Gulf Oil Spill - Your Comments
By Corporal Willy, June 9th 2010
When I asked you to weigh in on the Gulf Oil Spill, so many of you responded with ideas, suggestions and comments, that I was asked to put together a list of the better, more feasible ones on a separate posting. I’m not an expert but I have done my best here. This will be an ongoing work in progress at this blog post.
If your idea has not made it to this list yet, please be patient. I am working across many thousands of miles over the internet, with other collaborating minds and those contributing members that have taken time to make those comments.
I will also make an attempt to clarify the ideas that are featured here with some sketches and SolidWorks drawings similar to the one down below here that I did.
The Two General Categories
Plugging up the Leak: & Cleaning up the Mess:
Plugging up the Leak Comments.
In this first one from Mr. Charles Bowsher, the idea conveyed to the readers is on of simplicity. I thought this would be a workable idea but like most things that I am made aware of there could be more to the story here. This is open for comments so lets here your thoughts on this one.
Can someone please explain to me why they can't simply drop a mile long - five foot, six foot or 10 foot diameter culvert pipe right over the leak and just let the buoyancy of the oil drift up to the surface where it is pumped to waiting tankers, barges and large bladders? Obviously I am not a materials or fluid dynamics type of engineer, but it seems so simple to me. I realize there are incredible pressures and low temperatures at this depth, but if you insert an open tube into water of any depth the pressure is the same inside and outside the open tube isn't it? Or even if the less dense oil causes reduced pressure inside the pipe then it is outside, all you need do is drill some holes, inset one way valves the length of the riser and the pressure will equalize. Sure some water will leak in initially, but you are still able to somewhat control where the oil winds up. Certainly better than releasing it to the currents.
Further, it appears from the video on MSNBC that the drill mud is what is mostly coming out so that may be okay. It seems to me if the drill mud doesn't stop the leak then they should still be able to just pump seawater in at a slightly higher rate and thereby overcome the pressure of the oil coming out, thus slowing it at the very least. One thing that was a little odd on the MSNBC feed tonight was that it appeared to be on a 30-35 second loop......!
.By Charles A. Bowsher on 5/27/2010 3:51 AM
Cleaning up the Mess Comments.
Edit Re: SOS: Ideas, Solutions, Brainstorming.
Oil eating microbes pioneered by Exxon in Alaska.
By Bob on 6/3/2010 9:53 AM
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Now I will post Mr. Crawford's explanation. What do you think?
This has been revised-------
A general description:
In order to capture the oil not currently under control at the sea bed I suggest: A large diameter tube comprised of Dutch weave stainless steel cloth, floatation assistance comprised of low specific gravity materials or weights if needed and poly fiber Geotube plastic filter cloth anchored with 3 or more radially placed anchor cables attached to a surface barge all of which could be combined with a jet pump to direct fluids of oil/gas and seawater into a gravitational separation tube to collect the oil leaking from the sea floor. The tube would be similar in nature to a pipe and would be situated at an angle in such a manner that fluids move slowly through the pipe and separate gravitationally due to the slow movement of the fluid and due to the volume of the tube in relation to the volume of the leaking oil. The pipe could be in excess of 20' in diameter and neutral in buoyancy and possibly greater than one mile in length. The process is as follow:
1 Three or more anchors are set radially about 20' apart around the leak connected to cables set at an angle 45 degrees or greater relative to the horizontal and are connected to a barge on the surface.
2 A fabricated tube sock with access ports made of geofiber and Dutch weave stainless steel is slipped over the anchor cables to a position near the leak to within 300 feet of the surface of the sea.
3 The tube is held open near the leak by the radial placement of the anchor cables and pressure from the jet pump.
4 A jet pump is situated near the leak in such a manner that the force of the jet will suck in and discharge the leaking oil and a monitored portion of the gas into the tube.
5 The volume of the pumped liquid is considerably less than the capacity of the tube sock.
6 Most gas is allowed to bypass the sock in 500 ft-- oil and some gas is allowed to enter the sock.
7 The gravitational acceleration of the oil relative to the seawater and the force required for the oil to pass through the sock are adjusted by changing the angle of the sock relative to the horizontal such that the oil does not leave the sock.
