The main activities occurred within the framework of the two research centres the National Centre for Increased Oil Recovery and COREC. In 2015, the IOR-Centre organised the first IOR NORWAY conference at the University of Stavanger. The conference was extremely successful, with more than 300 delegates from the industry, research institutions and academia.
Polymer injection to increase recovery
One of the increased oil recovery projects looked at how we can avoid degradation of polymers in the injection valves.
Polymer injection is a promising and successful method of increasing recovery. Polymers increase water viscosity, leading to more favourable mobility conditions between water and oil. This leads in turn to delayed water breakthrough and increased oil production. But it is also known that polymer solutions degrade when the solution is pumped through standard valves to reduce injection pressure, thus reducing viscosity and the potential to increase recovery. One of the challenges is how to inject the polymer solution without reducing the potential for increased oil recovery.
In autumn 2015, a large-scale polymer degradation test was performed by Halliburton, IRIS and SNF. The test matrix included different polymer types, concentrations, pressure drops and valve concepts. It was confirmed that standard valves will lead to unacceptably high degradation, while degradation can be significantly reduced by increasing the polymer concentration, using valves in series or increasing the length of the valve. It was shown that it is not pressure drop but effective rate of shear that controls degradation and that results performed on different scales are compatible.
Better reservoir models
IRIS published the first article on the use of ensemble-based methods for improving reservoir models in 2002. IRIS has had major research projects in this area with support from the Research Council since 2004. In 2015, the third major Petromaks project was concluded, a collaboration project between IRIS, Uni Research CIPR and MinesParisTech. The project, Reservoir data assimilation for realistic geology, focused on the further development of ensemble-based methods for characterising complex geological properties in oil reservoirs (e.g. sudden transitions between different facies types, faults, cracks etc.). The aim has been to history-adapt the models without destroying the properties that must be there.
During the course of the project, we have further developed our methods in the following areas: data assimilation, parametrisation and integrated work flow. One important part of the project has been to describe for the industry what methods should be used for different reservoirs, and in 2015 the most promising methods developed during the course of the project were used and demonstrated on afield. The results of this study have been accepted for publication in SPE Journal.
During the course of the three and a half year project we have published 32 periodical articles and 16 conference articles, in addition to a number of presentations at conferences and reports. In 2015 we also organised the 10th conference on ensemble-based methods, which was well attended by both industry and academia in spite of the cost cutting in the oil industry. We know that the methods developed in this and previous projects are now being used by several oil companies that operate on the Norwegian continental shelf and are included in commercial products that the oil companies use. It took just over ten years from the publication of the first article by IRIS until the method became widely implemented in Norway’s largest oil company. In 2015, we started the fourth large project to develop the method yet further, and in this we include 4D seismic. The industry sees the importance of including this big data information in the reservoir models so as to give them an even better basis for making the right decisions, and we intend to help them in this in the best possible way.