f Instrumented Oil Fields

The instrumented oil field consists of deploying permanent instrumentation to monitor an<br>oil field and modify production continuously or on demand. This concept has evolved from<br>recent developments in both down hole instrumentation and time-lapse monitoring. Both<br>of these technologies are new and combining them, with permanent installations in mind,<br>require further steps in research and development.<br>The objective of instrumenting an oil field is to optimize production and minimize<br>development and operations costs, through early investment in continuous monitoring of a<br>field. In deepwater and ultra-deepwater, where well costs can reach $50 million,<br>instrumenting an oil field early on could considerably improve the bottom line economics.<br>In this case, both the investments required and the potential returns are large. On land, oil<br>fields can be instrumented much more economically. A basic example would be to install<br>pressure and temperature sensors at wells to make sure a reservoir is kept above bubble<br>point. Although the technology necessary to fully instrument an oil field is still being<br>developed, several field applications on different parts of the technology already exist.<br>Two examples in the area of permanent ocean bottom multi-component installations for<br>seismic monitoring are the Foinaven field in the North Sea (Kristiansen et al., EAGE<br>Meeting Abstract, 2000) and the Teal South field in the Gulf of Mexico (Entralgo and<br>Spitz, TLE, 2001). These two studies alone have created extremely useful results and<br>allowed the industry to address issues related to hardware deployment and longetivity,<br>hardware design changes to improve data quality, understanding the quantity of data being<br>produced and means to manage such large data to produce timely results to impact field<br>development, and the economics involved. On land, a state-of-the-art permanent surface<br>seismic example is the Cere-la-Ronde case study (Meunier et al., TLE, 2001). Again, many<br>lessons have been learned from this study ranging from hardware and data acquisition, to<br>data processing, to data management, to interpretation. Another technology currently being<br>used is a multi-level multi-component permanent borehole seismic sensor array placed<br>between the tubing and casing (Hottman and Curtis, TLE, 2001). Fully fiber-optic multicomponent<br>seismic sensors are currently in field trial stage. Passive seismic monitoring is<br>currently in use in oil fields (Maxwell and Urbancic, TLE, 2001) and will be more widely<br>used as oil fields are instrumented with borehole seismic sensors. On the non-seismic side,<br>permanent borehole sensors to measure reservoir pressure, temperature, fluid flow, and<br>fluid composition have been developed and tested. Crosswell seismic, electromagnetic and<br>electrical methods are currently being used for monitoring purposes and may well take<br>their own place in the instrumented oilfield of the future.