Patent Application
20150233221
1. Field of the Invention
This invention relates to a hydraulically powered jet pump for placement downhole in a well for the purpose of producing fluids (oil, gas, and/or water) from a formation which has special features that provide flexibility and ease of operations in various types of well applications. The operation of a jet pump is well known in the art and as such utilizes high pressure fluid pumped from the surface to a small interior diameter nozzle where the flow is converted to high velocity and lower pressure. As the fluid flow departs the nozzle, pressure at the exit point is greatly reduced thus drawing in fluids from an exterior source such as an oil and gas producing formation. The mixture is then flowed through a mixing tube which has a sequentially increasing interior diameter thus reducing velocity and increasing pressure. As the fluid mixture departs the pump into the well annulus, a sufficient pressure is available to cause the fluid mixture to return to the surface.
2. Description of Related Art
The patent to Coleman U.S. Pat. No. 5,372,190 discloses a jet pump that includes a jet orifice and diffuser portion not numbered in FIG. 9 and a second diffuser member 148 that is attached to a tubular member 164 that includes an alignment edge 166 that cooperates with pin 170. In order to remove the assembly, the jet orifice and diffuser portion must first be removed and then the second member 148 is retrieved using a tool that is lowered by a wire line or coiled tubing and that engages profile 204. The patent to Batho et al U.S. Pat. No. 7,114,572 discloses a jet pump 50 and a subsurface safety valve 52. The patent to Kelly et al U.S. Pat. No. 7,219,737 discloses generally a jet pump 44 that can be moved upwardly in tubing into a retrievable position by fluid injected into the casing of a well. Finally, Jackson U.S. Pat. No. 7,909,089 discloses a jet pump 110 that can be configured to pump well fluid up through a tubing string.
According to one aspect of an embodiment of the invention, a jet pump includes a housing and a carrier. The housing interior is of a constant diameter so that the carrier can easily be inverted and thus provide a means to use the pump as described above but with high pressure power fluid being conveyed down the annulus between the outer diameter of the inner tubular member and the well casing interior with the power fluid and formation production returning to the surface through the interior of the inner tubular. This flow method is preferred in wells where the produced fluid is corrosive and therefore not desirable to contact the well casing interior or in wells where a failsafe safety shut-in valve is desired or required. This configuration is typically called a “reverse flow” pump and requires wireline operations to run and retrieve.
The novel design of the reverse flow pump and latching device allows for placement of the pump into the well by simply dropping or pumping the assembly down to seat in the proper position and to latch into position to prevent the pump from being displaced upward when power fluid pressure is applied to the annulus. The novel design of the latching device is critical to the assembly and is activated to the locked position by means of pressure applied to the interior tubing and thus temporarily plugged assembly. In addition to placement and locking of the pump into the proper position, a novel mechanism is also provided that allows for retrieval of the pump without the use of a wireline conveyed pulling tool thus greatly reducing the operating cost normally associated with retrieval of a reverse flow pump.
The retrieval mechanism consists of a pulling tool with a seal cup positioned above. The mechanism is then pumped down the interior tube until it encounters and latches onto the fishing neck of the pump lock. Pressure is then applied to the annulus and causes an upward force via the seal cups to move the release sleeve upward and release the latching dogs and thus allowing the pump and latch assembly to be forced back to the surface thru continued circulation where the assembly can be captured at the surface and removed for design changes or repairs.
By developing a carrier which contains the nozzle and mixing tube in a single component, the housing can then be of simple design with enlarged interior diameter versus exterior diameter as compared to other tools on the market. The larger exterior diameter of the carrier therefore allows the use of larger nozzle and mixing tube diameters and thus increased production rates from a formation. For example, existing tools of a 3″ to 3.5″ outside diameter are limited to production rates in the maximum range of 100 gallons per minute whereas this novel design can easily achieve rates in excess of 200 gallons per minute.
Another objection for using existing jet pumps is the inability or difficult operations required to obtain access to the producing formation for purposes of evaluation of formation data or modification of the well completion. This novel design allows easy removal of the carrier, standing valve and safety valve from the interior of the inner tubing thus allowing full access through the remaining pump housing and to the wellbore below. Pending well conditions, the carrier, standing valve and safety valve can be removed from the well by reversing the power fluid circulation direction and capturing the tools as they reach the surface. In wells where the formation pressure is low and thereby will not allow reverse circulation, the tools (carrier, standing valve and safety valve) can be removed using a wire and special retrieving tool to provide full access to the wellbore below the pump housing assembly.
In wells located in hostile or sensitive environments such as the Arctic areas, wildlife refuges and offshore, rules and regulations often require that each well be equipped with a failsafe downhole valve to prevent the flow of oil and gas to the surface in case of a failure of the surface valving or integrity of the well. This tool configuration can include such a device when required or desired and operates by being open only when power fluid pressure is applied and automatically closes anytime power fluid pressure is reduced. Another advantage of the safety device is that there are no depth limits at which the valve can be placed as is the case in safety valves that are operated by a special tubular line run from the surface to the valve and the valve operated by applying pressure to the line and thus to the valve.
