Fracking Process: Drilling
The drilling process for a fracking well installation consists of drilling a surface hole, introduction of surface casing and cementing, vertical and horizontal drilling, and introduction of production casing. These and other findings are outlined below and encoded in Sheet 3, column A, row 27 of the attached spreadsheet.
Fracking Well Drilling Process
- Drilling begins after the rig site for the well fracking installation has been completed.
- Drilling rigs are brought to the location and assembled (around 20-30 truckloads) to begin the process.
- First, a surface hole is drilled 100 feet below the deepest known fresh water aquifer.
- The drill is then pulled back along with any accompanying loose rocks and sediment (known as drilling muds) which are then disposed of.
- Next, surface casing is introduced to the bore hole to protect freshwater aquifers.
- The casing acts as a physical barrier between further drilling materials and the aquifer.
- Cement is pumped through the casing all the way to the opening at the bottom to seal the wellbore from the freshwater supply.
- API.org reports that modern day casing have redundant layers of cemented steel piping (see graphic below).
- An average gas well casing has 3 million pounds of steel and cement.
- Drillers are required to monitor the pressure in the well to safeguard the integrity of the casing seals.
- The drilling process can also be redirected into horizontal drilling.
- According to CRED.org, horizontal drilling is the best way to minimize land disturbance from a well fracking installation as it uses only one drill pad for multiple wells instead of different pads for each.
- Horizontal drilling also represented 83% of total linear footage drilled.
Fracking Process: After Production
Flaring as part of the after-production process of well fracking involves controlled combustion of natural gas. Installation of wellheads and use of condensate storage tanks are also part of the after-production process. These and other findings are outlined below and encoded in Sheet 3, column A, rows 41 to 43 of the attached spreadsheet.
- As fracking fluid is removed from the well, gas travels with it upwards the pipe as well.
- Due to limited space, the amount of gas increases as the amount of water decreases.
- Flaring is done to ensure this gas is safely controlled and burned.
- The US Department of Energy defines natural gas flaring "the controlled combustion of natural gas for operational, safety, or economic reasons."
- Flaring for operational reasons include diversion of gas influx during drilling, well testing, and well completion.
- Fracking wells may also be flared due to system upsets, maintenance routines, or an emergency for pressure release.
- Lastly, fracking wells may be flared to dispose of waste gas from routine operations.
- Stanford shows a basic diagram of a flare stack used by an industrial plant.
- This diagram shows an inlet flow to release pressure and pilot flame for ignition at the top of the stack.
- A knockout drum and flashback seal drum is also readied for added protection and control.
- Natural gas may also be diverted without the use of flame through venting.
Installation of Wellheads
Impoundment / Use of Storage Tanks
- FracTracker states that once natural gas and oil as well as flowback fluid are obtained, these are pumped or impounded into closed storage tanks.
- These storage tanks are designed to hold natural gas liquids (NGL) or condensate after flaring and flowback have been completed.
- Wireless sensors and telemetry devices may also be integrated to monitor pressure on storage tanks.
- Condensate and brine storage tanks are used to contain materials that will quickly and absolutely vaporize at normal atmospheric pressure and temperature.
- API.org adds that storage tanks are equipped with secondary containment devices and barriers to prevent any possible runoff.
Fracking Process: Waste Disposal
Fracking waste can be disposed of or managed through use of pits, tanks, land application, and other methods including offsite landfills, treatment facilities, and recycling. These and other findings are outlined below and encoded in Sheet 3, column A, row 53 to 58 of the attached spreadsheet.
- FracTracker enumerates the types of waste products from a well fracking operation.
- These include liquid waste such as brine and flowback as well as semi-solids including sludge and tank bottom material.
- Concentrates of Technologically Enhanced Naturally Occurring Radioactive Material (TENORM) including filter cake, filter socks and media must also be disposed.
- Finally, solid waste including drill cuttings must be safely disposed.
Waste Management Methods
Fracking Well Costs
Drilling operations and equipment in a well fracking installation comprises 15% of total costs while well casing and cementing make up 11% of total costs. These and other findings are outlined below and encoded in Sheet 1, column B, rows 16-20 of the attached spreadsheet.
Average Cost Breakdown
- Drilling makes up 15% of total costs including rig, drilling fluids, and other expenses in the entire drilling activity.
- Well casing & cementing make up 11% of total costs as relevant to casing design according to well conditions as well as cost of material.
- Hydraulic fracturing make up the largest costs at 24% of total expenses and includes cost of fracturing pump and equipment as well as horsepower for fracturing.
- Proppant makes up 14% of total cost and includes the amount and rates for introducing the material into the well.
