Produced Water | Session X - Steve Jester

2,423 views
2,337 views

Published on

Evaluation of Produced Water Reuse for Hydraulic Fracturing
In Eagle Ford

Published in: Education
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
2,423
On SlideShare
0
From Embeds
0
Number of Embeds
3
Actions
Shares
0
Downloads
28
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Produced Water | Session X - Steve Jester

  1. 1. Evaluation of Produced Water Reuse for Hydraulic Fracturing In Eagle Ford Atlantic Council Produced Water Workshop June 24-25, 2013 Steve Jester, Sr. Principal Environmental Engineer Lower 48 HSE, Houston, TX Kevin Bjornen, Drilling and Completion Fluid Specialist, Production Technology, Bartlesville, OK Ramesh Sharma, Staff Process Engineer, Process and Facility Engineering, Houston, TX
  2. 2. ConocoPhillips’ Corporate Water Sustainability Position: As a responsible global energy company committed to sustainable development, we recognize that fresh water is an essential natural resource for communities, businesses, and ecosystems. Global population growth will increase demand for fresh water and all users – domestic, agriculture, and industry – will need to effectively manage supplies to meet demands. ConocoPhillips produces and utilizes water in its operations. We are committed to the development of water management practices that conserve and protect fresh water resources and enhance the efficiency of water utilization at our facilities. We will assess, measure, and monitor our fresh water usage and based on these assessments we will manage our consumption and strive to reduce the potential impact to the environment from wastewater disposal.
  3. 3. What is “Freshwater” Texas Bureau of Economic Geology (BEG) U.S. Geological Survey (USGS)
  4. 4. Fresh Water Utilization BEG / API
  5. 5. Eagle Ford – 16 Counties in TX- Water Demand Comparison 2008 Water Use Survey Summary Estimates Eagle Ford Counties Livestock 4% Drilling & Completions 5.5-6.7% Irrigation 64% Steam Electric 5% Mining 3% Manufacturing 1% Municipal 17% 540,000 Ac-Ft Total 347,000 ac-ft 29,700 - 36,000 ac-ft Source: TX Water Development Board (http://www.twdb.state.tx.us/wrpi/wus/2008est/2008wus.asp)
  6. 6. Why Look at Produced Water Reuse? – Key Drivers Part of an overall water management strategy Implementing our company position- how can we use less fresh water? Optimize our process Alternative Sources:  Brackish/saline water  Municipal wastewater  Produced water?  Where other water sources are scarce or expensive  Where ample volumes of PW are available and easy to treat and transport for reuse Alternative process?
  7. 7. Challenges Using Alternative Water Sources for Hydraulic Fracturing Transportation and gathering of water (logistics/traffic/envir.) Treatment of water (cost/lifecycle environmental impact) Storage of nonfresh water (bacteria/corrosion/environmental) Blending of water from different sources (produced/fresh) Consistent and predictable fracturing fluid performance (pre-testing & consistent stream) Impacts on reservoir and fracture conductivity (rock-fluid interaction & pack damage) Impacts on short & long term field production (emulsion, scaling, corrosion) Consistent and predictable fracturing fluid performance
  8. 8. When Does Using Challenged Water Sources Make Sense? Drivers for Produced or Alternative Water Source High Low High quality source water availability Produced Water Quality & Availability Low High Transportation & Logistics Adds cost Reduces cost Compatibility w/ frac chemistry Low High Compatibility w/ reservoir HighLow SWEET SPOT Landowner Agreements, Regulatory Considerations
  9. 9. Produced Water Quality Variability is the key term  Individual well  Well to well  Field to field  Region to region Produced water typically has a much higher  Total Dissolved Solids (TDS)  Suspended Solids  Iron  Hardness/Scaling potential  Boron  Oil residue and organic matter
