Paul Ziemkiewicz, PhD, Director WVU Water Research Institute NORM Workshop Columbus OH 12 May 14 SHALE GAS: RADIOACTIVITY IN SOLID AND LIQUID WASTES

Transcription

1 Paul Ziemkiewicz, PhD, Director WVU Water Research Institute NORM Workshop Columbus OH 12 May 14 SHALE GAS: RADIOACTIVITY IN SOLID AND LIQUID WASTES

2 THREE STUDIES WERE COMMISSIONED BY THE WV LEGISLATURE IN 2011 Characterization of water and waste Lead: Paul Ziemkiewicz, PhD, Water Research Institute, WVU Air, light and noise pollution Lead: Michael McCawley, PhD, School of Public Health Competency of pits and impoundments Lead: John Quaranta, PhD, PE, Dept. of Civil and Environmental Engineering

3 TASKS Characterize shale gas wastes flowback/produced water drill cuttings/mud Identify exposure pathways production casing migration to surface/shallow groundwater spills pit leakage How to control exposure

4 RISK For water it is assumed that the primary human exposure pathway is via contamination of domestic water supplies For that reason, we focussed on exceedances of either primary or secondary drinking water standards That may be a reasonable approach for liquid wastes but solid wastes have very different radioactivity criteria and standards

5 TERMINOLOGY: LIQUIDS Makeup water-impoundments/tanks fresh water waste water Hydraulic fracturing fluid-frac fluid ~ 100, 000 to 120,000 bbl injected Makeup water + Proprietary mixture of chemicals Proppant Flowback-produced water Fluids returned from the well after frac ~70-90% lost in formation Recycle Flowback-produced water used for makeup

6 Frac additives Surface ~0.5% Frac fluid Well completion water cycle Fresh water ~99.5% Makeup water Recycle ~80% Wellhead End of life cycle ~20% Disposal, treatment, discharge Flowback 10-30% return Produced water Downhole

7 TERMINOLOGY: SOLID WASTES Drilling mud Returns to the surface with cuttings during drilling Recycled after cuttings removed To disposal after well completed Drill cuttings Rock fragments-clay to fine gravel ~ tons/well or 25 to 50 truckloads To disposal after separation from drilling mud Flowback Solids-filter cake, precipitates, suspended solids

8 Cuttings pit SOLIDS AT THE WELL SITE Flowback pit Flowback tank Bag filters Plate and frame filter press

9 DRILLING MUD DRILL CUTTINGS

10 FLOWBACK SOLIDS ARE MORE RADIOACTIVE THAN VERTICAL DRILLING MUDS/CUTTINGS: BUT IS THE DIFFERENCE SIGNIFICANT? Vertical only Marcellus Drilling mud solid samples Flowback solids Solids units average Donna C pit Gross Alpha pci/g Gross Beta pci/g Potassium 40 pci/g Radium 226 pci/g Radium 228 pci/g Thorium 228 pci/g Thorium 230 pci/g Thorium 232 pci/g Uranium 234 pci/g Uranium 235 pci/g Uranium 238 pci/g Alpha + beta pci/g gamma pci/g Total pci/g

11 LIQUID FRACTION: DRILL CUTTINGS % SAMPLES > TCLP LIMIT Drill Cuttings: Vertical Section Drill %> Cuttings TCLP min max Cr 100% mg/l As 90% mg/l Pb 80% mg/l Ba 70% ,870.0 mg/l Benzene 70% µg/l Se 40% mg/l Hg 10% mg/l

12 LIQUID FRACTION: DRILLING MUD % SAMPLES > 1 O DWS Drilling Mud: Vertical Section Drilling %> Muds 1 DWS min max Ba 100% mg/l Cr 100% mg/l Nitrate 75% mg/l Pb 75% mg/l Nitrite 50% mg/l As 50% mg/l Hg 25% mg/l MBAS 50% mg/l Toluene 50% µg/l Benzene 25% µg/l Ethylbenze 25% µg/l Xylene (o) 25% µg/l Xylene (m,p) 25% µg/l

13 RADIOACTIVITY IN FLOWBACK

14 EXPOSURE: DRILL SITE SAMPLES RELATIVE TO BACKGROUND

15 SUMMARY: FLOWBACK

16 KEY FINDINGS Flowback constitutes the greatest risk volume transportation hazardous parameters Flowback concentrations higher than HF fluid Organics Inorganics NORMS No evidence of leakage at the impoundments Solid wastes: pit residues and drilling muds/cuttings were all severely contaminated

17 FURTHER STUDY: Assess the human and environmental risk of solid waste disposal options Identify testing protocols and hazard ratings Include Radioactivity Organic contaminants Inorganic contaminants With appropriate human exposure expertise in each area

18 FURTHER STUDY-SOLID WASTES Characterize NORMS in: Spent drilling mud Drill cuttings Flowback precipitates/filter cakes By formation-horizontal vs. vertical? Special handling as dictated by exposure risk

19 FOR MORE INFORMATION PLEASE CONTACT: Paul Ziemkiewicz, Director West Virginia Water Research Institute