Another feature of this novel design overcomes the typical problem associated with damaging or washing seals such as “O” Rings out of their grooves. In standard seal design, there is a requirement to provide some amount of “squeeze” as a seal enters into a bore such that the interference creates the initial seal between the part containing the seal and the receiving device bore. Most seals are activated to an improved “squeeze” when pressure is applied. When passing in and out of seal bores, each entry and exit of a seal from the bore has potential to damage the seal and eliminate or drastically reduce the interference and the efficiency of the initial seal. The initial seal is critical in order for applied differential pressure to further activate the seal. In the novel design, standard type seal which require some interference fit (squeeze) are replaced with a seal made of a swellable elastomer that does not require an initial squeeze. Swellable elastomers can be provided that increase in size (swell) in the presence of fresh water, salt water, oil or gas. All of these fluids are typically contained in oil or gas wells. By utilizing a swellable elastomer as the seal, there is no need for the seal to be installed at a larger outside diameter than the outside metal diameter of the tool and therefore the seal is not exposed to damage that may result from contact with the well tubing or from flow washing while running the tool into the well. Once the tool is positioned into the bores, swelling of the elastomer automatically creates the squeeze and establishes the initial seal between the inner tool and bore and may be further activated for controlling high pressure thru the application of pressure after some amount of swelling has occurred.
Another feature of the disclosed invention is to use shape memory materials, such as metals, for seal construction. Shape memory material can be manufactured in a specific shape at a base temperature and then formed into a different shape at a different temperature. It is therefore feasible to manufacture a shape memory material with a size that would create interference between the carrier and housing bore at a temperature such as 150 degree F., typical of even shallow oil and gas wells, but would not have interference at a lower temperature. Once the tool is placed into the housing bore without interference and the well temperature increases to above 150 degrees F., the material returns to the original manufactured shape which does provide interference and thus sealing capability. Using a corrosion resistant metal could greatly enhance the life of the seals in wells where corrosive fluids are produced.
a is a view along line A-A of
a is a partial frontal view of the carrier assembly.
a is a cross sectional view of the locking mechanism in a locked position.
b is a cross sectional view of a fishing tool engaging the upper portion of the jet pump assembly.
c is a view of the upper portion of the jet pump assembly as pressure is applied from above to pump out the assembly.
Included in
As shown more fully in
As shown in the cross section of the carrier assembly 10 in
The body 32 of the carrier is connected by threads 36 to the fishing neck 31 on the upper end and the lower carrier sub 39 on the lower end. Internal to the body are the critical components of the pump, nozzle 34 and mixing tube 35 which are each positioned properly by an interference fit shoulder 34a and 35a respectively. A series of ports 33 in the wall of the body allow produced fluids to enter into the interior of the body at the outlet end of the nozzle where a low pressure area has been created as a result of the extremely high velocity exiting from the tip of the nozzle. Fluid pumped down the interior of the tubing and into the interior of the carrier 46 passes into the tapered flow path 45 of the nozzle where pressure is decreased and velocity increased as well known in the art. As the fluid exits the tip of the nozzle at high velocity, a responding reduction in pressure occurs thereby pulling produced fluids into the area immediately below the tip of the nozzle. The mixture of fluids enters the mixing tube and flows down a sequentially larger diameter flow path 44 in the mixing tube. With the increasing interior flow area, velocity is reduced and subsequently pressure increased. The flow continues downward inside the lower carrier body with increasing diameter and turns to exit from the carrier 45 and through the ports of the exit port sub 23 of the housing as shown in
In addition to the interference seal achieved at the larger diameter of the fishing neck 31 a against the top sub restriction 27 an additional seal such as an “O” Ring 34a may be provided as a backup sealing mechanism. Additional seals 48a are required to seal above and below the exit port of the carrier and the exit ports of the exit port sub 23.
Under certain well conditions, a check valve 79 as shown in
In this series of depictions, the carrier body 36 containing the nozzle 34 and mixing tube 35 is inverted thereby providing a pumping means wherein the power fluid is pumped down the annulus between the tubing 15 and the casing 11 and produced fluid mixture returns to surface up the tubing.
a shows the assembly locked in position after applying pressure above the pump and forcing the shoulder 54 under the dogs 56 and forcing the dogs outward and into the groove 21a of the top sub 21. A variety of means can be added to the end area of the smaller outside diameter section 55 of the fishing neck 31 to provide some resistance to inadvertent upward movement of the fishing neck during operations of the pump.
b depicts the initial step of retrieval of the pump carrier wherein a standard type fishing tool 62 which is modified to contain a seal cup 61 or other sealing mechanism to at least partially seal between the fishing tool and tubing interior wall. The fishing tool and seal cup are then dropped into the tubing and allowed to fall to the top of the pump or the assembly can be pumped into position. The end of the fishing tool contains dog latching aims and a shoulder 63 that is allowed to expand over the pump fishing neck 31 and latch underneath the fishing neck shoulder 37. The fishing tool is also provided with a secondary fishing neck 62a in case operational problems require that conventional wireline operations are used to retrieve the fishing tool or pump.
c depicts the released position of the pump wherein pressure is applied to the annulus in the same manner as when the pumping operations were active. The applied pressure acting against the seal cup creates an upward force that move the fishing neck 31 and the large diameter section 54 upward and out from under the dogs 55, allowing the dogs to retract from the groove 21 a and releasing the locking mechanism to allow upward movement of the entire assembly. Continued circulation of fluids down the annulus and up the tubing causes the tool to be pumped to the surface where a variety of prior art and known methods allows the tool to be captured and removed from the well for repairs, redesign or other modifications.
Seals 48a may be made from a swellable elastomer material or from a shape memory material. As discussed above, the seals may be initially sized so that the seals are not deformed as the carrier assembly is positioned within the housing. Rather, upon exposure to well fluids or elevated temperatures, the seal increases in size to form a seal between the housing and the carrier assembly.
Although the present invention has been described with respect to specific details, it is not intended that such details should be regarded as limitations on the scope of the invention, except to the extent that they are included in the accompanying claims.
This application is continuation of U.S. application Ser. No. 13/357,730 filed on Jan. 25, 2012.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13357730 | Jan 2012 | US |
| Child | 14633978 | US |