  10. 10. pH Ferric iron (Fe+3) Ferrous iron (Fe+2) Total hardness Magnesium (Mg+2) Calcium (Ca+2) Specific gravity Chlorides (Cl-) Carbonate (CO3-2) Bicarbonate (HCO-3) Sulfate (SO4-2) Phosphate (PO4-3) Silica (SI+4) Boron (B+3) Total dissolved solids (TDS) Total suspended solids (TSS) Bacteria Water Quality Impacts on Fracturing Fluids Total Fe >25 ppm Impacts hydration and thermal stability of polymer. Dilute or dump. Cl- New CMC systems are intolerant Interferes with buffers in crosslink systems. Some friction reducers are prone to precipitation. SO4 -2 >200 ppm Interferes with delayed metallic crosslinkers. High temperature thermal stability also impacted. Precipitate out. HCO3 -1 >600 ppm Requires pH adjustment for polymer hydration. Impacts Zr crosslinkers (delay and/or stability) SI-4 Interferes metallic crosslinkers. PO4 -3 ties of metallic crosslinkers. Reduces fluid performance. Too High > 9.0 poor hydration. Too Low < 6.0 poor dispersion. Degradation of Organic Polymers Even after the bacteria have been killed their enzymes are still problematic B >4 ppm can cause crosslinking in guar gelling agents. Typical ionic species identified and quantified in source water analysis. Nearly every produced water will push these limits
  11. 11. Initiatives At ConocoPhillips – Where can we reuse Produced Water? West Texas  Produced water primarily  Modest water treatment  Low temperature reservoirs (<200 F)  Use of large portable storage tanks  Feasible w/ scarcity of fresh water in region Bakken  Challenging brine (High TDS and scaling species)  Blending with fresh water investigated  Challenges with high performance fracturing fluids (>225 F)  High temperature reservoir  Scaling potential in water Eagle Ford  Produced water volumes are low (20-30 bbl/day/well)  Blending with fresh water investigated  Challenges with high performance fracturing fluids (>270 F)  High temperature reservoir  Scaling potential in water
  12. 12. Fluid Package Compatibility w/ Produced Water Slick water and linear gels  Salt and hardness tolerant polymers are readily available  Possible pH adjustment for hydration  Verify compatibility from polymer identification and testing Guar borate systems  Generally adaptable to a variety of water conditions  Desirable characteristics (early viscosity, shear recovery) proppant placement  Requires high pH (8.5 to +12)  Low temperature (8.5 – 10.0)  High temperatures requires higher pH (10 – 12+)  Limited performance above 300 F Metallic crosslink system  More potential issues with challenging waters  Flexible pH (4 – 11)  Must be properly delayed (shear degrading)  Balancing delay and early crosslinking/viscosity is difficult Completion service industry  Existing crosslinked packages developed for fresh water  Adapting fluids to more challenging conditions  Need to develop packages specifically for challenged water
  13. 13. ConocoPhillips High Performance Fracturing Fluid Requirements Temperature testing (seasonally adjusted)  Hydration (70 – 80 F)  Wellbore transport (worst case no heat added)  Fast temperature ramp (10 – 20 minutes to BHST)  Stability for duration of pump time (practical limits) Shear testing  Rheometer geometry (R1B5 or R1B5X)  Shear History (representative shear for residence time)  Fracture Shear (100 s-1) Ideal viscosity  Slightly building apparent viscosity during high shear period  ~100 cp apparent viscosity when entering 100 s-1 period  Quick ramp to viscosity peak without thermal thinning period  >200 cp apparent viscosity for duration of pump time Ideal Viscosity Response (High Performance Fluid) 0 200 400 600 800 1000 0:00 0:30 1:00 1:30 2:00 Time (HH:MM) ApparentViscosity(cp)andShear Rate(1/s) 50 100 150 200 250 300 Temperature(degF) Shear Rate Apparent Viscosity Fluid Temperature High Shear Period Early Time Viscosity (Wellbore) Thermal Stability for Pump Time Ideal Viscosity Response (High Performance Fluid) 0 200 400 600 800 1000 0:00 0:30 1:00 1:30 2:00 Time (HH:MM) ApparentViscosity(cp)andShear Rate(1/s) 50 100 150 200 250 300 Temperature(degF) Shear Rate Apparent Viscosity Fluid Temperature High Shear Period Early Time Viscosity (Wellbore) Thermal Stability for Pump Time Ideal Viscosity Response (High Performance Fluid) 0 100 200 300 400 500 0:00 0:06 0:12 0:18 0:24 0:30 Time (HH:MM) ApparentViscosity(cp)andShear Rate(1/s) 50 100 150 200 250 300 Temperature(degF) Shear Rate Apparent Viscosity Fluid Temperature Slight Viscosity Build During High Shear 100 cp Coming Out of High Shear and No Thermal Thinning Ideal Viscosity Response (High Performance Fluid) 0 200 400 600 800 1000 0:00 0:30 1:00 1:30 2:00 Time (HH:MM) ApparentViscosity(cp)andShear Rate(1/s) 50 100 150 200 250 300 Temperature(degF) Shear Rate Apparent Viscosity Fluid Temperature Thermal Stability for Pump Time
