Enhanced and fine seismic recognition of organic reefs: a case study of the Changxing Formation, eastern Sichuan, China
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GMGDA 2019
Enhanced and fine seismic recognition of organic reefs: a case study of the Changxing Formation, eastern Sichuan, China Lifang Cheng 1 & Jin Yang 1 & Yanchun Wang 1 Received: 20 May 2020 / Accepted: 20 August 2020 # Saudi Society for Geosciences 2020
Abstract Organic reefs are developed in the Changxing Formation (Fm.) in the southeastern end of the Kaijiang-Liangping ocean trough, eastern Sichuan. Due to the ambiguous seismic reflection characteristics of organic reefs, application of organic reef recognition methods that have been successfully employed in other areas is limited in the study area, but these methods can still indicate development of favorable facies zones. Accordingly, supplemented by seismic reflection characteristics analysis, seismic attributes analysis and time-difference analysis, frequency decomposition and reconstruction interpretation technique, highfrequency uncompressing method, and dominant azimuth lightening method were optimized to be the core technologies of enhanced and fine depiction technique system of organic reefs. The technique system transforms seismic data from the time and reflection angle domain to the frequency and azimuth-offset domain; increases the differences in seismic reflection characteristics in and out of organic reefs, especially patch reefs of small volume and low recognition; enhances seismic reflection characteristics of both the outline especially the lateral boundary and interior of organic reefs; and achieves precisely depicting the boundary of organic reefs and fine recognition of the internal structure of platform margin facies reefs such as reef core, fore reef, and back reef. This technique system provides a new technical idea for organic reef recognition, has produced optimistic recognition effects in the study area, and is of certain guidance significant to the research into recognition of organic reefs with ambiguous seismic reflection characteristics. Keywords Kaijiang-Liangping ocean trough . Patch reef . Organic reef boundary . Dominant azimuth lighting . Organic reef structure
Introduction Organic reefs are characterized by pore-cavity development and dolomitization; due to their superior reservoir properties; it is easy for organic reefs to form natural gas enrichment areas/zones, and they are one of the most important oil and gas reservoirs (Fan and Zhang 1985; Feng et al. 2017). Currently, across the globe, comparatively large organic reef reservoirs are principally developed in northwestern America, northern Asia, and the Middle East. Within the border of
This article is part of the Topical Collection on Geological Modeling and Geospatial Data Analysis * Lifang Cheng [email protected] 1
School of Geophysics and Information Technology, China University of Geosciences (Beijing), Beijing 100083, China
China, organic reef reservoirs are chiefly distributed in the northwest, the southwest, north China and Northern South China Sea, etc. (Xu 2016). Among them, organic reef oil and gas reservoirs in the Sichuan Basin are of optim
