Offshore oil rigs are large structures that include equipment and facilities for drilling oil wells in the seabed to explore, extract, store, and/or process petroleum and natural gas. There are various types of offshore oil rigs including, for example, drilling barges, submersibles, fixed platforms, jackup rigs, tension leg platforms, spar platforms, etc. Offshore rigs generally include a derrick to support a drillstring, a rotary table or top drive to provide power to turn the drillstring, drawworks to reel out and reel in a drilling line, power generation equipment, mud tanks, and mud pumps.
Extraction and production of petroleum crude oil also results in the production of natural gas and other associated petroleum gases. Many offshore rigs do not have the equipment or ability to transfer or process all of the produced natural gas. Gases that cannot be processed or sold or that result from offshore well testing are flared. Flaring the gases helps reduce the threat of poisoning (inhalation) and explosions, and help regulate pressure. Offshore rigs include a gas flare for flaring unprocessed natural gas. A gas flare is a gas combustion device that includes burners to burn the combustible gases. First, the gases may be separated from the liquids and solids and then sent to a flare or flare stack where the gas is burned and released into the atmosphere.
In one aspect, embodiments disclosed herein relate to an apparatus for collecting spilled liquid hydrocarbons including a support beam coupled to an oil rig, the support beam positioned below a flare boom, and a spill pan coupled to an end of the support beam, the spill pan positioned below a burner nozzle of the flare boom.
In another aspect, embodiments disclosed herein relate to an apparatus including an offshore rig including a hull, a main deck, and a flare boom coupled to the hull proximate the main deck, the flare boom having a burner nozzle, and an oil spill collector coupled to the offshore rig, the oil spill collector including a support beam coupled to the offshore rig, and a collection device coupled to an end of the support beam and positioned below the burner nozzle.
In another aspect, embodiments disclosed herein relate to a method including coupling an oil spill collector to an offshore rig below a flare boom, the oil spill collector including a support beam coupled to the offshore rig and a collection device coupled to an end of the support beam, positioning the collection device below a burner nozzle of the flare boom such that the collection device is horizontally aligned with the burner nozzle, and collecting spilled liquid hydrocarbons in the collection device from the flare boom.
Other aspects and advantages of the invention will be apparent from the following description and the appended claims.
The following is a description of the figures in the accompanying drawings. In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn are not necessarily intended to convey any information regarding the actual shape of the particular elements and have been solely selected for ease of recognition in the drawing.
In the following detailed description, certain specific details are set forth in order to provide a thorough understanding of various disclosed implementations and embodiments. However, one skilled in the relevant art will recognize that implementations and embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, and so forth. For the sake of continuity, and in the interest of conciseness, same or similar reference characters may be used for same or similar objects in multiple figures.
Embodiments disclosed herein are directed to an apparatus and method for collecting hydrocarbon fluids that may not be combusted during a flaring operation. During flaring operations on offshore rigs, operating companies face concerns of oil falling into the sea below. For example, if a burner nozzle of a flare boom has a nozzle washout, the burner nozzle becomes partially plugged or leaks, or oil or condensate accumulates in a gas pipeline (slug), liquid hydrocarbons may suddenly drop into the sea and cause an oil spill. Such an oil spill could have environmental impacts that could lead to operational shutdown of the oil rig and require an oil spill cleaning operation, both of which can be costly and timely.
Further complications of flaring operations may include restrictions on the time of day such operations may take place. Generally, flaring is often restricted to daylight hours to enable monitoring of the flaring operation to avoid any spills into the sea. Such limited hours of operation of the flares limits optimization of the flaring operations.
One or more embodiments disclosed herein, therefore, relate to an apparatus and method for collecting liquid hydrocarbons from a flare on an offshore rig to reduce or prevent hydrocarbon fluids from falling into the sea. In accordance with one or more embodiments, an apparatus for collecting spilled liquid hydrocarbons may include a collection device, such as a spill pan, coupled to an end of a support beam extending from an oil rig. The collection device may be positioned below a flare boom extending from the oil rig. The position of the device is such that any liquid hydrocarbons that fall from the flare (i.e., from or proximate the burner nozzles coupled to the flare boom) will be collected by the collection device. Liquid hydrocarbons collected in the collection device may then be returned to the oil rig via, for example, a flow line and pump.
Referring to
A derrick 106 extends from a rig main deck 108 of the offshore rig 100 for supporting a drill string (not shown). As shown, the derrick 106 may be located toward an aft portion 113 (
The flare boom 110 includes a truss structure 116, as shown in
Referring to
As shown in
In one or more embodiments, the support beam 126 may be coupled to the hull 102 at a location proximate a lower surface 130 of the hull 102. As shown in
The positioning of the support beam a distance below the flare boom 110 provides an air gap 132 between the burner nozzle(s) 120 and liquid hydrocarbons or oil collected in the collection device 128. The air gap 132 helps ensure that collected liquid hydrocarbons are sufficiently distanced from the burner nozzle(s) 120 and resulting flames so that the collected liquid hydrocarbons do not combust within the oil spill collector 124. The height of the air gap, i.e., a vertical distance between the flare boom 110 and the support beam 126, may be selected based on a size of the hull 102 of a particular offshore rig 100 and a distance determined to ensure flames of the burner nozzle(s) 120 cannot reach the oil spill collector 124. For example, in one example, hull 102 may have a height of approximately 20 ft (6 m) and the oil spill collector 124 may have a height of approximately 3 ft (1 m) and be positioned on the side of the hull 102 proximate the lower surface 130 of the hull 102. Thus, in this example, height of the air gap is approximately 17 ft (5 m). However, one of ordinary skill in the art will appreciate that the length of the air gap may vary and may be between, 10 ft (3 m) and 15 ft (4.5 m), 15 ft (4.5 m) and 18 ft (5.5 m), or 18 ft (5.5 m) and 20 ft (6 m).
