Introduction to Hot Tapping & Line Stopping

What is a Hot Tap and why it is made?

Hot Taps or Hot Tapping is the ability to safely tie into a pressurized system, by drilling or cutting, while it is on stream and under pressure.

Typical connections consist:

• Tapping fittings like Weldolet®, Reinforced Branch or Split Tee. Split Tees often to be used as branch and main pipe has the same diameters.
• Isolation Valve like gate or Ball Valve.
• Hot tapping machine which includes the cutter, and housing.

What Is Underwater Welding?

Many of us won't have heard of underwater welding, but it's actually a very important thing in many industries. Underwater welding includes a lot of different processes that join steel on offshore oil platforms, pipelines, ships, and in many other applications.

Underwater Welding

It can be done at regular or at high pressures, and can be done in a wet environment or a dry one. Let's take a look at some of the benefits and downsides of different kinds of welding underwater, and the uses of this interesting technique.

Underwater Pipeline Inspection

XPLISIT

Pipeline owners in the North Sea normally inspects their pipelines at regular intervals. On the outside the condition of the pipe as well as the close proximity of the pipe are of special interest. Free spans, debris, fish nets and World War II mines are states and objects that will be reported. In the eighties traditonal video cameras and storage on analogue video tape were the state-of-the-art technology giving huge amounts of video cassettes. Some of the oil companies even rented huge barnes to store analogue video tapes.

Back in 1988 Norsk Elektro Optikk (NEO) proposed to use line scan cameras and digital storage for pipeline inspection. The main advantage of this concept was a reduction in the amount of data and the volume requirement of the storage media. A second feasibility study was performed in 1993 and the main development project started in 1994.

Xplisit is a dicontinued product. Below is explained the principle of operation. A total system concept is also shown as well as some of the results.

New Standards to Control Pipeline Corrosion

Many factors can cause pipeline failures, including overpressure, weld resistance, joint issues and construction damage. Yet, in the last 15 years, almost 60% of oil and gas production pipeline incidents in Canada have been caused by internal corrosion.

Corrosion is the deterioration of a substance, usually a metal, due to interaction with its environment. Oil and gas pipelines are vulnerable to corrosion in part because of the use of carbon and low-alloy steels.

Adding corrosion inhibitors, or chemical substances that decrease corrosion rates, is one of the most effective methods to control internal corrosion of pipelines. However, no single inhibitor suits all situations, which creates a challenge for industry when it comes to selecting the best product for the job.

To help oilfield and refinery industries select and use the best corrosion inhibitors, Natural Resources Canada’s CanmetMATERIALS, CanmetENERGY-Devon laboratories and industry partners have developed five standards for the testing and use of corrosion inhibitors.

A close up of the CANMET corrosion test
flow loop at an operating oil wellhead

Pipeline Route Selection

Oil and gas pipeline routes are pivotal pieces of information upon which pipeline engineering depends. The route will define the pipeline size, terrain, soils, and engineering analysis requirements. Engineering assessment based upon agreed alignment selection criteria is an important part of a linear project. To be able to reach the best construction line and optimise its components, the phases – namely corridor, route, alignment, and construction line selection — should be studied in the given order.

Subsea Pipeline

New Deepwater Pipeline Concept

London: DNV has developed a new pipeline concept, called X-Stream, that can significantly reduce the cost of a deep- and ultra-deepwater gas pipeline while still complying with the strictest safety and integrity regime. X-Stream is based on established and field-proven technologies which have been innovatively arranged.

Asle Venås, DNV’s Global Pipeline Director,
presenting the X-Stream gas transportation concept