The Rough-And-Tumble Oil And Gas Industry

Demand for oil and gas grew tremendously during the industrial revolution and grew even further to fuel the development of western economies. This demand spurred the need for deeper wells, longer pipelines and lower production costs, which required drillers and refiners to select equipment more carefully. As production, transportation and processing technology advanced, equipment performance requirements became more and more stringent to support increasing operational efficiencies. Today, performance expectations are higher than ever because the variety of operating conditions has expanded, and the protection of personnel and the environment have been added to the list of requirements.

Valve service environments and operating conditions within the oil and gas industry are unique and extreme. From exceptionally high temperature (greater than 1,500° F or 816° C) and high pressure (greater than 25,000 psig) to cryogenic (-150° F or -101° C) or cryogenic for LNG (-260° F or -162° C ) and very low-pressure applications, valves must be engineered to perform dependably. In addition to this wide range of conditions, the remote locations of valve services also present unique challenges. Examples include deep sea valves operating 10,000 feet (3,048 meters) below the sea surface and pipeline valves exposed to the extreme temperatures found in a desert. Valves in these tough environments may stay open or closed for extended periods of time, yet they are expected to operate reliably even when they have not been cycled in many years.

Each segment of the oil and gas industry—upstream, midstream and downstream—offers its own examples of extreme conditions for valves. In the upstream segment, valves control the flow of crude oil and natural gas from high-pressure injection systems to choke valves and blow-out preventers at the top of wells. Valve systems are asked to perform over the many years of a producing well’s life—a life that depends on different factors such as economies and new recovery techniques. New-found sources of oil and gas from tar sands and shale formations have added to the complexity of valve specifications because they require placing oil and gas into pipelines taken to processing facilities that can be many miles away.

The midstream segment—storage and transportation of oil and gas resources from remote sources such as the deepwater fields of the Gulf of Mexico or the frozen tundra of Alaska—has another unique set of conditions. Long pipelines require compressors along the way to keep the product moving, and valves are asked to protect equipment while offering minimal restriction to the flow. Extremely low temperatures are required for converting natural gas into natural gas liquids in preparation for transportation from isolated gas fields to gas-consuming markets. Cryogenic service demands that valves be made of materials for low temperatures and other special designs. Midstream solutions for loading/offloading terminals and storage tanks for oil and gas products offer more opportunities for valve suppliers.

The third industry segment—downstream—brings challenges to find solutions for the refining process of crude oil, as well as the sale and distribution of both the refined product (i.e., gasoline, fuel, asphalt, etc.) and natural gas. This sector is made up of industrial, retail and distribution businesses and is the segment that provides products such as heating and transportation fuels to consumers and businesses. Additionally, this segment feeds raw materials to a variety of petrochemical industries that use petroleum-based products to make plastics, fertilizers, pharmaceuticals and more. The valve requirements for the downstream market include higher-pressure designs and metal-seating technology and metallurgies to accommodate the temperatures at which modern refineries operate.

RELEVANT VALVES AND EQUIPMENT

Each of these industry segments faces unique and diverse environments that, in turn, create extreme operating conditions for valves and other flow control components. Because of the extreme temperatures and pressures, as well as the most remote and harshest environments, the types of valves and materials for those valves for each segment vary considerably. There are very few valve suppliers that could provide a complete range of solutions, and most suppliers today specialize in one or two segments.

This is because of the complexity of requirements. For example, in the upstream segment, offshore exploration and production operations create extreme conditions, a situation made even more complex as the search for untapped oil and gas fields continues into deeper and deeper waters. In these applications, valve strength and performance is critical because of the damage that leakage could cause to the seas and their fragile ecosystems. Standard options for this segment include gate valves produced with higher alloy materials and, on occasion, ball valves. They are used for a variety of reasons including resistance to corrosion and damage caused by constant exposure to raw seawater. In addition, these valves offer low-depth sensitivity and have proven over time to perform well in this high-pressure, remote environment.

In midstream applications that involve transportation of oil and gas, isolation valves play an important role in pipelines. There are primarily two types of pipelines for the energy industry—those for oil and those for natural gas. Within each group are subsets that serve specific applications. For example, oil pipelines gather crude oil from a production site and transport the unrefined oil to refineries. Once refined, additional pipeline networks distribute the refined oil products throughout the world. Natural gas, on the other hand, is typically transported directly from the source to the end user; however, it also includes the cryogenic service that compresses gas into liquid for economical transport to distant markets.

