TY  - JOUR
AU  - Chin, Wilson C.
PY  - 2026
DA  - 2026/09/09
TI  - Real-Time Prediction of Anisotropies kh and kv in Dual Axial Probe Formation Testing
JO  - Journal of Energy and Power Technology
SP  - 016
VL  - 08
IS  - 03
AB  - Understanding anisotropy in reservoir dynamics is essential to energy exploration, oilfield development and economic viability since this indicator describes the natural flow directions preferred by the underground fluid. Quantifying its effects allows oil companies to design drilling programs and production facilities that extract the greatest benefit from newly discovered resources. Formation testers are important because they provide direct clues on hydrocarbon properties and resistance to flow through fluid sampling. For example, in Formation Testing While Drilling or FTWD, “spherical” or “effective permeability” keff = kh2/3kv1/3 can be predicted from the author’s 1990s real-time GeoTap™ methods when source probe pressure transient data alone is available. In hydraulic fracturing, infill drilling, reservoir engineering and wellbore stability, knowledge of individual horizontal and vertical permeabilities kh and kv is preferred. This is possible when additional pressure data at a nearby axially displaced passive observation probe is available from dual probe instruments. New algorithms for both kh and kv are designed from first principles and solved analytically. In particular, a “forward simulator” (solving for pressure when permeability inputs are given) and “inverse simulators” (predicting permeability when (pressure, time) pairs are available at both sensors) are developed. Validation challenges arise related to prediction accuracy. In 2008, Halliburton completed sponsorship of a Doctoral Thesis at The University of Texas at Austin, in which extensive lab experiments validated this author’s keff model, also supported by Halliburton. However, such multi-year efforts are expensive and impractical. Because the basic inverse ideas had been successfully tested, this paper develops an alternative innovative approach in which synthetic pressures created by forward simulators with assumed permeabilities are used in inverse procedures which attempt to recover these same permeabilities from (pressure, time) pairs obtained at source and observation probe locations. Forward and inverse methods are governed by the same Darcy flow formulation, but are solved completely differently. Agreement provides strong evidence for physical and mathematical consistency behind the validation strategy. The state-of-the-art is reviewed and comprehensive examples are offered to demonstrate the versatility and practical use of the new technology.
SN  - 2690-1692
UR  - https://doi.org/10.21926/jept.2603016
DO  - 10.21926/jept.2603016
ID  - Chin2026
ER  -