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Course 903 - Well Site Completion and Servicing Safety

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Safety guides and audits to make your job as a safety professional easier

Hydraulic Fracturing

well pad

Hydraulic fracturing or "fracking" is a process used to "stimulate" well production in the oil and gas industry. It is not a new process, but its use has increased significantly in the last 10 years because of new horizontal drilling and multi-stage fracking (or "completions") technologies that improve access to natural gas and oil deposits.

Fracking involves pumping large volumes of water and sand into a well at high pressure to break up or fracture shale and other tight formations, allowing oil and gas to flow into the well.

Hydraulic fracturing generally involves the following activities:

  • rig up
  • well and equipment testing
  • perforating
  • fracturing fluid blending and pumping
  • isolation
  • flowback

Rig Up

secured lines

Rig up is the transport and assembly of equipment and materials to perform hydraulic fracturing operations. Hydraulic fracturing operations require more equipment on the well pad than conventional well completion. Due to the additional equipment, walking and working surfaces become even more restricted.

Potential Hazards:

  • falling from heights
  • slips, trips and falls
  • struck-by moving vehicles, equipment and pressure; falling or dropped equipment; and flying particles
  • caught-in or between pinch points (such as hammer union wings and hammers, pump iron and racks)
  • fires and explosions
  • inhaling respirable crystalline silica (see OSHA-NIOSH's Hazard Alert)
  • inhaling diesel particulate
  • exposure to concentrated chemical additives
  • exposure to high noise levels
  • overexertion or receiving sprains and strains while handling materials (such as sacks and buckets)

Rig Up (Continued)

chem additive

Possible Solutions:

  • Preplan equipment locations and use a spotter to position equipment out of the fall lane of the derrick and upwind of vents, vapor sources and gas sources.
  • Conduct a pre-job inspection to identify and eliminate or correct hazardous work surfaces.
  • Use appropriate fall protection equipment.
  • Require all non-essential personnel to stand clear of the work zone.
  • Secure all elevated lines.
  • Use proper hand and body positioning.
  • Provide adequate bonding and grounding for blending, pumping and sand transfer equipment.
  • Use hose covers or shielding for transfer or suction lines containing flammable liquids to prevent them from being ruptured resulting in fires or explosions.
  • Cap unused fill ports (e.g., cam lock caps) on sand movers.
  • Reduce the drop height between the sand transfer belt and T-belts and blender hoppers.
  • Apply fresh water to roads and around the well site to reduce silica dust.
  • Enclose points where silica dust is released. Use local exhaust ventilation to collect silica-containing dusts and prevent dust escape. Install dust collection systems onto machines or equipment that release dust.
  • Where possible, use enclosed cabs or booths. Consider providing operator cabs and booths with HEPA filters and climate controls to protect workers from silica dust and environmental extremes.
  • Replace proppant transfer belts with screw augers.
  • Ensure that workers follow the safe handling procedures found in Safety Data Sheets.
  • Conduct personal protective equipment assessments and require employees to wear prescribed personal protective equipment (PPE) including respiratory and hearing protection.
  • Use mechanical lifting aids, proper lifting techniques and team lifting where appropriate.

Well and Equipment Testing

fracequipment

Before the actual process of hydraulic fracturing begins, well servicers conduct a pressure test on the system.

The pressure test is conducted by pumping fresh water, brine or drilling mud into the well to gradually increase the pressure. The pressure test involves the gradual increase of hydraulic pressure on the system. The final test pressure is above the maximum fracturing pressure, but below the lowest component failure pressure.

Potential Hazards:

  • struck-by high-pressure lines or unexpected release of pressure (for example, mismatched or excessively worn hammer unions and line leaks or line failure)
  • rotating equipment hazards
  • inhaling diesel particulate
  • exposure to high noise levels

Possible Solutions:

  • Fasten high-pressure lines together properly.
  • Use proper equipment inspection techniques that include hammer unions.
  • Require all non-essential personnel to stand clear.
  • Direct equipment operators to remain at their controls.
  • Use proper equipment guards and covers.
  • Wear proper PPE, such as respiratory, skin and hearing protection, as appropriate for the hazards present.

Perforating, Fracturing Fluid, Blending, and Pumping

blending and pumping

The fracturing job begins by perforating the well casing.

The process of perforating involves piercing the casing wall and cement of a wellbore to provide holes through which formation fluids may enter or to provide holes in the casing so that materials may be introduced into the annulus between the casing and the wall of the borehole. Perforating is accomplished by lowering into the well a perforating gun, or perforator.

After perforating the well casing, workers blend and pump fracturing fluid into the well through high pressure lines.

Fracturing fluid is made up of a base fluid, proppant (sand, or an alternative proppant), and chemical additives. The blender and pump trucks run simultaneously for several hours while workers monitor well pressure and fracture progression.

Let's take a look at the potential hazards and possible solutions when perforating, fracturing fluid, blending, and pumping in the next two tabs.

