Scale Analysis and Inhibitor Evaluation for an Offshore Asset - PowerPoint PPT Presentation

Scale Analysis and Inhibitor Evaluation for an Offshore Asset Public Suyun Wang Oil & Mining Services 21.10.2014

Public 2 Suyun Wang, Oil & Mining Services, 21.10.2014 Table of Contents – Introduction – Data Gathering – Scale Modeling – DSL Experiment – Conclusion and Recommendation

Introduction Public Suyun Wang Oil & Mining Services 21.10.2014

Public 4 Suyun Wang, Oil & Mining Services, 21.10.2014 Objectives – Scale review of the offshore asset from the production wells to departing pipelines, then to CPP facilities. – Scale modeling to estimate the scaling severity. – DSL experiment to evaluate the scale inhibitor performance. – Recommendation on the suitable scale inhibitors and initial dose rates.

Data Gathering Public Suyun Wang Oil & Mining Services 21.10.2014

Public 6 Suyun Wang, Oil & Mining Services, 21.10.2014 Simplified Diagram of the Offshore Asset Production Departing CPP facilities wells pipelines HP Separator WA1 WA2 WA3 Oil Trim LP Exchanger Separator HGOR Oil Heater Separator Electrostatic IP WB1 Heater Treater Separator Prod. Water Flotation To Skim Pile Hydrocyclone Cell WC1

Public 7 Suyun Wang, Oil & Mining Services, 21.10.2014 Operation Conditions – Production Wells Production Departing Well THT (°F) THP (psig) Rate (BWPD) Pipeline WA1 144 704 122 HP WA2 142 661 208 HP WA3 137 649 103 HP WB1 140 1199 131 HGOR WC1 140 547 825 HP

Public 8 Suyun Wang, Oil & Mining Services, 21.10.2014 Operation Conditions – CPP Facilities CPP Facility T (°F) P (psig) HGOR Separator 129 1089 HP Separator 126 464 a 464 Oil Trim Exchanger 120 IP Separator 111 160 b 160 Oil Heater 132 LP Separator 128 10 Electrostatic Heater Treater 131 10 Prod. Water Hydrocyclone 120 168 Flotation Cell 128 30 – a Pressure of Oil Trim Exchanger was assumed to be the same as that of HP Separator. – b Pressure of Oil Heater was assumed to be the same as that of IP Separator.

Public 9 Suyun Wang, Oil & Mining Services, 21.10.2014 Brine Compositions Composition (mg/L) Ion/Neutral Species WA1 WA2 WA3 WB1 WC1 Na + 5,701 5,819 6,625 8,136 8,782 Ca 2+ 2.59 6.72 5.12 17.45 18.67 Mg 2+ 3 5 5 24 22 Ba 2+ 0.5 3.1 1.5 4.7 4.3 Sr 2+ 2.22 4.93 3.78 10.52 9.33 Fe 2+ 0 0 0 0 0.2 Cl - 7,500 7,000 8,500 12,500 13,500 SO 42- 230.4 211.2 25.6 44.8 12.8 HCO 3- 2,184 3,416 3,233 646.6 707.6 Dissolved CO 2 0.65 0.649 0.646 0.64 0.637 Physical Property Data pH 8.1 7.9 8.3 8.1 7.9

Scale Modeling Public Suyun Wang Oil & Mining Services 21.10.2014

Public 11 Suyun Wang, Oil & Mining Services, 21.10.2014 Modeling Method – Software: OLI ScaleChem – Scale modeling performed for - Production wells - Departing pipelines: HP and HGOR lines - CPP facilities – Scale modeling results reported as - Scale index - Precipitation potential in mg/L

Public 12 Suyun Wang, Oil & Mining Services, 21.10.2014 Modeling Results – Production Wells Barite (BaSO 4 ) Calcite (CaCO 3 ) Strontianite (SrCO 3 ) THT THP Well (°F) (psig) SI PP (mg/L) SI PP (mg/L) SI PP (mg/L) WA1 144 704 0.04 0.0 0.06 0.5 0.43 2.2 WA2 142 661 0.76 4.2 0.61 12.0 0.97 7.2 WA3 137 649 -0.46 0.0 0.42 7.3 0.79 5.1 WB1 140 1199 0.28 3.3 0.24 7.2 0.39 7.2 WC1 140 547 -0.31 0.0 0.32 12.4 0.40 5.9 – WA1: mild strontianite scale. – WA2 and WB1: mild barite, calcite, and strontianite scales. – WA3 and WC1: mild calcite and strontianite scales.

Public 13 Suyun Wang, Oil & Mining Services, 21.10.2014 Modeling Results – Departing Pipelines Barite (BaSO 4 ) Calcite (CaCO 3 ) Strontianite (SrCO 3 ) Departing T P Pipeline (°F) (psig) SI PP (mg/L) SI PP (mg/L) SI PP (mg/L) 144 464 0.48 2.2 0.47 8.0 0.83 5.4 WA HP 126 464 0.57 2.4 0.35 6.7 0.74 5.2 140 1089 0.28 3.4 0.24 7.5 0.40 7.3 WB HGOR 129 1089 0.31 3.9 0.15 4.1 0.34 7.3 147 464 -0.34 0.0 0.37 14.8 0.43 6.0 WC HP 126 464 -0.26 0.0 0.21 8.1 0.33 5.8 – WA HP and WB HGOR: mild barite, calcite, and strontianite scales. – WC HP: mild calcite and strontianite scales.

