Applications of Polymers and Composites in the Oil and Natural Gas Exploration and Production Industry

December 2018

The oil and natural gas exploration and production industry requires the use of materials providing many different combinations of outstanding performance characteristics, often under extremely demanding application conditions.  

Thermoplastic and thermoset polymers and their composites are used increasingly more frequently, in a wide range of applications in this industry, to perform many very different functions.

The main reason for this trend is the amazing versatility of polymers, which enables the design and manufacture of a vast range of products to meet very different application requirements at acceptable cost.

The abilities to prepare blends of polymers, to incorporate many types of performance-enhancing additives, and to prepare polymer matrix composites by incorporating reinforcing agents (such as fibers, platy fillers, and particulate fillers) all enhance the versatility of polymers far beyond the versatility provided by individual polymers on their own.

The general application areas of polymers and composites in this industry are as structural elements of infrastructure and as drilling fluid ingredients.  The polymers and composites used in these two general application areas are very different.  The industry and application highlights below, providing a sampling of the vast range of applications of polymers and composites in this industry, will therefore be presented under these two headings.

At Bicerano & Associates, our expertise in polymers and composites helps our clients to develop polymers and composites for any application they may require.

Applications as Structural Elements of Infrastructure

Structural elements used in infrastructure for oil and natural gas exploration and production are exposed to extremely harsh conditions.  These conditions include continuous periods of very high temperatures as well as exposure to chemicals ranging from hydrocarbons to salt water to strong acids.  Most polymer and polymer matrix composite structural elements, therefore, tend to be constructed from high-performance polymers.

The material needed for a particular structural element may be rigid or flexible depending on the function of the structural element.  In either case, it must satisfy the usual types of mechanical property requirements, such as having adequate stiffness or flexibility, strength, toughness, and impact resistance (if rigid) or tear and puncture resistance (if flexible). 

The most important selection criterion among materials that possess acceptable mechanical properties is the continuous operating temperature range over which the material retains its mechanical properties.  It is essential for ensuring durability for the material to manifest very slow thermal aging.  The maximum continuous operating temperature is usually the main limiting factor related to temperature.  It is not only when a component of the infrastructure is located in a very hot place such as a desert that a structural element may be exposed to extremely high temperatures.  Some structural elements are exposed to extremely high temperatures regardless of their geographical location because of their function.  Examples include structural elements located deep inside wells and/or inside machinery.

On the other hand, some structural elements may experience extremely low temperatures during use.  For example, the infrastructure may be located within the Arctic Circle, and a structural element may be outdoors.  Polymers used in such structural elements need to possess excellent low-temperature mechanical properties.  Most importantly, since polymers tend to become more brittle and stiffer at very low temperatures, it must be ascertained that a rigid element will retain sufficient impact resistance and toughness and that a flexible element will retain sufficient flexibility at the lowest anticipated temperatures of operation.

For many structural elements, used in many different application environments, chemical resistance is another important criterion.  Even if such a structural element has excellent mechanical properties and sufficiently high heat resistance, it will not continue to perform adequately unless it is resistant to chemical exposure even at elevated temperatures.

The combined effects of chemical exposure and load can cause a load-bearing structural element to undergo thermal aging even faster than caused by chemical exposure alone.  It is, therefore, important to consider both chemical exposure and load in estimating the maximum continuous operating temperature of a load-bearing structural element.

Many structural elements protect other structural elements from chemical exposure.  It is important for the materials of construction of such protective structural elements not only to  be resistant themselves to the chemicals present in the application environment, but also to be sufficiently impermeable to these chemicals to prevent the chemicals from going through and damaging the structural elements that are being protected.

Solvay and DuPont manufacture extensive product lines of high-performance polymers for the construction of structural elements used in infrastructure for oil and natural gas exploration and production.  Hence their product literature provides an excellent sampling of such applications and the polymers that meet their stringent performance and durability requirements.  The image reproduced below from the Solvay product literature shows how polymer manufacturers provide thermal ratings for their products as general guidelines for the maximum operating temperature.  The Solvay and DuPont product literature were also used to obtain most of the examples tabulated at the end of this section. 

