Date post: | 17-Dec-2015 |
Category: |
Documents |
Upload: | ashlyn-morgan |
View: | 215 times |
Download: | 1 times |
Hydraulic Fracturing Best Management Practices
Environmentally Friendly Drilling Program
John Michael FernandezMatthew Gunter
Objectives of Presentation
• Introduce and describe hydraulic fracturing
• Present environmental concerns• Discuss best management practices
Major Shale Plays with Hydraulic Fracturing
• Bakkeno North Dakota,
Montana, Canadao Oil
• Barnetto Texas (DFW Area)o Natural Gas
• Eagle Fordo South Texaso Oil and Natural Gas
• Haynesvilleo Texas, Louisianao Natural Gas
• Marcelluso Pennsylvania, Ohio,
New York, West Virginia
o Natural Gas• Woodford
o Oklahomao Oil and Natural Gas
What is Hydraulic Fracturing?
• Hydraulic fracturing is a process used to stimulate wells in tight, shale reservoirs.
• Uses water, sand and chemicals to extend, prop open fractures to allow for the flow of oil and natural gas.
Hydraulic Fracturing Process
• Drill the wello Some only verticalo Some have horizontal lateral
• Case and Cement possible hazard areaso Pressure zoneso Ground Water Areas
• Perforate casing and cementing with Perforating Guno Begins fracture process in rock formation
• Pump fracturing fluid down holeo High pressured fluid extend fractures
• Production
Casing and Cementing
• Casing and cementing a wellbore is used to:o Protect groundwater from contaminationo Keep integrity of well-bore
• Casing is steel pipe that is designed to handle:o over- or under-pressured zones and o high tensile stresses down hole
• Casing is cemented in place to safely deliver hydrocarbons to the surface
Perforating the Formation
• Perforated using a “perf gun”o Perforating guns use explosive charges to
fracture:o Casingo Cementingo Formation
Fracturing Fluid
• 98-99.5% Water and Sand• The other 0.5-2%:
o Additives that enhance fracturingo Many additives are used to protect casing,
cementing, and well integrity• 3-7 million gallons of fluid used in typical
horizontal well
Proppant
• Sand pumped down hole is known as proppanto Keeps fractures “propped” open
• Comes in three major formso Untreated sando Resin-coated Sand
Coated for strength in harsh conditionso Ceramic
Artificial Proppant, very strong at high pressures Said to be in shortage, more using resin-coated sand
• Selected based on strength needed and size
Chemical Additives
• Common Additives include:o Acids, Biocides, Gelling Agents, pH Adjusting
Agents, Corrosion Inhibitors, Iron Control, Clay Stabilizer, Acid Inhibitor
o Other additives could be used depending on well characteristics
o Additives considered harmful are often found in household items
Environmental Concerns
• Chemical concernso Pumping chemicals near water tableo Failure in pits and liners could leak chemicals
• High water usage• Air Emissions from truck use• Surface Area used
EPA Study
• Looking into groundwater protection• Major areas of study include:
o Water acquisitiono Chemical Mixingo Well Injectiono Flowback and Produced Watero Wastewater treatment/disposal
Water Table Safety – Fracture Facts
• Fractures are necessary for hydrocarbons to flow from the tight shale formations
• Fractures are typically thousands of feet below water table
• They extend only hundreds of feet at most in any given direction
Hydraulic Fracturing BMPs
• “Green Frac” Program Ideao Chesapeake Energy
• Refracturing wellso Restimulation via fracturing again
• Closed-loop Fracturing Systemo Chief Oil and Gas one of many users
• Pad Drillingo Drills multiple wells from same pad site
• Centralized Fracturingo Fracturing multiple wells from central pad
Green Frac Program
• Program instituted by Chesapeake Energyo October 2009
• Researching additives to:o Find which are unnecessaryo Find which are necessary, but harmfulo Find more environmentally friendly
replacements for harmful additives• Specific findings are proprietary
information
Refracturing Wells
• Used to restimulate wells with production slowed
• Reduces surface area taken by taking away need for new well for oil and gas
• 85% of success found in 15% of total wells drilledo Not universally successful
• When successful, greatly increases production
Closed Loop Fracturing System
• Rather than using water only once and putting in large pits, the frac fluid is circulated and stored in large steel tanks
• Solids are removed from water using mechanical and chemical methods
• Compared to older methods, CLF is o Environmentally friendlyo Economically efficient
Environmentally Friendly CLF
• Takes away use of pits and linerso Pits and liners have been known to burst,
releasing chemicals onto surfaceo Stores in large, sturdy steel tanks
• Uses much less watero Water is reused throughout fracturing processo Reduces water usage by as much as 80%
• Reduces truck traffico Truck loads have been observed to reduce by up
to 75%o Reduces air emissions and traffic congestion
Economically Efficient
• Water usage is reduced• Truck mileage is also reduced• Companies who have drilled similar wells
using CLF have saved about $10,000 in overall expenses compared to conventional drilling
Pad Drilling
• Drills multiple wells from single pad site• Allows for centralized fracturing
o Fracturing from single location for multiple wells
• Reduces acreage necessary for wells• Reduces truck traffic for making pad site• Enhances closed loop systems
Centralized Fracturing
• Fracing multiple wells on a site from a single, central pado Fraced up to 140 wells from single siteo Fraced up to 3 miles away
• Significantly reduces truck traffic and time expendedo Truck traffic was reduced by up to 30% for a single
well, up to 90% for the site as a wholeo Time was reduced by up to 80% to drill, complete
the well• When used with closed loop and pad drilling,
saves even more truck traffic and water used