Patent Application
20160069161
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1. Field of the Invention
The present invention relates to swab pumping apparatus. More particularly, the present invention relates to the use of swab pumping assemblies in place of traditional oil pumping apparatus. Additionally, the present invention relates to permanently installed swabbing units that are controlled by a three-phase motor.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Traditionally, newly drilled oil wells will flow due to the high bottom hole pressure. After it is no longer able to flow by its own pressure, oil is then pumped by using a traditional pumping unit. The complete setup of the pumping unit requires a string of sucker rods, tubings and a downhole pump. This setup may cost in excess of $100,000 per well that is 5000 feet deep or greater. The setup requires periodic workers so as to resolve various problems such as a hole in the tubing, a defective rod, pump failure due to trash in the pump, or wear-and-tear of the pump parts. These workovers, on average, may cost around $10,000 per occurrence. It is not uncommon to perform these workovers once every two years. Often, these workovers occur every 90 days.
The main problem which causes these workovers is the presence of gas associated with oil production. The oil, gas and associated water from an oil-bearing formation has to pass through a tiny pump barrel (approximately 2.5 inches in diameter with a total volume of less than 2 cubic feet). As long as all fluids coming in are pumped out, then the operation will run smoothly. However, over time, all gas coming in is not pumped out and keeps getting accumulated within the pump. As the gas volume builds up in the pump, it expands on the upstroke and compresses on the downstroke. Due to this compression force, the rods compress and start to bang the tubing. Eventually, this makes a hole in the tubing which will require a workover. Occasionally, due to this compression force, a weaker rod in the rod string will break. As a result, the well will stop pumping and will require repair. This problem is magnified severalfold in a well which is pumped under a packer. Under these cases, all gas produced from the formation has to go through the pump and cannot go up through the casing tubing annulus. Another reason for failure is the accumulation of formation trash in the pump barrel. Once again, the pump barrel has a very small volume. As result, even a small amount of trash coming in from the formation will eventually cause the plunger to become stuck and the well to quit pumping.
These problems have attempted to be solved by using progressive cavity pumps, also known as screw pumps. These are normally used to lift heavy oil, high sand production, gassy wells, etc. These are positive displacement pumps that have a pair of parts: (1) a helical steel rotor and (2) a steel stator. The stator is located at the bottom of the tubing string. The rotor is connected to the bottom of the sucker rod string. The rotator is rotated by surface drive equipment within the fixed stator. This creates the pumping action necessary to lift the fluids in the tubing.
These progressive cavity pumps have several limitations such as limited production rate and lift capacity, low-volume efficiency in gassy wells, fatigue failure of sucker rods, damage when pumped dry, rod and tubing wear it in directional and/or crooked wells, expensive repair cost when the tubing needs to be pulled out, vibration problems, and failure to work if the well produces paraffin.
Casing swabbing has been utilized using workover rigs to unload a heavy load of fluid from the wellbore. The well goes back into production until the production stops again due to the accumulation of produced water from the formation. The Klaeger Oil Retrieval System was developed in April 1999 in order to produce marginal wells. This concept revolves around using a mobile casing swab unit mounted on a truck to retrieve oil for marginal wells by swabbing. This technique was used mostly in shallow wells.
In the past, various patents have issued relating to oil well swabbing. For example, U.S. Pat. No. 3,072,193, issued on Jan. 8, 1963 to Ziegler et al., discloses a swab pump for oilfield production. The swab pump unit includes a horizontal plate, a block spaced above the forward end of the plate, and a means for vertically adjusting the block with respect to the plate. A yoke is resiliently supported on the block. The block includes a pair of tubular bushings extending in parallel relation thereto. The yoke is provided with a pair of parallel guide shafts slidably positioned in guide bushings.
U.S. Pat. No. 3,179,022 discloses an oil well swab cup for assembly over a mandrel. This swab cup includes a tubular body of elastomeric material having a base portion adapted to be received in a retainer and a flexible skirt portion adapted to expand toward engagement with a tubing wall. A sheath of Teflon™ is molded against the outer face of the exposed portion of the body. The sheath extends over that portion of the body and is juxtaposed to the open end of the retainer in the mounted position of the cup.
U.S. Pat. No. 4,392,528, issued on Jul. 12, 1983 to R. C Paulson, discloses a swabbing cup construction for swabbing an oil well pipe. This improved cup construction is manually adjustable on the mandrel to compensate for wear of the cup and to increase the life of the cup.
U.S. Pat. No. 5,199,874, issued on Jun. 9, 1992 to Ferguson et al., discloses a swab cup and swab assembly. This swab assembly is for use within a pump barrel and includes a longitudinal swab bypass mandrel which has a top end connectable to a reciprocating member and at least one longitudinal bypass channel on its circumference and axially spaced stop shoulders at each end of the bypass channel. A smooth sealing portion is located between the bottom end of the bypass channel in the lower stop shoulder. The swab cup is slidable vertically on the bypass mandrel between an uppermost fluid bypass portion and a lowermost fluid lifting portion. The swab cup has a generally cylindrical outer body formed of a resilient flexible material surrounding a tubular metal sleeve and has a central longitudinal bore coaxial with the bore of the sleeve. The cup body has an upper portion extending beyond the top end of the sleeve and a lower portion extending below the bottom end of the sleeve.
In these prior art patents, the swab cup is intentionally applied so as to reside against the inner wall of the tubing string. As such, they do not avoid the problems associated with a damaged tubing string caused by issues associated with the oil well pumping system. In any event, they are not a suitable approach to the workover of a well where the tubing string needs to be repaired or replaced. As such, need has developed whereby a swab pumping assembly can be utilized in place of or during the workover of the well during the process of working over the well.
