Managing Well Integrity, Safety, and Production Decline Caused by Scale

Abstract

TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractThis work will describe the management of scale in a United Arab Emirates offshore carbonate reservoir. Field pressure is sustained by water injection, which contributes to the formation of scale in downhole tubulars. This scaling can cause both safety and production problems, for example, by blocking a subsurface safety valve or chocking flow at downhole nipples.ZADCO has initiated a successful strategy to manage the sulfate-scaling tendency in the completion tubing. Software is used to identify wells early on as potential scale candidates. This software uses real field measurements and analysis of injected and produced water information. The results are used to plan well monitoring and/or treatment. The identified wells are monitored using both slickline gauge measurements to measure actual scale growth and produced water surface analysis to update the software model.Early corrective action is performed using a specialized sulfate scale-dissolving fluid pumped from the surface. More aggressive treatment for larger scale accumulations is performed using a barge, coiled tubing unit, and specialized downhole jetting system.Results have shown that early diagnosis of the scale allows earlier, easier, and far less expensive scale removal treatment. The effect of scale on production decline is also reduced.