The Technical and Economic Challenge of 'Mature Gas Fields': The Giant Altmark Field, a German Example

摘要

"Mature" fields today account for over 70% of the worldwide oil and gas production. In view of the increasing global demand for fossil fuels during the next decades, it is the task of the E&P industry to develop innovative and cost effective technologies to substantially increase the rate of recovery from today's average of 35% to over 50% for oil and from about 70% to over 80% ultimate recovery for gas. To achieve this goal it will be necessary to optimise the efficiency of operation and maintenance while minimizing environmental impact. In addition to the exploitation of new technologies the industry needs to be open minded for modem management techniques and new business models in order to keep control of the technical and economic risks. The successful integration of various new technologies will have a major effect on the reserve renewal rate as 1% increase in recovery would provide an additional 2 years of supply. Main focus will be on the presentation of the giant and mature Altmark gas field - with 9.4 Tcf GIIP the biggest gas field in Germany - which has currently reached a recovery factor of 78%. It will be shown how the operator, EEG, is applying various technologies and an alternative business model to constantly increase the field life and hence reserves. Due to the field specifics, e.g. high temperature, constantly decreased reservoir pressure and high formation water salinity, the main operational challenges the operator is facing are rock stability, water lifting, scales removal and remediation of formation damage, a variety of reserves development and maintenance methods are applied like sidetracks and chemical treatments with surfactants and polymers, respectively. Apart from presenting the range of well treatment and monitoring technologies, another important topic which will be presented in this paper is the economic approach to efficiently handle the compartmentalised brownfield reservoir and production issues that allow the expected ultimate recovery to exceed 80%.