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Origin Analysis And Logging Interpretation On The Low Resistivity Pay Zone Of Section 6th Of Upper Triassic Yanchang Formation In Shenglishan Area

Posted on:2010-11-26Degree:MasterType:Thesis
Country:ChinaCandidate:J Q LiuFull Text:PDF
GTID:2120360272494068Subject:Solid Geophysics
Abstract/Summary:PDF Full Text Request
Sandstone reservoirs with low porosity, high clay, low permeability and low saturation are always in connection with low resistivity reservoirs. Because it is difficult to distinguish the features of logging response between oil layer and water layer in low resistivity reservoirs, the conventional logging interpretation methods on fluid identification are always causing poor application. These days, demand for hydrocarbon resources are increasing ,so, it is necessary to find out the contributing factors for low resistivity reservoirs and develop the proper logging recognition methods.Mesozoic reservoirs of Ordos Basin are featured as low porosity and low permeability. The low resistivity oil reservoirs can be found in Many sections of the upper Triassic Yanchang formation in Ordos Basin. As a kind of unconventional reservoirs, oil and gas layers with low resistivity are dominated by many factors directly or not. Conventional log usually leads to mis-perforation or stratum skip, and brings adverse effect to the oilfield development performance.This paper analyzed the characteristics of the 6th sections of the Triassic Yanchang formation in Wuqi shenglishan area .The aim is to find out the main causes of the low resistivity pay zone. Based on the detailed information of the basic geological character of the reservoir(sandstone distribution pattern, lithology character, physical characteristics, water characteristics , clay minerals , cementation material and its change in plane) and testing for oil , this paper focus on the differences of oil layers with low resistivity and normal resistive zone. By the data of core analysis ,log, scanning electronmicro scope , porosity and permeability analysis, X-diffraction, acoustic emission test and mercury injection test, the main causes of low resistivity reservoirs in Shenglishan area were defined: Complicated pore structures in low porosity and permeability reservoirs will affect the productivity and electric properties of reservoirs; The additional conductivity for clay minerals dues to their sorts , contents and the clay in the formation and the invasion influence of drilling mud on the oil pay resistivity; The affection of sandstone reservoirs with high natural gamma ray existed; The influence by micro-sedimentary facies; Some ferruginous conductive mineral. Based on the main causes of the low resistivity pay zone, compare the lithology character, physical characteristics, oiliness character and electric properties of reservoirs. The rule of them can be analyzed.According to actual conditions of region of interest, this paper calculate the total porosity ,clay content and several parameters of the model, these parameters were matching the core analysis data in Shenglishan low resistivity pay zone. As the Archie's equation can not be used to compute Sw. cross plot, mathematics and comprehensive analyzing are put forward to identify oil layers qualitatively constrained by geological conditions, and the effects are satisfactory.
Keywords/Search Tags:Low permeability reservoir, Low resistivity pay zone, Origin Analysis, Log interpretation, Wuqi area
PDF Full Text Request
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