Study On Sequence Stratigraphic Characteristics And Sedimentary Microfacies Of Abu Gabra Formation With Sufyan Oilfield In Sudan

In this paper,high-resolution stratigraphy and sedimentology theory are used to guide the study,and the high-resolution stratigraphic study is carried out by using drilling core,logging,earthquake and logging.Based on the regional deposition model,Type and distribution of the reservoir,and analyzes the distribution of the reservoir,the distribution and heterogeneity of the reservoir and the layers,and lay a solid foundation for the future development of the oil field and the research.Research indicates:(1)Through the comprehensive analysis of core,logging and seismic data,it is identified that the Abu Gabra Formation is the unconsolidated surface of the top region of the Bentiu Formation,which corresponds to the ultra-long period of the first rupture period of the Abu Sufyan sag and in the Abu Gabra group Two AG3,AG2,and AG1;16 mid-period base-level cycles,and 45 short-term cycles,respectively,were divided into three long-term base-level cycles,And a high-resolution sequence stratigraphic framework of Abu Gabra Formation in Abu Sufyan Depression was established(2)According to the characteristics of local signs and cycles,the AbuGarba group is further divided into diversion channel,estuary dam,flood plain mud,shallow lake mud,underwater distributary channel,underwater diversion bay and underwater diversion estuary dam.The logging data were analyzed and the logging pattern was established.The main elemental analysis method was used to summarize the single-well sedimentary microfacies identification template for Abu Sufyan sag,and the Abu Gabra group was a small delta.(3)Based on the analysis of sedimentary microfacies distribution,the deposition pattern of Abu Sufyan sag is established,and the distributions of sedimentary microfacies are obtained.The distribution of sedimentary microfacies in this region is systematically analyzed.During the deposition period of the Abu Gabra Formation,the lake surface experienced a dilatation and contraction change,in which the expansion of the lake in the agglomeration period of the AG2 sandstone group,the retrogression of the delta,the sedimentation in the agglomeration period of the AG1 sandstone group,and the delta.(4)The reservoir properties of the reservoirs in the Abu Gabra Formation are studied,and the plane and longitudinal heterogeneity of the reservoirs are analyzed in detail.The reservoirs in the Abu Gabra Formation are mainly distributed in the AG1d-1 ~ AG2d-2 layer,the plane has strong heterogeneity,the permeability coefficient of variation is greater than 0.7,the protrusion coefficient is greater than 3.The coefficient of inter-layer protrusion is lessthan 3,the coefficient of variation is less than 0.7,and the heterogeneity is weak.