Oil & Gas Exploration & Production

It was estimated that global demand for high-performance polymers in oil and natural gas applications in 2015 was 17340 tons with a material value of US $ 430 million.  Demand for high-performance polymers for such applications was projected to grow at a rate of ~5.6% per year through 2021.

Metal replacement is a major driving force for the continuing growth in the use of polymers in structural elements.  Much greater corrosion resistance and much lighter weight are the two major advantages of polymers over metals for use in structural elements.  These advantages are leading to the replacement of metals by polymers or by polymer matrix composites whenever polymer-based alternatives are able to provide comparable performance.  For example, fiber-reinforced polymer matrix composites are gradually being used to replace metals in the construction of structures such as offshore oil platforms and components on such platforms because of their greater corrosion resistance and their lower weight.      

The development of composite repair systems as viable alternatives to the use of metals in the repair of metallic fluid system components such as high-pressure pipes that carry oil and/or natural gas is a major technology innovation of the last two decades.   Such systems use continuous fiber-reinforced thermoset polymers to repair damaged fluid system components in a reliable and cost-effective manner.  Hence they provide an alternative that is increasingly being preferred over conventional methods such as replacing a damaged steel pipe or installing a heavy steel repair sleeve over its damaged section.  Composite repair systems are tested extensively to demonstrate that they meet rigorous industry standards.  The use of composite repair systems for the repair, rehabilitation, and reinforcement of concrete structural elements is also growing.

Polymers are also used by the oil and natural gas exploration and production industry in plastic pipes and/or as pipe insulation materials.

The following industry and application highlights provide a sampling of the vast range of applications of polymers and composites as structural elements of infrastructure for oil and natural gas exploration and production.  For many of the polymers listed below, even if not mentioned explicitly, reinforcements such as glass fibers or carbon fibers are incorporated into product grades intended for use under the most extremely demanding conditions.

 

Materials

Applications

Adhesives (anhydride‐modified linear low‐density polyethylene, anhydride-modified ethylene acrylate, acid-modified ethylene acrylate, modified ethylene vinyl acetate)

Used to provide adhesion and bonding between layers in multilayer piping systems, with the ability to bond polyolefins to polyamides (nylons) and nylons to fluoropolymers as well as other engineering resin systems.

Adhesives (epoxy, acrylate, polyester, polyurethane)

Various adhesion and bonding needs

Coatings (epoxy, acrylate, polyester, polyamide, and polyurethane coatings can be used; most often, epoxy coatings will probably provide the best protection)

Inhibition of corrosion on metal surfaces of pipes, tanks, and other equipment.  Pipeline corrosion protection and rehabilitation in the harshest environments.  Some epoxy external and internal pipe coatings also help provide enhanced properties for operation at elevated temperatures, mechanical damage protection, compression, wear, abrasion, and cavitation resistance.

Continuous fiber-reinforced thermoset polymers:

  • Industry standards require the use of thermoset matrix polymers and continuous fibers.
  • Epoxy and polyurethane matrices and glass and carbon fibers are most commonly used.
  • Other matrices such as polyesters, vinyl esters, and phenolics, and other fibers, such as aramid fibers, may be used.

An application that has emerged over the last two decades is their use as composite repair systems for metallic fluid system components such as high-pressure pipes that carry oil and/or natural gas.  Composite repair systems can be used to repair external corrosion (where structural integrity is compromised), external damage (such as dents, gouges, fretting, or wear), cracks, internal corrosion or erosion (leaking or non-leaking), leaks, and manufacturing or fabrication defects.  The use of composite repair systems for the repair, rehabilitation, and reinforcement of concrete structural elements is also growing.

