Applications - Industrial - Oil Field

O-Rings / Oil Field / Rolls / Seals

Description

The oil field presents a most demanding and diverse group of applications for elastomers. Elastomeric materials in oil field service play major roles in protecting workers, equipment, and the environment as well as enhancing drilling and zone isolation to maximize well production. From blow-out preventers (BOP) designed to seal off the well from potentially destructive pressures to down-hole packers used to isolate zones for further evaluation, ZEON CHEMICALS offers performance proven elastomers and technical support that continue to meet the stringent requirements of the oil drilling industry.

Environment

Several key elastomeric components for oil drilling are detailed in this section. Each component serves a very unique and specific function and the service environments encompass a broad range of conditions. Please refer to the specific component section for a detailed description of the application requirements.

Recommended Polymers

Nipol NBR
Zetpol HNBR

Rapid Gas Decompression (RGD) Resistance

Rapid Gas Decompression (RGD) resistance is a failure mechanism of elastomer seals and other oil-field components caused by the rapid decompression of various gases.

When elastomers are exposed to high-pressure gas at elevated temperatures for a prolonged period, the gas absorbs into the polymer compound. When the external pressure is reduced (spontaneously or gradually), the gas dissolved within the material comes out to form micro-bubbles. As the gas expands, it permeates out of the material. However, if the rate of decompression and expansion is high, the trapped gas within the component expands beyond the material’s ability to contain the gas bubbles, causing cracks and tears within the elastomeric component.

There are various methods and standards for evaluating the RGD resistance of elastomer compounds. Specifications such as NORSOK M-710 Revision 2 and ISO 23936-2 are well-known test procedures used within the oil and gas industry.

ZEON has developed a number of compounds that meet the highest ‘0000’ rating for RGD resistance to both the NORSOK M-710-2 and ISO 23936-2 specifications. Please ask a ZEON representative for further information about RGD-resistant compounds.

RGD Test Certificate JN 2813 compound 3
RGD Test Certificate JN 2822Z COMPOUND 12A
RGD Test Certificate JN 2822Z COMPOUND 30

 

Additional Application - BOP

Description

"Blowout" is the modern term for the classic "gusher" and is something to be avoided at all costs. A volatile mixture of oil and gas escaping and exploding in a sudden blowout can cause loss of life and equipment and significant damage to the environment. The blowout preventer is the principle mechanical component in well control.

The well drilling fluid, known as mud, is pumped into the hole to hold the correct pressure on the well. When seawater and other fluids from the surrounding formation enter a hole, the drilling operator can often detect a change in performance of the drilling apparatus and respond by closing off the well. While the operator is the first line of defense in preventing a blowout, the BOP is the second line.

A typical BOP system is a stack of large, high-pressure valves that can be remotely controlled to seal off the well. The stack is attached to the top of the well below the rig floor. Special designs are required depending on the type of well. For land based drilling, the BOP sits at the base of the rig. For offshore applications, the BOP casing must be designed to withstand the salt water and external pressures of the ocean floor.

Two types of BOP's are incorporated into a typical stack. The annular BOP sits at the top of the stack and serves to seal off the annulus between the drill pipe and the side of the hole. An annular BOP can also seal off a hole with no drill pipe present. The ram BOP's are stacked beneath the annular preventer. A blind ram preventer is essentially two blocks of steel with rubber facings. These are forced or "rammed" together to completely seal off an open hole. The pipe ram preventer is similar to a blind ram, but the rubber and steel blocks are contoured to provide pressure against the drill pipe. A typical BOP stack is made up of several ram preventers, topped off with an annular preventer.

Environment

The rubber compound for a BOP must be designed to withstand exposure to liquids and gases at high temperature and pressure. Normal operating temperatures may reach 250º F (121º C) while high-temperature service may reach 350ºF (177ºC). Hydraulic pressure is applied depending on the operating conditions within the well. If the well "kicks" or experiences a sudden surge in backpressure, the BOP clamps down to provide a tighter seal. This imposes on the rubber compound a demand for high tear and tensile strength at high modulus while being resistant to extrusion. Rubber to metal adhesion is a very critical factor in compound design. Rubber compounds based on Zeon's Nipol® 1051 have a long history of meeting the demands of this application while providing good processability for large, high-performance parts such as these.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Diaphragms

Description

Diaphragms are large rubber seals used in pipelines, pumping stations and cut-off sections to regulate pipeline pressure.

