WO2013052007A1

WO2013052007A1 - Macondo oil recovery system

Info

Publication number: WO2013052007A1
Application number: PCT/SG2011/000355
Authority: WO
Inventors: Tai San NG
Original assignee: Ng Tai San
Priority date: 2011-10-04
Filing date: 2011-10-12
Publication date: 2013-04-11
Also published as: SG189558A1

Abstract

An oil recovery system consists of: a) minimum four or more buoys which is permanently anchored to seabed; b) numerous length of floating booms which can be extended or joint to suit distance between buoys and oil recovery structures; c) one or more oil recovery structures or vessel's to trap spill oil for separations, storage or pending transfer to shuttle tanker; d) one or more towing vessel's, using tow line to drop anchor and chain to seabed, for creating surface wave and pushing oil towards oil recovery structure. Several surface wave creation methods to speed up surface flow toward the oil recovery structure are also disclosed.

Description

MACONDO OIL RECOVERY SYSTEM

INTRODUCTION

[1] The presented invention is to show spill oil is being contained with various wave creating formations to help speed up and channel surface spill oil toward oil recovery structures or oil recovery vessel's for separation, before being transported to shuttle tanker or production platform.

[2]

BACKGROUND OF INVENTION

[3] Reference to oil spill at Macondo well in Gulf of Mexico, on 20^th April 2010, which caused wide spread of oil contamination to shoreline. An estimated 53,000 barrels per day of oil leak from the well before it was being stopped on July 15, 2010.

[4] The oil spill cause extensive damage to marine environment and affecting wildlife habitats and loss of fishing industries and etc. Many skimmer boats armed with floating containment boom were in operation which resulted dangerous navigational shipping route and not been properly planned. Floating boom and barricades along shoreline showed that it was not effective in stopping oil spreading to hundred miles of beaches.

[5] Oil recovery system at this junction is not able to cope with such a huge disastrous oil spill which is why the inventor has designed a system to copes with such event and called it MACONDO OIL RECOVERY SYSTEM', name after the MACONDO well in Gulf of Mexico.

[6]

DESCRIPTION OF MACONDO OIL RECOVERY SYSTEM

[7] In normal oil recovery system, an oil recovery vessel is required with aided

skimmer equipments, trawling vessels' and floating booms, to chase after thinnly spread oil spill in a vast area. As for MACONDO oil recovery system, it work exactly the opposite by permanently positioning an oil recovery structures/vessels in a designated location and attaching several floating booms to form an enclose area (Figure 12). At sametime an anchored vessels' is station within the enclosed zone to produce surface wave creation from vessel propulsion and push surface emulsified oil towards oil recovery structure (Figure 14).

[8] MACONDO oil recovery system shall consists of the following:

1. One or more oil recovery structures or offshore supply vessels, depending on depth of operation and area of containment.

2. Using floating boom to contain spill oil within defined enclosed area.

3. Method employed to aid in fast oil recovery.

[9] The system will only be effective if they above is integerated and amount of oil collected can be enormous. In any organization, an effective system is require and need to be planned and implemented. Likewise for any oil spill response in oil industries, an effective system must be carefully planned with relates to depth of operation, wave pattern and current flow direction and etc and to be further discussed and approved by responsible state authority before awarding the drilling contract. The initial plan will determine how oil recovery structure can best be positioned, to optimize surface oil flow toward its advantage.

Assumption to be made based on worst current condition and distance projection for spill oil to surface (Figure 10). Thereafter, area of containment need to defined and agreed by responsible authority

Minimum four permanent buoys or more can be positioned (Figure 11), which shall form an enclosed area when floating boom is connected. In the event of oil spill, floating boom can then be laid with special quick attachment to the permanent buoy and thus contain spill oil within the defined area.

At the same time, any oil recovery structures and vessels, positioned nearby can be deployed immediately to spill site to connect floating boom and form an enclosed perimeter.