Perforating, Fracturing Fluid, Blending, and Pumping (Continued)

blender hopper

Potential Hazards:

  • slips, trips and falls
  • struck-by high-pressure lines or an unexpected release of pressure (for example, mismatched or excessively worn hammer unions and line leaks or line failure)
  • rotating and moving equipment hazards
  • fires, explosions and uncontrolled chemical reactions
  • inhaling respirable crystalline silica
  • inhaling diesel particulate
  • exposure to concentrated chemical additives
  • exposure to high noise levels
  • overexertion or suffering sprains and strains during material handling such as sacks and buckets

Perforating, Fracturing Fluid, Blending, and Pumping (Continued)

Possible Solutions:

  • Conduct a pre-job inspection to identify and eliminate or correct hazardous work surfaces.
  • Require all non-essential personnel to stand clear of the work zone.
  • Fasten high-pressure lines together properly.
  • Conduct adequate pressure tests on pump(s) and lines and ensure proper valve alignment before pumping. Install a check valve as close to the wellhead as possible.
  • Use proper equipment inspection techniques that include hammer unions.
  • Direct equipment operators to stay by their controls.
  • Use proper equipment guards and covers.
  • Provide adequate bonding and grounding for blending, pumping and sand transfer equipment.
  • Use hose covers or shielding for transfer or suction lines containing flammable liquids to prevent them from being ruptured resulting in fires or explosions.
  • Substitute less hazardous materials.
  • Require the capping of unused fill ports (e.g., cam lock caps) on sand movers.
  • Reduce the drop height between the sand transfer belt and T-belts and blender hoppers.
  • Apply fresh water to roads and around the well site to reduce silica dust.
  • Enclose points where silica dust is released. Use local exhaust ventilation to collect silica-containing dusts and prevent dust escape. Install dust collection systems onto machines or equipment that release dust.
  • Where possible, use enclosed cabs or booths. Consider providing operator cabs and booths with HEPA filters and climate controls to further protect workers.
  • Replace proppant transfer belts with screw augers on sand movers in new designs or retrofits.
  • Ensure that workers follow the safe handling procedures found in SDSs.
  • Use proper mixing procedures.
  • Wear appropriate PPE, including respirators and eye, face and hearing protection.
  • Provide an eyewash station and other appropriate flushing equipment as recommended by the SDS.
  • Use mechanical lifting aids, proper lifting techniques and team lifting where appropriate.

Isolation

frac tank

Once a stage is fully fractured, workers isolate it from the rest of the well by inserting a plug into the well. This requires wireline operations.

Flowback

After the entire well has been fractured, workers decrease the pressure at the wellhead and drill out the isolation plugs. A mixture of fracturing fluid and gas or oil flows back out of the well through flow lines into pits or tanks.

Drilling out the plugs will require wireline operations, snubbing, or coil tubing procedures. See Wireline Operations, Snubbing, and Coil Tubing for further information. We will cover those special processes later in the course.

Beam Pumping Units

beam pump

If the well doesn't produce adequately, a beam pumping unit may be installed.

A beam pumping unit is a machine designed specifically for sucker rod pumping used to lift fluid to the surface by the reciprocating action of the sucker rod string. An engine or motor (prime mover) is mounted on the unit to power a rotating crank. The crank moves a horizontal member (walking beam) up and down to produce reciprocating motion. This reciprocating motion operates the pump.

There are four basic types of beam pumping units. Three involve a walking beam, which seesaws to provide the up and down reciprocating motion to power the pump. The fourth reciprocates by winding a cable on and off a rotating drum. The job of all four types is to change the circular motion of an engine to the reciprocating motion of the pump.

The pump units are brought in disassembled on trucks and off-loaded onsite. The many parts of the pump unit include large heavy metal pieces that need to be assembled.

Possible Hazard:

  • being pinched, struck, or crushed by falling or swinging parts during assembly

Possible Solutions:

  • Ensure the work crew understands the assembly procedures and hazards involved in the tasks.
  • Wear appropriate PPE.

Video

Instructions

Before beginning this quiz, we highly recommend you review the module material. This quiz is designed to allow you to self-check your comprehension of the module content, but only focuses on key concepts and ideas.

Read each question carefully. Select the best answer, even if more than one answer seems possible. When done, click on the "Get Quiz Answers" button. If you do not answer all the questions, you will receive an error message.

Good luck!

1. Which method of well stimulation pumps fluid under high pressure through the well casing to break up rock formations?

2. The hazards encountered on a hydraulic fracturing site while performing Rig Up include all of the following, except, _____.

3. The process of _____ involves piercing the casing wall and cement of a wellbore to provide holes through which formation fluids may enter.

4. The hazards encountered on a hydraulic fracturing site while conducting pressure tests include all of the following, except _____.

5. After the entire well has been fractured, workers _____ and drill out the isolation plugs.


Have a great day!

Important! You will receive an "error" message unless all questions are answered.