INCREASING PRODUCTION CAPACITY OF MATURE ASSETS THE CARDAMOM FIELD TIE-BACK TO AUGER TLP

Transcription

1 PRESENTATION OUTLINE 1) Separation and electrostatic destabilization 2) Separation prediction i. Empirical correlated prediction ii. Verification of prediction 3) Shell Cardamom field tie-back to Auger TLP i. Project presentation ii. Auger VIEC installation VIEC Electrode INCREASING PRODUCTION CAPACITY OF MATURE ASSETS THE CARDAMOM FIELD TIE-BACK TO AUGER TLP MARIUS TREBLER, WÄRTSILÄ OIL & GAS 1

2 SEPARATION AND ELECTROSTATIC DESTABILIZATION 2

3 Time (min) Separation process Separation process of water droplets in oil can be divided into a sedimentation process and a coalescence process: Sedimentation of water droplets in oil can be modeled by using the terminal velocity of water droplets: v t ( w o) gd 18 2 The sedimentation is proportional to the droplet diameter squared. The larger the droplet, the faster it separates from the oil. Coalescence of droplets is governed by a balance between attractive forces due to gravity and repulsive forces due to presence of surfactants Settling time in the oil layer Drop size (micron) Example of sedimentation: Mono-dispersion. Density: Water: 1000 kg/m 3 Oil: 878 kg/m 3 Viscosity: 5.4 cp Oil height: 1.0 m 3

4 Electro-coalescence An electric field over an water-in-oil emulsion will set up attractive forces between the water droplets. The attractive forces appear because of the large difference in electrical properties of oil and water. The water molecules aligns with the field, making the droplets polarized. Oil must be the continuous phase. L d s 5kV Fel Fel 5kV F el 3 0E 8 2 d d s 4 6 E U L 4

5 Electro-coalescence The electric field will cause the water droplets to coalesce resulting in larger water droplets. The droplets attractive force is proportional to the square of the electric field The settling velocity will be affected by the square of the droplet diameter. WiO emulsion in Electric field Bottle test with VIEC 5

6 SEPARATION PERFORMANCE PREDICTION AND VERIFICATION 6

7 Laboratory Multiphase Platform Plexiglass flow loop rig: Crude oil studies < 50 C HT flow loop rig: Crude oil studies < 100 C, < 22.3 API Large scale rig: Model oil studies and hardware tests Demo loop rig: Demonstrations and marketing 7

8 Scaling from laboratory to full scale verification Statoil test loop API 19 crude oil from a North Sea field Tests carried out at five different temperatures VIEC elements at Statoil s test loop in Porsgrunn, Norway 35 C Temperature [ C] Viscosity@op. pres. [cp] 40 C C 60 C 70 C

9 SHELL CARDAMOM FIELD TIE-BACK TO AUGER TLP 9

10 Shell Cardamom tie-back project Project background The Cardamom field was discovered in 2010 by using a new seismic technique, enabling identification of oil reservoirs under large salt domains. The field has an estimated production capacity of 55 MBOPD Production rate was too limited to carry an investment for a dedicated production facility. Tie-back to Auger The Auger platform in GoM was the world s first TLP, and was scheduled for decommissioning The tie-back from the Cardamom reservoir was a perfect match with Auger, meaning that Cardamom could be recovered and the life time of Auger extended The start-up of the Auger TLP with the new Cardamom tie-backs was done in September 2014, making Auger the largest net producer for Shell in GoM Auger location in GoM 10

11 Shell cardamom Cardamom tie-back Project project the weight issue The Auger TLP Auger was Shell s first deep-water floating tension leg platform in the Gulf of Mexico In the years since its 1994 installation, several projects added new production capacity, but also weight. By the time of the Cardamom discovery, the Auger TLP 20,000 tons hull support limit was reached. Shell Auger TLP This was a weight-neutral project from the start. Every new kilogram brought onto the platform meant another kilogram had to come off. Patrick Luquire, Auger senior business advisor 11

12 Auger separator bottleneck Existing separator, 2.6 m diameter and 6.1 meter tan/tan distance, had a production capacity of 30 MBOPD with Shell design guide lines defines a separator with diameter of 3m and a tan/tan distance of 10m for bulk-water separation for the Cardamom production rates. By installing VIEC in the existing separator the capacity was increased to 55 MBOPD meeting the production capacity requirement for the tie-back project with an added weight of only 2 MT Prior to installation Wärtsilä executed a laboratory feasibility study with a Cardamom representative crude oil sample. Testing included fluids characterization, batch tests, droplet size analyses and NIR microscopy. The tests confirmed VIEC treatment suitability Separator according to Shell design guide lines Existing separator with VIEC 12

13 Installation Trial-fit is performed before packing to make sure everything fits perfectly All equipment was installed through the man-way (18 inch) The installation was done in under 5 days Frequency converters, cabinets and penetration system was UL certified during the project phase Auger Trail-fit Separator on Auger TLP VIEC installed in separator VFC Cabinets 13

14 Start-up and initial results The system was successfully started up early September this year Initial testing with limited flow rates show good results and reduced BS&W output When putting the test condition into the VIEC empirical correlation tool, the actual performance was better than predicted: The initial results therefore shows that required BS&W is going to be achieved when increasing to full capacity of 55 MBLPD The test also shows that with the VIEC turned on, the demulsifier rate could be reduced drastically before the BS&W out of the separator got back up to the initial value without VIEC 14

15 Thank you Marius Trebler