Patent Application
20210231250
This disclosure relates generally to subsea oil and gas production facilities, and particularly to flowline jumpers extending between a subsea component and a subsea pipeline. The disclosure further relates to thermal management of such subsea pipeline using jumpers.
The production of hydrocarbons from offshore oil and gas reservoirs requires the transportation of production fluids from the reservoirs to subsea facilities for processing. Three phases, i.e., oil, gas and water, may be included in the production fluids. Subsea developments increasingly must accommodate high temperature production fluids that need to be safely transported to the production facility. The high temperature of the production fluids can have several undesirable effects. Special grade subsea pipeline materials, extensive qualifications of insulation coating and expensive modifications topsides may be required to handle the high temperature of the product. For instance, water cooled heat exchangers may be used topsides on an offshore platform to reduce the temperature of production fluids, e.g., from around 400° F. to a temperature below 250° F., involving weight, space, cost, etc. In the subsea facility, the high temperature of the product may undesirably result in the occurrence of upheaval buckling, lateral buckling and pipeline walking in flowlines (also referred to as subsea pipeline or conduit) carrying the product. The temperature may also undesirably accelerate corrosion and therefore reduce the life of the flowlines. Attempts have been made at providing a subsea cooling system for use with gas production. No established oil or three phase subsea cooling system is available in the industry.
There exists a need for cost-effective subsea cooling systems and methods to enable the development of high temperature subsea fields without the disadvantages of known systems.
In general, in one aspect, the disclosure relates to a system for thermal management of a subsea conduit or pipeline that carries oil and/or gas produced from a subsea well in a subsea production facility located on a seabed. The system includes a jumper for carrying produced fluid, the jumper having a first end for connecting to a first subsea component, and a second end for connecting to a second subsea component. The jumper includes a jumper segment that is sloped relative to the horizontal, such that gravity assists with drainage of fluid from the second end of the jumper independent from fluid pressure in the jumper. At least a portion of the jumper is uninsulated to allow exchange of heat with seawater surrounding the jumper as produced fluid travels through the jumper.
In another aspect, the disclosure can generally relate to a method for thermal management of the subsea conduit in the subsea production facility. The method includes transmitting production fluids between subsea components in the jumper described above. The amount of insulation on the jumper can be varied such that heat transfer from the production fluids to seawater surrounding the jumper circuit is adjusted as desired.
These and other objects, features and advantages of the present invention will become better understood with reference to the following description, appended claims and accompanying drawings. The drawings are not considered limiting of the scope of the appended claims. Reference numerals designate like or corresponding, but not necessarily identical, elements. The drawings illustrate only example embodiments. The elements and features shown in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the example embodiments. Additionally, certain dimensions or positionings may be exaggerated to help visually convey such principles.
Referring to
Systems and methods for thermal management of subsea pipeline 30 will be described. In one embodiment, referring to
At least a portion (e.g., a segment 10S) of the jumper 10 is uninsulated to allow exchange of heat with the cooler seawater surrounding the jumper 10 as produced fluid travels through the jumper 10. In one embodiment, multiple jumpers 10 can be connected together to achieve the desired amount of cooling. Thus, hot produced fluids can cool as they are transmitted through the jumper(s) 10 to the insulated pipeline 30. As a result, the insulated pipeline 30 can be maintained within its qualified temperature range, i.e., temperature spikes can be avoided. Similarly, the platform arrival temperature can be maintained within its qualified temperature limits.
Furthermore, thermal expansion of the pipeline 30 can be avoided or minimized since use of the systems and methods of the disclosure reduce the temperature of produced fluids reaching the pipeline 30. Thus the effects of pipeline walking, lateral buckling or upheaval buckling can be avoided in the insulated pipeline 30, since these phenomena are known to be caused by thermal expansion of the pipeline.
In one embodiment, the jumper 10 can be shaped in such a way that not only ensures self-drainage, but also thermal expansion. Referring to
In one embodiment, the amount of insulation on the jumper 10 can be varied such that heat transfer from the production fluids to seawater surrounding the jumper 10 is adjusted as desired. For instance, in one embodiment, referring to
However, such replacement of the jumper with fully insulated piping requires subsea vessel mobilization and shut down of the platform that results in loss of revenue. In order to avoid this shutdown of production and loss of revenue, during late life when the product temperature reduces and cooling is not required, referring to
In one embodiment, referring to
It should be noted that only the components relevant to the disclosure are shown in the figures, and that many other components normally part of a subsea oil and gas field are not shown for simplicity.
For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural references unless expressly and unequivocally limited to one referent.
Unless otherwise specified, the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub-generic combinations of the listed components and mixtures thereof. Also, “comprise,” “include” and its variants, are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that may also be useful in the materials, compositions, methods and systems of this invention.
