New Well-Testing Methods for Rod-Pumping Oil Wells — Case Studies

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractA new well testing method that provides high-resolution bottomhole pressure measurement has been developed for use with rod pumping oil well completions. This new well testing technique is conducted by running a high-resolution downhole pressure gauge in a specially designed carrier assembly with the downhole pump. The gauge assembly is run on the rod string without pulling completion packers or tubulars. Using the new method, a downhole pressure system is in place while the well is flowing during the entire well test. High-resolution downhole pressure data can then be recorded during all flow and shut-in periods of the well test, which provides more accurate pressure data and enhanced capability for reservoir analysis.Traditional techniques use wireline-conveyed pressure gauges, tubing-conveyed pressure recording devices, and surface pressure monitoring systems with advanced fluid-level measurement to record data from pumping well completions. These methods are limited in their capability to provide accurate test results when low-pressure conditions prevail. The new method allows operators of low-pressure oil well completions to use advanced well-test analysis software to analyze actual pressure data to obtain reservoir properties and quantify skin damage. Data can be acquired from many types of rod-pump completions, including wells with downhole gas separators. Excellent pressure resolution has been obtained with this new testing technique using either of two downhole assembly designs, depending upon the completion configuration.The results and the ensuing well test analyses in several pilot pumping wells will illustrate that the new process permits more flexibility in well testing and allows for greater accuracy and better interpretation of data in low-pressure rod-pumping oilwells.