Deepwater developments are very high cost ventures in complex reservoir environments. Acquiring insight into the reservoir inflow distribution and location of water inflow using conventional technology, such as production logging tools, is very problematic in the deepwater environment where wireline intervention into live wells is a major risk and cost.
Intelligent chemical tracers are an emerging technology that provides insight into the inflow distribution without intervention operations or major alterations to the completion design. The tracers consist of unique chemical compounds that are combined with unique polymer formulations into a matrix that resembles strips of plastic. The matrix is designed to release the tracer when contacted by the target fluid, either oil or water.
The matrix strips are deployed with the initial completion installation at strategic locations in the completion so that fluids entering the completion contact the matrix. At the surface, samples of the produced fluid are acquired and analyzed for the presence and concentration of each unique tracer that has been deployed in the completion. The concentration data is plotted vs time or produced volume. Analysis of these plots can yield answers to very valuable reservoir management questions such as:
Are all the intervals producing?
What is the relative contribution of each interval?
Where is water break-thru occurring?
Deepwater completions are frequently completed with sand screens. The typical sand screen design contains spaces where the tracer can be integrated without any changes to the design. If the screen design is not readily compatible with the matrix strips, specially design tracer carrier mandrels can be added to the completion.
The passive nature and very low risk of deploying this technology is very attractive in deepwater wells.
This paper reviews the fundamentals of intelligent tracer technology, methods of integration into deepwater completions and some field examples previous deployments.