Wells – With below and above ground modification – Eduction pump or plunger in well
Reexamination Certificate
1997-07-24
2001-02-06
Neuder, William (Department: 3672)
Wells
With below and above ground modification
Eduction pump or plunger in well
C166S105500
Reexamination Certificate
active
06182751
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of oil productions and, more specifically, concerns a borehole sucker-rod pumping plant for pumping out gas liquid mixtures.
This technical solution can be successfully used for increasing the operating flow rates of oil wells, predominantly oil wells with complicated conditions and, in particular, where there are large quantities of casing head gas, viscous and paraffinacous crudes, foreign particles in oil, and permafrost within the well section.
DESCRIPTION OF THE PRIOR ART
Borehole sucker-rod pumping plants are widely used in world practice for pumping out gas liquid mixtures. Usually such a plant comprises a driving rocker having an output member executing reciprocational movement in a vertical direction; a string of sucker rods connected to the output member of the driving rocker; a string suspension arranged in a well, said string of sucker rods being positioned in this string suspension so that it can reciprocate therein to follow the movement of the output member of the rocker; and a deep well pump secured to the lower end of the string suspension. The deep well pump is the most important component of the borehole pumping plant in that the efficiency of pumping out oil from a well is determined mostly by the technical characteristics of the deep well pump.
Thus, in particular, a borehole sucker-rod pumping plant is known in prior art to have a deep well pump (described in SU, A, 545769) which comprises a cylinder, a plunger installed in this cylinder so as to be capable of reciprocational movement and connected to the lower end of a string of rods, a pressure valve built in the plunger, and a suction valve mounted higher than the lower end face of the cylinder by the size of the dead zone.
The borehole sucker-rod pumping plant with such a deep well pump is characterized by a comparatively high efficiency factor, due to eliminating the influence of the dead zone of the cylinder on the operation of the pump. However, this plant shows low efficiency when pumping out oil having a high content of free gas, in so far as a gas content higher than critical value having its definite value in each particular case leads to a failure of the suction valve. In order to avoid this, the pumping plant is, as a rule, further equipped with a gas separator mounted in front of the cylinder. However, this leads to complicating the plant and, correspondingly, to an increase of costs.
In addition to this, a borehole pumping unit is known in prior art to have a deep well pump (see SU, A, 1323743) which, in contrast to what is described above, further comprises one suction valve more, installed at the lower end of the cylinder.
This plant allows the pumping out of a gas liquid mixture having a high content of gas; however, in order to ensure an efficient operation of the plant, the gas liquid mixture must not contain foreign particles and must be watered and contain at least 20% water, and the water stratum must underlay the oil-bearing stratum.
When pumping out gas liquid mixtures from waterless or slightly watered (less that 20% water) wells, free gas enters the lower part of the cylinder together with oil and disables the deep well sucker-rod pump.
In addition to this, in operation of the known pumping plants, the pumping out of the liquid gas mixture is substantially due to the power consumed by the driving rocker so that, in this case, the energy of casing head gas distributed throughout the entire volume of gas liquid mixture is practically not used.
SUMMARY OF THE INVENTION
It is one object of the invention to reduce consumption of power during production of oil by using as much as possible the energy of casing head gas when lifting oil from the well.
Another object of the invention is to ensure the operation of a borehole sucker-rod pumping plant on wells with complicated conditions, i.e., where there are high concentrations of casing head gas or viscous and paraffinaceous crudes, or where there is a permafrost zone within the well section.
A third object is to ensure a reliable and efficient operation of a borehole sucker-rod pumping plant when pumping out foamed oil having foreign particles from waterless oil wells.
These and other objects are accomplished in accordance with one aspect of the invention by a borehole sucker-rod pumping plant for pumping out gas liquid mixtures, comprising a driving rocker; a string of sucker rods having one end attached to an output member of the driving rocker and the other end secured to a plunger of a deep well pump having a main suction valve mounted in the lower part of a cylinder, a supplementary suction valve mounted in the cylinder wall at a distance from the main valve in the direction of the cylinder axis, and a pressure valve mounted in the plunger; a receiving chamber arranged to be disposed upstream of the cylinder and equipped with an outlet valve mounted in its upper part upstream with respect to the main suction valve; two substantially vertical channels arranged in the chamber cavity, the first channel having the upper end thereof in communication with an inlet side of the main suction valve of the deep well pump and having the lower end thereof open into the chamber cavity, the second channel having the lower end thereof in communication with an inlet opening of the chamber having the upper end thereof open into the chamber space at a level downstream with respect to the open end of the first channel.
Preferably, in order to reduce the overall dimensions of the plant, the supplementary suction valve and the outlet valve are to be made in the form of safety ball valves and arranged coaxially one under the other.
In accordance with a second aspect of the invention, the objects are accomplished by a borehole sucker-rod pumping plant for pumping out gas liquid mixtures, comprising a driving rocker; a string of sucker rods having one end attached to an output member of the driving rocker and the other end secured to a plunger of a deep well pump having a main suction valve mounted in the lower part of a cylinder, a supplementary suction valve mounted in the cylinder wall at a distance from the main valve in the direction of the cylinder axis, and a pressure valve mounted in the plunger; a receiving chamber arranged to be disposed upstream of the cylinder and equipped with an outlet pipeline disposed on the upper end thereof and in communication with an inlet side of the supplementary suction valve; two substantially vertical channels arranged in the chamber cavity, the first channel having the upper end thereof in communication with an inlet side of the main suction valve of the deep well pump and having the lower end thereof open into the chamber cavity, the second channel having the lower end thereof in communication with an inlet opening of the chamber having the upper end thereof open into the chamber space at a level downstream with respect to the open end of the first channel.
It is desirable, in order to minimize the overall dimensions of the plant, to have the outlet pipeline disposed coaxially with the supplementary suction valve.
Preferably, in order to ensure extraction of foreign particles, an accumulator of solid foreign particles is installed in the lower part of the receiving chamber.
A borehole sucker-rod pumping plant made in accordance with the present invention is characterized by high efficiency, allowing reduction of the consumption of power during extraction of oil due to the use of the energy of casing head gas and also due to preparing preliminarily the fluid thus extracted by separating liquid from gas and foreign particles, compressing the gas to a predetermined pressure, and introducing separately the liquid and the gas into the cylinder of the pump so that the liquid is fed into the lower part and the gas into the upper part of the cylinder.
REFERENCES:
patent: 1578720 (1926-03-01), Derby
patent: 2910002 (1959-10-01), Morgan
patent: 3483827 (1969-12-01), Hooper
patent: 3594103 (1971-07-01), Hillis
patent: 866133 (1981-09-01), None
Kljushin Ivan Yakovlevich
Koshkin Konstantin Ivanovich
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