RU2779282C1 - Rod pumping unit for the extraction of high-viscosity and paraffinic oils - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry and can be used for downhole production of high-viscosity and waxy oils. The installation contains strings of tubing and hollow rods, a plug-in pump with a rod and a lock support, a liner lowered to the bottom and fixed to the string of tubing. The column of hollow rods is connected to the rod of the plug-in pump by means of a transfer sleeve. In the lower part of the column of hollow rods, channels are made connecting the cavities of the columns of tubing and hollow rods.

EFFECT: design is simplified, the reliability of the sucker-rod pumping unit operation is increased.

1 cl, 2 dwg

Description

The invention relates to the oil industry and can be used for downhole production of high-viscosity and waxy oils.

The production of high-viscosity oil is complicated by significant hydraulic resistance to the movement of rod strings, paraffin deposits in the lifter and a weak inflow of formation production into the well. Mechanized extraction of such oil without the use of additional measures becomes unprofitable.

The most common technical means for pumping out high-viscosity oils are installations with two series-connected pump plungers of different diameters (A.S. USSR No. 1231261, F04B 47/12, claim. 2161268, 47/00, filed March 11, 1999, published December 27, 2000). Such a connection makes it possible to obtain an additional downward force, which makes it possible to partially overcome the hydrodynamic friction of the rods against the liquid during the downstroke of the string. This force is proportional to the difference in the cross-sectional areas of the plungers. A common disadvantage of these designs is the increase in maximum loads at the suspension point of the rods by the same value when the rod string moves upwards. Despite the fact that the probability of loss of equipment performance decreases, the increase in maximum loads and stresses in the metal of the rods leads to a decrease in their MTBF.

Known downhole rod pumping unit for the production of heavy, high-viscosity oils, which allows pumping to the bottom of the well through a tubing string and a coolant pump to reduce the viscosity of the product and increase its flow into the well (RF patent for utility model No. 132503, 47/02, Appl. 04/19/2013, published 09/20/2013). It includes strings of tubing and hollow rods, two pumps of different diameters, the plungers of which are connected by a hollow rod, a side intake valve of the upper pump and a liner lowered to the perforation interval of the well. The coolant is injected from the mouth into the tubing string and then through the pumps and the liner it enters the bottom of the well. The production of the formation is brought to the surface through a string of hollow rods. The installation has the disadvantage of large heat losses when the coolant is injected into the tubing string.

The closest in technical essence to the proposed invention is a sucker-rod pumping unit for the production of high-viscosity oil (RF Patent for utility model No. 141835, 47/02, applied on January 21, 2014, published on June 20, 2014). The unit makes it possible to pump coolant into the hollow rod string at the wellhead using a flexible high-pressure hose and thereby reduce heat loss to the near-wellbore space. The installation includes strings of tubing and hollow rods, two pumps of different diameters, the plungers of which are connected by a hollow rod, a side intake valve of the upper pump, a vertical channel inside the upper pump plunger, a liner lowered to the bottom of the well. The discharge valve of the upper pump is located inside the vertical channel of its plunger. However, the installation has significant drawbacks, consisting in the need to use two pumps and to make the suction valve of the upper pump side. All this complicates the design of the installation, increases the load on the equipment and reduces the reliability of its operation. The specified installation can be taken as a prototype.

The technical results of the claimed invention are to simplify the design and increase the reliability of the sucker rod pumping unit.

The set technical result is solved by the described rod pumping unit for the production of high-viscosity and paraffinic oils, containing tubing strings and hollow rods, a plug-in pump with a rod and a lock support, a liner lowered to the bottom and fixed to the tubing string.

What is new is that the hollow rod string is connected to the plug-in pump rod by means of a transfer sleeve, and in the lower part of the hollow rod string there are channels connecting the cavities of the tubing strings and hollow rods.

The proposed image is illustrated by drawings, where:

- in Fig. 1 scheme of the installation for the production of well products;

- in Fig. 2 - scheme of installation during heat treatment.

An insert pump with a rod 4 connected to a plunger 5 located in the pump cylinder 6 is lowered into the well 1 on the tubing strings 2 and hollow rods 3. In the plunger 5 and the pump cylinder 6, respectively, the discharge 7 and suction 8 valves are placed. The pump rod 4 is articulated with the string of hollow rods by means of a transfer sleeve 9. In the lower part of the string of hollow rods 3, channels 10 are made connecting the cavities of the tubing strings 2 and hollow rods 3. A liner 11 is connected to the tubing string of pipes 2 from below. , lowered to the bottom. At the wellhead, a string of hollow rods 3 is connected by means of a valve 12 to a flexible high-pressure hose (not shown in the figure). The tubing string 2 is connected to the manifold through a valve 13. In the lower part of the tubing string 2, there is a support 14 of a cone shape, and a similar reciprocal support 15 (Fig. 2) is installed on the pump housing, which generally form the lock support of the plug-in pump.

The operation of the rod pumping unit is as follows.

First, a string of tubing 2 with a liner 11 is lowered into the well 1. Then, a plug-in pump assembly with a rod 4 and a transfer sleeve 9 is lowered into the pipe string 2 on a string of hollow rods 3. The support 15 with its conical part enters the conical part of the reciprocal support 14 and seals the annular space between the pump and the pipes of the string 2. During the operation of the pump, the formation fluid enters the liner 11, then it is pumped out by the plunger 5 of the pump into the tubing string 2 and enters the collector through the valve 13.

If heat treatment is necessary, the well is stopped and the string of hollow rods is raised by an amount sufficient to separate the support 15 from the support 14 (Fig. 2). In this case, an annular gap is formed between the pump housing and the pipes of the column 2. After that, the coolant is injected into the column of hollow rods 3. The coolant then exits the string of hollow rods into the string of tubing 2 through channels 10 and through the formed annular gap between the pump and the pipes of the string 2 enters the bottom of the well through the liner 11.

After the bottomhole formation zone is warmed up, the hollow rod string is lowered and the support 15 is hermetically pressed against the support 14 due to the weight of the hollow rod string.

The well is also heated with a coolant when paraffin is deposited in the tubing string 2. In this case, the hollow rod string 2 is partially lifted to form an annular gap, and the pump is not stopped. The coolant injected into the hollow rods enters the pipe string 2 through channels 10 and, mixing with the produced product, is pumped out into the collector. In this case, melting and entrainment of paraffin from the walls of the pipe string 2 and the outer surface of the hollow rods 3 occur.

The technical and economic advantage of the proposed solution is to simplify the design of the pumping unit and increase the reliability of its operation. The unit also makes it possible to deliver the coolant with the help of a liner to the bottom of a well with a horizontal ending due to the possibility of using small-diameter pipes of the liner.

Claims (1)

Rod pumping unit for the production of high-viscosity and paraffinic oils, containing tubing strings and hollow rods, a plug-in pump with a rod and a lock support, a liner lowered to the bottom and fixed to the tubing string, characterized in that the hollow rod string is connected with a plug-in pump rod using a transfer sleeve, and in the lower part of the hollow rod string there are channels connecting the cavities of the tubing strings and hollow rods.

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