US20130333874A1

US20130333874A1 - Through Tubing gas lift mandrel

Info

Publication number: US20130333874A1
Application number: US13/830,813
Authority: US
Inventors: Leonard Alan Bollingham
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-04-16
Filing date: 2013-03-14
Publication date: 2013-12-19

Abstract

This mandrel places injection gas at the optimum production depth. It has been proven successful and could increase production in America and the world by bringing back into production wells that are not economical any other way. One well at a time, or entire fields can be produced with a single compressor. There is no need for additional packers or valves. Stripper wells account for 40% of total domestic production. There are 1000s of wells not being produced. Huge production OPEC type wells could be produced with this system better, faster, and less expensive than any other system. Using air, or gas in a closed loop this system outperforms every system like it or any other system. The key is to optimize compression with depth beneath the fluid level and reservoir abilities. Waiting to try this and prove it since graduate school seems extreme, but several devices are not allowed or kept from use in the oilfield for whatever reason. The key is to help the small guys compete, and this innovation is ready.

Description

A portable through tubing production system using high pressure gas to produce petroleum oil through the existing tubing or casing. The system does not require any changes to the current production tubing or casing, but requires some small wellhead modifications. Nothing needs to be altered below the surface. The system can be placed in low or no production wells, and will produce oil from these wells economically and efficiently. This device allows wells that cannot be produced at all, to be produced at an economical rate. This device could enhance production in wells that are still flowing on their own energy but would produce more with a little help. Also, it will be extremely productive in higher production wells that need a very controllable amount of extra energy.
The mandrel device is comprised of two sections. The trunk section 10 which extends from the well head to some depth required to reach the fluid level in the well, and allows high pressure gas to be delivered below this fluid level to the second section of this device. The jet 20 directs the gas from the trunk section out and up into the production tubing to lighten the fluid and assist in moving the fluid up and out of the tubing to the flowline and into the separator. The entire device fits within the production tubing 40. If the production tubing is damaged, too big for low production, or missing completely, a tubing and packer can be installed with the mandrel inside.
The gas will be recycled from the separator and into the compressor and back into the well. This is a proven effective system, the difference is the flexible design variables, efficiency of cost and production, and the economic delivery of the system described. The preferred production material has proven to be all stainless steel which works in every service.

