Optimized geomodeling and history matching of production data is presented by utilizing an integrated rock and fluid workflow. Facies identification is performed by use of image logs and other geological information. In addition, image logs are used to help define structural geodynamic processes that occurred in the reservoir. Methods of reservoir fluid geodynamics are used to assess the extent of fluid compositional equilibrium, especially the asphaltenes, and thereby the extent of connectivity in these facies. Geochemical determinations are shown to be consistent with measurements of compositional thermodynamic equilibrium. The ability to develop the geo-scenario of the reservoir, the coherent evolution of rock and contained fluids in the reservoir over geologic time, improves the robustness of the geomodel. In particular, the sequence of oil charge, compositional equilibrium, fault block throw, and primary biogenic gas charge are established in this middle Pliocene reservoir with implications for production, field extension,and local basin exploration. History matching of production data prove the accuracy of the geomodel; nevertheless, refinements to the geomodel and improved history matching were obtained by expanded deterministic property estimation from wireline log and other data. Theearly connection of fluid data, both thermodynamic and geochemical, with relevant facies andtheir properties determination enables a more facile method to incorporate this data into the geomodel. Logging data from future wells in the field can be imported into the geomodel allowingdeterministic optimization of this model long after production has commenced. While each reservoir is unique with its own idiosyncrasies, the workflow presented here is generally applicable to all reservoirs and always improves reservoir understanding.

The deepwater Gulf of Mexico is one of the most actively explored deepwater basins in the world, with hundreds of wells drilled to date. However, although much knowledge has been derived from extensive drilling experience, the Gulf's geology offers many surprises. In general, if the horizons of interest are not located subsalt, then seismic-derived attributes can provide a reasonable understanding of the subsurface geology. In practice, the deepwater Gulf of Mexico geology is sufficiently complex that technology such as borehole imaging, borehole seismic data, and pressure and fluid sampling need to be included in the well evaluation to complement the surface seismic interpretation. Incorrect subsurface interpretations impact the drilling and well placement decisions to result in additional well and facilities costs.In an example from the Gulf of Mexico, the sub-seismic-scale geological interpretations from borehole image data and high-frequency vertical seismic profile (VSP) reflection data were integrated with state-of-the-art lower frequency surface seismic data. The dip and image data obtained from the borehole imager, VSP, and surface seismic appeared to be contradictory when individually considered; however, a careful evaluation of the data reconciled the differences and provided a more complete picture of the subsurface. The example demonstrates how the combination of these different borehole data types was able to identify cycles of high-energy mass-transport deposits followed by relatively lower energy phases of sand deposition.The impact of geological deformation affects the geological interpretation and the connectivity and types of fluids present in the reservoir. Pressure and fluid analysis from formation testing data confirmed nonlinear relationships at different depths, which were analyzed for implications to the reservoir.In the challenging geology of the deepwater Gulf of Mexico, geological analysis based on only one kind of data often leads to incomplete understanding of the reservoirs, and that, in turn, can lead to ineffective field development plans. Integrating surface seismic, borehole seismic, borehole geology, and reservoir pressure and fluid data is essential for better understanding Gulf of Mexico deepwater reservoirs, especially in regions of complex geology.

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