One or more vessel's are to be anchored to sea bed with tow-line attach to anchor towing winch and within the enclosed area. Several surface wave creation methods can be form which shall speed up surface flow toward the oil recovery structure as shown in Figure 14.

Another possible way of pushing surface oil near to oil recovery structure is by utilizing existing fast rescue craft and towing floating oil boom as shown in Figure 19 & 20

Advantages of the MACONDO oil recovery system are:

1. With four minimum buoys permanently anchored, it does not obstruct any vessel navigating movements but at same time operating zone is visibly marked and easily known to navigation route

2. Can be easily modified on any offshore structure that has a wide breadth

3. Small space is taken up compare to offshore structure size and still can retain basic design of the offshore structure performance.

4. Large amount of oil can be recovered and temporary store while waiting for transfer to shuttle tanker, oil barge & etc

5. Capacity of oil recovery will increase over each day due to accummulation of trap oil spill within the enclose area and capacity recover could slowly match to the capacity of oil leakage from the well ober period of time.

6. Oil recovery structure can be instantly activate to spill site as it is usually working nearby

7. Can carry and store huge amount of chemical, oil dispersant, oil boom for emergency use 8. Can be incorporated into any supply vessel and still function their original task

9. Making use of vessel propulsion thrust to push surface oil towards the oil recovery structure is very much faster than having oil recovery vessel to chase after oil spill in vastly spread area with speed limitation.

10. Surface coverage per horse power is higher.

11. Shuttle tanker can be moored alongside the oil recovery structure without disturbing the oil recovery operation

OIL RECOVERY STRUCTURE / VESSEL

This section of the invention is the heart of the MACONDO oil recovery system. The wide opening passage is gradually narrow and pass through several sluice gates into an open sea chest concept (Figure 2 & 3) . Water level in open sea chest must be maintain below sea level to trap floating oil for separation. Oil recovered are to be temporary store in the oil recovery structure and waiting to be transferred to shuttle tanker or FPSO for further separation process. Transferring process from oil recovery structure to shuttle tanker does not hinder oil recovery operation as it is park outside the enclosed boundary area. Water pumping out from open sea chest shall pass through an oily/water cyclone, which ensure discharge is below MARPOL requirement (15ppm)

BREIF DESCRIPTION OF THE DRAWINGS

Figure 1 showed general arrangement of an offshore structure incorporated with basic oil recovery concept.

Figure 2 showed partial plan view of an offshore structure incorporated with basic oil recovery concept.

Figure 3 showed partial profile view of an offshore structure incorporated with basic oil recovery concept.

Figure 4 showed mirror images of partial offshore structure within operating range.

Figure 5 showed an oil recovery procedure Step 1

Figure 6 showed an oil recovery procedure Step 2

Figure 7 showed an oil recovery procedure Step 3

Figure 8 showed an oil recovery procedure Step 4

Figure 9 showed an oil recovery procedure Step 5

Figure 10 showed an profile view of oil leakage from blow out preventer (BOP) Figure 11 showed a plan view of an assumed oil first surface.

Figure 12 showed a plan view of area of containment enclosed by an offshore structure or vessel.

Figure 13 showed a profile view of the buoy, floating boom and offshore structure. Figure 14 showed a plan & profile view of the vessel creating surface wave and towards the oil recovery offshore structure

Figure 15 & 16 showed a plan view of area of containment with surface wave created by one vessel formation

Figure 17 & 18 showed a plan view of area of containment with surface wave created by three vessel's formation

Figure 19 to 20 showed a plan view of area of containment with fast rescue craft scoping surface oil towards oil recovery structure.

Figure 21 showed plan view of the opening access into oil containment area is being sealed to prevent oil flowing out.

Figure 22 showed plan view of the opening access into oil containment area is opened up to allow vessel access oil spill zone.

Figure 23 showed a plan view of area of containment enclosed by an offshore structure with four wave creating vessels.

