Flow Analysis In Producing Wells

Abstract

Curtis, M.R., Member AIME, Schlumberger Well Services, Houston, Texas This paper was prepared for the 42nd Annual Fall Meeting of the Society of Petroleum Engineers of AIME, to be held In Houston. Tex., Oct. 1–4, 1967. Permission to copy Is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines. Abstract Production Logs provide information for downhole flow analysis of producing wells. These flow analyses determine the various amounts, types, and depths of fluid entry into the casing. This information may be used to study a reservoir, to catalogue an initial completion, or to engineer remedial action. Gradiomanometer and Flowmeter surveys are used to analyze two-phase, bubble-flow production. The average density of the flowing fluids is obtained from the Gradiomanometer; the total flow rate from the Flowmeter. Two facts complicate mathematical flow analyses. First, the bubbles of the lighter phase travel upwards at a greater velocity than the continuous heavier phase. Second, the down-hole volumetric fractions of the phases are different from surface fractions. It is necessary to consider the slippage velocities and the phase holdups in analyzing the down-hole flow. Charts have been prepared to provide a simple and fast graphical means of flow analysis. Each individual chart is prepared for a specific casing size, tool size, and slippage velocity. The latter can he estimated with reasonable accuracy from knowledge of the densities of fluids being produced. On the charts, Gradiomanometer and Flowmeter data are used to graphically compute a flow analysis. The charts may also be used when only a Gradiomanometer is available. In this less accurate application it is assumed that only a single fluid phase enters at any given level, and that a zone without change on the Gradiomanometer is not producing any fluid. The Gradiomanometer-Flowmeter method of analysis is effective in high-flow-rate oil wells producing gas or water, and in low-to medium-flow-rate gas wells producing oil or water.