This technical proposal pertains to oil and gas industry, namely, to the equipment for lifting well fluid to the surface.

Prior Art Let's look into «Oil well pumping assembly» (patent RU N°

2118708, F04B 47/02, published 10.09.1998), consisting of a plunger pump, a top drive with at least one reel and pulling equipment for tape package, package tape length compensator set between the plunger and the pump drive, characterized in that compensator includes at least one gear, teeth of which are locked with two racks, located on either side of it and are placed in the case. At least one of these racks is traveling along longitudinal axle, with the outer coil tapes tied on the sliding rack, gear axle is tied on the plunger pump, inner tapes being tied on the case when having one movable rack, or with the second movable rack when having two movable racks.

Now let's look into «Oil well sucker-rod pumping assembly» (patent RU Ns 57388, F04B 47/00, published 10.10.2006), consisting of an oil-well rod pump with the plunger or piston stroke up to 12 m, while polished rod is pulled through the stuffing box, and is connected with a mast drive by a wireline. The distinguishing feature of this assembly is that the mast is made as a drive installed on the carriage frame like that of a car, or a crane with a boom extension not less than maximum rod pump plunger stroke length. Alternatively, as a rod pump there may be used a HCB plunger rod pump or a HH-2CI1 piston rod pump. Maximum pump rod tension at maximum load is no more than 0.12 of the plunger stroke length, and maximum tubing joints tension is no more than 0.04 of the plunger stroke length.

The most similar to the proposed unit is «Oil well pumping assembly» (Patent RU Ns 2314434, F04B 47/02, published 10.01.2006) consisting of a Oil well rod pump, tubing joints and wellhead stuffing box. The distinguishing feature is that it is equipped with an antiphase device made in the shape of a cylinder connected to the bottom part of the wellhead stuffing box located inside the tubing joints and a piston tied on the rod string and a wireline hanger. Piston length provides constant tight connection with the barrel in case of breakage, and the diameter of the cylinder and antiphase piston device are equal to the diameter of the pump case and plunger to ensure equal displacement volumes at working strokes of the assembly. The disadvantageous features of all similar assemblies are: high cost, poor functional capabilities due to strict restrictions on minimum pump diameter as well as its valves (and hence, the diameter of a borehole), borehole curvature, well production viscosity, and showings of sand in the formation in the result of availability of rods inside the tubing string along their entire length to transmit reciprocating motion from drive to plunger, which causes paraffin accumulation and hence greater load on the drive and, all these consequently reduce the performance coefficient for the entire pumping assembly. Summary of the Invention

Technical goal of the proposed model is fabrication of a cost- effective advanced function pumping assembly with no rods along the entire length of the tubing string. This technical goal can be reached by installation of a Oil well plunger pumping assembly including plunger pump with suction and traveling valves, rods tied on the plunger, tubing connected to the pump barrel, a stuffing box located on the wellhead, and a top drive. The distinguishing feature of this assembly is location of rods below plunger, and they are equipped with an anchor assembly which can be set on the walls of the well, the tubing being connected to the drive and able to transmit reciprocating motion. Besides, the stuffing box allows sealing of the tubing during reciprocating motion through a drain pipe located above the stuffing box.

Detailed Description of the Invention See the drawing fig.1 of the pumping assembly, view in longitudinal section. Oil well plunger pumping assembly consists of a plunger pump (2) with a suction valve (3), traveling valve (4), rods (5) tied on the plunger (6), tubing (7) tied on the barrel (8) of the pump (2), a stuffing box (9) located on the wellhead (1 ), and a top drive of the oil well pump (not shown in the drawing). Rods (5) are located below the plunger (6) and are equipped with an anchor assembly (10) to be set on the walls of the well (1). Tubing (7) is tied on the connecting rod 11 (not shown in the drawing) to transmit reciprocating motion. Stuffing box (9) allows for sealing the tubing string (7) during reciprocating motion through a drain pipe (12) located above the stuffing box (9) on the wellhead (1 ).

Either of hydraulic or mechanical action anchor assembly (10) of any known design may be used. Hydraulic anchor assembly (10) is tripped in hole on tubing joints under pressure to the desired interval until it is set with slips (13) against the walls of the well (1 ). Oil-well plunger pump assembly operates as follows. Either of hydraulic or mechanical action anchor assembly (10) of any known design may be used. Hydraulic anchor assembly (10) is tripped in hole on tubing string under pressure to the desired interval until it is set with slips (13) against the walls of the well (1 ). After that the tubing string is tripped out of hole. Then a plunger pump is tripped in hole on tubing attached at the bottom by coupling (14) through the stuffing box (9) until the rods (5) are set in the anchor assembly (10) using, for example, a spring ring or a spring-loaded lock (not shown in the drawing).

Mechanical anchor assembly (10) is set on the rods (5) at the surface, then it is run in hole to the desired interval of the well (1 ) completed with the plunger pump (2). Anchor slips (13) are set on the walls of wells (1 ) by turning them from the wellhead (for this purpose the plunger (6) is set against the pump barrel (8) using shear ties - not shown in the drawing), or by pulling the tubing string (7) up. Well fluid fills the plunger (6), the pump barrel (8), and the tubing string (7) through valves 3 and 4. Then the polished area (15) of the tubing string (7) is set against the stuffing box (9) to extend its service life, and to reduce friction. Sealing rings (16) are inserted into the stuffing box (9) and tightened with landing seat (17) for better sealing of the tubing string (7). Drain pipe (12) is pressure-tight tied on the tubing string (7) above the stuffing box (9). Then the drain pipe is tied on the pipeline with a flexible line or a hose (not shown in the drawing) to pump-off well fluid. The tubing string (7) is connected to the drive (for example, pumping unit, chain drive or hydraulic drive) by connecting rod (11 ).

To prevent plunger (6) from falling out of the pump barrel (8) while tripping in, it is fitted with a limiting device 18 at the bottom.

Then the drive is started up, and it transmits reciprocating motion to the tubing (7) and to the barrel (8) of the pump (2) by force of the connecting rod (11). As the rod (5) and plunger (6) are fixed with anchor assembly (10) on the walls of the well (1 ), they remain immobile. While tubing string (7) is moving downward, the suction valve (3) closes, well fluid is displaced out of the barrel (8) into the tubing (7) through the traveling valve (4). While tubing string (7) is moving downward, the traveling valve (4) closes under hydrostatic pressure, and the suction valve (3) opens under vacuum pressure occurred in the pump barrel (8). Well fluid flows into the pump barrel (8) through the rod (5) end (19) (if hollow) or through the lateral bores (20) of the plunger (6). The cycles are repeated forcing well fluid to move upward through the tubing string (7) to the surface of the well (1 ), where from it is pumped-off through the pipeline through the nipple 12.

No rods in the tubing string of the proposed plunger pump (this cheapens the design on the whole) prevents fluid from flowing, hence decreasing by 3 - 6 times paraffin depositions on the barrel, piston, valves and tubing string in the process of recovering viscous oil. All this reduces the load on the drive making possible to use tubing of smaller diameter (this also cheapens the design). Thus, average well fluid flow rate exceeding solid inclusions deposition rate (sand, etc.) prevents from deposition of sediments in the barrel. All the above-mentioned increases the efficiency of the assembly upgrading functional capabilities, and making it possible to operate the assembly in highly deviated boreholes to recover high-viscosity oil from the reservoirs with sand showings, as well as in wells with parallel pipes used due to the minimum possible size of the assembly.

Industrial Applications

This invention is embodied with the use of multifunctional and easily available up-to-date equipment and substances that are widely used in the industry and health care.