Research On Heterogeneity Of Chang1 And Chang3 Reservoir At H152 Well Block Of Huachi Oilfield

The lithologic reservoir of Huachi oilfield H152 well block locating in the south of Shanbei.slope of the Ordos Basin is low-porosity and low-permeability.At present,there are several problems after water injection production,such as low producing degree of water flooding and reservoir blockages.The C1 and C3 oilgroup of H152 well block is taken as the target layer in the paper.Some theories and measure methods about reservoir sedimentology and reservoir geology are applied to study the sedimentary microfacies and reservoir characteristics systemically.The controlling factors of heterogeneity are setted up.The result offers theoretical basis for further development.The conclusions can be drawn from this paper as follows:(1)On the basis of the respective microfacies analysis for the core wells,sedimentary microfacies types and the electronicfacies model of various sedimentary microfacies are established.Depositional model of the studied area is setted up.We recognize that the target layer is a suit of meander river-meandering stream's delta deposition system.(2)Based on petrographic thin section,cast section,scanning election microscope,mercury penetration data,the characters of petrology and pore structural have been studied systematically.The sandstones of the study area mainly consist of powdery-fine grained arkoses and lithic arkoses.Intergranular dissolved pores,intragranular dissolved pores and residual protozoal intergranular pores consist the pore spaces of the reservoir;and the structures of pores are mainly belong to typeâ…¡B and typeâ…¢A.The reservoir of study area is middle-low-porosity low-permeability or low-porosity super low-permeability.(3)Through the above studies,combined with physical property analysis and well logging interpretation,the intra-formational heterogeneity,the interlayer heterogeneity,and the plane heterogeneity of the reservoirs in C1 and C3 oil group are all studied detailedly.The results show that the intraformational heterogeneity is serious.The interlayer heterogeneity is Weaker than intraformational and plane heterogeneities,and the distribution of interbeds is stable and there is little difference in the development of sandbodies.(4)Due to the study of intra-layer heterogeneity and micro-heterogeneity of the reservoir,in Huachi area,the conclusion has been achieved that the intra-layer heterogeneity of sandstone reservoirs is mainly controlled by sedimentation and that the sedimentary structure and;the sedimentary rhythm determine the characteristics of intra-layer heterogeneity of reservoirs.