The Production Combination Tool-A New System for Production Monitoring
Authors: Meunier D. , Tixier M.P. , Bonnet J.L. 
Published: December 2007

Data for diagnosing production problems or for zone-by-zone analysis of well performance are obtained with speed and safety using a combination production logging tool. As many as six items can be measured and recorded production logging tool. As many as six items can be measured and recorded sequentially in one trip, under essentially stable (or purposely varied) well conditions.

Introduction
Production logging is often used for diagnosis of Production logging is often used for diagnosis of production problems and sometimes for reservoir production problems and sometimes for reservoir analysis. To be valid, all measurements must be made under stabilized well conditions. In the past, the necessary information has been provided by a number of single-purpose through-tubing tools. In many cases the length of time required to make the various measurements raised doubt that the conditions remained constant throughout the survey. Moreover, the scope of application of production logging has been limited by the lack of a companion bottom-hole pressure measurement. pressure measurement. With the Production Combination Tool (PCT) the necessary information - flow rate, pressure, temperature, hole size, and fluid density, along with casing collar depths - is obtained sequentially in one trip in the hole. Usually only a few minutes are required for each measurement, so it can be assumed that uniform conditions prevail for the entire survey. A new technique for in-situ calibration of the flowmeter section establishes an accurate response curve for the particular fluids and casing size. particular fluids and casing size. When used with dynamic pressure control at the wellhead, the PCT makes it possible to obtain the measurements under normal production or injection conditions. (Or, if desired, well conditions can be changed and additional measurements made without the need to wait long periods for stabilization.) Zone-by-zone evaluation of initial production, as well as periodic reservoir auditing during the life of the well, can be done with a minimum of time, equipment, and surface data. Information for planning remedial procedures in workover wells is also provided. procedures in workover wells is also provided.

The PCT Equipment
The PCT is a combination of five different sensors and a casing collar locator (Fig. 1). The sensors are: continuous flowmeter, caliper, gradiomanometer, thermometer, and manometer. By means of a relay in the tool, controlled from the surface panel, any sensor may be selected. The corresponding property is recorded simultaneously with the casing collar log so that proper depth control is ensured. The various measurements are made sequentially in one trip in the hole, so a minimum time elapses between the different recordings. The principal advantage is that all necessary measurements are made in such a short time that the well producing conditions can be considered stable, and the different recordings are quasi-simultaneous. It is possible to change the producing conditions and monitor this change from the producing conditions and monitor this change from the surface through the various senors to obtain, in a very short time, information on the reservoir dynamics. The PCT is small in diameter (1 11/16 in.) so it can be lowered through the tubing against high pressure and flow to make dynamic measurements in the casing or open hole below the tubing shoe. The tool is centered in the fluid vein by spring centralizers. The tool ratings and specifications are summarized in Table 1.
JPT
P. 603