Method for Determining Oil and Gas Saturation in Gas Logging Wells

Abstract

The invention relates to a method for determining the hydrocarbon saturation of gas logging. The method comprises the following steps of: acquiring and recording values of non-hydrocarbon components such as gas logging total hydrocarbon and methane through logging devices such as a gas logging apparatus and a comprehensive logging instrument; reading the maximum abnormity value Ct of the total hydrocarbon or methane in an oil-gas abnormity display interval; preferably selecting a gas logging background value Cb of an oil-gas display layer; selecting the hydrocarbon saturation index n of regional gas logging; and working out the hydrocarbon saturation Sh of a specific oil-gas display interval, and outputting a computed result. The method is low in cost, is easy, convenient and accurate, and has a wide application range. According to the method, the hydrocarbon saturations of gas logging oil-gas display layers in 3,700 intervals of more than 610 wells are explained and computed in the Jianghan Basin, the Western Hubei-Eastern Chongqing Area, the Tsaidam Basin, the Ordos Basin and the Tarim Basin, errors do not surpass 15 percent generally in comparison to the logging measurement computed result, the hydrocarbon saturation accuracy is increased by over one time in comparison to the hydrocarbon saturation accuracy determined with a thermal vacuum distillation all-dehydration technology, and the rapid explanation requirements of logging oil-gas display fields can be well met.

Description

technical field [0001] The invention relates to determining the oil-gas saturation of abnormally displayed layers in gas logging during the mud logging process, and providing a method for explaining key parameters for reservoir evaluation. Background technique [0002] In the process of oil exploration and development logging services, the traditional method for determining oil and gas saturation in gas logging is to use thermal vacuum distillation (VMS) data to obtain it. [0003] Determination of oil and gas saturation by thermal vacuum distillation and complete removal mainly involves stirring a certain amount (generally 250ml) of drilling fluid samples with a total removal device, heating them in thermal vacuum, collecting gas samples, and extracting all the natural gas in the drilling fluid from them. The extracted gas volume is collected and measured, and the content of hydrocarbons, carbon dioxide, hydrogen and other non-hydrocarbon natural gas is quantitatively deter...

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Problems solved by technology

[0004] The thermal vacuum distillation technology actually measures the content of each component of natural gas in a unit volume of drilling fluid under surface conditions, and there is a certain correlation between the oil and gas saturation of the formation, and the oil and gas in the formation can be estimated by correcting the loss of natural gas Saturation, relatively low accuracy, poor reliability, difficult to determine the loss correction coefficient

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