BACKGROUND OF THE INVENTION

This application claims a priority having been first invented in the Spring semester of 1986, and used inside an aquarium bottom filter tube with air to simulate a controlled blowout. A single bubble could be studied or water could be blown to the ceiling. The mandrel was never mentioned, but was kept under study for decades. The resulting simulation was my master's thesis, and could not have been so incredibly accurate without this mandrel to show the accelerations and expansions which were required to perfectly simulate this event. There is another through tubing system, currently pending but it requires standing valves, and other extras which make it more like a pump than pure gas lift.
The present invention generally relates to enhanced oil recovery, and more specifically relates to gas lift for enhanced oil recovery. This system uses just the tubing space as the low pressure producing section, and a brand new high pressure tubing within the production tubing, thus protecting the annular casing buffer zone, and pressuring the tubing outward in its strongest capacity. Older wells may have issues in the tubing that will not allow the annular space to be pressurized. Also the annular space may fail allowing pressure to escape the well into a formation. Old or new, this system is by far the safest innovation environmentally ever devised. This is not a pump as are jet pumps and other down hole pumps. This is a system which utilizes the nature and physics of the injected gas to assist the production of the reservoir fluid.
When the energy from the reservoir becomes insufficient to produce the oil an enhanced method of production is necessary. These methods vary, but the state of the art is gas lift. The current art uses the annular area to add pressure and this is dangerous and can fail in older wells with weakened tubing from corrosion, rust and age. The problem with current gas lift technology is the cost to set a rig, remove the tubing and then replace the tubing with a mandrel attached to the bottom of the production tubing. High pressure gas is then injected into the annular space between the casing and tubing. The gas enters the production tubing space through valves in the gas lift mandrel. The gas rushes up the tubing to the separator and carries oil along with it. The gas is separated from the liquid, pressured up again and recycled in a closed loop. This is a very efficient system, but costs are very high, and many wells produce at uneconomical volumes to ever allow this type of system to be utilized. The current system must be designed and installed before a flow rate can ever be realized. To change the system causes the well production to be stopped, and costly rig time and the possibility of an accident is always eminent. Other enhanced methods are positive displacement which move a certain amount of fluid and are proven uneconomical in these older low production wells. Half to nearly 80% of the oil is left in place from every form of recovery usually due to cost.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to an apparatus that satisfies the above needs of cost and increases in production only limited by the reservoir not the production system, and is a vast improvement over other previously patented designs. In every other patent the gas is pressured down the annular space, through a packer valve and/or a gas lift valve and into the tubing. This system goes through the tubing exclusively or provides its own, protecting the annular space and earth beyond by not using the annular buffer zone. This system may use no downhole valve and depends on the back pressure of the fluid and reservoir to provide the perfect pressure point for injection which changes nearly constantly through production intervals. The portable gas lift mandrel with trunk and jets in specific configuration and shape to position the mandrel in a certain place for instance centered or to one side which ensures precise and even delivery of gas into the produced fluid for optimum production. The mandrel is installed completely through the tubing and does not affect the annular space in any way. The mandrel is portable in that it can be changed and tweaked without taking the well off production, and also can be used effectively to test wells before production decisions are made, and in case there is no tubing in the abandoned well this mandrel can be placed within an additional smaller tubing section which acts as a smaller diameter tubing to assist production in wells with large production tubing diameters but very low flow characteristics, or where there is no tubing at all. The mandrel can be configured in countless ways where the trunk and jets in specific configuration and shape to position the mandrel in a certain place for instance but not limited to, centered or to one side which ensures precise and even delivery of gas into the produced fluid for optimum production. The mandrel can be used to test the well upon permit approval and actually produce the well in a matter of hours with portable equipment. The jets 20 can be placed at intervals up the entire trunk 10 to near the surface to boost production. Various pressure from higher shallow pressures about 800 psi, to lower operating pressures deep of 400 psi will automatically unload a well filled with fluid. These are just a few of the fundamental differences in this proposed system over the prior art. This system is considerably less expensive, quicker to install for production tests or permanently, and more effective in costs and production volumes by design.
The research began as a Blow Out simulator similar to the BP Oil Spill and developed into a Masters Thesis. Without these types of abandoned wells to consider the work has lied dormant until last year when a lease with 6 abandoned wells was acquired. The new application follows the original design goals: A system like a blow out that could work at any depth, pressure, flow rate and worked straight up like the reservoir was just drilled into. This is vastly different from every other system where the gas lift mandrel is placed at the bottom of the well as part of the production tubing. Originally after leaving Mobil in 1990, it was attempted to use this system on a field equipped with gas lift but having several extra wells not being produced because it was uneconomical to install mandrels. The bid for that and other fields were highest but not accepted. The inventor tabled the concepts until the price and availability of oil and fields made a small oil company possible. That has happened just last year. The perfect and most optimum design calls for the jets to point straight up. Not upward or outward even though that is possible, but straight up. This system can replace every other form of enhanced recovery quickly and effectively. It is more effective than any other form of enhanced recovery and could be put into use in every extra well on every field using gas lift where the extra wells are not economical to equip with the prior art. This patent is an emergency correction to the production of scarce commodity oil. This is also very successful in transferring fluid from the bottom of a source tank to the top of a destination tank as long as the total elevation change is positive or uphill. Oil production has been proven using this mandrel design in an 800′ well and a compressor that produces 3 cuft a minute at 175 psi. That is much less than the current art of 400 psi to 1000 psi. That difference in compression means big dollars in savings and makes these little wells economical and the bigger wells more economical.
The gas lift mandrel can be placed in the well with no rig, with no change to the current production tubing in place. The mandrel can be located at various depths, with various configurations and number of jets, and with various pressures. All of these variables allow the system to be tailor fitted to the needs and abilities of the reservoir to adjust production to the most efficient possible. This system is proven effective and efficient and is of the utmost importance to the economical production of oil.
The basic mandrel by design has no valves and is lowered to the optimum production depth where economical compression can unload and produce the well. At this point it production economically optimized, as the reservoir will replace the removed fluid as fast as the mandrel and system can produce it. This depth may change over time as reservoir pressure drops, but the mandrel can easily be extended further into the production tubing.
An enhancement involves multiple wells per compressor and requires control valves at the surface to maintain exact injection gas volume and pressure.
Another enhancement would involve preset valves that are set in decreasing pressure increments as depth increases. This will automatically unload the well.
The mandrel device involves a trunk section and various jets:

