After a prolonged period of calls from Norwegian oil authorities to develop complex oil and gas reservoirs, operators in the country have begun implementing a number of new projects in this area.

Potential of Complex Reservoirs

The Norwegian Offshore Directorate (NOD) highlights the significant potential for oil and gas extraction from dense and high-pressure, high-temperature (HPHT) reservoirs. Estimates suggest that such formations in Norway contain between 15 and 16 billion barrels of oil equivalent.

A dense reservoir is an oil or gas deposit in rock with very low permeability, making it difficult for hydrocarbons to flow to the well at a commercially viable rate. While Norway has traditionally been known for production from highly porous sandstones, recent years have seen the discovery of dense zones and even entirely tight reservoirs.

Modern drilling and hydraulic fracturing technologies now make it possible to unlock substantial volumes of gas from these reservoirs. The industry is seeing growing interest in these opportunities.

Key Projects and Technologies

Aker BP is actively advancing projects to develop complex reservoirs. The company is implementing the first specialized project for the development of a dense and HPHT field, Victoria/Warka, in the Norwegian Sea. In 2019, it was acknowledged that traditional technologies did not provide economic feasibility for development, but recent technological advances have prompted a reassessment of this conclusion.

In January, Aker BP received licenses for Victoria and Warka as part of a consortium with Equinor, Harbour Energy, and Orlen. A two-phase development plan has been presented, with gas production scheduled to start at the end of 2029. The first phase includes three wells without stimulation, followed by three years of pilot production. The second phase foresees nine inclined wells without stimulation, starting from 2033.

The project's economic viability is ensured by the ability to connect the fields to the floating Skarv facility, from where gas is transported to shore via the Aasgard Transport pipeline system.

Victoria is considered one of Norway's largest undeveloped gas fields, with reserves of around 140 billion cubic meters of gas and a production potential of 29 billion cubic meters. The field was discovered in 2000, with an appraisal well drilled in 2009. The HPHT reservoir lies at a depth of about 5,400 meters, with a pressure of 820 bar, a temperature of 190°C, and CO₂ content ranging from 8% to 10%.

Various stimulation methods are being considered to enhance well productivity, including the Fishbones technology, which creates multiple branches in the dense reservoir to increase exposure.

Aker BP has also obtained licenses for the Norvarg and Ververis discoveries in the Barents Sea and plans to leverage its HPHT drilling experience from the Fenris field, as well as expertise gained from working with dense reservoirs at Valhall.

Outlook for Other Fields

Successful development of Victoria could pave the way for the exploitation of similar areas and reservoirs, including Storjo and other dense gas accumulations in the region.

DNO is also considering the use of hydraulic fracturing to increase gas and condensate recovery at the large Carmen field. A recent appraisal well confirmed the presence of 21 to 107 million barrels of recoverable oil equivalent, most of which is located in the Etive formation with variable reservoir quality.

The Role of Hydraulic Fracturing

Hydraulic fracturing, a technology widely used in the United States, has seen little application on the Norwegian shelf. However, recent successes indicate that this method can also be effective in Norway. The NOD supports the development of large and complex discoveries such as Victoria and Gro, as their successful development could open new opportunities for the industry.

To improve economic efficiency, it is important to utilize existing offshore production facilities, as Aker BP is doing with Victoria via the Skarv FPSO or Heidrun. There is also a noted need to commence production from dense reservoirs by 2030 or soon after, to make use of the remaining service life of the infrastructure.

Experience of Other Operators

Equinor also recognizes the potential of dense reservoirs and has already achieved success in addressing related challenges at mature fields such as Statfjord and Gullfaks. The company applies experience gained in the US and conducts stimulation on certain fixed drilling rigs, which has led to good results in increasing production from dense reservoirs.

Conclusion

The development of complex and dense reservoirs is becoming a priority for Norway's oil and gas sector. Modern technologies and accumulated experience now make it possible to tap into significant reserves that were previously considered difficult to access.