April 6, 2011 l 1 

### Hydraulic Fracturing Fluid Considerations in Marcellus Shale Completions EPA Hydraulic Fracturing Tech Workshop

Feb 24-25, 2011 Dennis Degner Director of CompletionsApril 6, 2011 l 2 

### Agenda  Introduction  Additives used in Marcellus Shale fracturing  Why we use these additives  Testing performed  Where do we go from hereApril 6, 2011 l 3 

### Introduction  Hydraulic fracturing is key to shale development – Fracturing creates a small conductive flow path for hydrocarbon to flow from low permeability reservoirs – “Slickwater” style design most commonly used in Marcellus as well as other shale reservoirs • Slickwater design consists of water, proppant (sand) and small amounts of additives for placement and water management  Additives used – Friction Reducer – Biocide – Scale inhibitor  Why do we use these additives in Marcellus fracturing?April 6, 2011 l 4 

### Friction Reducer  A key to shale fracturing is pumping fluid at high rates – High rate helps to transport proppant (usually sand) – Creates a fracture network  To reach required pump rates friction reducer is added reducing pressure at surface  What is friction reducer? – Polyacrylomide polymer – Comes in dry powder and liquid form with mineral oil base – Also used for soil stabilization and some children’s toys  Friction reducer selection impacted by: – Chemistry of source water for fracturing – High salinity vs. fresh water = different productsApril 6, 2011 l 5 

### Friction Reducer - flow loop test dataApril 6, 2011 l 6  Various water sources are used for Marcellus fracturing – Ground water – Surface water – Produced water  Pre-job water testing is conducted to assess preexisting bacteria present  Test involves inoculating specific media in a serial dilution bottle with 1 ml of frac source water  Change in bottle color directly relates to bacteria count  Results guide additive concentrations used during fracturing 

### BiocideApril 6, 2011 l 7 

### Biocide  What are some impacts of untreated bacteria? – Microbiological influenced corrosion – Formation souring (creation of H 2S in the formation) – Microbial growth downhole restricting production  How do we control bacteria? – Add an organic biocide to sterilize the fluid – Glutaralehyde/quaternary ammonium blend – Added at low concentrations (± 0.5 gal/Mgal) – Post fracturing testing conducted over life of a well – Results used for biocide optimization  Similar approach seen in medical equipment sterilization and hand sanitationApril 6, 2011 l 8 

### Scale Inhibitor  Due to minerals in the source water scale can form  What are some ways scale can form? – Pressure drop – Temperature changes – Mixing of different waters – Agitation  To prevent scale from forming a solvent based scale inhibitor is added to the fracturing water  Added at low concentrations (± 0.1 gal/Mgal )  Similar additives used in municipal water treatment, deicing agents and household cleanersApril 6, 2011 l 9 

### Scale Inhibitor  Common scale that could form in Marcellus Shale wells – Barium Sulfate (BaSO4) – Calcium Carbonate (CaCO3)  Scale is difficult and expensive to remove – Can require remedial large volume chemical treatment – In certain cases mechanical removal is required  Water testing can determine scale tendency  Test results drive additive plan  Produced water dissolves small amounts of minerals from the shale – As a result scale inhibitor becomes more importantApril 6, 2011 l 10 

### Where do we go from here?  Continue additive advancement with service provider and University partnerships with focus on salt water reuse (recycling)  Develop fluid systems in line with 12 principles of Green Chemistry  We share chemical best practices with: – Industry – State agencies – Trade groups  Keep volume used low – < 1% of job volume  Transparent operationsApril 6, 2011 l 11



## Thank You 

# Questions? EPA Hydraulic Fracturing Tech Workshop

Feb 24-25, 2011 Dennis Degner Director of Completions