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Method Study On Using Imaging Logging Data To Improve The Conventional Logging Resolution In Thin Layers

Posted on:2015-12-12Degree:MasterType:Thesis
Country:ChinaCandidate:J TengFull Text:PDF
GTID:2180330431475679Subject:Earth Exploration and Information Technology
Abstract/Summary:PDF Full Text Request
With the development of oil and gas exploration, most large reservoirs have been developed, looking for larger reservoirs become increasingly difficult, therefore, many oil companies pay their attention to the thin layer which they had neglect in the past. However, the identification and evaluation of thin layer is still an urgent problem to the petrophysicist, it is still a long way to go for them to solve the practical problem encountered in thin layer evaluation.Thin reservoir evaluation has been a problem for petrophysicist for a very long time. It is because the thickness of the layer is much smaller than the resolution of most logging tools, and investigation depth of the high-resolution tools is too shallow. But the technology used in thin layer evaluation should be with the abilities of high vertical stratification and radial investigation depth, so that we can obtain the true resistivity of the thin layer. However, the tools with high-resolution costs a large amount of money, in order to save the costs, petrophysicists would rather using the existing data to set up models suitable for thin-bedded layer evaluation.In the sand shale section, affected by the surrounding rocks, in thin-bedded sandstone layer, the value of apparent resistivity is smaller, and the shale content is higher, so that the calculated value of porosity is lower and the saturation is higher. All these factors affected the discovery of the thin oil layer, leading to the missing of some commercial field. And the anisotropy of the resistivity in the thin layer will also cause the different mean value in resistivity logs. The existence of thin layer also leads to the increasing uncertainty in the porosity calculating method. Conventional log analysis methods, including traditional muddy sandstone analysis method, generally underestimate the oil and gas volume more than30%in the thin layer. In response to this phenomenon, researchers at home and abroad make many efforts in instruments development and data processing, and developed new high resolution logging tools and established interpretation model suitable for thin layer evaluation,In order to accurately evaluate and interpret the thin layer, according to the geological characteristics of thin reservoir, in this paper, combining the electrical imaging logging technology and the conventional logging data to identifying thin layers, and do some evaluation and interpretation works. As a high-resolution logging method, electrical imaging logging obtained the imaging of the formation which obtained with a wealth of geological information. We obtain a plate average response curve from the processing of the imaging logging data, and then use this curve to scaling a RLLS curve, finally get a high-resolution curve. Due to the high vertical resolution of the imaging logging, we can use this curve to evaluate the effective thickness of the thin layer.In this paper, we use the high-resolution curve, anisotropy calculation method based on image and anisotropy calculation method based on Delhomme to do some research on anisotropy calculation. We use the high-resolution resistivity curve derived from imaging logging data to divide the layer, and then calculate the anisotropy coefficient by using the anisotropy model, and calculate the horizontal resistivity (Rh) and vertical resistivity (Rv), and finally combine with the Dual-Electrical-Layer (DEL) model to calculate the water saturation and other parameters in thin layer evaluation.
Keywords/Search Tags:thin interbed, electrical imaging logging, anisotropy, DEL model
PDF Full Text Request
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