Hydraulic Fracturing Terms and Definitions

Hydraulic fracturing is the process of using fluid, sand, chemicals, and gels to create or exploit small fractures in a sub-surface rock layer formations in order to stimulate production from oil and gas wells. This fracturing creates paths and reservoirs which increase the rate at which fluids can be taken from the wells. In some cases, this process can increase production by many hundreds of percent.

Below are common terms and definitions* used in the hydraulic fracturing process:

• Additive Pumps – used to inject liquid additives; different types based on the additive type and additive rate.
• Annulus – Area between two concentric casing strings or tubular strings.
• Bottom Hole Treating Pressure (psi) – pressure being applied to the formation including net pressure.
• Centrifugal Pumps – used on the low pressure equipment to mix and move fluid.
• Clean Volume (gal or bbl) – volume of fluid pumped without proppant.
• Dirty Volume (gal or bbl) – volume of fluid pumped with proppant.
• Flowmeter – used to measure and transmit fluid flow rates; different types depending on application.
• Frac Gradient (psi/ft) – pressure at which fluid will cause the formation rock to part.
• High Pressure Pumps – Positive displacement pumps used for pumping downhole.
• Hydraulic Horsepower (hhp) – horsepower being applied to the formation while pumping .
• Hydrostatic Pressure (psi) – pressure the fluid column exerts on the formation.
• Instantaneous Shut-in Pressure (psi) – a pressure used to calibrate the frac gradient.
• Kick-outs – mechanical or electrical devices that activate at a preset pressure to disengage high pressure pumps.
• Liquid Additive (gal/Mgal) – any liquid chemical added to the fluid system for a specific purpose
• Max Pressure (psi) – the maximum WHTP that will be allowed.
• Net Pressure (psi) – excess pressure over frac pressure required to extend the fracture .
• Perf Friction Pressure (psi) – pressure drop across the perforations.
• Pipe Friction Pressure (psi) – friction pressure of the fluid being pumped down the wellbore.
• Pop-off – a mechanical device activates at a preset pressure to prevent damage to surface and downhole tubular.
• Pressure Transducer – device used to measure and transmit pressure data.
• Proppant – small diameter material used to keep the fracture open.
• Proppant Concentration (lb/gal) – the amount of proppant added to one gal of fluid.
• Shut-in Pressure (psi) – a pressure used to calibrate the frac gradient.
• Solid Additive (lb/Mgal) – a solid chemical added to the fluid system for a specific purpose.
• Treatment Rate (bpm) – the downhole rate that fluid is entering the formation pumping.
• Wellhead Treating Pressure (psi) – the surface pressure at the wellhead during.

Thompson Equipment (TECO) manufactures highly engineered flowmeters designed for optimum performance in fracing applications. Contact TECO to discuss any severe flow measurement application.

TECO

https://teco-inc.com

800-528-8997

* from EPA.gov workshop titled "Fracture Design and Stimulation – Monitoring" (DC01:570405.2)

Magnetic Flowmeters for Fracing

Fracing illustration (USGS)

Hydraulic fracturing, or fracing, is the process of exploiting small fissures or cracks in rock layers deep under the earths surface, and increasing their number and size for the purpose of freeing up trapped natural gas. The process includes drilling horizontally in the bedrock and then forcing "frac fluid" into those cracks under very high pressure. The fracturing fluid is made up of water, a special type of sand (referred to as the proppant) and a mixture of chemicals.

Flow measurement is very important in fracing and requires instrumentation with long life and high accuracy.  Frac fluid is a very nasty slurry and it's flow measurement is challenging. Flow instruments are exposed to high pressures, erosive materials and corrosive chemicals.

Frac sand is very erosive and the high pressure and corrosive chemicals complicate things exponentially. Any flowmeter used in fracing applications must not only be rugged enough to withstand these harsh conditions, but the flowmeter must also provide the accuracy required for reliable data reporting to supervisory agencies. Cost-effectively meeting accuracy and longevity requirements for these applications can be frustrating.

Magnetic flowmeters have always appealed to the fracing industry because of their unfettered flow path, availability of sizes and level of accuracy. Their downfall is their longevity. Standard, off-the-shelf magnetic flowmeters don't last in this environment and can't be considered an economically viable choice.

An excellent solution that provides all the the virtues of magnetic flowmeters, and overcomes the longevity and economics issues, are specialized magnetic flowmeters. Referred to as "severe service flowmeters" or "slurry flowmeters", they are designed with components matched specifically to withstand the mechanical and chemical abuse they will see.

Magnetic flowmeters, specialized for fracing, provide all of a "magmeters" desirable features with these critical enhancements:

1. A ceramic sleeved liner made of magnesia partially stabilized zirconia. This ceramic can handle the abrasion and chemical attack with very little degradation.
2. Highly polished, ultra-smooth Tungsten electrodes. The Tungsten provides outstanding wear resistance while the high-polish reduces electrical noise introduced in the electrode circuitry.
3. Special coatings, or paints, to provide exterior protection.

By specifying magnetic flowmeters, specialized for fracing, not only do operators save money through increased uptime and decreased health, safety and environmental risk, but also through reduced costs related to flowmeter purchase and repair.

For more information on fracing magnetic flowmeters, contact Thompson Equipment Company (TECO) by calling 800-528-8997 or visit https://teco-inc.com. 

World's First Magnetic Flowmeter Developed Specifically for Hydraulic Fracing

When suspended solids are mixed with a liquid (such as water), a mud-like substance referred to as a “slurry” is formed. Slurries are challenging because of their abrasive nature. Add a highly caustic or acidic condition to the slurry, and the magnetic flowmeters (Magmeters) used to measure flow become particularly susceptible to failure. In these situations off-the-shelf magnetic flowmeters won’t last, so consideration must be given to custom flowmeters built specifically to withstand the application’s unique requirements. Hydraulic fracturing (fracing) is one industry where the movement and handling of slurries is very common, and specially designed Magmeters should be used.

Thompson Equipment (TECO) is now offering their "Severe Application Meter (SAM)" (patent pending) which is specifically designed as the world's first Magmeter developed specifically for the hydraulic fracing industry. It is designed with an impact and wear resistant ceramic liner, solid tungsten carbide billet electrodes, and quick change Victaulic flanges. The SAM can also be retrofitted to the customers existing electronic secondary system, such as Rosemount, E+H, Yokagawa, etc.

For more information, contact TECO by calling (504) 833-6381 or by visiting https://www.teco-inc.com.