Evaluation method for distribution of supergene karst reservoir of carbonatite

Abstract

The invention relates to an evaluation method for reservoir distribution of a supergene karst of a carbonatite. The method comprises the following steps that features of the supergene karst are identified, a logging response standard for the supergene karst structure is established, the cyclicity of the supergene karst structure is divided, growth differences of different karst cyclicity are compared, and distribution benefit for the karst reservoir is evaluated. On the basis of analysis on geological and logging data, the karst cyclicity caused by change of the reference surface of karst in the supergene karst generating process is considered, and the multi-cyclicity of the supergene karst is divided and compared according to the geology observation and logging discrimination; and the cyclicity of the supergene karst and the discovered karst reservoir are analyzed in a combined manner to determine the karst cyclicity and vertical growth segments benefit for growth of the karst reservoir, the planar distribution of the corresponding karst cyclicity is used to determine planar distribution benefit for the karst reservoir, the disadvantages in evaluating the karst reservoir via the supergene karst structure are overcome, evaluation for the karst reservoir satisfies the practical geological evolution history more, the evaluation result is more accurate, and the success rate of exploration is effectively improved.

Description

technical field [0001] The invention belongs to the technical field of oil and gas geological exploration, and in particular relates to an evaluation method for the distribution of carbonate supergene karst reservoirs. Background technique [0002] Epigenetic karst is extremely important in the study of paleokarst in carbonate rocks. It often forms an extensive dissolution system of pores, caves and fractures under large unconformities, and becomes one of the key factors controlling the development of high-quality reservoirs and the formation of oil and gas pools (Loucks, 1999; Hopkins, 1999; Wang, 2002). Oil and gas reservoirs such as the Ordovician Ellenburger Oilfield in the United States, the Permian Yates Oilfield, the Cretaceous Fateh Oilfield in the United Arab Emirates, and the Cretaceous Gold Lane Oilfield in Mexico are all related to the karstification of unconformities (Saller, 1994; Moore, 2001). China has discovered a large number of reservoirs related to epige...

AI Technical Summary

Problems solved by technology

These methods do not consider the cycle of epigenetic karst structures, not only cannot realize the prediction of the spatial distribution of favorable karst reservoirs on a small scale, but also the macroscopic evaluation results are not accurate enough, which affects the understanding of the development law of karst reservoirs and reduces the Drilling success rate in oil and gas exploration

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