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13
Section 4. Technical sciences
DOI: http://dx.doi.org/10.20534/AJT-17-5.6-22-25
Allahverdiyev Zamaddin, Azerbaijan State Oil and Industry University E-mail: rahimova-mahluqa@mail.ru
DEVELOPMENT OF SPECIAL SUCKER ROD PLUNGER PUMP
Abstract: Special design change has been made to reduce wear in the pair "cylinder-plunger", that's an additional component (centering element) and packing unit have been installed.
As a result of such design change, the alignment of the plunger and cylinder of the pump is provided, which reduces wear of these components, oil leakage through annular gap between cylinder and plunger of the pump, and also coefficient of the pump feeding.
The given offer has practical value, as it increases durability of the given pump.
Keywords: filtration, development, bottom hole pressure, functional dependence, position, reservoir, discharge, reduce.
In the sucker rod pumps one of the main reasons of the refuse of the work of plunger is that the chromium-plated coating of its surface is subjected to wear [1]. Practice proves that the biggest wear in the plungers is met at the distance of10^15 sm from its ends and mainly the wearing place unilaterally along the diameter, as well as along the length [2; 3].
In the conditions of exploitation of the particles of mechanical mixtures, mainly sand particles entering in the annular gap between the plunger and cylinder of the pump moving there unilaterally press the plunger to the interval wall of the cylinder and as a result of it, powerful friction takes place because of the increase of normally compressing force and increase of the wearing the plunger and cylinder of the pump and in reverse extended excentric annular zone, consumption of hydroabrasive mixture increases, and also as a result of absence of alignment in the connection of the plunger and extending rod and compressing of the plunger in the lower and upper
final points in the cylinder is one of the main factor making condition for wear of the plunger and cylinder [8; 9].
For partial liquidation of abovementioned factors influencing on the wear of the pair plunger+ cylinder, sucker rod pump having plunger of special type has been offered [4; 5].
The difference of the considered sucker rod pump from the existing pumps is the transfer the force into the cylinder, occurring in the extending rod in radial derection accepting it. In fig.1 sucker rod pump supplied with the plunger of special type has been shown.
Sucker rod pump consists of cylinder 1, plunger 2, discharge valve 3, suction valve 4, extending rod 5, alignment element 6 and packing unit 7.
As it is seen from the figure, extending rod was connected with the end of the lower part of the plunger. But alignment extending rod has state type along the diameter then its lower part as the bush is smaller than
the upper part that enters the plunger. Annulus packer is installed into the lower part of the bush, which sets against the upper part of the lateral section. In the upper part of the alignment there is internal facet. The alignment has possivility to make some movement relatively to the plunger up and down, which is limited, in the movement up it sets against the ledge in the extending rod and moving down it sets against the ledge in the lower part inside the plunger.
Work principle of sucker rod with the offered design of plunger is described below. In the process of suction, that's in the movement of the plunger 2 up, discharge valve 3, installed on the plunger is closed under the pressure influence created by the fluid column inside the tubing column. As a result of the pressure in the alignment 6, getting displacement in the direction down proportionally to it, presses packing unit 7 to the upper lateral section of the plunger. As a result packing unit causes lateral deformation and forms leakage froOm the tubing reversely into the pump cylinder. Let's mention that in the construction with the restriction ofbeforehand installed to the displacement of the alignment, pressing of the packing unit is adjusted. The purpose of the forming of internal facet in the upper end of the alignment 6 is to direct particles of mechanical mixtures sticked in the internal wall of the cylinder inside the plunger selecting them and to provide more effective work of the packer 7.
In the movement of the plunger down, that's in the process of discharge as a result of increasing the pressure in the space under the plunger discharge valve opens and suction valve closes. At this time pressure in the space over the alignment is considered.
As a result of friction it is separated from the plunger and gets displacement up. It gives an opportunity to restore its initial position of the packer. This, the condition for reduce the friction force to the minimum is formed, which creates obstacle to the free drop of the plunger.
It is necessary to mention that in the movement down, as a result of moment formed relatively to the force in the upper point directed up hydraulic resis-
tance in radial direction, pressing of the plunger to the cylinder is eliminated. In the movement of the plunger in the direction down the force, connected with lateral deformation of the extended rod and a result of these forces, pressing the plunger to the cylinder is eliminated.
