Integrated Formation MicroImager (FMI) and Spectral Noise Logging (SNL) for the Study of Fracturing in Carbonate Reservoirs

Abstract

Abstract Carbonate reservoirs are known to contain considerable hydrocarbon reserves. There are, however, several challenges that may complicate the process of development of this type of reservoirs, such as low porosity and high degree of fracturing and heterogeneity, which, cumulatively, could result in a low oil recovery factor (RF). Optimisation of development process in carbonate fields is impossible without preliminary reservoir studies focused on assessment of their production potential. Such studies include an analysis of complex pore space structure and local system of faults and fractures that may serve both as enhanced reservoir capacity and flow channels. Conventional logging techniques (for example, high-precision temperature logging and spinner surveys) solely used for estimation of reservoir productivity may have a limited scope of application. An integrated approach based on concurrent deployment of Formation MicroImager (FMI) and Spectral Noise Logging Tool (SNL) has considerably improved the interpretation of this scenario. This paper gives some examples of carbonate reservoir surveys conducted in the wells located in one of the Middle Eastern fields. It has been shown that spectral noise logging data have a high degree of correlation with FMI data resulting from fracturing analysis. The active fracture flow zones have been distinctly outlined by Spectral Noise Logging data and further confirmed by High-Precision Temperature Logging data. The advantages offered by joint application of SNL and FMI techniques for studying carbonate reservoirs have therefore been clearly demonstrated. This approach can be successfully applied for the study of both natural and induced fractures.