When operating in a subsea environment with long subsea pipelines and risers, one of challenges is to keep up a sufficient production rate and the right amount of pressure to flow fluid from the wellheads to the production facilities. Due to this reason, multiphase pumps are widely used in subsea operations in order to overcome these issues.
Coiled tubing was developed in 1970s and is one of the most important pieces of well intervention equipment in the oil and gas industry. There are several different types of it available in the industry market with several different designs of a coiled tubing unit; however, the components of a coiled tubing unit are very similar. The main differences are performance capabilities and hydraulic power control systems. This article will give an overview of the essential components of a coiled tubing unit. (Read about the history of coiled tubing here – Introduction to Coiled Tubing (CT) in Oil and Gas)
Figure 1 shows the mounted truck coiled tubing unit, which is normally used for the land operation and Figure 2 is the coiled tubing unit used for operating in an offshore environment.
Figure 1 – Coiled Tubing Unit on a Truck (Courtesy of Stewart & Stevenson)
Figure 2 – Offshore Coiled Tubing Unit (Courtesy of NOV)
Development of the coiled tubing like we know it today started in early 1960’s. Now it is an important component of various workover and service applications. While still the use of Coil Tubing is about 75% in workover/service applications, the technical advancements have resulted in an increase in utilization of Coil tubing in drilling as well as completion applications.
Ability of performing remedial work on live well was an important driver associated with development of Coil Tubing. In order to achieve this feat, there was a need to overcome three different technical challenges: These were:
Coiled Tubing Unit (Credit: ShutterStock)
The Origin of Coiled Tubing Continue reading
This section will compare the pros and cons of both vertical subsea trees and horizontal subsea trees and list the criteria to select a subsea tree.
A subsea horizontal tree is designed so that all flow control valves are outside the central wellbore. A tubing hanger is located inside of a subsea horizontal tree body. A horizontal tree is well known as a workover friendly tree because it offers easy access for tubing retrieval because the valves are not located at the centre of the wellbore. Figure 1 shows an image of a horizontal subsea tree from GE oil and gas.
Figure 1 – Horizontal Subsea Tree Model VetcoGray M-Series MVXT and MHXT (Courtesy of GE Oil & Gas)
