Abstract
Accurately monitoring oil production from individual wells is essential for optimizing the economic performance of any primary or enhanced oil recovery project. In this regard, the cyclic steaming process used in the ChevronTexaco 1Y Antelope project introduces unique well gauging challenges. Steam is injected into low permeability; siliceous shale reservoirs at roughly 1,000 psi pressure (∼ 540°F). During a well's production cycle, hot liquids, gases and steam flow to the surface. The production cycle of these flowing wells is short-lived, typically ranging from 3 to 4 weeks, with flow rates declining rapidly during the first week. The ratios of water, oil and gas production also change over time. Fluids entering the automatic well test (AWT) units can exceed 350°F, especially during the early stages of the production cycle.
This paper presents the results of comprehensive testing and analysis of the existing 1Y Antelope AWT units, which consist of horizontal pressure vessels to separate and meter oil, water, and gas. Key components also include a coriolis mass flow meter and a capacitance-based cut probe. The results of field tests to assess the impact of vessel size and fluid temperature on separation efficiency and emulsion stability are presented. Test results showing the impact of fluid temperature on cut probe performance are also presented. Recommended equipment and procedural modifications to improve oil rate measurement accuracy are discussed. Finally, comparisons of oil rate measurement accuracies for existing and improved AWT equipment are presented.
