Research On Inversion Method Of Mud Shale Reservoir Parameters In Fu2 Section Of Subei Basin

The shale reservoir in China is the key and difficult point of exploration and development.The method of obtaining mud shale reservoir parameters has been a forward-looking topic in the logging field at home and abroad.Compared with conventional reservoirs,tight reservoirs are usually characterized by low porosity and low permeability,complex pore structure,and strong heterogeneity so that the evaluation of reservoirs is difficult.Based on the related logging data,the logging evaluation method and model are established,which is of great significance to the theoretical methods and practical exploration of the mud shale reservoir evaluation.In this paper,Fu2 Formation in the Subei Basin was the main research object.To solve the problems of mud shale tightness,complex lithology,and difficult logging evaluation in the Subei Basin,a mud shale reservoir parameter inversion method and comprehensive logging evaluation study were carried out.Firstly,the formation lithology characteristics in the study area were analyzed,and the reservoir lithology,electrical properties,physical properties,oil-bearing characteristics and their relationship were studied.Based on the study of the four-reservoir relationship of the reservoir and the logging response characteristics,the sensitive logging curve was selected to establish the lithological response characteristics and the identification plate.The lithology model q was constructed and an intuitive lithology characterization map was formed.On this basis,the analysis of mineral content and the calculation of rock mechanical parameters constituted a reservoir brittleness index model.Secondly,a sensitive curve was selected to construct a multivariate fitting method model,a variable skeleton method model and a volume method model of physical parameters(porosity,permeability),which were compared with core analysis data to verify the effectiveness of the method.Thirdly,based on the TOC analysis data,a single-parameter method model for calculating TOC and a improved model of Δlog R method were constructed.And considering that the shale reservoir was rich in organic matter,the shale reservoir was divided into organic and inorganic parts.The TOC and the Archi formula of the conventional reservoir were used as the saturation of organic and inorganic parts of the shale reservoir respectively.So,an oil-bearing saturation model combining organic and inorganic was constructed.Finally,the quantitative characterization of mud shale reservoir parameters was achieved,which provides data support for the comprehensive evaluation of the reservoir.The data was also used to construct a comprehensive evaluation model of the reservoir to grade the reservoir and give the classification criteria.By comparing with the oil test data and the field test,it proves that the application effect is effective.In this paper,a set of inversion methods and logging evaluation characteristics suitable for complex reservoir parameters were established,which provides the technical support for oil and gas exploration of mud shale reservoirs.This paper also points the way for the further study.