T-Surf held the 2001 GoCad users meeting in Houston last month. GoCad is proving a popular way of integrating data types from different parts of the E&P value chain, from structural modeling to reservoir simulation.
BP showed how GoCad was used to model complex seismic velocities in the deepwater Gulf of Mexico using ray tracing software from Norsar. An illumination study, performed during the acquisition of an ocean bottom survey was used to optimize acquisition geometry.
Texaco’s deepwater Petronious field has received the GoCad treatment to create a robust structural model and rock property grid. Iterating between GoCad and a fine-grained fluid flow simulation in Eclipse generated a final poro/perm model for the reservoir engineers. Jacta was used to assess resource volumes from seismic impedance to porosity correlation coefficients.
Version 2.0 of Jacta, T-Surf’s geostatistical uncertainty modeling extension was demonstrated by Emmanuel Gringarten. Jacta 2.0 has an improved user interface with a tree-view parameter browser which guides users through the uncertainty modeling workflow. Microsoft Excel is now used to display intermediate results and histograms. Jacta also now links to third party products such as GeoQuest’s FrontSim and StreamSim’s 3DSL streamline flow modeler.
Chevron’s Petroleum Technology unit has been using GoCad to assess geobody connectivity. A variety of connectivity measurements have been developed such as gross connectivity and path length. These were tested for their potential for predicting oil recovery and were shown to be valid measures of dynamic reservoir performance.
Grid builder ecstasy
BP’s geoscientists were ecstatic about GoCad’s grid-building capabilities. This ‘mission impossible’ modeling project involved complex overthrust geology with stacked reservoirs and repeat sections. With help from T-Surf’s Stanislas Jayr, BP’s modelers built the complex model in less than two weeks. Interactive QC and model clean-up took just a day using the latest GoCad editing features.
CSIRO Petroleum has developed a geostatistical toolbox module for GoCad for modeling highly heterogeneous rock property distributions. The LevySim module integrates structural interpretation and conditioning of stochastic reservoir modeling with seismics.
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