3D Multiphase Streamline-Based Method for Interpretation of Formation-Tester Measurements Acquired in Vertical and Deviated Wells

Abstract

Complex heterogeneous reservoirs penetrated by deviated wells pose significant challenges when modeling and interpreting packer-and probe-type formation-tester measurements. This paper introduces a streamline-based method specifically designed for near-wellbore fluid-flow modeling in vertical and deviated wells. The primary application of the method is for efficient simulation and automatic history matching of formation-tester measurements in the presence of invasion and variable petrophysical and geometrical properties. Based on the spatial distribution of pressure calculated with a previously validated near-wellbore finite-difference model (FDM), the method traces streamlines from the reservoir into fluid sampling probes. The calculated spatial distribution of pressure is input to the streamline-based method to propagate the spatial distribution of water saturation. Subsequently, the calculated spatial distribution of water saturation is input to the FDM to update the spatial distribution of pressure. Streamlines are then recalculated and this repeated pressure-saturation procedure continues until reaching the desired final simulation time.The combined FDM and streamline-based method utilize full-tensor permeability to couple wellbore-reservoir systems during fluid sampling in horizontal and deviated wells. It is shown that the spatial rendering of streamlines permits rapid assessment of the time evolution of fluid saturation near the sampling probe. We successfully test the streamline-based method in the dynamic simulation of fluid contamination into conventional and focused-type probes operating in vertical, horizontal, and deviated wells for the case of multiphase, immiscible fluid-flow in heterogeneous formations. The method implements successive streamline and FDM time steps adaptively to decrease computational time by a factor of four while achieving less than 5% relative difference in the simulation of fluid production measurements when compared to FDM results.For formation testing in deviated wells, the streamline-based method permits more rapid appraisal of anisotropy, bedboundary, and complex geometrical effects on fluid-sampling times than conventional 3D fluid-flow simulators. It also quantifies the sensitivity of measurements to variations of permeability, invaded zones, anisotropy, and well deviation. Our simulations indicate that fluid sampling in deviated wells subject to mud-filtrate contamination requires adequate positioning of the probe around the perimeter of the wellbore to secure the fasted cleanup possible.

A new streamline model for near-well flow validated with radial flow experiments

“…Hadibeik et al [18] presented a streamline simulation method for near-wellbore fluid flow modeling in vertical and deviated wells.…”

“…Little literature can be found in the near-wellbore streamline simulation. Skinner [46], Skinner and Johansen [47], and Hadibeik [18] reported the streamline simulation in the near-wellbore region. In this paper, a rigorous treatment of the principles of streamline tracing and transport problem solving along streamlines in the near-wellbore region is presented and validated experimentally.…”