A practical calculation of the distance to a discontinuity in anisotropic systems from well test interpretation

Abstract

Well testing is the cheapest and most accurate tool available to find the distance from a well to a linear constant-pressure boundary or fault. Several methods exist in the literature with which to determine this parameter. Most of them use conventional analysis and are only useful for isotropic reservoir systems. The few methods for anisotropic systems obtain the well-to-discontinuity distance through conventional analysis, type-curve matching and TDS technique, and then a correction by anisotropic effects is applied. In this work, a unified behavior of the pressure derivative was found, so the new shorter and most practical expressions used to find the distance from the well to the discontinuity, including the simultaneous effects of anisotropy angle and anisotropy index, are included. These new formulae were successfully tested with two synthetic examples and one field case example, and deviation errors higher than 30% are observed if an anisotropic system is treated as an isotropic one.

Pressure and Pressure Derivative Interpretation of a Well in a Completed-Perforated Multilayer Reservoir with Crossflow

“…In order to provide an interpretation procedure, it is necessary to find a relationship between the semipermeability, pressure derivative, and time. To do so, the affected parameter, which is time, is multiplied by the dimensionless permeability raised to a given power, which is found by either trial and error or using a mathematical procedure as outlined by [15]. The unified pressure derivative behavior is given in Fig.…”

“…Table4shows the results obtained for Example 2.The theoretical values were calculated using Eqs. (13), (14), and(15).When applying the TDS technique, the value calculated using Eq. (26) was found to correspond to ω2; this implies that the storativity coefficient value calculated by Eq.…”

Integro-Differential Solutions for Formation Mechanical Damage Control During Oil Flow in Permeability-Pressure-Sensitive Reservoirs

“…depth of investigation, well-testing derivative, flow regimes, and well productivity, but the model can predict transient pressure and flux contour maps distribution. Escobar, Bonilla & Hernández (2018) proposed a model based on the unique features of the pressure derivative plot to compute the distance for a discontinuity in anisotropic porous media from well-test interpretation.…”