As in the upstream segment, the most common valve solutions for the midstream market include full-port gate and ball valves in materials chosen specifically for the service. For example, nozzle check valves with low-pressure drops and rapid responses to changes in the flow are a critical component to compressor stations, which energize the media for long pipelines. Some major factors when selecting a pipeline valve include the pipeline size, the media that will run through the pipelines and the environment in which the pipeline will operate. Shut-off valves must be full-port designs, not only to minimize pressure loss, but also to accommodate pipeline inspection gauges (nicknamed “pigs”), which are used to inspect and clean the inside of pipes or to separate different media as it flows through the line. Regardless of valve style, dependability is critical. Although these valves may only rarely be cycled, they may be needed for pipeline flow diversion, shut-off or isolation performance so reliability is vital. For example, if a pipeline rupture occurred, isolation valves would play a significant role in minimizing environmental damage by shutting off the flow.

Within the downstream segment, there are many harsh environments that require a variety of design solutions. In particular, within refining, applications such as delayed coking present challenges for valve operational integrity. Delayed coking is a heat-intensive process in which heavyweight oil undergoes a thermal cracking process that produces the gas oil and petroleum coke. During this process, valves are subject to temperatures of more than 900° F (483° C). Adding to the challenge is the fact that delayed coking process valves are cycled every 12 to 16 hours (for a typical two-drum base cycle). Failure of one valve can shut the entire refinery down, which could cost untold millions of dollars in operating revenues. High-temperature applications such as delayed coking place a significant amount of thermal stress on all valve components. Added to the temperature extremes, coking fines are highly abrasive, which impacts plug/disc and body seating surfaces, as well as the gaskets and stem packing.

To support the operational integrity of this application, valves can be equipped with many special characteristics, including heat-dissipating fins, materials designed for high-temperature functionality and remotely-controlled operating systems.

SPECIFIC VALVES FOR THE INDUSTRY

HSE REQUIREMENTS

Health, safety and environmental (HSE) requirements are critical factors in the oil and gas industry, and key players must meet these HSE standards to maintain the license to operate. These requirements can be affected by the equipment used within a given facility, including valves, and money lost from unplanned shutdowns or costly repairs are a significant threat to the industry.

Because of this, an important aspect of the industry includes acknowledgement of available certifications and quality standards. The most relevant organizations in the industry include the Environmental Protection Agency, International Standardization Organization, American Society of Mechanical Engineers and American Petroleum Institute. Examples of what these bodies produce in the oil and gas industries include detailed specifications for valve construction, emissions testing and technical standards for safety.

FAVORABLE MARKET TRENDS

Market trends are particularly relevant in the oil and gas industry because some experts identify capital investments in this industry as a predictor of global valve market success. In North America, oil and gas investments favor expansion of current facilities, including throughput improvements, sulfur removal and increased spending on maintenance.

According to the Energy Information Administration (EIA), the International Energy Agency and the Organization of the Petroleum Exporting Countries, three of the most respected oil- and gas-related organizations worldwide, crude oil demand is rising again after several years of negative growth. These organizations predict this rate of growth will increase over the next two years, which will inevitably lead to consumption rates that reach above pre-recession usage.

For natural gas, on the other hand, the short-term demand and consumption are projected to decrease minimally in 2011. This information is based on forecasted weather trends and the economy as a whole, among other factors. However, the EIA also predicts that in 2012, natural gas is expected to rebound from the slight decline at a rate of approximately 1.5% growth over 2011.

CONCLUSION

The oil and gas industry provides valve manufacturers extreme application challenges brought about because of harsh environments in discovery, transporting and refining. Control, regulating, shut-off and backflow prevention services are required in every piping system of the industry. Valve manufacturers have responded with specialized valve designs, materials and machining procedures to meet the industry’s critical specifications. With a rebound expected for the markets, valve producers in the oil and gas field have some reason to be excited about the future.

Nicholas Williams has over 21 years experience in the industrial valve industry with a specialty in severe service applications in mining, power generation, and the oil and gas markets. He is currently vice president, engineering for Crane Energy Flow Solutions, Shenandoah, TX. Reach him at news@craneenergy.com.