Chang 8 Reservoir Logging Evaluation In Y Area Of Longdong QH Oil Field In Ordos Basin

Chang 8 reservoir in Y area of Longdong QH oil field in Ordos Basin is a typical low permeability reservoir.In order to better serve the field development work and explore the exploration potential of the area,it is necessary to carry out fine logging interpretation of the reservoir in the area to provide reference for the next development and adjustment of the study area.This paper takes the Chang8 reservoir in the Y area of the Longdong QH field as the research object.Based on extensive literature research,the collection of geological data,logging data and testing data in the study area,the study of stratigraphic classification and comparison,the study of sand top microstructure and sand body spreading characteristics,the study of reservoir deposition characteristics,the study of"four properties"relationship and secondary interpretation of logging data under geological constraints,the study of reservoir inhomogeneity and the evaluation of the classification of the Chang8 reservoir.The study shows that the Chang 8 reservoir in the study area can be divided into two sub-layers,Chang 8₁and Chang 8₂,which can be subdivided into six sub-layers,Chang 8₁¹,Chang 8₁²,Chang 8₁³,Chang 8₂¹,Chang 8₂²and Chang 8₂³;the overall structure of the study area is simple,showing high in the northeast and low in the southwest,and a small nose-like uplift with a certain degree of inheritance is developed;the spreading of the sand body shows a strip-like spreading from the southwest to the northeast,with good ductility.The sand body is thick in the central part of the study area,and gradually becomes thinner in the west and east directions,among which the sand bodies of Chang 8₂²and Chang 8₂³are thick and have good oil content,which are the main oil layers in the area;the study area is deposited in the shallow water delta leading edge,and the sedimentary micro-phase mainly develops submerged diversion channels,submerged natural dikes and submerged diversion interbay,the submerged diversion channels in the study area are mainly distributed in the central part of the study area,the submerged natural dikes are distributed The submarine diversion channel is mainly located in the middle of the study area,the submarine natural dike is located near the channel,and the submarine diversion interbay is developed in the eastern and western edges of the study area;based on the study of the"four properties",a logging interpretation model for the mud content,porosity,permeability and oil saturation of the Chang 8 reservoir was established,and a secondary interpretation of the logs in the study area was carried out,and the porosity,permeability and oil saturation planes of the Chang 8 reservoir were mapped.The porosity and permeability of the Chang 8 reservoir are in good agreement with the planar spreading characteristics of the thickness of the Chang 8 sand body,and the planar map of oil-bearing saturation is influenced by the reservoir physical properties,sand top microstructure and sedimentary microphase together;the comparison of various characterization parameters of the non-homogeneity of the Chang 8 reservoir shows that the non-homogeneity of the Chang 8₂²and Chang 8₂³is weaker compared to the other layers;the reservoirs in the study area can be divided into four categories,among them,Class I and Class II reservoirs are generally developed in submerged diversion channels with good physical properties,while Class III and Class IV reservoirs are generally developed in submerged diversion channels and submerged natural dykes with relatively poor physical properties,and the good reservoirs in the study area are mainly located in Chang 8₂²and Chang 8₂³.The research results have important results supporting significance for well network optimization and development technology policy formulation in the study area,and have some reference significance for oil field development in neighboring areas.