The project goals are to:
University of Alaska, Fairbanks, AK
Alaska’s North Slope is a unique petroleum province in the United States in that it is underlain by thick permafrost, which is a tremendous heat sink for produced fluids. Because of the severe conditions and remote location, Alaska’s North Slope is also a very high-cost petroleum province, effectively raising the economic limit well above that for other onshore fields. Solving the wax deposition problem in producing wells could significantly reduce the economic limit and spur development of smaller accumulations of oil resources on Alaska’s North Slope.
The project researchers have:
The production rate of an oil well decreases significantly if wax precipitation in a wellbore acts to reduce the cross-sectional area available to flow. Being able to predict the wax deposition properties of oil allows an operator to know when the conditions in the wellbore need to be modified to maintain the oil production rate.
Wax deposition in pipelines during transportation of oil causes increasingly severe pressure drops along the length of the pipeline, requiring increased energy consumption to move the oil. By utilizing the solutions obtained from this study, the wax deposition in pipelines can be avoided and power consumption can be drastically reduced.
The primary goal of the project is to come up with a solution for preventing wax deposition and the first step toward that end is to characterize the wax-forming properties of the oil being produced. The evaluation of possible solutions is supported by the development of a simulator that considers thermodynamics and kinetics of wax deposition, along with related heat transfer in the wellbore. In order to characterize wax properties, it is necessary to measure molecular weight, density, and viscosity, along with pressure-volume-temperature and composition analysis. A thermodynamic model will be developed that can predict wax deposition and the effect of various parameters on it. A dynamic model will be developed that will utilize this thermodynamic model and predict wax deposition in the wellbore and the effect of wellbore heat transfer on depsition. This simulator will then be used to evaluate various methods of wax prevention.
The project is in its second year, which began October 1, 2005. The project is scheduled to be completed by September 30, 2008.
This project was selected in response to DOE’s Oil Exploration and Production solicitation DE-FC26-01NT41248.
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No publications have been released. An abstract has been submitted to the 2007 Society of Petroleum Engineers’ international petroleum technology conference focusing on the determination and prediction of wax deposition.