Thus, in the offered sucker rod pump, at the expense of the wear in the contact of plunger and cylinder and reduce of volume losses of the fluids, as a result of inverse leakage into the cylinder makes possible to significant increase of the service term and productively in compareson with corresponding indices of series production.
Analysis of the work of the offered sucker rod pump has been carried out. As it was mentioned the purpose of the presented construction is the supply of alignment of the area (surface) reduce of the wear in the considered pairs. 10 pumps of R and T type with 44 mm conditional diameter have been tested to determine work ability of sucker rod pump and its efficiency.
Before the test corresponding sizes of plunger and cylinder of the pumps marked for comparison with indicator micrometer and nutrometer. Have been taken sizes were mentioned along plunger length in equal distances from each other on lateral sections in 12 places, but on the cylinder on six places. Based on arithmetic mean value of the obtained sizes, their diameters has been determined and the size of the gap between the plunger and cylinder has been accepted as difference of the diameters of the cylinder and plunger. After the lifting of sucker rod pumps out of the wells their conditions were examined, sizes of plunger and cylinder have been taken. Degree ofwear of each pump has been determined on the basis of it.
In table 1, information about technical indices and about the wear of sucker rod pumps have been given. As it is seen from the table, in all cases indices of the tested pumps are higher than corresponding indices of mass pumps. The results show that in the tested pumps arithmetic mean wear is 21% less than in the compared mass pumps.
For clearness wear epure of mass produced and offered plungers operating in well N2275 has been shown in figure 2.
In figure 2 a wear along the plunger diameter has been shown, but in figure 2b wear of the special type has been shown. As it is seen from this figure, wear intensity for time unit of special type plunger is much lower and wear along the surface of plunger takes place uniformly. As it is from epure, at the end parts of the offered plunger wear quantity is sharply
a)
44,200 44,190 44,160 44,130 44,100
6)
44,220
44,190
44,160 44,130
44,100
Figure 1. 1-cylinder, 2-plunger, 3-discharge valve, 4-suction valve, 5-extending rod, 6-alignment element, 7-packing unit
lower Abovementioned can be explained fig the facts that in the process of pump work in up and down
movement of special type plunger its alignment with cylinder is provided and reverse leakage of fluid through annular gap reduces.
Let's mention, in carrying out of the tests no constructive blunder has been observed in the plunger and after the lifting out of the well it is useful for the secondary exploitation.
Figure 2. Epure of plunger wear of sucker rod pump of R type with 44 mm conditional diameter
a) Epure of mass produced plunger wear; b) Epure of special type plunger
Mass pumps Tested pumps
N-of well Average diameter of plunger, mm Durability of pump work, day n e U—1 ÎH ? Average diameter of plunger, mm Durability of pump work, day n e U—1 ÎH ?
Before lowering into the well After lifting out of the well Plunger w mkm Intensity plunger w mkm/d; Before lowering into the well After lifting out of the well Plunger w mkm Intensity plunger w mkm/d
1 2 3 4 5 6 7 8 9 10 11
936 44.200 44.130 24 70 2.196 44.130 43.050 40 80 2.000
2657 44.300 44.200 43 130 3.023 44.330 44.192 66 138 2.090
Table 1. - Comparative wear indices of special type and mass produced plungers
1 2 3 4 5 6 7 8 9 10 11
2538 44.210 44.985 150 225 1.500 44.210 43.963 190 247 1.300
6068 44.400 44.290 59 110 1.865 44.400 44.134 64 86 1.344
655 44.220 44.127 30 93 3.100 44.220 44.205 46 115 2.500
3332 44.280 44.180 79 100 1.266 44.280 44.220 60 60 1.000
2270 44.220 44.185 10 35 3.500 44.220 44.109 37 111 3.000
2430 44.280 44.137 55 143 2.600 44.280 44.097 76 183 2.407
2195 44.350 44.307 34 43 1.265 44.350 44.283 73 67 1.089
1191 44.215 44.143 38 72 1.895 44.215 44.132 55 83 1.509
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