Utilizing fiber optic measurements in these wells

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Unformatted text preview: nada. Utilizing fiber optic measurements in these wells reduces operating costs and should ultimately lead to increased efficiency of reservoir stimulation practices. Introduction Temperature logs were the first type of production logging sensors employed in the oilfield in the 1950’s and many papers have been dedicated to their interpretation. Most notable were Ramey1 who defined the basic heat transfer equations pertaining to flow and temperature, Kunz and Tixier2 and Schonblom3 who introduced the interpretation of multi-zone gas wells, and Smith and Steffensen4 who discussed the impact of the Joule-Thomson effect5. The temperature log faded in importance with the advent of the spinner flowmeter, mainly due to the relative ease of spinner log interpretation. One of the major historical problems with temperature log interpretation has been the length of time for a well to stabilize thermally often exceeds the production log duration, causing incorrect temperature log interpretations while the well is responding to transient shut-in effects. The introduction of permanently installed fiber optic distributed temperature measurements (DTS) in the late 1990’s revived the interest in temperature log interpretation and new rigorous thermal models were developed for the interpretation of DTS data. The combination of permanent installation and continuous temperature curve acquisition overcame problems with early temperature log interpretation by providing large data sets to properly identify transient temperature behavior. The natural extension of permanently installed DTS systems was wireline conveyed fiber optic systems where the distributed temperature sensor can add to, complement, or perform measurements not possible with standard production logs, including monitoring gas lift valves6, leak detection7, and detecting flow behind casing/tubing. 2 SPE 115816 This paper offers a novel solution for generating a gas inflow distribution in the multi-zone gas wells in Western Canada (Fig 1) by interpreting DTS data measured through the tubing when the well is flowing up the annulus. These wells typically produce 1 to 5 MMscf/day of gas with small quantities of fluid (condensate and/or water) so the production tubing is often run to a point above the lowest perforations, increasing the gas velocity up the tubing thus lifting the water to the surface. Standard production logging is not possible with this well configuration unless a snubbing unit or workover rig is used to pull the tubing above the upper perforated intervals, run the production log, and reset the production string to its original position. This process adds considerable cost to running a production log and consequently few production logs are run in these wells. Therefore, the cost effective solution to the problem of reservoir monitoring using DTS was desirable. Slickline Fiber System A 1/8th inch diameter slickline fiber optic system has been developed for deployment into oil or gas wells with a full range of surface tubing pres...
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This note was uploaded on 02/04/2014 for the course PGE 312 taught by Professor Peters during the Spring '08 term at University of Texas at Austin.

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