Study On Seismic Prediction Method Of Fractured Cave Reservoirs In Carbonate Rocks In Yubei Area

Carbonate reservoir has become an important exploration area in the world for its wide distribution and over half of global reservoir production in oil and gas resources. The main reservoir space of carbonate reservoir is karst and fissure, because of carbonate's early formation, deep burial, diverse sedimentary environment, times of tectonic evolution and complex diagentic evolution. In addition,the characters like complex cause of formation and distribution, diverse form, as well as strong heterogeneity on horizontal and vertical distribution, increase the difficulty in reservoir prediction. Therefore, the prediction of carbonate reservoir is a difficult point in oil and gas exploration area. However, it has important research significance and development prospect to identify carbonate fractured reservoir with the seismic method.Taking the Ordivician fractured-vuggy carbonate reservoir in YuBei area as object, based on data about geology, seismic, logging, drilling, core and test in target area, this paper studies the methods to predict fractured-vuggy reservoir, from the perspective of fault distribution and fracture-cave prediction. The detail procedures are as flowing:To make structure oriented filtering processing of seismic data to demonstrate tiny fractures in research area more clearly. To extract various seismic attributes, with the guidance of drilling and logging data, then to portray the distribution of fault system and development scale of fracture-cave objectively. To select sensitive attributes from different angles based on the former findings, and fuse multiple sensitive algorithms with the purpose of strengthen reservoir characteristics, then to improve the accuracy of explanation. To use the seismic inversion technology in carbonate reservoir to summarize the low speed response characteristics of reservoir in research area. Having made a prediction to carbonate reservoir in YuBei area with the above seismic technologies, this paper obtains the following results:1. Structure oriented filtering processing of stack seismic data not only get rid of much noise, but also largely reserve the information from the direction of seismic events. In this way, the boundary of fault and litholgoy is protected and the tiny characteristics of fault turn obvious.2. A multi-attribute analysis is made, based on the attribute characteristics, and the development scale of fracture-cave in research area is portrayed.3. The combination of multi-attribute algorithms strengthens the characteristics of carbonate reservoir and also improves the accuracy of prediction.4. The low speed response model of this fracture-cave reservoir is summarized through the wave impedance inversion technology. Furthermore, based on that, a comprehensive analysis is made with the combination of attribute prediction, to obtain reliable reservoir prediction results.In brief, based on the seismic identification of carbonate reservoir, combined with the data about geology, drilling, logging and so on, this paper has formed a seismic identification technology system that is suitable for the prediction of carbonate fracture-cave reservoir in research area. In addition, this technical system can make contribution to the fine depicting of fracture-cave distribution, and also to the prediction of favorable exploration area.