ABSTRACT: Using a combination of petrophysical log sensors to monitor the progress of a fluid flow experiment has long been recognized as a powerful integrator of petrophysics and reservoir engineering. Reservoir saturation monitoring is one such area of collaborative effort. Another recent technological innovation is the MicroPilot* single-well in situ enhanced oil recovery (EOR) evaluation, which combines advanced petrophysical logging sensors with a formation tester device to execute a flood of a desired secondary or tertiary recovery agent in situ in the reservoir and measure the parameters of the resulting flood in terms of the dimensions and the variation of fluid saturations away from the injection point. In this paper, we describe initials trials of the technique to evaluate the performance of an EOR agent. The technique is executed under in-situ conditions downhole in a very short time. The method is described and we discuss the considerations in planning and executing the tests. In the first trial an alkaline-surfactant-polymer (ASP) was selected for a high-permeability sandstone formation containing medium-viscosity oil. In the second trial an alkaline-surfactant (AS) was selected for a low-permeability carbonate formation containing light oil. We demonstrate the value of the technique in confirming the performance of the EOR agent under downhole conditions. Results of simulations are presented to support the feasibility of the technique.
INTRODUCTION As fields mature there is an increasing need to resort to tertiary recovery techniques to extract the remaining hydrocarbon. The planning and execution of such projects require accurate knowledge of several key petrophysical properties such as residual oil saturation to water flood (Sorw) and to the enhanced oil recovery (EOR) fluid, relative permeability to oil and water under water displacement, and horizontal and vertical permeability for each layer. Traditionally such data has been sourced from core measurements performed under controlled conditions.