In accordance with one or more embodiments, the support beam 126 may be a hydraulic beam such that the support beam 126 may be hydraulically actuated, including extended or retracted horizontally, or moved vertically. For example, in one embodiment, as shown in
The collection device 128 is coupled at or proximate to the end of the support beam 126. Generally, in one or more embodiments, the collection device 128 is an open topped structure configured to receive and collect liquid hydrocarbons falling from a burner nozzle(s) 120 and/or an end of the flare boom 110. The collection device 128 may be shaped so as to collect the liquid hydrocarbons and funnel the liquid down toward a bottom 142 of the collection device 128. For example, the collection device 128 may be cylindrical and/or conical in shape, or may be any other suitable shape that is deep enough to avoid oil splatter of the collected oil. A suction line 144 may be coupled to the bottom 142 of the collection device 128 to drain the liquid hydrocarbons from the collection device 128 and return the liquid hydrocarbons to the offshore rig 100. A suction pump 146 disposed on the offshore rig 100, for example, on the rig main deck 108, may be coupled to the suction line 144 to draw the liquid hydrocarbons from the collection device 128 and pump the collected liquid hydrocarbons back up to the rig main deck 108. Once on the rig main deck 108, the liquid hydrocarbons may be pumped into a surge tank 148, processed, or returned to the flare boom 110 for combustion. The suction line 144 may be manufactured from heat resistant alloys, such as iron, nickel, and/or cobalt, to withstand high temperatures of the collected liquid hydrocarbons after passing through the burner nozzle 120.
The suction line 144, coupled to the bottom of the collection device 128, may extend from the collection device 128 to the hull 102 along the support beam 126. For example, as shown, the suction line 144 may be positioned below the support beam 126 and may be coupled at various locations along the hull 102 as the suction line 144 returns the collected liquid hydrocarbons to the rig main deck 108. The suction line 144 may also be coupled at one or more locations along a length of the support beam 126. In one or more embodiments, a length of the suction line 144 may be varied to accommodate extension and retraction of the support beam 126 during positioning of the collection device 128 with respect to the flare boom 110. A diameter of the heat suction line 144 may be selected based on, for example, the length of the flare boom 110, and, therefore, the length of the suction line 144 extending from the hull 102, or a desired flow rate through the suction line 144. In one example, the diameter of the suction line 144 may be approximately 4 in (10 cm). However, in other examples, the diameter may be approximately 2 in (5 cm), 3 in (7.5 cm), 5 in (12.7 cm), etc.
The collection device 128 may be coupled to the end of the support beam 126 by any means known in the art, such as welding, mechanical fasteners, etc. The collection device 128 includes an open top 150 and a coupling for the suction line 144 at or near a bottom of the collection device 128. The collection device 128 may be manufactured from heat resistant alloys, such as iron, nickel, and/or cobalt, to withstand high temperatures of the collected liquid hydrocarbons after passing through the burner nozzle 120.
The first and second sections 766, 768 of the collection device 728 may be manufactured separately or integrally formed. The size of the collection device 728 may vary depending on, for example, the size of the support beam (126,
The first and second sections 866, 868 of the collection device 828 may be manufactured separately or integrally formed. The size of the collection device 828 may vary depending on, for example, the size of the support beam (126,
A method in accordance with embodiments disclosed herein is shown in
The method further includes collecting spilled liquid hydrocarbons in the collection device that are not burned from the flare boom, as shown at 974. Positioning of the collection device below the burner nozzle of the flare boom such that the collection device is aligned with the burner nozzle in a horizontal direction ensures that falling liquid hydrocarbon droplets are collected in the collection device and do not reach the sea.
The oil spill collector may further include a suction line coupled to an outlet of the collection device and a suction pump coupled to the suction line. In accordance with one or more embodiments disclosed herein, the method may further include pumping the collected spilled liquid hydrocarbons with the pump to move the collected spilled liquid hydrocarbons from the collection device to a tank on the offshore rig, as shown at 976. The support beam is located or positioned such that the collection device is spaced vertically below the flare boom a distance to provide an air gap between a flare of the burner nozzles and the collected spilled liquid hydrocarbons. The air gap ensures a safe distance between the flare and the collected spilled liquid hydrocarbons to prevent the collected spilled liquid hydrocarbons from combusting within the oil spill collector.
Embodiments disclosed herein may advantageously provide an apparatus and method for collecting spilled liquid hydrocarbons that fall from a flare boom without combusting from a flare. Embodiments disclosed herein may provide an apparatus and method that help prevent liquid hydrocarbons from falling into the sea and thereby prevent an oil spill. Thus, embodiments disclosed herein may help prevent environmental pollution. Additionally, embodiments disclosed herein may provide increased time for flaring operations on an offshore rig. For example, the protection from an oil spill provided by an oil spill collector as disclosed herein may allow for flaring operations to be run during non-daylight hours, or 24 hrs a day continuously, which may optimize the flaring operation.
While the method and apparatus have been described with respect to a limited number of embodiments, those skilled in the art, having benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope as disclosed herein. Accordingly, the scope should be limited only by the attached claims.