Subsea Induction Heating Technology Solves Hydrate and Wax Issues in Subsea Flowlines

Abstract

A new technology called local heating offers the possibility of significantly raising the temperature of the multiphase production fluid in order to improve flow assurance and consequently the economics of field developments. Heating the flowlines is a way to overcome the thermal constraints, mitigate hydrate & wax risks and provide operational flexibility. Indeed, in the case of long distance tie-backs, very deepwater applications or when the fluid temperature at the wellhead is too low, conventional flow assurance solutions might be very expensive or even not applicable. While other heating technologies such as DEH and Heat tracing are only used under transient operations (start-up, shutdown, preservation), local heating is a different solution, mainly to be used continuously during production and also during transient operations as long as there is fluid circulation in the flowline. The local heating device is a very simple and robust system integrated into a compact subsea module, installed in parallel of the main flowline and which can be retrieved for maintenance or relocated. The technology is compatible with any type of field architecture and can be implemented either on greenfields or brownfields. In the case of greenfields, the use of local heating is a way to mitigate uncertainties on production fluid temperature or solve an unexpected poor thermal performance of the design. The main principles of the local heating technology, as well as a preliminary design performed for a specific case provided by an operator, will be described in the paper. This solution is based on induction and is therefore able to provide very high-power levels (several MW) with a compact module. The temperature is continuously monitored throughout the heating module by means of fiber optic distributed sensors. The technology is fully compatible with preservation by flushing and allows pigging in the event of deposits. The paper will also present the qualification work performed by Saipem to date including heating performance tests performed mid-2018 on a small-scale submerged prototype operated under atmospheric conditions with multiphase fluid. The tests have confirmed the good electrical and thermal behaviour of the system. The next qualification step entails new tests to be performed on a medium scale prototype using crude oil as process fluid. The main objective is to qualify the heating performance tests and the fabrication method of the local heating module under representative conditions: representative process fluid and representative module geometry. The intention is to perform these tests on an existing Brazilian onshore test site in the frame of a JIP.

A Comprehensive Review on Well Completion Operations and Artificial Lift Techniques for Methane Gas Production from Natural Gas Hydrate Reservoirs

“… Induction heater (IH): Induction heating is a process of producing varying magnetic fields by using a source of electrical energy, which is then used to heat a conductor without direct contact. This entire phenomenon is governed by Maxwell equations and has certain advantages over other heating technologies, such as high power density, energy efficiency, noncontact process, and provides uniform power . In gas hydrate reservoirs, there is always a risk of gas hydrate reformation with the gaseous fluid near the sea floor.…”

“…Therefore, IHs are installed to prevent hydrate reformation in the borehole and prevent plugging by locally heating the multiphase production fluids in the wellbore. IH not only helps in generating additional heat fostering flow assurance but also helps in maximizing gas separation from the water train, thus improving economics of field developments Bridge plug: Bridge plug is a down-hole tool that is composed of slips, a mandrel, and a sealing element .…”

“…This entire phenomenon is governed by Maxwell equations and has certain advantages over other heating technologies, such as high power density, energy efficiency, noncontact process, and provides uniform power. 115 In gas hydrate reservoirs, there is always a risk of gas hydrate reformation with the gaseous fluid near the sea floor. Therefore, IHs are installed to prevent hydrate reformation in the borehole and prevent plugging by locally heating the multiphase production fluids in the wellbore.…”

“…IH not only helps in generating additional heat fostering flow assurance but also helps in maximizing gas separation from the water train, thus improving economics of field developments. 115 (e) Bridge plug: Bridge plug is a down-hole tool that is composed of slips, a mandrel, and a sealing element. 116 It is set as a barrier in the well that isolates the lower part of the wellbore from aquifers along with maintaining the integrity of the well.…”

Thermal system for a new flexible composite tank

“…The coil is wound on the pipe but is not in direct contact with the pipe. The coil itself does not heat after power is applied but rather uses the magnetic induction heating capacity of metal to induce self-heating of the pipe and ensure that the oil in the pipeline does not form wax plugs (Bjørvik, 2015;Yakhibbaeva and Chaturova, 2017;Anres et al, 2018;Anres et al, 2019). Many methods are used in practical engineering applications.…”