Technical and Economic Challenge of Mature Gas Fields: The Giant Altmark Field, Germany
Authors: Denney Dennis 
Published: February 2015

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 94406, "The Technical and Economic Challenge of Mature Gas Fields: The Giant Altmark Field, a German Example," by J. Ruckheim and G. Voigtlander, SPE, Erdgas Erdol GmbH, and M. Stein-Khokhlov, SPE, E.ON Ruhrgas E&P GmbH, prepared for the 2005 SPE Europec/EAGE Annual Conference, Madrid, Spain, 13–16 June.
Mature fields account for more than 70% of worldwide oil and gas production. The E&P industry must develop innovative and cost-effective technologies to increase the ultimate oil and gas recovery substantially. It will be necessary to optimize the efficiency of operation and maintenance while minimizing environmental effects. In addition to exploitation of new technologies, modern management techniques and new business models must be used to control the technical and economic risks.

Introduction
The focus of this paper is the giant mature Altmark gas field (9.4 Tcf of gas initially in place) in Germany, which has reached a recovery factor of 78%. The operator is applying various technologies and an alternative business model to increase the field life and, hence, reserves. Because of high temperature, constantly decreasing reservoir pressure, and high formation-water salinity, the main challenges are rock stability, water lifting, scale removal, and remediation of formation damage.
During the last decade, industry efforts have increased to develop new technologies to unlock reserves in mature fields. Mature fields—often called brownfields—are oil and gas fields in a state of declining production, having passed their peak production level. More than two-thirds of today's hydrocarbon production originates from this field category, representing a significant energy resource. Advanced technologies are needed, and the industry must improve the cost efficiency of maturing assets to compensate for declining production and high fixed costs.

Advanced Technology vs. Advanced Business Model
Generally, mature fields have the advantage of an existing infrastructure, but the disadvantage of the marginal economics combined with comparatively high project risks. Therefore, the industry has developed fit-for-purpose technologies. Significant areas for improving recovery by use of technology include the following.Reservoir knowledge to identify bypassed pay and stranded hydrocarbons.Knowledge of fluid and pressure behavior and drainable hydrocarbons.Assessment of production-enhancement opportunities by use of recompletion, stimulation, and changes in lifting strategy.Fluid management, especially downhole water separation and disposal.Tools for real-time data management and data analysis to improve reservoir management.
Technological needs of the oil and gas industry have been identified, and much technological progress has been achieved by focused R&D activities. However, much more effort is required to fill technological gaps and extend current techniques.
The R&D activities have been performed in the research centers of major oil companies, service companies, and, to some extent, universities and state-owned research centers. Consequently, the source and ownership of technology is spread very widely. This circumstance has forced arrangements between operators and the service industry to field test the technologies, especially to share the risks associated with such trial phases.