Advanced LWD Technology Application at the Caspian Offshore Oilfields

Abstract

Offshore oilfields are characterized by complex geological structure, such as presence of fault blocks, significant lateral changes of the rock properties. These features require accurate technology selection used during horizontal production wells drilling. Offshore drilling is fundamentally different from that on land, that requires a special selection of logging-while-drilling (LWD) technologies. The number of exploration wells is limited, therefore LWD tools and data interpretation should solve the problem of additional field exploration, that is impossible without advanced LWD technology application. Currently, LWD allows perform measurements similar to wireline logging – nuclear magnetic resonance logging (NMR), formation testing and obtain azimuthal density data. In addition, it is possible to perform measurements using reservoir-mapping-while-drilling service to solve geosteering tasks. This paper discusses examples of optimal well placement within the target zone, considering integrated interpretation of advanced LWD data for reservoir properties estimation, reservoir pressure behavior understanding, and choosing completion strategy. According to reservoir-mapping-while-drilling service data interpretation, density azimuthal data the geological model was updated. To clarify the petrophysical properties LWD-NMR data were used. These data allow to obtain porosity estimation, permeability, residual water saturation coefficient, evaluate bottomhole formation zone damage. Formation testing data were used to estimate reservoir pressure and hydrodynamic parameters of the target zone. Integrated interpretation of LWD data has been used to select the most optimal design of lower completion scheme and to control the development of reservoir.