the degree of oil-bearing is in the direct proportion.According to the structure map of Fuyu formation, 32 fault seal traps, 8 sealed fault traps and 1structure trap have been identified. By the principle of"oil area, channels or sheets and traps",16 favorable prospecting plays have been drawn.