Environment

Diaphragms must exhibit high tensile strength and high resilience with low compression set. Some components may be as large as seven feet in diameter. Underwater applications demand that the compound have good water resistance while maintaining resistance to hydrocarbon fluids and gases in the pipeline.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Drill Bit Seals

Recommended Polymers

Nipol NBR
Zetpol HNBR


Additional Application - Drill Pipe Protectors

Description

This seal at the base of the drilling apparatus prevents contact between the drill pipe and the outer casing. The seal acts as a sacrificial wear surface to protect the interior of the drill casing from fluids in the down-hole environment.

Environment

The seal or pipe protector is worn down by rotational forces of the drill motor and is exposed to oil and water based muds, mixed hydrocarbons (liquid and gaseous) in the well. Compounds of NipoL® 1051 exhibit the wear characteristics to make this the polymer of choice.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Packers

Description

A packer is a sealing device used down-hole to block the flow of fluids through the annular space between the drill-pipe and the wall of the hole. The packer consists of a tubing string encased in a packing element. The packing element is a rubber component that expands to block the annulus and allow fluids to flow only through the encased tubing. Packers are classified according to their function, configuration, and method of setting. Some packers are designed to be retrievable from the hole and reconditioned for multiple uses.

Environment

Down-hole packers may see pressure differentials of 15,000 psi and seal gaps as large as ¼ inch wide. Packer compounds based on Nipol® 1051 provide the high strength necessary to resist extrusion up-hole while maintaining good resistance to abrasive oil and water based muds and corrosive drilling fluids.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Pipeline Pigs

Description

A pig is a scraping tool that is forced through a pipeline or flow line to clean out debris from the walls of the pipe. A cleaning pig is a rubber cylinder or spheroid that may have blades or brushes attached to the surface. It travels with the flow of product in the line, cleaning the pipe walls. Pigs also can be used to separate products within the line. A separator pig is a rubber ball or cylinder with cups attached. It is introduced into the line in between the inputs of two different products. Another type of pig is a "prover sphere." In hydrostatic testing of a pipeline, a pig may be used to push air out ahead of the test water and to push water out after the test.

Environment

Since pigs operate inside pipelines under moderate pressures, the compound should have strong hydrocarbon fluid resistance and withstand abrasion from the walls of the pipe or debris. Carboxylated nitriles such as Nipol® NX775 or 1072 are recommended for pig applications.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Pump Down Pistons

Description

Pistons are cylindrical rubber components that can be pumped down-hole to increase downward pressure and insert or retrieve tools and equipment. A piston is placed in the well and forced down-hole via mud pressure.

Environment

Good fluid and abrasion resistance is key for this component since it will be in contact with the well bore surface and the pumping mud. As with pipeline pigs, a carboxylated NBR is recommended. Nipol® 1072 and NX775 provide the necessary abrasion and fluid resistance for such applications.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Stators

Description

One of the most crucial pieces of equipment in the drilling process, the stator is a tube with an elastomeric lining that houses the steel rotor of a positive displacement drill motor. This is the key power section that drives the drill unit. This component is also referred to as a mud motor or mud pump, or PDM (Positive Displacement Motor). Stator life is dependent on a number of factors. One of the most important is the rubber compound formulation for the elastomeric lining.

Environment

The elastomeric lining must withstand the wear of a rotating shaft and exposure to high temperature and pressure in the down-hole environment. Mud or drilling fluid composition has an important effect on the stator lining. The compound must be designed to withstand highly corrosive and abrasive materials in both water and oil based muds. A general stator formulation is provided based on Nipol® DN 4555, an NBR with high acrylonitrile content, compounded to high tensile, modulus and wear resistance.

Recommended Polymers

Nipol NBR
Zetpol HNBR

 

Additional Application - Wipers

Description

Pipe wiper elements provide a low-pressure seal for the removal of mud and debris from the interior of the drill pipe.

Swabs are devices used for cleaning pipes or pipelines. Unlike pigs, these devices are typically hollow metal cylinders with a rubber cup attached to provide a wiping and sealing surface. A swab is introduced into the well to remove fluid when the pressure is insufficient to support flow. The swab is inserted into the well and pulled out (much like a plunger) to reduce pressure and bring fluids to the surface.

Environment

The wiper element should have good chemical and fluid resistance, high tensile strength, elongation and tear resistance. Wipers are used for long durations during the drilling process so polymers such as Nipol® 1072 or NX775 are recommended for good abrasion and wear resistance. The selection of either polymer is a matter of the fabricator's preference and processing requirements.

The swab cup must withstand exposure to mixed hydrocarbons. Similar to a pipe-wiper, the compound must exhibit good tensile strength, tear resistance, elongation, and abrasion resistance properties. While Nipol® 1051 is the general purpose polymer of choice for this application, some fabricators may require the improved abrasion resistance that can be achieved using Nipol® NX775 or 1072.

Recommended Polymers

Nipol NBR
Zetpol HNBR

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