Boron in Oil and Gas Production

ADDRESSING TECHNICAL CHALLENGES

Oil has been a dominant energy source for more than five decades and is likely to remain so for several more as alternative primary energy sources are fully developed. As oil and gas exploration and production projects increasingly operate in challenging environments, at greater depths, and in more remote regions, the industry demands more sophisticated engineering solutions. Challenges include the drilling of longer and deeper (i.e., hotter) deviated wells, better-performing oil-well fluids and fluid additives, and increased yields via stimulation and enhanced oil recovery (EOR) techniques.

From initial reservoir prospecting to end-of-life production, the oil and gas industry increasingly relies on bulk and specialty chemicals to ensure continued, affordable supply. Borates’ unique properties and behaviors make them ideal options for multiple oilfield applications:

FACT
Borates are considered more environmentally friendly than competing transition metal cross-linkers used in oil and gas stimulation.
  • Retarder in concrete
  • Drilling fluids
  • Lost circulation treatments and profile control
  • Alkaline surfactant
  • Hydrogen sulfide scavenger
  • Pulsed neutron well logging
  • Hydraulic fracturing fluids
Borates can work to control set timing in magnesium oxychloride and calcium aluminate cements as well as those based on Portland cement, such as the American Petroleum Industry’s class G and H cements.
Polymer cross-linking

A unique range of capabilities

Polymer cross-linking via borate ester formation is controllable and reversible—impossible with other cross-linkers. Borates for oil and gas production range from highly soluble, rapidly dissolving products to low-solubility, slowly dissolving products. Solubility curves of borates are strongly dependent on temperature.

At low concentrations, borates form soluble ion-pair complexes with alkaline earth metal cations that are present in sea and formation water. Perborate releases hydrogen peroxide when dissolved in water. And the 10B nucleus is exceptionally effective at neutron absorption.

Borates are anodic inhibitors, promoting the formation of passivating oxide layers on various metal surfaces to inhibit corrosion. And borates are considered to pose a low risk.

Drilling and exploration

20 Mule Team® Borax borates provide essential capabilities for oil and gas drilling and exploration.

Borax oil

Oil well cement set retardant

Borates, in combination with other materials, are added to cement reinforcements that stabilize drilled well bore walls. The set rate of the cement must be carefully controlled to ensure that it remains fluid enough to be pumped into the well and into place before setting—particularly challenging when temperatures at the bottom of a well can easily reach 300°F (149°C). Borates adsorb into the surfaces of cement grains, reacting with the available calcium ions to form calcium borate coatings that are a barrier to grain hydration and cement setting.

Borates are combined with sugars, gluconates, lignosulphonates, phosphonates, or synthetic polymers for use as a cement retardant.

Lost circulation treatments

Drilling operations sometimes encounter fractures in reservoir rock formations, especially in carbonate rocks. Rapid repair is necessary to avoid the loss of thousands of barrels of expensive drilling fluids. Soluble borates are a common component of the lost circulation pills that are frequently used to plug such fractures. These pills are based on polymer gels; borates enhance the gelation of these polymers via cross-linking.

Non-damaging completion fluids

Fluids used during well-completion operations sometimes contain sparingly soluble borates, which act as bridging agents to help stop the inflow of fluids into the reservoir. The borate particles dissolve cleanly away at the end of the operations

Pulsed-neutron well logging

Pulsed-neutron logging, which exploits differences in the extent to which neutrons are trapped by various atomic nuclei, is a technique for mapping the location of oil- and water-bearing zones and tracking fluids in an oil or gas reservoir. Such mapping can be an important part of monitoring the progress of an enhanced-oil-recovery flooding trial, diagnosing fluid leaks from a well bore, measuring the porosity of regions in the reservoir, and other tasks. Borates—which have several advantages including low cost and ease of handling—help to enhance the contrast between water and oil or rock zones.

Drilling fluids

Borates fulfill several functions when used in drilling fluids (aka muds), including enhancing the performance of some polymer-based fluid-loss additives; improving the lubricating characteristics of muds; helping to control the pH of water-based muds; helping to inhibit corrosion in water-based muds to protect steel tubing, casing, and pipework; reversibly cross-linking viscosity-modifying polymers in water-based muds, especially when drilling deviated or horizontal wells; and working with salts (such as potassium chloride) or mono- and oligosaccharides to stabilize shale or clay strata in the reservoir formation rock.

