Technical Paper: Testing Conventionally Untestable High-Flow-Rate Wells with a Dual Energy Venturi Flowmeter

Society: SPE
Paper Number: 77406
Presentation Date: 2007
 

Abstract

Evaluating the productivity of a well through well testing is an essential aspect of managing production operations and reservoir recovery. When the reliability of gas, oil, and water flow rates is challenged by common events such as flow rates beyond the separator capacity or oil-water emulsions, the value of the well test can be severely diminished or even negative. Action taken or not taken as a result of an erroneous well test result can be counter to the production objectives and costly to the reservoir recovery.

This paper documents the use of a mobile dual-energy multiphase venturi flowmeter to test high- pressure and high-flow-rate wells in an offshore Nigeria field. Problematic fluid properties and challenging separation conditions limited the capabilities of the test separators to adequately measure the flow rates of the individual phases of the well effluent. Reliable rate measurements were hindered by the well's high pressure and high flow rates and by the presence of oil-water emulsion, which made phase separation extremely difficult.

Examples of well tests performed with the flow meter demonstrate the benefits of robust measurement principles in these adverse conditions. The value of capturing the flow transients using a high-frequency dual-energy spectral gamma ray detector is also illustrated, as it allowed a better understanding of the behavior of fluid flow in the wellbore. The flowmeter data enabled production diagnostics. Based on the flowmeter information, recommendations to further investigate the sources of water entry into the wellbore were made.

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