Research On The Four-Property Relation And Net Pay Cut-Off Thickness Of He8and Shan2Reservior In Yanqi2Well Block

Yanqi2well block located in the east of Shanbei Slopes in Ordos Basin, major gas reservoir is Shihezi formation He8layers and Shanxi formation Shan2layers of Neopaleozoic, it is Low permeability of tight sandstone gas reservoirs. The reservoir’s physical property is bad, anisotropy is strong and gas/water relationship is complicate. The difference of diagenesis, pore configuration and pouring degree of gas seriously affected the ability which takes well logging data to identify and evaluate gas reservoir.This thesis focuses on the question in log interpretation of the tight gas reservoir with strong heterogeneity of the Neopaleozoic, on the basis of previous research results, in a large number of well logging, mud logging, gas test and analysis of test results, use the variety of analysi and testing tools and research methods, we study the reservoir structural attitude, sedimentary facies, reservoir characteristics, gas deposit characteristic of He8and Shan2reservoir in Yanqi2well block.Based on the analysis of gas reservoirs in the study area, the use of rock-electricity experiments, physical property analysis, gas test, producing tese and other data, combination of log presentation study of the Four-property relation of He8and Shan2in the study area, and porosity, permeability and saturation log interpretation model of He8and Shan2are established; and use of the data of sealed and coring well to verify the saturationlog interpretation model; the net pay cut-off thickness are ascertained; and statistics the net pay thickness of every well in the study area, and the gas bearing area is delineated and predicted. The main technical results of this work are as follows:(1) Using the acoustic travel time and the relative value of gamma ray binary regression method create He8and Shan2porosity and permeability interpretation model;(2) On the basis of core and rock-electricity experiments and formation water analysis, the parameter value of Archie’s equation (a, m, b, n, Rw) are obtained, saturation log interpretation model are established, which are verified by the data of sealed and coring well;(3) Based on the log information, gas test, producing tese and so on, using experience statistical method, porosity-water saturation-permeability ratio curve method create the lithologic character, physical property, degree of saturation and log parameter net pay cut-off thickness standard of He8and Shan2reservior;(4) Account the porosity, permeability, gas saturation of He8and Shan2of59wells in the well block, and draw the porosity, permeability, gas saturation planar contour map;(5) Fine interpretation59wells in the study area, and statistics the effective thickness of each well, and draw the contour map of the effective thickness; and combine the data of the sedimentary facies, sand body distribution, gas test, trial production and well control degree in the study area, we block out the proved area and influence area.