Thermal Simulation and Economic Evaluation of Heavy-Oil Projects

Abstract

Abstract Many recent hydrocarbon discoveries in the Gulf of Mexico are heavy and extra-heavy oils. Additionally, given the imminent decline of lighter crude oil fields such as Cantarell (the primary Mexican oil field), it seems that most of the crude oil production in Mexico, in the midterm, will come from heavy-oil reservoirs. The need to analyze the feasibility of unconventional recovery methods becomes readily clear. This paper presents a methodology to evaluate heavy-oil projects using thermal simulation and economic evaluation. Thermal recovery methods are used to exploit heavy oil reservoirs, where oil viscosity is very high and mobility low at the reservoir temperature. It is desirable to reduce the oil viscosity by increasing its temperature. An affordable and easy-to-implement technique is by means of heaters or an electric cable. This paper presents the results of this methodology, which includes thermal compositional simulation of a synthetic grid model, with the fluid properties mimicking those of heavy oils recently discovered in the marine region of the Gulf of Mexico. PVT analysis, viscosity curves, rock properties, relative permeabilities, capillary pressure, and reservoir pressure and temperature are also studied. The economic analysis was performed using current capital expenditures for drilling and completion and operating and maintenance costs. Different scenarios for costs, oil and gas prices and capital investment were studied. A sensitivity analysis was performed to determine the variables having the highest impact on the economic value of the project.1 This methodology showed that introducing heat by means of an electric cable is a technically viable and profitable alternative, even for projects under off-shore economic premises, which are considerably higher than those for onshore projects. Implementing the heating from the beginning of the project and continuing to its completion, was found to be the most important factor for the economic success of this method.