Public 14 Suyun Wang, Oil & Mining Services, 21.10.2014 Modeling Results – Departing Pipelines WB HGOR line to CPP Mild calcite and strontianite scales WC HP line to CPP Mild barite, calcite, and strontianite scales

Public 15 Suyun Wang, Oil & Mining Services, 21.10.2014 Modeling Results – CPP Facilities Barite (BaSO 4 ) Calcite (CaCO 3 ) Strontianite (SrCO 3 ) T P CPP Facility (°F) (psig) SI PP (mg/L) SI PP (mg/L) SI PP (mg/L) HGOR Separator 129 1089 0.33 3.9 0.17 4.1 0.37 7.30 HP Separator 126 464 0.40 3.4 0.46 18.2 0.65 8.5 Oil Trim Exchanger 120 464 0.42 3.7 0.39 16.5 0.59 8.5 IP Separator 111 160 0.50 4.1 0.38 15.0 0.62 8.6 Oil Heater 132 160 0.36 3.4 0.48 19.7 0.64 8.9 LP Separator 128 10 0.39 3.5 0.47 19.1 0.64 8.9 Electrostatic Heater 131 10 0.37 3.4 0.48 19.8 0.65 9.0 Treater Hydrocyclone 120 168 0.43 3.8 0.41 17.1 0.61 8.7 Flotation Cell 128 30 0.38 3.5 0.46 19.1 0.64 8.9 – All facilities: mild barite, calcite, and strontianite scales.

DSL Experiment Public Suyun Wang Oil & Mining Services 21.10.2014

Public 17 Suyun Wang, Oil & Mining Services, 21.10.2014 DSL Equipment – Three-pump system to enable testing of multiple dosages of a scale inhibitor. – Monitor differential pressure change across the coil for indication of scale formation.

Public 18 Suyun Wang, Oil & Mining Services, 21.10.2014 DSL Schematics

Public 19 Suyun Wang, Oil & Mining Services, 21.10.2014 Test Method – Test conditions - Brine: adjusted synthetic WA2 produced brine (100 mg/L Ca 2+ ) - Temperature: WA2 tubing head temperature of 142 ° F - Scale inhibitors: SCALETREAT A and SCALETREAT B (phosphonate types) - Inhibitor dosages: 70 ~ 0 ppm - Test duration: 75 minutes for each inhibitor dosage – Test procedure - Prepared the cation, anion, and inhibitor dosed anion brines according to water compositions. - Pumped the cation and total anion brines in a 1:1 ratio, with a combined flow rate of 3 mL/min. - Introduced the inhibitor stepwise from high concentration to low concentration. Pressure increase during dosing indicated that the inhibitor was not effective at the dosed concentration.

Public 20 Suyun Wang, Oil & Mining Services, 21.10.2014 Blank Test Results – DSL blank tests with various adjusted calcium contents to make sure scale forms in reasonable time at 142 ° F.

Public 21 Suyun Wang, Oil & Mining Services, 21.10.2014 Inhibitor Test Results – DSL inhibitor tests with 100 mg/L calcium in brine at 142 ° F. – MIC = 60 ppm for SCALETREAT A, 40 PPM for SCALETREAT B.

Conclusion and Recommendation Public Suyun Wang Oil & Mining Services 21.10.2014

Public 23 Suyun Wang, Oil & Mining Services, 21.10.2014 Conclusions – Scale modeling results suggested - Production wells: mild strontianite scale for WA1 well; mild barite, calcite, and strontianite scales for WA2 and WB1 wells; mild calcite and strontianite scales for WA3 and WC1 wells. - Departing pipelines: mild barite, calcite, and strontianite scales for WA HP and WB HGOR lines; mild calcite and strontianite scales for WC HP line. - CPP facilities: mild barite, calcite, and strontianite scales for all facilities. – DSL experimental data showed - Both SCALETREAT A and SCALETREAT B were able to inhibit scale formation at 142 ° F in the adjusted synthetic WA2 produced brine (100 mg/L Calcium). - MIC were determined to be 60 ppm for SCALETREAT A and 40 ppm for SCALETREAT B. - SCALETREAT B exhibited better performance than SCALETREAT A.

Public 24 Suyun Wang, Oil & Mining Services, 21.10.2014 Recommendation – Two treatment plans - Continuously inject SCALETREAT A with an initial dosage of 60 ppm upstream of the departing pipelines. - Continuously inject SCALETREAT B with an initial dosage of 40 ppm upstream of the departing pipelines. – The actual dosage can be optimized in field trials. – Final selection on SCALETREAT A or SCALETREAT B for field trial are based on their compatibility with produced fluids and other production chemicals, product price, raw material availability, etc.

Questions? Public Suyun Wang Oil & Mining Services 21.10.2014

Thank You! Public Suyun Wang Oil & Mining Services 21.10.2014