Abstract

Offshore developments in deepwater are very high cost ventures in complexreservoir environments. Seismic imaging challenges induce significantuncertainty in reservoir descriptions. Reservoir surveillance, especiallyinflow distribution across the reservoir interval, is a valuable contributor tounderstanding reservoir performance however acquiring this information usingconventional technology, such as production logging tools, is very problematicin the deepwater environment where wireline intervention into live wells is amajor risk and cost.

Intelligent chemical tracers are a new technology that provides insight intothe inflow distribution without intervention operations or major alterations tothe completion design. The tracers consist of smart plastic and unique chemicalcompounds that are combined into a matrix that resembles strips of plastic. Thematrix is designed to be sensitive to either oil or water. For example, whenwater sensitive matrix is contacted by water, the matrix releases its uniquechemical fingerprint (tracer) at a prescribed rate. The water sensitive matrixis dormant when contacted by oil, gas or air. Oil sensitive matrix behavesexactly the same way but with oil being the target fluid.

Unique chemical tracers are deployed at strategic locations in the completionso that fluids entering the completion contact the tracers. At the surface, samples are taken and analyzed for the presence and concentration of eachunique tracer that has been deployed in the completion. The concentration datais plotted vs time and produced fluid. Analysis of these plots can yieldanswers to very valuable reservoir management questions like:

  • Are all the intervals producing?

  • What is the relative contribution of each interval?

  • Where is water break-thru occurring?

This paper reviews:

  • How the technology works.

  • Interpretation techniques.

  • Case histories of intelligent tracer responses.

  • The value this knowledge can bring to deepwater reservoir management.

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