Marat Basyrov, Director, Reservoir Management Functional Excellence Dept., Reservoir Management and Reserves Division, Upstream
The main goal of water flooding is to maintain reservoir energy (reservoir pressure) and the displacement of oil to production wells. The amount of injected water and the location of the injection site are very important. Improvement of water-flooding efficiency critically depends on these two factors. TNK-BP produces 95% of its oil in fields developed with water flooding, and the importance of water-flooding efficiency improvement is hard to overestimate
Since its inception, TNK-BP has been increasing its’ oil production, which requires the improvement of field development and waterflood efficiency. Oil production enhancement and development of new reserves require that the reservoirs energy is maintained. The need for efficient reservoir pressure maintenance solutions became even more urgent after the significant production: increase of 2005–2006 caused by well interventions in production wells and the development of new fields, such as Ust-Vakh and the Kasparovsky dome in Samotlor. The initial flow rates were high but the subsequent oil production declined in new and worked over wells was so significant that the Company had to focus its attention to waterflood efficiency.
In 2007, Upstream and Technology established the Waterflooding Governance Board consisting of representatives from subsidiaries, the Tyumen Petroleum Research Center (TNC), and the Corporate Center. The main goal of this council was to improve of waterflood efficiency. As a result, the base production decline rate has slowed down and may improve even further.
From Extensive to Innovative Development
However, the period of easy progress in waterflood efficiency improvement attained by large-scale conversion of wells to injection is coming to an end. Further optimization and improvement require better analysis and better solutions. The current challenges are to develop personnel competencies, improve waterflood management efficiency and integrate new technologies. The ultimate goal is to ensure an innovative development of waterflood management in the company.
This development relies on the sequence of Competencies Processes Technology, which is key for the integration of innovations. For example, any company can buy any technology, but only the right people can identify its strong suites and application, properly integrate it with due regard to all necessary processes, and eventually make an efficient use
of the technology. In other words, the know-how of using the technology is much more important than the technology itself.
Water-flood efficiency improvement is based on the competencies of the employees engaged. One of the main goals of the Company in this direction is to create of a pool of experts in subsidiaries with worldclass competencies. For this reason, the Company is implementing a program of personnel development based on master classes and advanced courses in waterflooding.
Waterflood efficiency improvement processes may be divided into organizational and technological (workflow) processes. Organizational processes are related to elaboration of roles and responsibilities of all parties involved (oil and gas production shops, subsidiaries, TNC and the Corporate Center) and their motivation. The latter condition is essential to continuosly integrate improvements and establish commitment to the use of improved practices. Another aspect of motivation is maintenance of the right balance between short-term production results, which may cause premature introduction of a waterflood system, and long-term effects of reservoir pressure maintenance program. Waterflood system analysis is a comprehensive process that relies on reservoir model analysis and the use of analytical engineering methods.
Reservoir modeling methods based on stream lines are being integrated throughout the Company to visualize waterflood systems, determine injected water distribution across the production wells, and select of the most efficient patterns. Proper use of the models requires high competencies from those who those, who make decisions on the reservoir pressure maintenance system on a daily basis. Therefore, the Company is implementing the concept of “Engineering Access to Models.” Models are created and monitored by specialists of modeling sections and used by engineers in the production / wellwork section, who utilize dedicated software with a simplified Russian interface. As a result, engineers and production specialists in subsiduaries and oil and gas production shops get interactive access to the reservoir model of a field and can thus forecast the efficiency of different well interventions, sidetracking operations, and reservoir pressure maintenance operations for the next three to five years (Fig. 1).
Analytical engineering approaches are being developed in TNK-BP in stages. In the beginning, much attention was paid to the analysis of blocks, since it is the easiest and the most convenient approach for the analysis of an extensive well stock, and it also corresponds well to the conventional closed-block development pattern used in Brownfield reservoirs in West Siberia. Today TNK-BP is shifting to the analysis of development cells or waterflood patterns (Fig. 2). Both technologically and geologically separated blocks are analyzed in cases requiring a different approach to reservoir separation.
DeepDive into a New Culture
Waterflood patterns are analyzed based on practical analytical solutions and formats demonstrated by our colleagues from BP in subsidiaries during the DeepDive sessions. The Company launched the DeepDive program as one of the ways to improve the efficiency of field development in West Siberia. The DeepDives proved to be efficient for the development of waterflood management skills, and it was decided to roll out this practice in all assets of the South-East Area. A series of DeepDives is being carried out in the fields of TNK-Uvat and Orenburg Region.
The main advantages of the DeepDives include consistency of analysis, identification of vital information and the visualization and the combination of data. An analysis culture is being formed even though it is based on methods and approaches that are not new. The analysis culture implies optimization of the data, actions, time, and involvement of specialists participants and will ensure deep and comprehensive analysis of an area and provide recommendations for injection, well work over and futher subsurface studies.
Another aspect of waterflood efficiency improvement is the automation of analysis processes. Analysis automation reduces labour costs, which is especially important when large numbers of wells are to be analyzed routinely. BASPRO is the main software package used by field geologists and reservoir engineers in TNK-BP. Terms of reference have been developed, in cooperation with the West Siberia Area, for developing of a waterflood management module in BASPRO and its subsequent integration in subsidiaries across the Company.
Aiming at World-Class Performance
Organizational improvement is of course not sufficient for an improvement in the efficiency of waterflooding, especially in reservoirs with complex geological structures or reservoirs with high oil watercuts. New technologies are to be implemented to increase the efficiency of waterflood and enhance oil recovery. One example of new waterflood technologies is the injection into horizontal wells of AB1(1-2) reservoir in Samotlor (Fig. 3), which has been tested in 2010-2011 and is now being rolled out in subsidiaries. Another example is injection BrightWater polymer, which is used in BP fields. The pilot injection of this polymer was carried out in TNK-BP in 2011. If this technology proves efficient, it may have a great potential in the Company.
Improvement of water-flooding efficiency requires continuous development of personnel competencies, use of best waterflood analysis methods, and integration of new technologies. Owing to the well-coordinated activities of the subsidiaries, TNC, and the Corporate Center, the Company is developing and integrating new world-class waterflood practices.