INTEGRATION OF NMR AND WIRELINE FORMATION TESTER DATA FOR ROBUST FORMATION EVALUATION AND HYDROCARBON PROPERTIES DETERMINATION

摘要

Key reservoir properties for determining hydrocarbon in place and ultimately reserves are formation porosity, hydrocarbon saturation, permeability, fluid contacts, and net productive thickness. Once the commercial viability of a prospect is proven, it is necessary to ascertain the reservoir fluid properties, such as viscosity, in order to adequately design the production facilities. Often, Wireline Formation Tester (WFT) tools are used to measure formation pressure, with the aim of identifying fluid contacts, and to obtain reservoir fluid samples so that the fluid properties can be measured in a laboratory. Although the WFT tools provide valuable information in the evaluation of reservoirs, they have the unfortunate quality that they only provide data at discrete locations along the wellbore. Because of their ability to measure porosity independent of mineralogy, estimate permeability, and determine reservoir fluid type, Nuclear Magnetic Resonance (NMR) logging tools are in the unique position of providing the data necessary to optimize a WFT logging program. Only those reservoir intervals that are porous, permeable, and contain sufficient hydrocarbon saturation are selected to obtain formation pressure or reservoir fluid samples. Additionally, the NMR data can be analyzed to determine reservoir fluid properties, such as in-situ viscosity, as a continuous log along the length of the wellbore. A case study is presented illustrating how the NMR data is used to optimize the WFT logging program. In addition, it is discussed how the data from both instruments complement each other and can provide a more robust evaluation of permeability, reservoir fluid properties, and reservoir producibility than either log would provide alone.