Simultaneous Petro- and Geophysically Conditioned Lithologic Simulation High Resolution Deconvolution

The effectiveness of the alkali, surfactants, and polymers used in tertiary recovery in oil reservoirs is heavily dependent upon the chemical composition and spatial distribution of shale bodies within the reservoir rock. Seismic data gathered at the surface produces only an "averaged" response to the fine scale architecture of many reservoirs. On the other hand, wireline logs provide high resolution information, but often from vertical boreholes at a spacing greater than the lateral extent of the reservoir. Because these two forms of information have not been successfully combined to provide a fine-scale rock-composition image, the high sweep efficiencies predicted for alkali-surfactant-polymer injections, which are greatly influenced by rock-fluid interaction, have not been achieved. This project will develop a unique method for combining these modalities to simultaneously simulate inter-well lithology and invert seismic reflection data, in order to produce the most probable composite image. In Phase I, data from Clark County, Arkansas will be used to demonstrate feasibility. Starting at the borehole and moving out in both directions along the seismic line, probabilistic information will be used to dynamically constrain the spatial composition of the simulation and reflection coefficents of the inversion. The resulting compositional image will be compared to a nearby outcrop, excluded from the probability development, in order to determine the technique's effectiveness. Commercial Applications and Other Benefits as described by the awardee: The resulting digital rock-composition images, which include both porosity and percent mineral, should find application in the design of enhanced oil recovery (EOR) and carbon dioxide sequestering (CDS) projects. For EOR, there would be a reduction the volume of chemicals injected and an increase in the volume of petroleum produced. For CDS, there would be an increase in the pore volume of carbon dioxide injected and recovered.