Abstract
The objective of this research and development program is to qualify for 3000 mWD the chemical injection pump, one of the main key components of the subsea chemical storage and injection station (SCS&I). The development of the SCS&I system responds to the need to develop oil and gas reservoirs at deeper water depths and further distances from host or from shore and to reduce CAPEX and GHG released associated.
Indeed, one of the high CAPEX of a subsea project and a weak point during operation is the umbilical chemical lines. Storing the chemicals close to the wells will reduce the umbilical cross section and cost and avoid plugging of those lines. The development of the SCS&I is an enabler for "all electrical" simplified architecture, reducing both costs and GHG emissions. This qualification is a first for a high dosage chemical pump under subsea environmental conditions.
The HAMPRO® 70V injection pump from Hammelmann was selected as the most promising pump for marinization and qualification for 3000 mWD. Its big advantage is that the contact between the oil used for lubrication and cooling of the pump and motor is separated from the chemical pumped fluid by sealed bellows. The other advantage is that its duty allows the injection of high rate, batch injected chemical products like methanol, and at the same time its design allows reducing the piston diameters and stroke giving the flexibility to inject low dosage chemical products.
The pump has been modified for its marinization. For installation subsea, it is capital to ensure its robustness regarding the high external pressure and discharge pressure, but also reliability of the chemically exposed parts, the pump and motor rotating parts and the impact of lubricant performance, the reliability of the electrical components and finally the impact of transient behaviors on the pressure compensation system.
To assure all these aspects, a complete R&D qualification program has been launched. This program includes short term batch operation with high flow rate and high differential pressure, long term continuous operation with low or high differential pressure and finally, transient operation with large variation in differential pressure but also different strokes imposed to the pump. The program is to be completed with a hyperbaric performance test and specific endurance tests performed to ensure the bellows robustness.
For endurance testing, the pumps have already been running for more than 2000 hours. This paper will describe the main findings and support the qualification required for subsea use.
