TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn Abu Dhabi offshore carbonates, it is recognized that fractures play an important role in influencing reservoir flow and connectivity both vertically (between reservoir units) and areally within the same reservoir unit. Image logs and borehole seismic surveys have been run to extensively identify fracture location and direction to understand the flow path of these reservoirs. However, in this paper an advanced step has been achieved in quantifying the fracture permeability from Conventional Logging Data, which is Micro-Resistivity Log, aided with Gamma-ray and Neutron-Density porosity logs. We all realized how vital, useful and critical this type of information would be as an input to reservoir simulators. This paper presents two techniques that have been developed to determine fracture permeability in reservoir rock and dense zones, these two techniques are merged to call it UFLIP (Universal Fracture Log Integrated Permeability).

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractPermeability modeling and permeability prediction has always been a critical phase in building geological models. In a major Abu Dhabi offshore oil field, several reservoir characterization and evaluation studies have been conducted during the last five years. The estimation of permeability in each well is required to identify and model reservoir flow units in the field, Rock types are identified from cored wells using thin section and conventional core analysis (rock fabric, porosity, permeability,) in parallel with relating it to capillary pressure curves. In non-cored wells (90% of total wells), a backward model of rock type classification is achieved through the utilization of well logging data which is proved to provide (1) Porosity & (2) Lithology information using Neutron, litho-Density and Sonic tools, therefore, Permeability from logs is the missing information to make the log rock typing backward model working.In the second approach, the clay content distribution constructs the permeability alteration model that is reflected in Gamma-Ray (GR) response, where GR horizontal changes within a layer found to be different from another layer. Therefore, a statistical GR analysis that searches for the optimum GR-Permeability model is developed. This permeability estimation approach is called Permeability Active Searching (PASZ).

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractIn Abu Dhabi Offshore areas, the development of Lower Cretaceous fractures carbonate reservoir is a challenge that can be achieved using fracture characterization modelling approach.

This paper presents the successful integration of an advanced nuclear magnetic resonance (NMR) log, a source-less technology, with core data and other openhole logs to resolve the challenges of reservoir characterization (including identification of tar mat) and to place the wells in targeted reservoirs zones. This enabled subsequent inflow control devices (ICD) completion design for optimal production in these complex carbonate Jurassic reservoirs. A comprehensive suite of advanced logs, conventional logs and core data were used. The wireline suite covered conventional (resistivity-density-neutron-gamma ray-acoustic) and advanced (NMR-elemental spectroscopy-image) technologies in one of the pilot wells. In another calibration well, data gathering was achieved with wireline (resistivity-density-neutron-gamma ray) and LWD NMR to log the same reservoirs. Integration using these conventional logs, advanced logs and core data established the correlations to derive permeability in this complex carbonate Jurassic reservoirs. From these study wells, a correlation was established between the NMR porosity, density/neutron porosity and core porosity to enhance confidence on NMR-measured porosity. The NMR permeability index was calibrated using parameters that were developed by integrating NMR results with the core data. This permeability relationship (core and NMR) was applied in all lateral wells with LWD NMR results that targeted the same reservoirs in the field. For delineating the tar mat interval, a combination of NMR, density and resistivity measurements was used. The LWD NMR results provided real-time reservoir characterization with rock quality (porosity distribution, permeability) that helped in ICD completion design and enhanced well placement. This approach and technology also enabled substantial rig time savings and reduced HSE risks. This approach demonstrates strong benefits of data integration and proven LWD NMR source-less and lithology-independent technology, in addition to the resistivity and gamma ray, as the preferred solution for advanced reservoir characterization, ICD completion design, and enhanced well placement in complex carbonate reservoirs. The solution for reservoir characterization enabled confident decisions on ICD completion design and enhanced well placement by implementation of source-less technology, eliminating the risks of using radioactive source-based technology.