  14. 14. Eagle Ford Produced Water - Fracturing Fluid Testing Borate systems employed: Adaptable systems Service Companies adapted formulations  Similar performance  Some cost Increase possible Challenges for fluids  Naturally occurring boron in water (require low pH during gel hydration, early crosslinking)  High temperature challenge +270 F (requires high pH for borates)  Enough hardness in water – immediate precipitation possible  CaCO3  Mg(OH)2 Viscosity Profiles with 70:30 Source:Produced Water Mix 0 200 400 600 800 1000 0:00 0:30 1:00 1:30 2:00 Time (HH:MM) ApparentViscosity(cp),ShearRate(s-1) 50 110 170 230 290 350 Temperature(degF) Viscosity - 70:30 Mix Shear Rate - 70-30 Mix Temp Thermal Stability for Pump Time Early Viscosity & Some Thermal Thinning
  15. 15. Challenges with High pH Guar Borate Systems – Eagle Ford High pH to achieve borate cross-linking drives CaCO3, and Mg(OH)2 scale formation  No blending  7000 lb solids with P95 fresh water  3000 lb solids with P50 fresh water  90/10 Fresh Water/Produced Water blend  9800 lb solids P95 fresh water case  4900 lb solids P50 fresh water case 250,000 lb of proppant used per stage Impact of calcite solids and other scaling solids on proppant conductivity not well understood  Do the these solids flow back due to small micron size? Calcite solids
  16. 16. Six Inch Pipe – 6 months of operation
  17. 17. Well Prep Frac Operation Plug Mill Out Tubing Installation Well TestingProduction ~80-90 K bbls of water per job Typical Completion Activities – Eagle Ford 95% + water use Other 5% of water used currently matches produced water volumes where fluids would typically be Slickwater and Linear Gel systems employed in routine well work. Produced water a realistic option here.
  18. 18. Our Approach: Minimal Treatment. Blend PW with Source Water Goal: TSS and Oil and grease reduction < 1/bbl treatment cost Easy operation, smaller foot-print, mobile units available (15 bbl/minute) Polishing filter TSS < 20 mg/L pH = 7.5-8.0 TSS ~ 100 mg/L pH = 7.5-8.0
  19. 19. Summary of Eagle Ford PW Reuse Challenges Small % well work can be done with filtered produced water Blending (90/10) source water/produced water for hydraulic fracturing fluid preparation is possible  Pre-mature cross linking of high boron content is an issue  Higher concentration blends possible where slick water is used  Consistent water quality is important Immediate scaling is an issue with typical source waters with borate systems and is magnified with produced water blends.  Significant small fines will be pumped into fracture system  Potential negative impact on fracture conductivity?  Also true in other high temperature plays where pH needs to by high (+10) Need to develop frac packages specifically for challenged waters Issues around flow assurance, logistics, and sub-surface rock- water interactions need to be resolved for challenged water sources
  20. 20. Conclusions Produced Water Reuse is One Option – Subset of Overall Water Management Strategy  Optimize Process – 45% reduction  Alternative Source – Brackish water 60%  PW Reuse - challenging Reuse of Produced Water – Depends on complex evaluation of Compatibility, Logistics, Reliability, Cost, Environmental Considerations Reducing Freshwater Use has been better accomplished via other alternatives No Single industry-wide “Fit for Purpose” Solution
  21. 21. Questions?
  22. 22. Backup Slides
  23. 23. Water Quality Data Gathering Well Produced water Saline water (Carrizo) Fresh Water (Gulf Coast) Calcium, mg/L 690-2600 10 90.7 (42.2) Magnesium, mg/L 54-210 Not available 17.7 (10.8) Boron, mg/L 54-130 < 1 < 1 TDS, mg/L 17000-36000 1200-1600 1722 (763) Bicarbonate, mg/L 330-1400 720-950 480 (252) Iron, mg/L 4-98 <8 <8 Sulfate, mg/L 18-160 30 385 (157) • PW sampling in Jan/Feb 2012 • Carrizo data is based on limited sampling • 95th percentile (median) values shown for fresh water
  24. 24. Impact of Water Quality: Scaling Tendency SI >0 means precipitation can happen SI >2.5 scale inhibitor dosage increases significantly SI>3 scale inhibitor will not be effective All water sources are saturated with respect to calcite 0 0.5 1 1.5 2 2.5 3 3.5 100% Carrizo 100% Fresh water P95 100% Fresh water P50 100% PW P75 CalciteSaturationIndex 0 100 200 300 400 500 600 700 800 Calciteconcentration,mg/L Surface PT Bottom-hole PT concentration, mg/L

×