EOR. Jorge Monzon Reservoir Engineer, SNF

Transcription

1 New insight on thermoresponsive polymers for EOR Jorge Monzon Reservoir Engineer, SNF

2 Presentation content Introduction to thermo-responsive polymers What are they? Main characteristics Interest in CEOR Oman case study In house expertise: Long sand pack experiment Conclusions

3 Introduction to thermo-responsive polymers

4 Thermo-responsive polymers What are they? T < LCST* Hydrophilic moieties T T > LCST* Hydrophobic moieties Regular HPAM polymer with a thermosensitive monomer, which will be activated at a specific temperature T< LCST Regular polymer T> LCST Associative polymer

5

6 Main characteristics - Regular polymers: viscosity decreases as temperature increases - Thermo-responsive: viscosity increases as temperature increases

7 Salinity effect on thermo-responsive polymers Salinity Thermo-responsive polymers can be fine tuned (salinity, transition temperature)

8 Interest in Chemical EOR - Decrease the polymer concentration Improve the economics - Reversible effect Quicker dissolution Easier injection Handling low viscosity solutions when backproduced

9 Oman Case study

10 Case study (South field Oman) Polymers considered: Properties and design SAMPLE LCST group Active Molecular content Content (%) weight (MDa) Thermo-SL Low Thermo-SH High AM / AA / ATBS backbone T = 60 C 20 g/l TDS Despite a higher molecular weight, Thermo-SL shows a lower viscosity than Thermo-SH SPE MS Development of Thermo-Responsive Polymers for CEOR in Extreme Conditions: Applicability to Oman oil fields T. Divers

11 Case study (South field Oman) Thermal stability: Test conditions Polymer Concentration (ppm) ITW (%) Test conditions Thermo-SL ppb O 2 0 ppm H 2 S Thermo-SL ppb O ppm H 2 S Thermo-SL + F3P ppb O ppm H 2 S Thermo-SL ppb O ppm H 2 S Thermo-SH ppb O 2 0 ppm H 2 S Thermo-SH ppb O ppm H 2 S Thermo-SH + F3P ppb O ppm H 2 S Thermo-SH ppb O ppm H 2 S - Long term stability in presence of H 2 S under controlled amount of O 2 - Impact of ITW and polymer protective package (F3P) investigated - Percentage of degradation (%DG) recorded over time SPE MS Development of Thermo-Responsive Polymers for CEOR in Extreme Conditions: Applicability to Oman oil fields T. Divers

12 Case study (South field Oman) Thermal stability: Results - Similar behaviour for Thermo-SL & Thermo-SH - No degradation whatever the conditions - Viscosity increase: hydrolysis + unstable measurements - No degradation in presence of contaminants SPE MS Development of Thermo-Responsive Polymers for CEOR in Extreme Conditions: Applicability to Oman oil fields T. Divers

13 Case study (South field Oman) Injectivity assesment: Test conditions Objective = Assess the propagation and compare resistance factors (RF), retention (tracer) and residual resistance factors (RRF) on Bentheimer core Cores properties: Samples Thermo-SL Thermo-SH Core properties Bentheimer 1 Bentheimer 2 D (mm) L (mm) Dry weight (g) Wet weight (g) PV by weight (cc) Kg (md) Kw (md) Ø (%) SPE MS Development of Thermo-Responsive Polymers for CEOR in Extreme Conditions: Applicability to Oman oil fields T. Divers

14 Case study (South field Oman) Injectivity assessment: Results Polymer injection at 16 cps 4 ml/hr (frontal velocity of 1 foot/day) Polymer Retention (µg/g) Thermo-SL 13.5 Thermo-SH ND Rm Stabilization after 1 PV Rm = 4 ml/hr Shear thinning up to 40 s-1 Stabilization after 4.8 PV Little face plugging Rm = 4mL/hr Shear thinning up to 260 s-1 Rk Rk = 4 ml/hr Rk = higher flow rate Rk = 4mL/hr Rk = higher flow rate SPE MS Development of Thermo-Responsive Polymers for CEOR in Extreme Conditions: Applicability to Oman oil fields T. Divers

15 In house expertise Long sand pack experiment

16 Coreflood in house development: Length: 5x1 feet sections Diameter: 1 Independent temperature for each section

17 Thermo-sensitive evaluation in long coreflood with temperature gradient Injectivity assessment: Test conditions Polymer design : TR 1 AM/ATBS backbone 1000 ppm Brine: Synthetic Sea Water (TDS: 33500, R + =0,13) R + = C mono [Cdiv] +[Cdiv] Cores properties: Sand pack

18 Thermo-sensitive evaluation in long coreflood with temperature gradient Injectivity assessment: Results Fluctuation coming from temperature differences during the day

19 Thermo-sensitive evaluation in long coreflood with temperature gradient Injectivity assessment: Results Thermoresponsive effect at 90 C

20 Thermo-sensitive evaluation in long coreflood with temperature gradient Injectivity assessment: Results Good reversible effect

21 Thermo-sensitive evaluation in long coreflood with temperature gradient Properties required for a good polymer of EOR High viscosifying power Good propagation in porous media Good filtration and solubility Thermally-stable Easy to produce Economical

22 Thank you Questions? Jorge Monzon Reservoir Engineer, SNF