DETAIL DESCRIPTION OF THE DRAWINGS

A) BASIC CONCEPT OF OIL RECOVERY STRUCTURE / VESSEL

Figure 1 showed general arrangement of an offshore structure incorporating a basic oil recovery design, which shall be used as an illustration throughout the descriptive. An offshore structure is refer as an accommodation work barge which has big storage capacity with wide opening channel and long body for shuttle tank to alongside.

Figure 2 showed partial plan view of an offshore structure with wide opening at the front and which shall converge into the narrow passage and leads to Open Sea Chest Forward (1 & 2). Three sluice gates (SGI, SG2 & SG3) are install before the open sea chest (1) for regulating water flow. Hydraulic compensator system can be incorporated to control sluice gate opening relative to wave movement.

Figure 3 showed profile view of water flow through the sluice gates and into Open Sea Chest (OSC - Forward). Opening of sluice (1) can be regulate to ensure flow-in capacity is slightly smaller than flow-out capacity and thus making level in OSC to fall below sea level. This will trap emulsified floating oil in open sea chest forward. To prevent Open Sea Chest (OSC) from dropping below certain set level , float switch (LI) will activate sea suction valve and allow more sea water to flow in. Likewise when level raise to float switch (L2), it will close sea suction valve and thus maintain level within a certain operating draught range. Oil accumulate on surface, are separate by gravity method and surface oil is drain-off / pump to collection tanks for further separation or to be transfer to shuttle tanker. Continuous incoming flow of sea water into OSC (Fwd), will flow underneath the compartment and pass though OSC (Aft). Any tiny oil particles accumulate in OTSC (Aft) will be force downward by an agitator pump, into the suction area. The oily/water is being suck in by the large capacity pump and pass through centrifugal cyclone separator or any oil separation equipment available in the market.

Figure 4 showed oil recovery structure can operate within certain draught by lowering the sluice gate to suit the flow rate. With an operating draught range, offshore structure need not to be constantly trim or ballast which can hinder oil recovery operation.

B) OIL RECOVERY PROCEDURE

Figure 5 (Step 1) - Fill-up Open Sea Chest (OSC) with sea water up to draught of the offshore structure by opening/lowering down the sluice gate to below the sea water level. Design of sluice gate can be of electrical or hydraulic operated.

Figure 6 (Step 2) - Keep centrifugal pump running and manipulate opening of sluice gate slowly until the level in OSC start to drop. Bear in mind that the wave oscillating movement can affect the flow, therefore it is best to have three sluice gates opening at different height to ensure that at least one of the gate is almost at all time below the sea water level or design of sluice gates opening can be control by hydraulic compensator system.

Figure 7 (Step 3) - When sea water flow into OSC is smaller than outlet flow, water level in OSC will fall to LI level, then the float switch will activate and open sea suction valve which will allow sea water to flow into OSC. When level reaches L2, it shall close sea suction valve. The frequency of Cut In/Out of the sea suction valve shall depend on inlet and outlet flow differences. Agitator is constantly in operation to ensure no surface oil is accumulated in OSC (Aft). A 15ppm centrifugal cyclone will ensure that sea water pumping out is not contaminated with oil.

Figure 8 (Step 4) - Level in OSC is maintained within the operating range and these will ensure no surface oil is able to flow out and thus trapped oil in OSC (Fwd). When oil accumulates reach SI level, it will open solenoid valve (SV1/SV2) and drain/pump oil into Oil Recovery Tank (ORT)

Figure 9 (Step 5) - Likewise, when oil reaches S2 level, it will close the solenoid valves (SV1 & SV2) or stop eccentric screw pump. Numbers of solenoid valve or diameter of the pipes and valves can be increased to require oil recovery capacity.

C) AREA OF CONTAINMENT

Figure 10 showed oil leak from under the seabed, thousand meters below surface level, it is important to gauge how far oil will surface from point of leak and decide where to station offshore structure from point of leak. Under water current will affect how far it will surface and we have to predict that in worst scenario.

