Temporary Flexible Pipelines for Oil & Gas Exploration

    Temporary Flexible pipeline systems (FPS) comprised of lay-flat hoses are proving to be an innovative solution for temporary pipelines deployment for crude oil, petrochemicals, water and other fluid delivery. They are widely used as a bypass line for the repair of oilfield pipelines and gas pipelines, as well as in hard-to-reach areas, in emergency situations and where there is a need for rapid deployment of a pipeline system.

    By Artiukhov Jurij, Commercial Chief — Balticflex, Ltd.

    Flexible pipes were introduced in the oil industry in the early 1970s. One of its first applications was in drilling as a 15,000 psi Kill and Choke line; today, more and more oil and gas companies are using flexible pipeline systems in their exploration activities and flexible pipe designs have improved to produce the flowlines and risers that are now used in the offshore oil industry.

    Permanent flexible pipes are made up of several different layers, the main components of which are leakproof thermoplastic barriers and corrosion-resistant steel wires. Helically wound steel wires give the pipe its high-pressure resistance and bending properties, and its modular construction—in which the layers are independent but designed to interact with one another— means that each layer can be customized and adjusted to meet a specific application requirement.

    By contrast, temporary flexible pipeline systems, or temporary FPS, are constructed of high-strength polymeric flexible pipeline. Flexible pipeline is manufactured by extruding polyurethane through a textile frame, filling the space between filaments. The textile framework is made on circular knitting machines and has a seamless tubular structure (Figure A). The frame provides high working pressure of the flexible pipeline, and polyurethane provides resistance to corrosion, wear resistance, oil and petrol resistance, resistance to chemical, physical, bacterial, erosion, hydrolysis and ultraviolet radiation.

    Figure A

    The flexible pipeline, or “lay-flat pipeline”, consists of 3 layers: the inner layer is a knitted framework of nylon threads, and the outer and inner layers are made of thermoplastic wear-resistant polyurethane. Through the entire length of the lay-flat pipeline, an anti-static wire is laid in the sheath, with an electrical resistance of no more than 0.5 ohms /m.

    Temporary FPS can be used to construct temporary water and oil pipelines, restore drinking /domestic water supply and wastewater disposal in emergency situations, assist in vessel bunkering and other applications.  

    This article examines temporary flexible pipeline systems for use in oil & gas exploration activities. Not just a flexible pipe for delivery from “A” to “B”, temporary FPS is a high-level engineering and technical solution, comprised of a complex system of equipment, from spooling systems to valves.

    Advantages & applications

    The main advantages of temporary flexible pipeline systems are ease and speed of installation, good insulation and resistance to corrosion and little to no maintenance required for the life of the project. In the oil & gas sector, they are used to transport oil and water from hard-to-reach areas, to create bypass lines during pipeline repair, act as water pipes and oil pipelines on exploratory wells and as temporary infield pipelines for a variety of other purposes.

    Using a temporary FPS, oil & gas companies can accomplish:

    Oil exploration before the steel pipe has been built

    Oil companies are constantly searching for new oilfields. In many cases, their search leads them to remote areas with swamp, rock or other impassable terrain. Drilling and oil well input is an expensive procedure in these conditions, and there is always the risk that the oil well will become “watered” or the amount of oil in the reserve could be very small.

    In these cases, flexible pipeline systems could be an ideal solution, as deployment, even across many kilometers of rough terrain, can be accomplished in mere hours. The company can begin exploration immediately after drilling, thereby reducing expenses.

    Construction of bypass lines

    On average, oil exploration companies will need to build bypass lines once or twice per month. In the above conditions (swamp, marsh, rock, etc.), deploying steel pipelines is next to impossible, because of serious time and financial costs. If exploration needs to be halted, it can affect the entire schedule.  By contrast, temporary flexible pipelines can be installed—in many cases—in a matter of hours, providing a full-service engineering solution from design to installment.

    Bypass while hot tapping

    Hot tapping, or pressure tapping, is a method of making a connection to existing piping or pressure vessels while the pipe or tank is in operation. This method is commonly used during maintenance or while modifications or repairs are being done to the pipe. There are economic and environmental advantages to performing this work without removing a pipe from service; this includes avoiding the release of harmful greenhouse gases, such as methane. Temporary flexible pipelines can be used as an expansion line in lieu of traditional steel pipes.

    Thermal EOR (Enhanced Oil Recovery) and steam injection

    In reservoirs containing high viscosity or heavy crude oil, steam is injected into the well to help push oil to the surface. This process requires special mobile steam equipment, which in turn needs water to operate. A water source could be very far away, but a temporary FPS can be used as a pipeline from the source to the location of the steam engine.

    This is especially useful when you consider that steam equipment is typically moved from well to well every 3–6 months, which is a serious barrier for any exploration company. Nevertheless, a temporary FPS can help alleviate that burden when compared with the cost and time expenditure of deploying steel pipelines.

    To read the article in full, which features case studies from some of the biggest names in oil & gas, please contact the Editor.