Sedimentary Characteristics and Control of Oil Accumulation of Chang6 Reservior of Yanchang Formation in Yanwumao Area , Ordos Basin

Combined with structure background and sedimentary evolution of Yanwumao area in Ordos basin,based on the data of coring drilling,mud logging and well logging,through analysis of log facies,sedimentary microfacies section and surface exhibition characteristics,space-time evolution law of sedimentary microfacies of Chang 6 reservoir in Yanwumao area was analyzed.The results show that Chang 6 reservoir has three main kinds of sedimentary microfacies including subsea distributary channel,its flank and subsea natural barrier.Sedimentary microfacies influence the distribution of reservoirs,in addition the oil and gas accumulation and reservoir types is obviously controlled by the sedimentary facies.Large thickness and good continuity underwater distributary channel is main sandstone reservoir.So the study on the sedimentary microfacies has important meaning to understand oil enrichment regularity and guide the next step of exploration and development.