Permeability, Compressibility and Pressure Prediction in Supercharged Wireline and FTWD Environments

In conventional wireline and LWD/MWD formation testing, downhole predictions for rock fluid properties are based on simplified Darcy flow models, but only mathematical expediency. These require initially constant pressures that uniform throughout the reservoir. This limitation precludes common applications in overbalanced drilling, so supercharge or near-well invasion effects - associated with rapidly decreasing at sandface where measured completely ignored. Such 1990s math models commonly used despite documented field results overbalances as high 2,000 psi. Incorrect modeling can produce incorrect predictions, leading to misleading evaluation economic analyses. Here, conventionally accepted model (developed by last author over two decades ago) is rigorously extended allow general also underbalanced drilling effects. The formulation algorithm explained detailed pressure examples offered showing essential differences between earlier newer algorithms.