Study On The Evaluation Model Of Shale Reservoirs And Well Logging Interpretation Of Zhen Jing Region

The relationship between the development of national economy and the energy supply is more and more close and the development of national economy is increasingly affected by the shortage of energy supply, at present. Countries around the world are actively looking for new alternative energy sources. Shale oil and gas, coal bed gas, oil sands, heavy (thick) oil, natural gas hydrate and other new energy’s exploration and development has gained unprecedented attention. Shale oil and gas is the world’s one of the most important and practical significance of the alternative energy currently through analysis the new energy exploration and development status and the current technical means as well as the development prospects. And the evaluation of shale oil and gas is one of the hot spot of researches of logging methods.Zhenjing region is the survey region of the paper, which located in the south section of Tianhuan syncline of Ordos basin. The main research formation is the shale of Chang 7 formation of triassic system (Zhangjiatan shale). In the process of exploration and development and a series of research work carried out in Zhenjing region, it is found that "ZhangJiaTan" shale distributes widely with large thickness and high organic carbon content and thermal maturity. And so Zhenjing region has great exploration potential.The main research purpose of this passiage is to analyse the geological characteristics, distribution characteristics etc and carry out research of reservoir comprehensive evaluation on "ZhangJiaTan" shale with well logging, mud logging and laboratory analysis datas, and establish the computing methods of Shale reservoir evaluation model and shale reservoir parameters, the evaluation criterion of shale reservoir. Finally, according to the parameters and evaluation criterion, forecast the distribution of shale favorable exploration area. The main research process and results are as follows:1. Investigate and survey relevant literature home and abroad, summarize the historical process and technical methods of exploration and development and evaluation methods of shale reservoir, and the calculation methods of key parameters of shale reservoir evaluation at home and abroad; understand the index and technical state of using logging information to evaluate shale reservoir;2. Collect and analysis core laboratory analysis data of research region, and understand tectonic feature and stratum feature, sum up litho logic feature, geochemical feature and physical feature etc in Zhenjing region through systematacially analyzing basic data;3. Sum up logging response characteristic of shale reservoir, the main performance is high natural gamma, high resistance (partly medium and low resistance), low bulk density, low photoelectric cross section absorption index, high neutron, high acoustic interval travel time;4. Use multiple methods to identify shale reservoir, first, use gas logging data and logging response characteristic of conventional logging, then accurately identify top and bottom boundary depth through curve overlap method (RT and AC) to establish the thickness and cover depth distribution diagrams of shale reservoir;5. According to core laboratory analysis data of research region and the need of evaluating shale reservoir, establish rock physical model of research region. The model consists of four parts, skeleton, clay, water and organic matter;6. Use different logging principle of nuclear magnetic resonance logging, density logging and elemental capture logging and difference between the definition of kerogen volume which compute porosity according to three logging methods, establish the computing method of kerogen content;7. Use cross plot method, ΔlgR method, U content method, multiple regression method of logging curves to calculate TOC content, and compare the results of 4 calculate methods, finally determine using multiple regression method of logging curves to calculate TOC content in this paper;8. Use prosity logging method and multiple regression method of logging curves to calculate shale prosity, and compare the results of 2 calculate methods, finally determine using prosity logging method to calculate shale prosity;9. Calculation of the content of skeletal mineral by using the fast simulated annealing optimization algorithm to solve the skeleton mineral component analysis model. Calculation of the content of clay mineral by using chart method, linear statistical method and the fast simulated annealing optimization algorithm. Finally determine using the fast simulated annealing optimization algorithm to calculate s the content of skeletal mineral and clay minera;10. Propose two improved methods to calculate the content of absorbed hydrocarbon:improved Freundlich isothermal adsorption equation and improved isothermal adsorption equation, finally determine to use improved Freundlich isothermal adsorption equation to calculate the content of absorbed hydrocarbon after using test data to check the two models;11. Classify shale reservoir of research region, according to Classification criteria for shale reservoirs at home and abroad, then optimize key parameters of shale reservoir, finally confirm 5 favorable shale exploration areas by overlaping key parameters chart in research region.