Analytical solutions of pressure-production tests with permanent multisensors in oil gas and water zones
The petroleum industry has invested millions of dollars in developing technologies for improving the monitoring methods for wells. These wells may have up to eight pressure sensors, recording infrastructure, and data transmission. The information from the sensors is at the disposal of the analyst immediately after the measurements are performed to make decisions about the exploitation of the reservoir. The usage of this information has not been completely useful because there are no developments in the literature on how to evaluate the combination of the pressure behaviors obtained through the sensors. Additionally, they present a high complexity as a result of the interrelationship between phases.
The present work develops analytical pressure solutions for several cases, considering information from gauges at different fluid zones in the reservoir (Gas-cap, oil zone, and aquifer). The author presents approximations for both homogeneous and naturally fractured reservoirs and shows specialized graphs for the analysis of particular cases. Also, an analytical solution is developed to define the movement of the gas-oil contact. In this work, an approach to the study multiphase flow in the oil zone and a semi-analytic method to calculate properties for each phase are presented. All the proposed solutions are validated through the comparison of analytical and numerical solutions are denoting good agreements. Additionally, the researcher establishes approaches for the evaluation of production systems through well-test analysis using analytic solutions.