A) A trunk section 10 runs from the wellhead down to the most effective depth beneath the fluid level fits completely inside the production tubing, accepts the high pressure gas from a compressor and carries it to a depth in the well to deliver the gas to the second section, the jets. The trunk can have a section of flexible tubing also for use in horizontal and other offset type wells. The trunk can be lengthened or shortened depending on what works best for the well. The trunk can be of any diameter which fits in the tubing as long as it allows flow up the tubing and delivers the gas with acceptable pressure drop. These variables can all be tested very quickly, and efficiently.
B) The second section of the device is described as the jets 20. These jets deliver the gas into the oil which forces the oil out of the tubing and into the flowline and to the separator. There can be any number of jets, and they can be of varying length, shape, diameter, and nozzle size. Also, they can be spaced along the depth of the trunk from the joints reaching from the surface down. If it is decided not to just find the depth at which the well can be produced efficiently, but to unload all the way to the production zone or just above: Valves of varying pop off pressure can be placed along the mandrel from highest pressure at the top to lowest pressure at the bottom. The pressure is regulated with a control valve at the surface. If there is a fluid head that does not allow a valve to unload then one above will unload. Eventually the lowest pressure valve that will produce oil will be the ones that are producing the wells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the of the invention version of the gas lift mandrel.

FIG. 2 is a Cross-Sectional Front View

FIG. 3 is a Side View

FIG. 4 is a Top View

FIG. 5 is a Cross-sectional Side View of Mandrel inside existing casing 30 and existing tubing 40

FIG. 6 is a Cross-sectional view of the well and replacement mandrel tubing system 50 with a perspective view of a 3 jet Mandrel within the outer tubing section 50.

FIG. 7 is a perspective view of a mandrel with 8 jets, 4 for centering, and 4 for velocity. All straight up.

IDENTIFICATION OF PARTS/COMPONENTS OF INVENTION:

10 Mandrel Trunk
20 Jet
30 Outer Mandrel Tubing
40 Production Tubing in well
50 Oil and Gas leaving in outer mandrel tubing to the surface.
60 Annulus
70 Hole in failed tubing. (FIG. 6)
80 Casing.
90 Earth
100 Reservoir Fluid
200 Injection gas into mandrel
300 Injection gas out of mandrel

DETAILED DESCRIPTION AND BEST IMPLEMENTATION

While the invention is susceptible to various modifications and alternative constructions, certain illustrated embodiments thereof have been shown in the drawings and will be described below in detail. It should be understood, however, that there is no intention to limit the invention to the specific form disclosed, but, on the contrary, the invention is to cover all modifications, alternative constructions, and equivalents falling within the spirit and the scope of the invention as defined in the claims.
Referring in general to FIG. 1, a gas lift system device constructed in accordance with the principles of the invention is seen. Only one jet 20 is pictured but many configurations and numbers can be utilized. A preferred version of the portable gas lift mandrel 10 is constructed of stainless steel, typically the trunk is drilled and the jets are welded into place and facing straight up to the surface. The bottom of the mandrel is sealed welded to allow a smooth flow characteristic past it by the produced fluid. As a result, the device is light-weight, high pressure, low-cost and able to be placed quickly, economically, and efficiently into the well to produce oil/water/gas even in corrosive services. It is important to note that certain parts of the device may be referred to individually, but the entire device would be made in one piece for reasons of economy and quality. Sections of the trunk tubing or one long piece construction are being tested. If the tubing or casing was damaged or too big to sustain flow this embodiment could be placed in a smaller tubing and packer system which would fit inside the existing tubing 40 or replace it completely. A production tubing and high pressure system mandrel FIG. 5 could be lowered into the existing tubing or abandoned casing for testing and short term production to prove the well is economical. The reduction in tubing size 50 actually increases velocities of the gas and fluid combination. All without great investment and possible loss with a well that produces only saltwater, or very little oil. Tests have been conducted on wells and have proven very successful. Fluid flow rates out were a variable function of pressure, depth, and gas flow rates in, with two different jet configuration tests. An abandoned field has been acquired and the two embodiments have been used successfully. The problem discovered with these wells involve very little oil or slow seepage flow rate out of the reservoir and therefore it is much more sensible to use a pump jack as loading the well will prove impossible to buck the head pressure. With thousands of abandoned wells in just the United States this development is very exciting. The results at various depths were pleasantly surprising which hints that jets placed as boosters up the trunk might prove beneficial in unloading the fluid in big producing wells. As current art is an overkill of every design facet this system is a finessed optimization of engineering wonder. Cost for classic gas lift installation to a single well: 300 K to 1,000 K. This system: 3 K to 10 K or 11100^ththe cost with every advantage over the current art. Although the present invention has been described in considerable detail and with reference to certain preferred versions with 1, 3, and 8 jets, and within a tubing section, other versions are possible. The jets have preset orifices and may or may not have backpressure or check valves, but definitely no pump like standing valves.
For example, while certain portions of the device have been described to have specific configurations, it is clear that some variation could be introduced, while still keeping within the teachings of the invention. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions disclosed. It is noted that no standing valve is used in this system, and that is vastly different from some of the other low production systems that are pending patent approval. These other systems require vastly more compression to unload the well. This innovation depends on first finding the proper depth below the fluid level that will relieve the pressure from the reservoir to flow, or a system of unloading variably pressured relief valves along the mandrel.
In compliance with the U.S. Patent Laws, the invention has been described in language more of less specific as to methodical features. The invention is not, however, limited to the specific features described, since the means herein disclosed comprise preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
While there is shown and described the present preferred embodiment of the invention, it is to be distinctly understood that this invention is not limited thereto but may be variously embodied to practice within the scope of the following claims. From the foregoing description, it will be apparent that various changes may be made without departing from the spirit and scope of the invention as defined by the following claims.