When oil leak from under seabed, thousand meters below sea level, oil and gas will jet up immediately and break into oil droplets and gas bubbles, which will form into raising plume. Gas present in the rising plume will ultimately absorbs into the sea water which in turn will render rescue operation safe at the surface level. For safety precautions, all electrical fixtures exposes on open deck must be of explosion proof standard. It is rather difficult to gauge when spill oil will surface on the water as it will depend on the followings:

Surface current are mostly cause by wind

Deep water current cause by density difference at different water depth due to salinity and temperature changes

Buoyancy of the oil droplets will varies according to their size and etc

Some fine oil droplets will take much longer time to surface and are most difficult to predict where else the large oil droplets will usually surface within hour. This group of large oil droplets will eventually surface and can be sighted by scanner or human naked eyes and immediate action to contain this group of spill oil shall be taken.

Figure 11 showed four buoys laid in a square formation of 2450m apart as per Figure 10 prediction. Without proper contingency plan, once oil spill spread it almost a disastrous to the environment, marine life and people lively hood is affected greatly. It is not possible to have the working area surrounded with oil boom during normal operation but we can permanently laid buoy within assumed area of containment. When oil spill occur, the oil boom can be easily fitted within short span of time to prevent from spreading further. To have fast and easy fitting, it shall be discussed and standardized for usage anywhere.

Minimum of four buoys are to be position permanently to effectively contain spread of oil. When oil spill occur, oil boom can be laid first before any oil recovery structure or vessel is been deployed.

Base on depth of water we can lay buoy permanently in place within assumed area of containment. Position of the buoy has to be planned subject to following condition:

1. Rig anchor laying pattern. We can even make use of rig anchor buoy if it is within oil spill containment area.

2. Under sea pipes laying condition around operating zone .

3. Numbers of offshore structure to be deployed.

4. Position of offshore structure can be located at any of the buoy.

Figure 12 showed an assumed area of containment is enclosed by floating boom in the event of oil spill. It is important to have oil recovery disaster plan with the following considerations:

1. Under water current pattern to be determine so that offshore structure can be position to its best advantages. But in general this shall not be a big concern as the area of plan containment is much bigger and should be able to contain within the specified area. Once decision has been decided, it should be easier for barge master to decide locating the offshore structure, at any of the four mooring buoy.

2. Standby proper tools for removing and cleaning of connection area due to fouling or barnacles.

3. As oil boom to be laid is extremely long, plan shall state which supply vessel or oil recovery structure should carry the oil boom.

4. Numbers of supply vessel to be deployed to assist in laying the oil boom

Figure 13 showed a partial profile view of a moored oil recovery structure, floating boom and buoy secured to the bottom of sea. Detail dimension and design has to be studied further as buoy size are subject to depth of operation area and types of mooring lines to be used. Oil recovery structure or vessels can be moored using its mooring system or dynamic position system.

D) METHOD TO AID IN FAST OIL RECOVERY

Oil recovery structure can only create high surface velocity within few meters away from its opening passage which will made oil recovery process slow. Following are several ways to make surface oil few hundred meter away, flow toward the offshore structure in fastest way in order to achieve maximum oil recovery:

1. Making surface wave created by propulsion trhust

2. Using floating oil boom to scoop surface oil towards oil recovery structure.

DMAKING SURFACE WAVE CREATED BY PROPULSION THRUST

Secured tow wire onto the center of the offshore structure or buoy or drop anchor in front of offshore structure as shown in Figure 14 and pay out tow wire several hundred meters away with engine running, just like performing a bollard pull condition. When moored structure are anchored down by four point mooring, with tugboat and offshore structure in stationary position, surface oil will flow toward offshore structure. Tow wire can be release longer to reach further and push more oil towards the offshore structure. This method is the most effective as surface spill oil can travel few kilometers at higher speed with much wider surface coverage area. Speed and coverage area will varies according propeller thrust load. Point to take note are that safety range from floating boom has to established, in order to ensure that propeller thrust do not force spill oil out under the floating boom. Following are several formations of making wave flow toward oil recovery structure:

