Extending the Life of Mature Assets: How Integrating Subsurface & Surface Knowledge and Best Practices Can Increase Production and Maintain Integrity
Authors: Khatib Z. , Walsh J. M. 
Published: October 2014

Many producing assets in the world have reached the so-called mature phase of development. Some of these assets have been producing for 30 to 40 years or more, which is typically beyond the design life, and have reached a water to oil ratio of 3 to 9 or more. There are many issues that affect the productivity and economic viability of these fields. Some of the challenges include integrity uncertainty in the wells, flow lines, and facilities; production bottlenecks due to the shift in gas, oil and water ratios; erosion/corrosion; increased sand production and handling costs; high chemical consumption and treatment costs; and obsolete monitoring and control systems that are incompatible with new technologies and which contribute to the need for a large number of operations staff. Generally operators are faced with the commercial decision whether to sell the asset to a low cost operator, reinvest in the asset, or incur the cost of decommissioning.

While the number and complexity of these challenges are significant, there are nevertheless a number of viable options for extending the economic life of such assets. Hydrocarbon recovery and production from these fields can be enhanced by infill drilling; acid and fracture stimulation; by implementing a range of remediation techniques such as recompletion with smart systems to reduce water and solids influx to surface facilities; and by the implementation of improved and enhanced recovery methods. Selecting the optimal strategy requires a holistic perspective on subsurface issues, wells, and surface facilities, and an ability to make projections of integrated performance. This is greatly facilitated by first developing a root cause understanding of the reservoir and production fluid characteristics, and second, the use of analysis tools that allow quick and reasonably accurate assessment of options.

In order to increase value from matured fields, the goal is to increase oil recovery from the historical average of 35% and to optimize production by improving the operational efficiency. To achieve this goal, in this paper we will put forward two key imperatives that extend the life of a mature field: (1) Finding and accessing the by-passed oil and (2) Maintaining High uptime during Asset production and operation.

In this paper, several mature fields in Europe, Far East and Middle East are analyzed and presented in order to: –highlight the root causes for either low production and or higher operating costs;–assess the impact of both surface and subsurface uncertainties in multiple development planning scenarios;–develop the best strategies and options for improved reservoir, well and facilities management;–demonstrate the contributions of implemented new technologies that optimized performance of artificial lift, minimized downtime by well intervention and reduced operational costs by fluids flow assurance in well and surface facilities; and–list the technical and economical challenges that still face the industry.