Up until today operators have been facing a challenge on how to place memory gauges as close to the perforations as possible when collecting data to perform pressure transient analysis. Various methods have been used including hanging the memory gauges in nipple profiles or below a retrievable packer or even setting the memory gauges at the bottom of the well to be retrieved later. Suspending the memory gauges in the well using slick line is another commonly used method in certain areas.
Pressure transient analysis (PTA) plays a key role in determining reservoir parameters for both stimulated and non stimulated wells. Some of the results from PTA include permeability, skin factor, flow efficiency, average reservoir pressure, system geometry and reserve estimates.
To make the collection of such key data more efficient in both vertical and horizontal wells Saudi Aramco is now using a Retrievable High Expanding Gauge Hanger®, Figure 1, which has been designed incorporating a large by-pass flow area to minimize restriction in the wellbore. With a simple adjustment the hanger can be set in 4½ in., 5 ½ in. or 7 in. tubing or casing. The tool can be run through smaller ID tubing and set in larger ID liners and is designed for the memory gauges to hang below. The tool is run on slick line and set using a non-explosive hydrostatic setting tool. Retrieving the tool is easy utilizing a standard JDC Pulling Tool. High levels of H2S and CO2 in some Saudi Arabian gas wells required the re-useable hanger to be made from an Inconel® material.
This paper will compare the different methods used for data collection; discuss the development process of the gauge hanger tool as well as the final design of the hanger and setting tool currently being used. Case histories will also be presented from several prolific Saudi Arabian gas wells.