Geosciences and Reservoir Integration – Key to Better Predict Behavior Of Complex Fractured And Karstified Kharyaga Field

Abstract

This paper presents an integrated Geosciences and Reservoir work approach used for complex fractured and karstified carbonate Kharyaga field. Synthesis is fulfilled for all available data, such as seismic interpretation, static well data, well tests etc. It has been launched on Kharyaga field mid 2012. Kharyaga field is a NW-SE elongated anticline lying 60km north of the Artic polar Circle, in Nenets Autonomous Territory on Kolva regional swell. Total E&P Russie (TEPR) is operating Object 2 and 3 of this field. The Object 2 accumulation, subject of this study, is characterised by oil bearing Devonian carbonate reservoir with a gross thickness of 160–250m with high vertical and lateral heteregenity. Current production from Object 2 is around 23 kbopd. The purpose of the synthesis is to create new and more reliable geological and dynamic models in order to better optimize next development phase and fine tune production profiles estimation. Geosciences and Reservoir synthesis imply the following: gathering all available information starting from newly reprocessed seismic data, various static well data and ending by well tests and production history over the whole life of the field,depth analysis and putting in coherence of all information in order to better address the various heterogeneity scales and reservoir characterization. There are two main challenges related to characterization of existing heterogeneities: defining the fault pattern including sub seismic faults, understanding karst and fractures distribution,defining vertical and lateral sedimentary heterogeneity as well as reservoir extension. Many experts and specialists are involved in this synthesis. The joint approach between geologist and geophysicist, based on tectno-stratigraphic timing and stress field combined with seismic attributes and thickness map, allowed to proposed a new fault pattern which honors FMI data and dynamic interference tests recorded during the 14 years of field production. Interpretation of newly reprocessed seismic data helped the sedimentologists in inter-well correlation. Looking just at seismic amplitudes cubes, it was possible to propose a new sedimentary model and change inter-well correlation accordingly. This led to the updated vision of the reservoir.