Study On Logging Interpretation Technique Of Complex Oil And Water Layers Of Chunguang Oilfield

The lithology of Paleogene and Cretaceous strata is complex in Chunguang oilfield,resulting in unclear boundary between reservoir and nonreservoir and difficult identification of effective reservoir.At the same time,high salinity formation water results in low resistivity of reservoir,and there is no obvious difference in electrical characteristics from surrounding rock.Moreover,the reservoirs of these two formations are heterogeneous and and the reservoir oil inhomogeneity is widespread.The Cretaceous is the main producing horizon of the Chunguang oil field,It is of great limitations to evaluate the storage with current evaluation methods,such as:lithology recognition,reservoir identification and oil and water layer identification of strata have Poor precision,log evaluation of interpretation is consistent with the low rate of problems,has seriously affected the further improve oil field development level.Henan oilfield has carried out the research on improving the coincidence rate of interpretation of oil and water layers in Wang Ji west area.Through a variety of means and methods,the coincidence rate of logging interpretation and interpretation is increased from 75.6%to 86.4%,and the effect is obvious.From the analysis of reservoir characteristics,it is found that the reason of low coincidence rate of logging evaluation is similar to the reason of low coincidence rate of interpretation in the west of Wangji oilfield,This paper uses its successful interpretation experience,methods and means,and improves,develops and improves the logging interpretation coincidence rate.In this paper,firstly,the rock electricity experiment,oil-water relative permeability test and capillary pressure experiment are carried out,and then the lithology identification method of complex formation in the work area is studied.At the same time,based on the data of logging,logging and oil testing,the "four properties" relationship of the reservoir in the work area is analyzed and studied,and the reservoir parameters interpretation model of each layer is established.In addition,this paper studies the method of identifying reservoir fluid properties by using conventional logging data and array induction logging data,and establishes the qualitative and quantitative interpretation evaluation standards of oil and water layers.Finally,a fine logging interpretation and evaluation method for complex oil and water layers in spring oilfield is formed,which provides reliable geological data support for related research,and achieves the following results:(1)According to the rock physics experiment,the geological parameters of the target stratum are obtained,such as the 4 key parameters of Archie formula a,m,b,n.The pore throat structure and reservoir performance of the reservoir are analyzed by the oil-water relative permeability curves and the capillary pressure curves of the three kinds of pore structures.Reservoir with medium and partial characteristics of strong water sensitivity,the water permeability increases with the increase of water saturation.(2)The logging identification parameters of effective lithology identification are extracted,and the graphic database of lithology identification by electrical imaging is established.The recognition of lithology by electrical imaging is intuitive and fast and effective.(3)Based on the study of the "four properties" of reservoir,the lower limit of identification of lithology and physical property of reservoir is obtained.The lithology of Paleogene and Cretaceous reservoirs is mainly composed of fine sandstone,pebbly fine sandstone and glutenite,with high porosity,medium and high permeability characteristics,and good physical properties.For example,the lower limit of Cretaceous porosity is 12%.(4)A fine log interpretation model for parameters such as shale content,porosity,permeability and saturation in Paleogene and Cretaceous reservoirs is established.The relative error of porosity is less than 4%,the relative error of saturation is less than 6%,and the relative error of permeability is less than 20%.(5)By extracting and constructing well logging discriminant parameters which sensitively reflect reservoir fluid properties,a set of methods to identify fluid properties of complex reservoirs by using conventional data and array induction data is developed,The coincidence rate of logging interpretation is increased to 84%,the effect is good,and the expected target is achieved.