SHAH GAS PLANT OPERATION AT 110% DESIGN CAPACITY Abu Dhabi Gas Development Company Ltd.
AL-HOSN GAS BLOCK DIAGRAM NGL 4,380 TPD Sweet Gas Dehydration, Gas NGL Recovery, 520 MMSCFD 2 Trains 8 Pads , 32 Wells, 2 Transfer Lines 700 MMSCFD Gas Gathering System 1,030 1,000 Sulphur Granules Gas Separation Sulphur Sulphur Acid Gas MMSCFD MMCSCFD 9,091 TPD & Condensate Recovery Units Storage & Removal Units Stabilization and TGTUs Granulation 4 Trains 2 Trains 4 Trains 12 Granulators Condensate Condensate 33,000 BPD Hydrotreaters 2 Trains 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 %) CO 2 9.48 9.74 1 H 2 S 22.81 24.09 2 Methane 56.32 55.25 3 Ethane 4.32 3.91 4 Propane 1.88 1.77 5 Abu Dhabi Gas Development Company Ltd.
TEST RUN BACKGROUND No Component Design (Mol %) Actual (Mol %) CO 2 9.48 9.74 1 H 2 S 22.81 24.09 2 Methane 56.32 55.25 3 Ethane 4.32 3.91 4 Propane 1.88 1.77 5 • Higher H 2 S 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 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 3 rd 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 Well Fluid flow MMSCFD 1030 1155 1 H 2 S in Feed Gas % 22.81 24.53 2 CO 2 in feed gas % 9.48 9.85 3 Condensate BPD 33,000 35,307 4 Sales Gas MMSCFD 520 579 5 NGL TPD 4,380 4,525 6 Liquid Sulphur TPD 9,091 10,776 7 • 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 m 3 /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 Abu Dhabi Gas Development Company Ltd.
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