8 The pump is activated sucking and forcing the oil / water and a small amount of the gas into the sock.
9 The length of the sock is possibly as long as one mile and the velocity of the solution is such that the oil is allowed to separate from the water slowly and the trapped gas is allowed to "air lift pump" the fluid up the sock toward the surface. The tube is held open by the movement of the fluid from the pump, and the position of the anchor cables.
10 Located along the sock and transverse to the center-line of the sock are outlet ports that are controlled from the surface with simple ropes. The ports are connected to the sock with vertical collection tubes of the same material as the sock but situated in a vertical plane.
11 As oil is collected in the sock it is allowed to bypass outlets until it is gravitationally separated from the water and gas. Then ports are opened and the oil is allowed to progress to pumps located within the outlets. Gas is allowed to exit the sock in predetermined places to maintain the angle of the sock relative to the sea floor and to support the weight of the sock and anchor cables.
12 The movement of the oil relative to the gas is slow and whatever gas that enters moves through the system and passes out of the open weave ports and at any place it collects and is unwanted. Particles of sand, shell and rock trapped in the flow settle gravitationally and slide down the tube and discharge naturally out the lower end of the tube due to the undulating motion of the sock.
13 Gas that enters the tube is within a relatively closed system and lowers the average specific gravity of the water within the tube to be lower than the specific gravity outside the tube.
14 Oil is allowed to separate and be removed by pumps, gas is both bypassed in the first section and separated due to the velocity of the gas and SG relative to the oil, water is discharged through the fabric and out the end of the tube. Soil and debris is allowed to fall back to the sea floor either through the entrance or through outlet ports in the bottom of the sock.
Items taken into consideration: Temp of oil at leak, temp of sea water at ocean floor, water pressure and effect on cloth and geo fabric, specific gravity, properties of crude oil, effect of changes in volume of gas relative to pressure, effect of angle of tube and pore pressure of oil relative to pressure exerted by vertical movement of oil, movement of water and oil through filter cloth, pumping effect of gas, life of system relative to time needed to drill wells number of socks used, currents of ocean, effect of surface winds, location of existing damaged drill rig, ability to work around sock with other tools to try other repairs, change in location of barge, storage capacity of sock if barge must be moved, alternate methods of anchoring sock, rainbow type anchor on both ends rather than barge, large storage socks next to separation sock for storm use, strength of materials and weights of materials.
A specific description with reference to the sketch of the separation / fractionalization tube:
1 The inlet of the of the tube is 20’ in diameter and supported by steel anchor cables to the surface. The anchors are connected to multiple helical anchors drilled into the seafloor to withstand a 40k load each. Number of anchors depends on the load anticipated.
2 The placement of the inlet is near the leak above the BOP where it intersects the production pipe to the surface. The intent is not to block the production pipe. An arm of material from the tube around the BOP will direct wasted oil into the tube or:
3 A jet pump is located within the separation tube that causes a vacuum at the inlet of the tube to suck in liquids and gas and maintain the flow (not in the entire tube) of 1 fps to spread the buoyancy of the crude along the tube .
4 The volume of the 20’ diameter x 1.2 mile long tube would be 1,990,000 cf and would be restrained with steel anchor cables and constructed with Geotube fabric, stainless steel fabric and ballast to be sufficiently weighted to balance the load imposed by gases and liquids that are to be transported. It is anticipated that the specific gravity of the oil will be .835 and the force imparted by the gas will be in proportion to the depth of the gas in relation to the surface.
5 It is assumed that the production tubing is currently capturing half the gas and oil produced by the well. Therefore the separation tube could be reasonably expected to encounter at least 18,000 bbl day of oil. Assuming an even distribution of oil though out the day, a load on the lower end of the pipe would be expected as follows 18000 x 5.6146 cf / bbl x 10.296 negative pressure/cf for a lift of 1,040,542.59 pounds due to the difference in the specific gravity of water and oil. This is divided by 24 hrs day / 60 min hour and 60 seconds per min for a buoyancy load of 12.04 pounds per sec due to oil negative pressure. The jet pump will maintain a flow of 1 ft per sec in the upper portion of the tube as the kinetic energy of the water is transferred to the oil to jump start its movement up the tube. A load on the tube for the full length due to oil would be 5280*1.2*12.4 or 78,566 pounds that would need to be offset by anchors, the weight of the device and ballast. It is anticipated that the oil will separate from the gas and water at some point before using the entire tube. At the point of separation the oil will be siphoned from the tube to the surface or to a below surface storage bladder. For that reason I believe loads on the order of 1/3 those I estimate will be actually encountered.
