1. PWRI JIP Meeting Advantek International Presentation

2. Objective Review analyzed dataReview analyzed data Report findings from data analysisReport findings from data analysis Make recommendationsMake recommendations

3. Outline Data OverviewData Overview Historical PlotsHistorical Plots Water SourceWater Source Water TreatmentWater Treatment StimulationStimulation

4. Conclusions Decline in injectivity more a function of particle countDecline in injectivity more a function of particle count Observation suggest potential improved correlation (Count, size). This correlation needs verification by other field dataObservation suggest potential improved correlation (Count, size). This correlation needs verification by other field data New correlation may quantify the influence of filtrationNew correlation may quantify the influence of filtration

5. Conclusions Delayed, gelled, buffered and/or chelated acids will do better than normal acidsDelayed, gelled, buffered and/or chelated acids will do better than normal acids Highly recommended to initially stimulate an injector to lower the standard of RIIHighly recommended to initially stimulate an injector to lower the standard of RII Improvement Due to stimulation returns well to the average best historical Injectivity Index. (Cannot do better than my past best)Improvement Due to stimulation returns well to the average best historical Injectivity Index. (Cannot do better than my past best)

6. Input Data PerformanceMetrics Historical Plots Water Treatment Water Source FractureAnalysis Stimulation

7. Historical Plots Data Overview Raw Data Plots Processed Plots Back

8. Questions on PBU Conclusions SW out performs PW in a general sense, confirms BP dataSW out performs PW in a general sense, confirms BP data The difference is not as evident as PBU experience. (PW out performing the SW in some cases)The difference is not as evident as PBU experience. (PW out performing the SW in some cases) Interplay between thermoelastic and viscous effects controls the injector response.Interplay between thermoelastic and viscous effects controls the injector response. Injection of SW after PW will not always return injector to previous stateInjection of SW after PW will not always return injector to previous state

9. Conclusions Brief periods of gas injection between PW injection seems to maintain good injectivity (Success of WAG)Brief periods of gas injection between PW injection seems to maintain good injectivity (Success of WAG) The addition of AW to PW water seems to enhance the performanceThe addition of AW to PW water seems to enhance the performance –Quality –Temperature –Bacteria

10. Water Management PW vs. SW Water Mixing Temperature Gas Injection Back

11. Observations PEA 23 correlation using PBU experience contains proper parameters but requires expansionPEA 23 correlation using PBU experience contains proper parameters but requires expansion Particle count maybe a control parameterParticle count maybe a control parameter

12. Conclusion The effect of TSSW is better related to particle count (ppm) rather than mass concentration (mg/lit).The effect of TSSW is better related to particle count (ppm) rather than mass concentration (mg/lit). Most of the damage is caused by smaller particles (<5  m) yet these particles have a deceptively small combined mass.Most of the damage is caused by smaller particles (<5  m) yet these particles have a deceptively small combined mass. Further direct relation between particle size presence and injectivity loss can be seenFurther direct relation between particle size presence and injectivity loss can be seen

13. Water Treatment Particle Concentration Particle Size Back

14. Conclusion Example of good stimulation timingExample of good stimulation timing –Caught decline early. –Injection rate remains constant for a long period of time after the stimulation. –Watch for constant pressure limit, it may cause accelerated plugging of stationary fractures.

15. Conclusions Severe decline in injectivity if not treated leads to permanent damageSevere decline in injectivity if not treated leads to permanent damage Well stimulation may have no effect if no damage was perceived to warrant Acidizing.Well stimulation may have no effect if no damage was perceived to warrant Acidizing.

16. Q1 1997 All wells stimulated using the bullhead techniqueAll wells stimulated using the bullhead technique Effective HCl concentration of 15%Effective HCl concentration of 15%

17. Q2 1999 12 wells stimulated12 wells stimulated Treatment Method “On the Fly”Treatment Method “On the Fly” 1.5 to 2 % HCl acid (watch for Inj Rate).1.5 to 2 % HCl acid (watch for Inj Rate). As seen from previous graphs the effectiveness of both concentrations is about the same.As seen from previous graphs the effectiveness of both concentrations is about the same. Recommendation: it is not necessary to use High concentrated acid.Recommendation: it is not necessary to use High concentrated acid.

18. Horizontal vs. deviated Wells Deviated wells treated with HCl onlyDeviated wells treated with HCl only Horizontal wells treated with mixture of HCl and HAcHorizontal wells treated with mixture of HCl and HAc According to reports an improvement was seen in performance due to the addition of the HAc (placement, delay, buffering)According to reports an improvement was seen in performance due to the addition of the HAc (placement, delay, buffering)

19. Conclusions The trailing injectivity index is higher at first yet levels off with time. (P set)The trailing injectivity index is higher at first yet levels off with time. (P set) RII after acid stimulation seem to average 70% of its trailing RII average.RII after acid stimulation seem to average 70% of its trailing RII average.

20. Stimulation Timing Stimulation Types Back