Oil Target Area Forecast Of Chang6Reservoir In Dianpingbei Block, Wayaobao Oilfield

The Triassic Yanchang formations6in Dianpingbei block, which is a new exploratory area of Wayaobu Oilfield located in Ordos Basin, are the typical extra-ultra low permeability reservoirs.Under the studies of formation in relevant subjects, such as sub formation compareing and deviding, formation characters, diagenesis, structure, microfacies and dominating factors of the reservoir, the advantageous regions are prospected in this paper.Chang6formation of Dianpingbei block which located in the front facies belt of Ansai-Zichang delta, and the subaqueous distributary channel, crevasse splay and natural levee deposit are the most favorable facies. Four stable channels of NE—SW tending,which is controlled by sedimentary, are found in the block.The average value of the porosity and rate of the reservoir are separately11.65%and1.89×10-3μm2, and the heterogeneity showed extremely unbalanced in the vertical and plane. Debris-feldspar sandstone and feldspar sandstone were main types of the reservoir rock.Residual intergranular pore is the mainly saving type of reservoir and dissolution pore followed. The dominating zones of hydrocarbon accumulation and distribution is mainly controled by micro sedimentary facies, secondly controlled by reservoir property, and most of the oil formation distribute in the sand with good physical property.The reservoir is devided into three types according to edimentary micro facies, sand body and distribution, based on reservoir characteristics and oil production. According to sedimentary micro facies, sand body and distribution, based on reservoir characteristics, oil production area reservoir can be divided into three categories, and the I type as the best is mainly distributed in Chang6-1and Chang6-2strate in this block.