6 It is assumed that the current production of 31.35 MMscf/day of gas is about half the amount actually to be produced on the site. The weight of methane gas per cf at 2166 pounds per sq inch normal pressure at the well head on the sea floor is based on the DOE weight of methane at standard temp and pressure of 42.28 pounds /1000cf. This yields 1,325,478 pounds of methane per day and the gas laws reveal that this is divided among 210,529 cf at the ocean floor or 6.296 pcf for methane on the sea floor. The buoyancy load on the tube from the gas is 210529 cf / 24 /60 /60 * (62.4-6.29 lb) is 136.72 pounds per sec entering the tube. It is anticipated that the gas fraction of the well production will completely exit the separator tube in the first five hundred feet therefore the buoyancy imparted to the structure is 500 x 137 pounds per ft/sec or 68,361 pounds continuous load. It is anticipated that the first few hundred feet of the tube will be constructed of stainless steel or be weighted to balance the load the gas places on the tube.
7 In operation, the production from the well that bypasses at the BOP would either be directed into the separation tube by diverting the flow with collection arms to trap the oil or would be sucked into the tube by a jet.
8 The specific gravity of the fluids and gas is such that the gas floats on the oil and the oil floats on the water.
9 The separation tube is built similar to a fractional separator with baffles and plates at specific locations for specific purposes.
10 As the gas / oil / water mixture enters the tube it is in the state of mixture shown on the various videos as shown by the ROV cameras.
The oil and gas are highly mixed with water.
11 The gas in the well is the lightest fraction of the mixture and can be captured by constructing a separator across the tube directly after the first few ports that lead toward the surface. This gas will fill the tube to the extent of the separator dam and will replenish itself from the well production. Once a separator has backed up enough volume of gas the outlet port is opened to the surface. The gas can be allowed to rise without being contained in a tube or it can be harvested in a tube for use later. At this point in the process the gas will likely be produced with little volume of ice crystals as proven by the video that shows little production and due to the fact that the gas has not had a chance to change in volume and thereby decrease in pressure absorbing energy and lowering temperature causing crystals to form. If ice does form it is anticipated that a outlet port in this first separation area of 3’ diameter will pass any ice produced. And it is anticipated that the first separation chamber will be relatively large and be capable of adjustment with a fiber cloth throttle valve operated from the surface.
Exit of gas from the system in the first 500 feet is anticipated to require some initial adjustment and then infrequently adjusted. The goal is for the vast majority of the gas to exit in the first hundred feet and the remainder to be substantially removed by the 500’ mark.
12 The oil in the system floats underneath the gas. Therefore as the gas is trapped by the baffles and plates, the oil will slip past and move up the tube. Additional baffles, traps and plates will be located within the tube to direct the flow of the oil toward the surface and outlet ports. It is anticipated that some lighter oils and gasses will be within the flow from the well. For that reason the tube will act as a passive fractional separator with each baffle placed at a location that will assist in the separation of the crude into products with different properties. Some volatile fluids will go from a liquid phase into a gas phase as pressure is lowered in the tube as the crude moves to the surface. Each identifiable fluid will have its own port to the surface such that a more uniform product can be removed from each port. The primary methods of separation are via specific gravity and change from liquid phase to gas phase due to decrease in pressure.
13 The tubes leading to the surface can either be open, lead to a storage blatter that is anchored to the sea floor, or be used as a siphon or pump outlet as need requires.
14 In periods of hurricane activity the tube will hold an estimated 1.5 million gallons of oil and the blatters can hold additional oil with additional sea floor anchors. After the storm the system can be pumped into waiting tankers. During the storm the gas bypass can be fully open thereby lightening the load on the separator tube.