SHAH GAS PLANT OPERATION AT 110% DESIGN CAPACITY Abu Dhabi Gas - - PowerPoint PPT Presentation

Abu Dhabi Gas Development Company Ltd.

SHAH GAS PLANT OPERATION AT 110% DESIGN CAPACITY

Abu Dhabi Gas Development Company Ltd.

AL-HOSN GAS BLOCK DIAGRAM

Gas Gathering System 8 Pads , 32 Wells, 2 Transfer Lines Gas Separation & Condensate Stabilization 2 Trains Condensate Hydrotreaters 2 Trains Acid Gas Removal Units 4 Trains Sulphur Recovery Units and TGTUs 4 Trains Sulphur Storage & Granulation 12 Granulators Sweet Gas Dehydration, NGL Recovery, 2 Trains 1,030

MMSCFD

1,000

MMCSCFD

NGL 4,380 TPD 700 MMSCFD Condensate 33,000 BPD Gas 520 MMSCFD Sulphur Granules 9,091 TPD

Abu Dhabi Gas Development Company Ltd.

BACKGROUND

• Shah Gas Development (SGD) Facilities have been designed to process 1,030 MMSCFD of Well Fluid
• As part of design, most equipment has a 10% built-in design margins
• Facility started up in January, 2015 and successfully achieved design capacity in August, 2015
• Actual feed gas composition is found to be slightly different than design. Composition to plant varies depending on

chosen well combinations No Component Design (Mol %) Actual (Mol %) 1 CO2 9.48 9.74 2 H2S 22.81 24.09 3 Methane 56.32 55.25 4 Ethane 4.32 3.91 5 Propane 1.88 1.77

Abu Dhabi Gas Development Company Ltd.

TEST RUN BACKGROUND

• Higher H2S concentration in feed gas consumed some margins in DGA acid gas removal units, but less load on

Hydrocarbon processing units

• Reduced co-firing provided extra margin in Sulphur Recovery Units (SRUs).
• Condensate Hydrotreaters Units were designed with higher margin (50,000 BPD design vs 33,000 BPD required)
• In House study started in Nov-2015 to utilize available margins to process additional 10% feed gas

No Component Design (Mol %) Actual (Mol %) 1 CO2 9.48 9.74 2 H2S 22.81 24.09 3 Methane 56.32 55.25 4 Ethane 4.32 3.91 5 Propane 1.88 1.77

Abu Dhabi Gas Development Company Ltd.

EVALUATIONS – PREPARATION FOR TEST RUN

Several evaluations were conducted prior to performing the 110% Test Run

• 1. Wells head flow distribution and well fluid composition at plant battery limit was set in consultation with sub-

surface and production planning

• 2. Target feed gas flow rate was set at 1,133 MMSCFD vs. 1,030 MMSCFD design
• 3. Flow assurance modeling for gas gathering system was carried out using OLGA software
• 4. Heat and material balances for all plants were generated for new feed composition and flow rate using HYSYS

/ SULSIM models

• 5. Adequacy of flares, relieve valves, emergency shutdown systems and depressurization systems were

checked in-house and then validated by 3rd party M/S Petrofac.

• 6. Performance of licensed units were validated by Fluor / UOP / Ortloff for new flow rates and compositions.
• 7. Utilities were reviewed and determined to have sufficient margins, no external evaluation carried out for

adequacy checks of utilities.

• 8. Test run procedure was prepared considering in house evaluations, existing operating issues and guidelines

provided by licensors.

Abu Dhabi Gas Development Company Ltd.

110% TEST RUN AND RESULTS

Test run at increased feed rate was carried out in August 2016. Facility successfully processed 1,155 mmscfd well fluid. Following are some key parameters achieved during test run

No Parameters Units Design Test Run 1 Well Fluid flow MMSCFD 1030 1155 2 H2S in Feed Gas % 22.81 24.53 3 CO2 in feed gas % 9.48 9.85 4 Condensate BPD 33,000 35,307 5 Sales Gas MMSCFD 520 579 6 NGL TPD 4,380 4,525 7 Liquid Sulphur TPD 9,091 10,776

• Guaranteed Performance test run parameters were achieved for all units
• No limitation observed in utilities including main refrigeration system
• No control loops operated on manual due to high load operation
• Higher throughput resulted in higher pressure drop at sweet gas treating units , getting feedback from licensor for

adjusting alarm settings for high DP.

Abu Dhabi Gas Development Company Ltd.

110% TEST RUN - LIMITATIONS OBSERVED

Following are some limitations observed at high load operation

• 1. Recommended amine circulation rate is 1,750 but limited to 1,720 m3/hr due to pump motor power
• limitation. This is leading to higher RDGA temperature (during summer) affecting the flash gas flow

and composition. Lean solvent flow to the packing column of the flash drum adjusted accordingly.

• 2. Pressure drop across rich / lean DGA exchanger higher due to higher circulation rates, but was kept

within limits by operating bypass without affecting process conditions.

• 3. NGL recovery units refrigeration compressors became limiting factor during day time due to ambient

temperature (during summer)

• 4. Pressure drop across filter coalescers and cold boxes in NGL recovery unit section increased but

remained within the design limits.

• 5. No Limitation observed in any SRUs at 110% Throughput operation.

Abu Dhabi Gas Development Company Ltd.

QUESTIONS