Overview

Torsten Clemens, SPE, Senior Reservoir Engineer, OMV

Optimizing hydrocarbon production and recovery requires fluid-production allocation from the different layers encountered in the wells. In recent years, downhole-monitoring systems have been used increasingly to unravel bulk production data measured at the surface. In particular, multilateral and “smart-well” technologies require much more-detailed spatial information about inflow than conventional wells.

One technology that has been improved significantly is the use of fiber-optic sensors. The first oilfield application of this technology was in steam-injection projects. With advanced understanding, improved sensors, and simulation of the well/reservoir coupling, fiber-optic sensor data can now be used for flow profiling, monitoring minifrac treatments, or diagnosing pumped wells, as discussed in the first featured paper.

On the reservoir scale, time-lapse (4D) seismic is used to monitor fluid movements directly. This method determines changes in seismic signals to infer fluid-saturation changes in the subsurface. However, techniques other than seismic can detect changes at the reservoir level. The second featured paper gives an example of such a technology: Surface-gravity measurements were used to monitor water injection into the gas cap of a large field.

The methods described above, for which gathering detailed downhole data or reservoir-scale time-lapse data is required, can be expensive and time consuming. However, a wealth of production data is continuously recorded at surface. These data are the key source for reserves evaluation by decline-curve analysis and for simple forecasting of hydrocarbon production. Paper SPE 107967, which is recommended for further reading, shows that much more information about the well and reservoir can be derived from these data by use of a new derivative function.

Real-Time Fiber-Optic Distributed Temperature Sensing: Oilfield Applications

4D Microgravity Surveillance of a Waterflood—Prudhoe Bay, Alaska

Identifying Condensate Banking With Multiphase Flowmeters—A Case Study

Torsten Clemens, SPE, is a senior reservoir engineer for OMV. His duties include improving recovery from OMV fields in Libya, Austria, and Romania. Previously, Clemens worked for Shell on reservoir-engineering and production challenges. He holds MS and PhD degrees in geology from Universität Tübingen. Clemens has authored several SPE and other technical papers, has served on several SPE meeting organizational committees, and is Chairperson of the SPE Vienna Basin Section. He also serves on the SPEREE Editorial Review and JPT Editorial Committees.

Overview

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