Method and system for identifying buried-hill cracks

Abstract

An embodiment of the invention provides a method and a system for identifying buried-hill cracks. The method includes steps of determining whether rock types are a metamorphic rock type or a dyke type according to geological information of research areas; classifying minerals into first-series minerals and second-series minerals according to chemical compositions of the rock-forming minerals of metamorphic rock and dyke; combining logging curve values of corresponding sections of the minerals to determine logging response characteristics of the two series of minerals; identifying lithologic characters of the metamorphic rock according to the logging response characteristics and rock core and slice data and classifying the lithologic characters into three categories; combining the rock core and slice data and fracture pressure tests with one another to form lithologic series, and further determining whether the metamorphic rock is reservoir rock or non-reservoir rock; applying combination of dual-lateral resistivity logging, sonic time-difference and verification and determining development conditions of the cracks. The method and the system in the embodiment of the invention have the advantages that the crack identifying precision can be improved by the aid of the method and the system, and exploration targets can be quickly and accurately determined during buried-hill oil and gas reservoir exploration.

Description

technical field [0001] The present application relates to the application field of well logging technology, in particular to a method and system for identifying fractures in buried hills. Background technique [0002] In recent years, with the sharp decline in the output of old oil areas, the serious shortage of reserve reserves has become more and more serious. However, in order to discover new oil and gas reservoirs and find new reserves, the exploration level of old oil areas has been continuously improved. The deep layer of the old oil field is regarded as a key exploration area for discovering new oil and gas reservoirs and searching for new reserves. Therefore, buried hill oil and gas reservoirs in the deep layer of old oil fields are regarded as one of the key areas of oil and gas exploration at present and in the future. [0003] The storage space of buried hill oil and gas reservoirs is mainly fractures, which is one of the most difficult reservoir types in oilfield...

AI Technical Summary

Problems solved by technology

According to the different measured elements Si, Ca, Fe, S, Ti, Gd, referring to the different mineral composition and content in each rock in the metamorphic rock and the characteristics of the comprehensive logging curve, the lithology identification is carried out; the above methods all exist in one way or another However, the crossplot method and mathematical method are not very operable, and the probability of misjudgment is high. Although the ECS curve has a high accuracy of lithology identification, due to its high cost, few wells use this logging method.

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