# Marcellus Shale - Gas Development



# and Water- Resource Issues

John Williams New York Water Science CenterTompkins County, NY



### High TOC and 

### elevated radioactivity in basal Marcellus Shale

Levanthal and others (1981)

### Uranium & Thorium to Radium & Radon Radioactive Decay Series

Radioisotope and half lifeDrill Core Sample Analysis

Lash and Engelder (2009) Gamma Log 

### High TOC and abundant pyrite in basal Marcellus ShaleTeff ( 2011)



### Horizontal wells target basal Marcellus Shale

### Directional rig for drilling

horizontal leg Top - set rig for drilling vertical 

### surface - cased interval

### Walking legs on directional drilling rig Wellheads of first two of six 

### horizontal wells ~15 ft

### Target horizon (Union Springs Shale) mapped

using offset well logs and seismic Logging -while - drilling used to steer lateral

within target beds Schlumberger (2010) Gamma Density• Elevated uranium and abundant pyrite in high -TOC black shale • Multi - horizontal well site will generate more than 500 times the volume of shale cuttings than single -vertical well site



## Drill Cuttings Core of target interval Drill cuttings

### Lined pit



### Mixed with sawdust Closed - loop system Offsite disposal in landfill 

## Drilling Fluids and CuttingsPapso and others (2010 ) Blauch (2010 ) Contains elevated TDS, chlorides , barium, and radioisotopes whose concentrations increase during the flowback period approaching formation brine 

## FlowbackWater quality of flowback (1.5 million gallons) from Marcellus shale well after completion of hydraulic

fracturing (Samples were taken at 1, 2, and 3 third intervals of the 2 -week flowback period, PADEP) 1,160 22 19,000 668 6,100 8,730 18,600 80,500 109,000 34,600 134,000 192,000

### Uranium & Thorium to Radium & Radon Radioactive Decay Series

Radioisotope and half life Brine from a Marcellus Shale - Gas Well

Gross Alpha 20,800 pCi/L Gross Beta 2,390 pCi/L Radium 226 10,200 pCi/L Radium 228 1,250 pCi/L Thorium 228 47.5 pCi/L Thorium 232 0.0 pCi/L Uranium 234 0.5 pCi/LReuse of frac water, onsite treatment for

solids / blend with 70 % freshwater Municipal wastewater treatment plants not designed to handle flowback chemistryHalliburton ( 2010)



## Microseismic Mapped Frac Tops and Bottoms Marcellus ShaleTrenton Salt Marcellus Utica Lockport Onondaga

Smith and Leone ( 2010) 

## Structure (folds and faults) Seismic survey250 600 223 3.8
0.18 1.12 0.0008 0.011 14 7 Water quality of water well impacted by Medina gas drilling

### Methane in Water Wells Marcellus/Utica Gas - Play Area

Osborn and others ( 2011) Sampling sitesFRESH WATER AQUIFER ZONE
SHALLOW PRODUCING ZONE INTERMEDIATE PRODUCING ZONE CONDUCTOR PIPE SURFACE CASING PRODUCTION CASING 

## Good Zonal Isolation

TARGET PRODUCING ZONE

## Poor Zonal Isolation PRESSURE BUILDS UP CONDUCTOR PIPE SURFACE CASING PRODUCTION CASING FRESH WATER AQUIFER ZONE
SHALLOW PRODUCING ZONE INTERMEDIATE PRODUCING ZONE TARGET PRODUCING ZONE CASING CEMENT

FORMATION

## Fractured Zones in Upper Devonian Bedrock

Pathways for methane and brine migration2,500 – 4,000 feet Characterization of deep freshwater and shallow gas and saltwater Engineered zonal isolation by casing, cement, packers, and venting 

## Protection of Freshwater AquiferF reshwater Transition Saltwater 

## Geophysical Logs and Base of Freshwater Aquifer