- Completion fluids including flow back make up 12% of total costs and includes sourcing and disposal of water and other materials used in the hydraulic fracturing.
- Other costs make up 23% of total expenses depending on each well case.
- The EIA report notes that rig drilling costs are dependent on efficiency, well depth, day rates, use of mud and diesel fuel prices.
- Rig costs can range from $0.9 million to $1.3 million and comprise 12% up to 19% of a well fracking operation's total cost.
- Casing costs are impacted by casing and steel process, well dimension, and pressure that affect casing strings.
- Costs of casing can range from $0.6 million to $1.2 million and comprise 9% up to 15% of a well fracking operation's total cost.
- Frack pumping costs are determined by the horsepower needed as well as the number of fracking stages.
- Costs of frack pumping range from $1 million to $2 million and comprise 14% up to 41% of a well fracking operation's total cost.
- Completion fluid costs are dependent on water amount, chemicals required, and frack fluid types.
- Costs of completion fluid range from $0.3 million to $1.2 million and comprise 5% up to 19% of a well fracking operation's total cost.
- Proppant expenses are driven by market rates as well as the total amount needed for an operation.
- Costs of proppant can range from $0.8 million to $1.8 million and comprise 6% up to 25% of a well fracking operation's total cost.
From Part 01
- "Directional Drilling
1. The process begins by drilling to the bottom of a fresh water aquifer"
- "2. The drill is then retracted and pulls the loose rocks and sediment to the surface to be discarded (i.e., drilling muds)."
- "3. Surface casing (steel piping) is inserted into the bore hole to protect freshwater aquifers by creating a physical barrier between the aquifer and drilling materials. This casing also serves as a foundation for the blowout preventer – a safety device that connects the rig to the wellbore. Cement is then pumped through the casing and out through the opening at the bottom of the casing."
- "4. Drilling continues vertically, creating a well approximately 6,000 feet (~1,828 m) deep. The depth of the well will vary by region and formation. In the Marcellus Shale the well is then drilled horizontally an average of 10,000 more feet (~3,048 meters)."
- "5. When the target length is achieved, “production casing” is inserted throughout the length of the wellbore."
- "6. The drilling process is now complete and well stimulation can begin."
- "The Drilling Process"
- "As the well is drilled deeper, additional casing is installed to isolate the formation(s) from which oil or natural gas is to be produced, further protecting groundwater from the producing formations in the well. Numerous protective measures are in place at well sites, including liners under well pads, rubber composite mats under rigs, storage tanks with secondary containment measures, and barriers to control any potential runoff."
- "STEP 2: DRILLING
First the drill rig is brought to the location—maybe 20 or 30 truck loads—and put together. Now It’s time to build the infrastructure necessary to unlock the oil and natural gas trapped more than a mile below the ground."
- "Stage 1: Water Acquisition
The withdrawal of groundwater or surface water to make hydraulic fracturing fluids."
- "Stage 2: Chemical Mixing
The mixing of a base fluid, proppant, and additives at the well site to create hydraulic fracturing fluids."
- "Stage 3: Well Injection
The injection and movement of hydraulic fracturing fluids through the oil and gas production well and in the targeted rock formation."
- "Stage 4: Produced Water Handling
The on-site collection and handling of water that returns to the surface after hydraulic fracturing and the transportation of that water for disposal or reuse."
- "Stage 5: Wastewater Disposal and Reuse
The disposal and reuse of hydraulic fracturing wastewater."
- "In 2016, hydraulically fractured horizontal wells accounted for 69% of all oil and natural gas wells drilled in the United States and 83% of the total linear footage drilled. "
From Part 02
- "1. Flaring for Operational and Safety Reasons
• Diversion and disposal of gas influx (kick) during drilling."
- "2. Flaring for Economic Reasons
(Figure 3 and Figure 4)
• Associated gas produced with crude oil (also called casinghead gas) that has a ready market, but where the gathering, compression, and sales infrastructure for the gas is under construction but not yet operable, and where economic factors require early oil production in advance of natural gas capture."
- "• Associated gas produced with crude oil that has a ready market, but where construction and installation of a gathering, compression, and sales infrastructure for the gas is not economic, or where the required expansion of the existing system is not economic."
From Part 03
- "4. Waste Management
Wastes that are generated over the course of E&P operations must be managed prior to disposal or reuse. "
- "4.1 Pits
4.1.1 Reserve Pits
4.1.2 Production Pits
4.1.3. Other Pits"
- "4.2 Tanks
4.2.1. Closed-Loop Drilling
4.2.2 Production Tanks
4.2.3. Modular Large Volume Tanks"
- "4.3 Land Application
4.4 Other Offsite Disposal
4.4.2 Other Treatment and Disposal Facilities"