Claims

I claim:

1. A gas lift oil production enhancement system mandrel, comprising:

A trunk portion which is sized to uniquely and efficiently deliver enough gas through the production tubing, at sufficient pressure, to a sufficient depth from the surface to produce oil/water/gas.

A jet portion which receives the high pressure gas from the trunk and directs its delivery into the oil at sufficient pressure, velocity and volume to transport the oil/water/gas to the separator or the storage tank.

2. Device according to claim 1, wherein the gas lift mandrel with trunk and jets in specific configuration and shape to position the mandrel in a certain place for instance centered or to one side which ensures precise and even delivery of gas into the produced fluid for optimum production.

3. The device according to claim 1, wherein if tubing is present the mandrel is installed completely through the tubing and does not affect the annular space between the tubing and casing or open hole in any way.

4. The device according to claim 1, wherein the through tubing gas lift mandrel is placed within an additional outer tubing section which acts as a smaller diameter tubing to assist production in wells with large production tubing diameters but very low flow characteristics, or where there is no tubing at all. When the depth of the fluid is extremely far from the surface this is necessary.

5. The device according to claim 1, wherein the jets have preset orifices and not pressure relief valves.

6. The device according to claim 1, where the depth can be changed by adding or subtracting trunk segments as production continues to drop.

7. The device according to claim 1, where the pressure exerted on the mandrel from the surface can be increased or decreased with the usage of various compression sources or pressure/flow control valves in the injection system upstream of the well.

8. The device according to claim 1, where the flow rate of the high pressure gas can be controlled from the surface compression or from pressure/flow control valves in the injection system upstream of the well.

9. The device according to claim 1, where the number of jets can be increased or decreased.

10. The device according to claim 1, where the size of the orifice of the jets can be changed.

11. The device according to claim 1, where the configuration of the jets can be set to point straight up to simulate a controlled blowout to maximize flow up the original tubing or into the replacement mandrel/tubing system.

12. The device according to claim 1, where the reservoir production limits and content can be determined by changing any or all of the design variations simply by pulling the mandrel out of the well, and not the tubing.

13. The device according to claim 1, wherein any or all of these variations can be changed quickly by retrieving the tubing and mandrels onto a spool.

14. The device according to claim 1, wherein the device can be used to test the well upon permit approval and actually produce the well in a matter of hours, with portable equipment.

15. The device according to claim 1, wherein the jets can be placed at intervals up the mandrel to the surface to boost production with highest pressure valves at the top and the lowest pressure at the bottom to unload the well manually by pressure regulation. The bottom most valve will be working at continuous operating pressure and production will be optimized.

16. The device according to claim 1, this system can retrofit the well using the packing box used to seal the polished rod of the pump jack as a seal, in much shorter time and much less the cost of any other current art.

17. The device according to claim 1, wherein the mandrel depends only on the researched and tested physics and nature of the injected gas to assist in producing the reservoir fluids. There are no standing valves to load the well and no packers required.

18. The device according to claim 1, wherein the mandrel can be used to transfer fluid from one source to one or more destinations over land as long as the elevation change is positive.

19. The device according to claim 1, wherein the mandrel can be used on multiple wells with a single compressor by adding control valves at the surface injection point, which regulate injection pressure and volume.

20. The device according to claim 1, wherein the mandrel can be enhanced to unload a well by using preset pressure relief valves that are decreasing in pressure as the depth increases.