Showing posts with label oil and gas. Show all posts
Showing posts with label oil and gas. Show all posts

Understanding Pigging and Pig Valves in Industrial Pipelines


Pigging is a method of introducing a mechanical device, commonly referred to as pigs or scrapers, inside a pipeline to perform various internal maintenance operations.The term PIG is said to be an acronym for "Pipeline Intervention Gadget". The process has been used for many years to scrub large diameter pipelines in the oil and gas industry. Today, the use of smaller diameter pigging systems is growing in many continuous and batch processing plants, as plant operators are looking for improved productivity and ways to reduce costs. 

Pig valves were successfully implemented into the oil and gas industry over five decades ago.  They are used extensively on oil and gas pipelines throughout Western Canada and the United States. They provide an efficient way to launch and retrieve pigs in the oil and gas industry, water treatment facilities, or anywhere critical pipelines need to be maintained.

Pigging is used to mechanically sweep and/or visually inspect inside of the pipeline. The pig or scraper is moved through the line by the differential pressure caused by the process fluid moving past at a higher velocity. The pig is inserted into what is known as a "pig launcher" (or launching station) which is a part of the pipeline with an oversized diameter to accomodate the installation of the pig. The launching station is then closed and the pressure driven flow in the pipeline is used to move the pig down the pipe until it reaches the receiving trap (the pig catcher or receiving station) where it can be removed. Pigs are used daily in the operation of pipelines for a variety of reasons, the most common are: pipe cleaning for improved line efficiency; locating flow obstructions; pipeline inspection; separating different products flowing through the pipeline; corrosion control; air purge; water removal; and flow volume validation.

For more information about pigging valves, contact Mountain States Engineering and Controls. Call them at 303-232-4100 or visit https://mnteng.com/pig-valve.

Pipeline Cyber Security

binary stream representing industrial process control network data transfer and cyber security threat
Cybersecurity is a process control challenge that consistently evolves as new technologies come into use and new threats emerge. Since process control methods are constantly developing, the protective measures need to match the rate of change to ensure adequate levels of protection are in place. Pipelines used in the oil and gas industry, as well as in the transportation of a multitude of liquid and gaseous products, account for more than 2.3 million miles of process piping in the United States.  Natural gas pipelines are commonly monitored and controlled by, for example, programmable logic controllers or other microprocessor and communications based systems, responsible for flow regulation and various process conditions. Because of the prevalence of these systems, they are a target of increasing attacks, on both PLCs and other SCADA related devices, such as compressors, remote terminal units, communication networks, and other critical process infrastructure elements.

While developments in technology have provided operating advantages and improvements to the process industries, the more complex and advanced the systems may also increase the exposure to malicious penetration and mischief by unauthorized parties (hackers). Because of this, diligence by industry professionals, while always a strong component of protecting against outside threats, has been augmented via new guidelines meant to better prepare all process operators against more coordinated cyber-attacks.

Basic preventative measures, such as a firewall, are no longer a sufficient bulwark against the increasing threats. Instead, the entire process must be evaluated and monitored so that each individual piece of the network is understood fully. If a part of the system starts behaving in an abnormal way, then an understanding of what that specific PLC or component affects must be immediately known. The most effective protective programs will be able to function without needing any downtime, and will also be able to learn the network easily. Whenever the defense program gets triggered, it needs to not only provide a general alert to the process operator, but must also be able to provide context so that the previous knowledge of how the system works can be applied to mitigate the current problem.

Currently, the oil and gas industry has transitioned to what is being termed a ‘holistic’ approach to cyber defense. In order for the best security possible to be employed, the human element of process control must function in tandem with the autonomous programs. The human component of process operation, where it exists, can be unpredictable and present vulnerabilities that may not be known or anticipated. Everything must be considered.

Industrial process operation involves many areas of risk, with cyber attack being just one. The right kind of planning and response to risk can mitigate the potential impact. Security efforts, technology, and knowledge must keep pace with threats which emerge to process pipeline security. Mountain States Engineering and Controls participates in the oil and gas industry throughout the western U.S.

Wellhead Valves Meet Special Application Challenges

Wellhead in oil and gas industry with equipment and valves
Numerous valves are employed at oil and gas production site
Industrial valves are manufactured in a huge array of configurations to accommodate the specialized needs of a broad range of industrial process applications. The oil and gas industry is but one segment of many throughout the industrial sphere that presents its own set of application specific criteria.

Oil and gas production, essentially pulling raw material from the earth, has unique valve performance challenges. Extreme pressure and abrasive or erosive material are common elements of oil and gas production at the wellhead. The valves also need to tolerate the range of outdoor temperatures at the production site. Safe and reliable operation throughout these and a range of other conditions are part of the design criteria for these valves. Here are some of the specific valve variants and configurations applied in the oil and gas industry at the production wellhead.
swing type check valve for oil and gas production wellhead or manifold
Swing Type Check Valve
Courtesy DHV Indutries
cutaway view of slab gate valve for oil wellhead use
Cutaway view of Slab Gate Valve
Courtesy DHV Industries

  • Slab Gate Valve - Provides metal to metal seal and employs parallel gate and seal with a preloaded spring to assure positive upstream and downstream seal. Full port design allows for pigging.
  • Expanding Gate Valve - A parallel expanding gate seals positively against both seats, which are protected from the flow medium in the open and closed positions.
  • Mud Gate Valve - Designed to provide positive closure under rigorous field conditions with abrasive media. 
  • External Sleeve Adjustable Choke Valve - Designed to regulate production well flow and downstream pressure. Different trim configurations provide appropriate levels of control.
  • Needle Adjustable Choke Valve - Utilizes different trim arrangement than external sleeve type to provide good flow management, abrasion resistance, erosion resistance, and reliable service over a long life with low maintenance requirements.
  • Check Valve - Check valves of various types are utilized throughout practically all fluid flow operations, essentially anywhere that fluid is supposed to flow in only one direction. Oil and gas production presents some special conditions of abrasion, erosion, and pressure that call for special accommodation in design and materials of construction.
There are other specialty valves employed at or near the wellhead, but the key take away here is that oil and gas production generally cannot be accommodated by general purpose valves. I have included a document below that provides additional data and engineering detail for the valves touched upon in this article. Share your oil and gas production challenges with a valve specialist. The combination of your process and production experience with their product expertise will produce effective solutions.