GE Completes Tests For High-Pressure Gas Re-Injection Train
Based on well-proven re-injection train architecture that incorporates a double-shaft GE Frame 5-2D gas turbine and three centrifugal compressors, the turbo-compression train reached 820 bar pressure during full density tests, topping the former record of 690 bar, also achieved by GE technology.
Other highlights of the tests included:
- 1050 bar pressure capability (API 15000) of the casing used for the BCL304/E centrifugal compressor, exceeding the 915 bar design pressure required for the Kashagan project
- Hydraulic testing of the BCL304/E compressor showed capability up to 1370 bar pressure, which is 1.5 times the required design pressure of 915 bar for this project
- Highest gas density ever reached, nearly 500 kg/m3 (25 MW test gas mixture with methane and carbon dioxide)
- Casing zero leakage system was successful validated during the full-load test. This will ensure no sour gas ambient emission during site operation, where H2S content may reach 33%
- Testing on the highest pressure casing at full-load, full-density conditions yielded absorbed power that is 10% below the predicted values stated in the contract data sheets, with vibration level staying below 10 microns (7 microns at 820 bars vs. 38 microns allowed)
- Full operability along the entire operating range of the re-injection train, with no aero excitation
All of the compressors were first tested separately in GE's Oil & Gas facilities in Florence, Italy, followed by tests for the entire, assembled train at GE's plant in Massa, Italy at full-density, full-speed, full-pressure and full-power conditions, according to the ASME Type I test requirements.
"The tests have validated the capability of our compressors to operate at the ultra-high pressures required for today's most challenging sour gas re-injection applications," said Claudi Santiago, President of GE's Oil & Gas business. "From the perspective of our customers, this technology enables increased efficiency and high reliability for oil recovery operations."
Protecting the ecology of the region is a critical requirement for the Kashagan project. "To meet the demanding environmental and safety standards, the entire re-injection train has been designed and tested for zero leakage of sour gas," Santiago noted.
The train is the first of two units that will be mounted on off-shore modules and provided to Agip Kazakhstan North Caspian Operating Company N.V. (Agip KCO), which is acting as operator for and on behalf of the North Caspian PSA Partners.
Each of the two re-injection trains will be designed to inject 5.4 million scm/day of sour gas. Driving each train will be a GE Frame 5-2D gas turbine, a 30-megawatt class machine that provides the high reliability and availability required for high-pressure applications. In addition to the ultra high-pressure BCL304/E, the other centrifugal compressors for each train include the BCL404/B and the BCL304/C.
"GE was selected for this project because it is considered the compressor manufacturer with the most experience in the re-injection of sour gas at the pressures required by the Caspian Sea fields," Santiago said. "The test results for the first train have been outstanding and fully meet the customer's specifications."
Both trains are scheduled to be shipped to the project site by the end of 2006.
The Kashagan oil field is one of the largest fields discovered in the past 30 years. To recover crude oil from the field, associated sour gas will be re-injected into the reservoirs at ultra-high pressure. Basically, the sour gas injection process has three main goals: to avoid massive sulphur production as a by-product of the sweetening process; to avoid the flaring of sweetened gas and subsequent CO2 production; and to keep the oil well pressure at levels suitable for full exploitation.
SOURCE: GE Oil & Gas