Fiber-reinforced polymers (matrix polymers can be thermoplastics or thermosets, and fibers can be continuous fibers or short fibers)

Replacement of metals in the construction of structures such as offshore oil platforms and components on such platforms because of their greater corrosion resistance and their lower weight

Perfluoroalkoxy alkane (PFA)

Semicrystalline, melt processable perfluoropolymers; used in pipe liners, coatings, bushings, bearings, seals, control line encapsulation, power cables, valve plates, pump wear rings, tubing, and films

Perfluorocarbon synthetic rubbers (FKM and FFKM)

Seals and gaskets

Perfluoropolyether (PFPE)

Lubricants

Poly(amide imide) (PAI)

Compressor components, valves, plates, and electrical connectors

Poly(aryl ether ketone) (PAEK)

Flexible riser anti-wear tapes, umbilicals, pipe liners, coatings, power cables, tubing, seals, gaskets, compressor components, valves, plates, electrical connectors, and films

Poly(ether ether ketone) (PEEK)

Flexible riser anti-wear tapes, umbilicals, pipe liners, coatings, power cables, tubing, seals, gaskets, compressor components, valves, plates, electrical connectors, and films

Poly(ethylene-co-chlorotrifluoroethylene) (ECTFE)

Pipe liners, coatings, control line encapsulation, power cables, and films

Poly(p-phenylene terephthalamide)

Situations where barrier performance is needed for wire and cable applications, liners, risers, and reinforced thermoplastic pipes

Poly(vinylidene fluoride) (PVDF)

Flexible riser pressure sheath, flexible riser anti-wear tapes, umbilicals, pipe liners, reinforced thermoplastic pipes, coatings, control line encapsulation, power cables, tubing, and films

Polyamide 11

Reinforced thermoplastic pipes

Polyamide 6,12

Hydraulic control line, siphon string, gathering line, produced water piping, pipe liner; situations where barrier performance is needed for wire and cable applications, liners, risers, and reinforced thermoplastic pipes; and jacketing and insulation for seismic, power, and instrumentation cables

Polyethylene (PE) and high-density polyethylene (HDPE)

Applications can be summarized as follows:

  • PE pipes are preferred in most gas distribution applications throughout the world.  They are break-resistant, rustproof, corrosion-free, resistant to harsh chemicals, and abrasion-resistant.  Their semi-rigidity enables them to withstand high external loads.  Their flexibility enables their expansion with pressure surges, increasing the life of the pipeline.
  • HDPE pipes are used in hydraulic fracturing operations, for collection and transportation of hydrocarbons and of water used in the process.
  • HDPE and PE are also used in reinforced thermoplastic pipes.  For example, composite pipes consisting of (a) an extruded inner tube of HDPE, (b) wrapped diagonally with two to four layers of a composite tape of nylon, PET, glass, or carbon fibers impregnated with PE, and finally (c) an outer layer extruded HDPE over the tape wrapping, can be used at pressures of up to 3000 psi.  Such reinforced thermoplastic pipes compete with steel pipes which need frequent replacement because of corrosion.

Polyimides (both thermoset and thermoplastic versions are available)

At the top of the performance pyramid in their ability to maintain physical and mechanical properties under high loads and temperatures.  Structural elements manufactured from some product grades can resist temperatures from -196 °C (in the cryogenic range) to 350 °C (with excursions of up to 480 °C).  Can be used in many applications as lightweight replacements for metals and ceramics.  They are noted here although they are used more often today in transportation (aerospace and automotive) applications than in oil and natural gas infrastructure applications where polymers such as the PFAs and PEEK tend to be preferred.

Polyphthalamide (PPA)

Rod guides

Polypropylene (PP)

PP foam coatings are used as insulation materials for deepwater pipelines.  Such insulation keeps the heat of the produced oil above the cloud point; preventing the formation of hydrates, waxes, and asphaltenes, which would diminish the flow through the pipeline or stop the flow entirely by plugging the pipeline.

Polytetrafluoroethylene (PTFE)

Pipe liners, power cables, tubing, seals, gaskets, and compressor components

Thermoplastic polyester elastomers

Hydraulic control line, siphon string, gathering line, produced water piping, pipe liner; situations where barrier performance is needed for wire and cable applications, liners, risers, and reinforced thermoplastic pipes; jacketing and insulation for seismic, power, and instrumentation cables; and replacement of thermosets for coil cords, jacketing, gaskets, and more

 

Applications as Drilling Fluid Ingredients

Oil and natural gas drilling operations use drilling fluids (also known as drilling muds) that serve many important functions.  These functions include fracturing geological formations, carrying and depositing “proppant” particles into fractures so that fractures do not collapse under the closure stress imposed by the weight of the geological formation above them, removing cuttings from wells, suspending and releasing cuttings, controlling formation pressures, sealing permeable formations, maintaining wellbore stability, facilitating cementing and completion, etc.