It is an object of the present invention to provide a swab pumping assembly for use with an oil well that avoids the need for well workover.
It is another object of the present invention to provide a swab pumping assembly for use with an oil well that can be permanently installed at the oil well.
It is another object of the present invention to provide a swab pumping assembly for use with an oil well which effectively removes oil that is accumulated within the casing.
It is still a further object of the present invention to provide a swab pumping assembly which avoids the need for workover personnel.
It is still a further object of the present invention to provide a swab pumping assembly for use with an oil well which minimizes the expense associated with attempting to repair pumping systems associated with traditional pump jack assemblies.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a swab pumping assembly for use with an oil well. In particular, in the swab pumping assembly, there is a shaft that has at least one swab cup affixed thereto. The shaft and the swab cup are movable vertically in an up-and-down manner within a casing. The outer edge of the swab cup will be suitably flexible so as to bear against an inner wall of the casing string. As such, when the shaft is moved upwardly, the swab cup will be carried by the shaft so as to lift oil from the well.
A sand line is affixed to the shaft. The sand line extends from the shaft through the interior of the casing and outwardly of the well.
A base is located adjacent to the wellbore. A boom extends upwardly from the base. The boom will have a bottom that is affixed to the base and another location generally above the wellbore. A sheave or pulley can be rotatably mounted to the top of the boom. The sand line will extend from the well up and over the sheave. The sand line can be engaged with a reel. A suitable amount of sand line can be retained on the reel so as to allow for the playing in-and-out from the reel.
A motor is operatively connected to the reel. In the preferred embodiment of the present invention, this motor is a three-phase motor. The motor is operatively connected to the reel so as to drive the reel so as to play the sand line in-and-out from the reel. As the sand line is played in and out from the reel, the shaft will move upwardly and downwardly within the wellbore. As such, the swab cup can move upwardly so as to deliver fluid to a surface location for discharge. The sand line can be played from the reel so as to cause the swab cup to lower into the well. In the lower location, oil can be accumulated above the swab cup for later lifting.
A timer is connected to the motor so as to selectively cause the playing and in-and-out of the sand line. A gearbox is cooperative between the motor and the reel. The gearbox and the timer facilitates the ability to control speed, frequency and swabbing depth.
The present invention is also a method for removing oil from a well. In the method of the present invention, a swab cup is lowered within the casing below a location of an oil-producing formation. Oil from the formation will penetrate through the casing so as to reside in a location above the swab cup. After a desired amount of time, a timer activates a motor so as to drive a reel so as to effectively lift the swab cup and the accumulated oil toward a surface location. Oil can then be discharged from the surface location for cumulation and containment. After the oil is discharged, the swab cup can be lowered back through the casing to a location below the oil bearing formation for further accumulation of oil thereon.
Referring to
In normal use, the swab cups 16 and 18 will be lowered to a location at or below the oil bearing formation. Holes in the casing will allow the oil in the oil-bearing formation to slowly penetrate therethrough so as to reside in a space located above the upper edge 20 of the swab cups 16 and 18. As the shaft 14 is moved upwardly by a upward pulling force applied to the sand line 28, the cups 16 and 18 will lift the oil accumulated thereabove upwardly toward a surface location. Once the oil reaches a surface location, it can be discharged and accumulated in a conventional manner.
After the oil has been discharged, the sand line 28 can be lowered such that the shaft 14 and the attached swab cups 16 and 18 will lower through the casing 22 by gravity. Ultimately, the swab cups 16 and 18 can then be lowered to the location at or below the oil bearing formation so that the accumulation of oil within the casing 12 and above the swab cups 16 and 18 can continue. Since the oil can flow rather slowly, it may be necessary to keep the swab cups 16 and 18 at the lowered location for an extended period of time.
A reel 46 is positioned on a base 48. The base 48 can be part of a permanent installation adjacent to the wellbore. The reel 48 can include an extended length of the sand line 28 wrapped therearound. As such, as the reel 48 would rotate clockwise, the sand line 28 would be played outwardly from the reel 46 and over the sheave 42 such that the portion 44 will move downwardly into the casing. As a result, the swab cups 16 and 18 can be moved to their lowermost location within the casing 12 so as to allow for the accumulation of oil thereon. The reel 46 is mounted on a support 50 that extends upwardly from the base 48. Support 50 allows for the rotation of the reel 46. A suitable sprocket 52 can be connected to the reel 46 so as to control the rotation of the reel 46 as desired. A chain (or other mechanism) 54 extends around the sprocket 52 so as to cause a rotation of the reel 46 and the playing in-and-out of the sand line 28.
A motor 56 is mounted on the base 48. Motor 58 can include a suitable shaft so as to cause the chain 58 to rotate. A gearbox 58 is cooperative with the motor 56 so as to allow for the adjustment of torque required for the playing in of the sand line 28 and for the lifting of the swab cups 16 and 18, along with the accumulated oil.
A timer 60 is electrically connected to the motor. The timer 60 can be set by the operator so as to fix a time at which the motor 56 is activated so as to cause a rotation of the reel 46 in a counterclockwise direction such that the sand line 28 is played in and the swab cups 16 and 18 are lifted. The timer 60 can be set, as desired, to the expected time of accumulation of oil above the swab cups. As such, the timer 60, the gearbox 58 in the motor 56 cooperate so as to control speed, frequency and swabbing depth.
The present invention eliminates the need for rods, tubing, downhole pumps and pump jacks. The only wearable item would be the swab cups 16 and 18. The swab cups can be changed by the pump or by stopping the unit when the cups come to the surface.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated construction or in the steps of the described method can be made within the scope of the present invention without departing from the true spirit of the invention. The present invention should only be limited by the following claims and their legal equivalents.
