Wireless Reservoir Surveillance Using Intelligent Tracers
Today's field developments are increasingly characterized by very complex wells in very demanding and costly operating environments. Not only are individual wells challenging, but most are part of a complex reservoir network that must be managed over an extended time period.
The high cost and risks of acquiring reservoir surveillance information using conventional technology, such as production logging tools, is forcing operators to forgo acquisition of fluid inflow distribution information and manage these fields with a blurred understanding of the reservoir.
Intelligent chemical tracers are an emerging technology that consists of engineered polymers and unique chemical compounds that are combined into a matrix that resembles strips of plastic. The matrix is designed to be sensitive to either oil or water. For example, when water sensitive matrix is contacted by water, the matrix releases its unique chemical fingerprint (tracer) at a prescribed rate. The water sensitive matrix is dormant when contacted by oil, gas or air. Oil sensitive matrix behaves similarly as the tracer is released only when it comes in contact with oil.
Strips of matrix are readily integrated into most any completion configuration including conventional sand screens, ICD sand screens, multi-stage frac systems, pup joints and intelligent completions. The matrix can be deployed in any well type without impacting the installation process.
Samples of produced fluid are analyzed for the concentration of each tracer. Tracer concentration data, combined with model-based interpretation techniques, enables the operator to understand where oil is entering the well, where water is entering the well and relative oil contributions of monitored zones.
The technology has been deployed onshore and offshore in locations such as Alaska, North Sea, Australia and Gulf of Mexico. Operators have benefited from this technology by gaining insight into inflow distribution without having to run a PLT log.
Examples of insight that operators have gained from this technology includes:
- Majority of flow coming from toe of long horizontal.
- One lateral of a multilateral not producing.
- No flow coming from intervals thought to be productive.
- Location of water break-thru as it changes over time.
- Flow detected from downhole sliding sleeves thought to be closed.
- No flow from sliding sleeves thought to be open.
- Assurance that remotely activated sleeves performed as expected.
This talk will review how the technology works, case histories of intelligent tracer responses and the value the operator gained from deploying the technology.