A typical drilling fluid formulation contains a base fluid and many additional ingredients carried by this base fluid.  The type of drilling fluid is identified by the type of base fluid that it uses; such as oil-based, water-based, or synthetic-based.  The additional ingredients often include polymers and/or polymer matrix composites, as summarized below.  Each additional ingredient provides its own benefits.  The additional ingredients work well with each other and with the base fluid in an optimized drilling fluid to facilitate the extraction of hydrocarbons with maximum possible productivity for as long as possible. 

Clays such as sodium montmorillonite (bentonite) are the most commonly used primary fluid loss control additives in water-based drilling fluids.  Polymers such as starches (carbohydrates consisting of glucose repeat units), sodium carboxymethylcellulose, polyacrylates, styrene acrylate copolymers, styrene butadiene copolymers, synthetic and biobased copolymer latexes, polyolefin copolymers, lignosulfonates (water-soluble anionic polyelectrolytes obtained as byproducts of wood pulp production), tannins (a class of polyphenolic biomolecules), and proprietary polymers of undisclosed composition, are also used as fluid loss control additives, often in addition to clays rather than by themselves. 

Some fluid loss control additives also act as thinners and thus reduce the viscosity of the drilling fluid.  There are also additives that have been developed specifically to serve as thinners.  Examples include alkyl polyamide complex esters and proprietary polymers of undisclosed composition.

Lost circulation refers to losses of whole drilling fluid to the subsurface formation as a result of uncontrolled flow so that fluid pumped down a well does not return to the surface.  Many types of materials are used to help prevent or reduce lost circulation; including polymeric materials such as wood fibers (cellulose, hemicellulose, and lignin are the main ingredients), cotton fibers (cellulose is the main ingredient), other natural fibers, shredded automobile tires (rubbers), paper pulp (derived from wood), shredded cellophane (regenerated cellulose film), ground nut hulls (containing carbohydrates, proteins, and lignin among their ingredients), pieces of plastic laminate, and proprietary polymers of undisclosed composition.

Better fluid loss control and the prevention or reduction of lost circulation contribute to wellbore stabilization so that fluid loss control additives and lost circulation control additives also help in stabilizing the wellbore.

Viscosifiers are designed to increase the viscosities and thus improve the hole-cleaning and solids-suspension capabilities of drilling fluids.  Various clays, biopolymers (such as xanthan gum and guar gum which are polysaccharides), polymerized fatty acids, synthetic polymers such as acrylamide-based polymers, and proprietary polymers of undisclosed composition are among the materials used as viscosifiers.

Temperature-stabilizing agents enhance the heat resistance of drilling fluids and thus allow drilling fluids to retain acceptable performance at higher temperatures.  Examples include acrylic polymers, sulfonated polymers and copolymers, lignosulfonates, and tannin-based additives.

Defoamers are designed to reduce foaming action, particularly in brackish and saturated saltwater drilling fluids.  Examples include silicone emulsions.

Wetting agents preferentially wet drill solids to enhance rheology and emulsion stability.  Examples include alkyl polyamide complex esters and derivatives of alkyl polyamides and vegetable oils.

Proppants are load-bearing particles.  They are transported into a fracture by a drilling fluid during a hydraulic fracturing operation.  They remain in the fracture and keep it open (prop it up).  Resin-coated sand particles, where the protective coating is usually a phenolic, epoxy, or urethane-based thermoset polymer, have been used as proppants in large volumes for a long time.  The commercialization of ultralightweight (ULW) thermoset copolymer nanocomposite proppants with high load-bearing ability during the last 15 years was a major breakthrough.  Such ULW proppants are nearly neutrally buoyant in water, so that they can be transported with much greater ease than sand and ceramic proppants deep into a fracture.  Similar thermoset copolymer bead products are used for other purposes, such as synthetic gravel pack materials for superior sand control in horizontal wells and mechanical lubricants that reduce drill string wear and casing wear.

 

Call Bicerano & Associates Consulting, LLC at (912) 235-2238 or use our online form or email us at info@polymerexpert.biz today!

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