TY  - JOUR
AU  - Chin, Wilson C.
PY  - 2026
DA  - 2026/09/11
TI  - Formation Testing Permeability and Pore Pressure Prediction in Open Hole and Isolated Straddle Packer Applications
JO  - Journal of Energy and Power Technology
SP  - 017
VL  - 08
IS  - 03
AB  - Knowledge of permeability, which measures a rock formation’s resistance to fluid flow, is essential to energy exploration, oilfield development and economic viability, since its value directly relates to cash flow and outlay: the greater permeability is, the faster monetary gains are realized, the lower the initial investment required. Formation testing is crucial to this understanding. It assists with reservoir characterization as it enables direct fluid sampling, reducing the need for resistivity, acoustic and nuclear data, and also because pressure changes measured during pumping can be analyzed with Darcy flow models to predict permeability and pore pressure. The author invented Halliburton’s real-time 1997 GeoTap™ model in U.S. Patent 5,703,286 for an isotropic permeability “k,” one which assumes uniform initial pressure conditions. However, real world environments include overbalanced boreholes whose “supercharged, invading” flows strongly affect events at the anisotropic sandface. In practice, dual packers are used to improve predictions by isolating local zones from nearby high pressure surroundings, thus reducing contamination and enabling deeper transient analysis. Within these zones, pressures are high but constant, providing a key entry point for math modeling. This paper extends the 1997 model, so that a newer exact, closed form, analytical “forward” method is available to predict pressure fields when formation parameters are inputted, and which improves “inverse models” to help predict permeability and pore pressure under highly supercharged conditions when (pressure, time) pairs are known at the source probe, also demonstrating how synthetic data from forward analysis can be used to validate overall workflow and inverse development strategies. How the new approximate models relate to recent, more complete 2024 azimuthal multiprobe models requiring substantial computation is also explained, with the aim of facilitating drilling and well logging operations and more effective reservoir characterization. The present work provides a rapid and convenient platform for field use, just as the 1997 GeoTap™ model simplified both math and physics for use during initial logging when fewer input modeling parameters are available. We additionally review our recent 2024 azimuthal multiprobe methods which fully account for dynamic invasion, transient mudcake growth and multiphase effects, which again complement the approximate tools developed here to estimate permeability. Quantifying these effects with the approximate model allows oil companies to rapidly formulate drilling and production programs, leaving more complete analysis to detailed models only when satisfactory input data are available. The combined tools support cost effective processes in commercializing newly discovered resources, thus improving on an understanding essential to energy exploration, oilfield development and economic productivity.
SN  - 2690-1692
UR  - https://doi.org/10.21926/jept.2603017
DO  - 10.21926/jept.2603017
ID  - Chin2026
ER  -