Production and oil recovery

The rate of production of oil and gas can be increased by enhancing the permeability of the reservoir—a practice known as stimulation. One type of stimulation is hydraulic fracturing, which creates open fractures in the reservoir rock, thus increasing the permeability and improving the fluid flow through the reservoir. Borates can be used in hydraulic fracturing, both for fluid gelation and fluid breakdown.

In fluid gelation, boron’s cross-linking capabilities help to prevent gels from being irreversibly degraded under extremely high shear conditions. And because borates are water soluble, the gels that they form are easier to clean up than those containing other cross-linkers, such as zirconates or titanates. Borates have been used in this application for 40 years.

At the end of the fracturing operation, cleanup and removal of gelled-polymer solution residues is required. The high-molecular-weight polymer chains can be broken down with enzymes or chemical oxidants. Perborate, which has a favorable environmental profile, is an oxidizing breaker that supplies hydrogen peroxide. The breaker particles can be coated to delay release of the perborate, which can be made more water soluble by blending with polyols. Borate cross-linked fluids clean up better than those that employ other cross-linkers, regardless of the breaker system that is used.

Borates in drilling fluids

Water-flooding profile control

Borates can be used to improve the overall efficiency of water-flooding processes in recovering oil from reservoirs by helping to block off high-permeability “thief zones.” Slow-release systems that are based on borate glasses and borate esters are used to control viscosity via cross-linking and viscosity-delay mechanisms and improve performance. And a “thermal precipitation” process—in which a hot, nearly saturated borate solution is pumped into the reservoir, migrating into high-permeability zones and precipitating borate compounds on cooling—can help to block pores.

DID YOU KNOW?
Slow-release systems that are based on borate glasses and borate esters are used to control viscosity via cross-linking and viscosity-delay mechanisms and improve performance.

Alkaline-flooding agents

Borates are also being developed as an alkaline agent in several EOR processes, such as alkali-polymer and alkali-surfactant-polymer (ASP) flooding. Laboratory data shows that when used to substitute or partially replace existing alkalis, borates can extend the use of this technology to many reservoirs containing water with very high salinities and levels of hardness ions. Neobor® and 20 Mule Team Borax borax decahydrate promote excellent oil recovery despite a lower pH, an effect attributed to a strong pH buffering capacity and pH maintenance over a wide concentration range. In combination with conventional EOR surfactants and polymers, borates can help to obtain the necessary ultra-low oil/water interfacial tensions. Tertiary oil recovery from borate-based ASP core floods is comparable to that obtained with similar formulations that contain conventional alkalis and exhibit no injectivity problems in core flood trials. And flooding compositions that contain borates benefit from a substantial reduction in alkali consumption on certain rock types, notably those rich in anhydrite (calcium sulphate) and dolomite (calcium magnesium carbonate), having a significant positive impact on the economics of the tertiary flooding process.

DID YOU KNOW?
Neobor and borax decahydrate promote excellent oil recovery despite a lower pH, an effect attributed to a strong pH buffering capacity and pH maintenance over a wide concentration range.

20 Mule Team Borax Products

These 20 Mule Team Borax products are developed for use in oilfields and gas production.

Borax Decahydrate

From detergents to dyes to adhesives, this mild alkaline salt does it all, particularly excelling as a buffering and fluxing agent. Learn More

Dehybor

This hard, glassy, granular product is excellent when forming flux or glass, where it helps to increase yield and reduce energy consumption. Learn More

Neobor

With lower transportation, handling, and storage costs, this concentrated sodium borate is used in glass and fiberglass, cleaning products, flame retardants, and more. Learn More

Optibor

From reducing melting temperatures in fiberglass production to inhibiting corrosion in fuel additives, Optibor has a multitude of uses in numerous industries. Learn More

Polybor

Polybor earns its spot in industrial cleaning compounds, fire retardants, and the manufacture of water-treatment chemicals. Learn More

Sodium Metaborate

Used in the preparation of starch and dextrin adhesives, this product provides increased viscosity, quicker tack, and better fluidity. In textile processing, sodium metaborate helps to stabilize hydrogen peroxide solutions and neutralizes acidic oxidation by-products. Learn More

Rio Tinto Borates is a global leader in the supply and science of borates - naturally-occurring minerals containing boron and other elements. Refined borates are essential nutrients for crops. We are 1,000 people serving 500 customers with over 1,700 delivery locations globally. We supply 30% of the world's need for refined borates from our world-class mine in Boron, California, about 100 miles east of Los Angeles.  Learn more about Rio Tinto

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