1. Figure 15 showed one vessel position in (Posn.l), is used to create surface wave toward oil recovery structure. Vessel is steered to position (Posn.2) as shown in Figure 16 to cover wider surface area

2. Figure 17 showed three vessels position in (Posn.l), are used to create

surface wave toward oil recovery structure. Vessels are steered to position (Posn.2) covering three sets of triangle area, as shown in Figure 18 . The surface wave do not stop at the end of the triangle but will continue moving until all the energy dies off or discharge to ocean. Number of vessels can be increase shall depend on area of containment

2^{^}1 USING FLOATING OIL BOOM TO SCOOP SURFACE OIL TOWARDS OIL RECOVERY STRUCTURE

Following are procedures to scoop surface oil towards oil recovery structure:

1. Figure 19 showed vessel trawling floating boom and moving away from oil recovery structure to position (Posnl), with one end of floating boom secured to the oil recovery structure. Thereafter it shall move to position (Posn.5) in anti-clockwise direction, which scoop surface oil toward open sea chest inside the oil recovery structure.

2. As shown in Figure 20, floating boom is passed round the motor driven

vertical roller (7) and moving away to position (Posn.6). Floating boom secured at one end and the vertical roller shall form an enclose loop which will eventually get smaller when vessel moves away from the oil recovery structure. Surface oil will flow pass sluice gate (8) and into open sea chest (9) which trap oil. Whole process can be repeated again in the clockwise direction by swapping secured end of the floating boom from port to starboard

E) OPENING ACCESS TO OIL CONTAINMENT SITE

If containment is fully enclosed by floating oil boom an alternative method is needed to allow maintenance vessel/drillship/etc to enter the enclose zone .

1. Figure 21 showed plan view of the opening access into oil containment area is being closed at all time to prevent oil from escaping. A vessel (Posn.l) is creating surface wave from the propulsion thrust to push surface oil toward oil recovery structure

2. Figure 22 showed plan view of the opening access into oil containment area is opened up. When any drill ship/maintenance vessel/etc, is required to enter the enclosed site, a trawling tug/standby skimmer vessel (1) is required to open the short length of floating boom (2) and at same time the vessel is move to position (Posn.2), which is out of the enclose zone and keeping the tow wire as close to any of the moored buoy. A clear passage is created (arrow indicated) between the two moored buoy and any maintenance vessel can easily access to the enclose area. Due to the wave creation from the

■ propulsion thrust, which is sucking clean water from outside the enclose area, thereby preventing oil from escaping out of the enclosed zone. Any small amount of oil escaping out from initial opening of the floating boom can be picked up by standby skimmer vessel outside of the enclosed zone.

F) DRAWING FOR ABSTRACT - Figure 23 showed oil spill is begin surrounded by floating oil boom and oil recovery structure (1) and with four units of wave creating vessels (2) pushing surface oil spill towards the opening channel of oil recovery system. At the sametime the shuttle tanker (3) is parked alongside the oil recovery structure but outside of the oil spill with do not hinder oil recovery operation.

Claims

MACONDO OIL RECOVERY SYSTEM is an integrated system which consists of: a) minimum four or more buoys which is permanently anchored to seabed; b) numerous length of floating booms which can be extended or joint to suit distance between buoys and oil recovery sturctures; c) one or more oil recovery structures or vessel's to trap spill oil for separations, storage or pending transfer to shuttle tanker; d) one or more towing vessel's, using tow line to drop anchor and chain to seabed, for creating surface wave and pushing oil towards oil recovery structure.

OIL RECOVERY STRUCTURE / VESSEL - Wide surface streamline flow into open sea chest which trapped emulsified oil for further oil/water separating equipment by technology available in the open market. System able to incorporated into any offshore structures or vessels which has a very large storage capacity to cope with very huge oil spill. System can also be installed at onshore structure that is operating nearby oil terminal or facilities.

Creating surface wave formations using vessel's propulsion thrust, like performing a bollard pull operation, to push surface oil towards oil recovery structures/vessels