A bottom-fixed sealing anti-sand sucker rod pump
The sucker rod pump is a common down-hole device driven by the pumping unit to pump the crude oil in the well to the surface, an important part of the artificial lifting system.
The safety and reliability of pump operation and long inspection period are critical, which can greatly reduce the loss of operation time and increase oil production. But for heavy oil wells with high sand cut, sand stuck failures will occur from time to time, seriously reducing the profit of crude oil production.
Sand production refers to the phenomenon that the formation sand flows into the wellbore and blocks the oil and gas channel during the production of oil and gas Wells due to the large production pressure difference and loose rock cementation of sandstone oil and gas layers.
In the petroleum industry, sand production in oil wells is a common problem, and the research on sand production in oil wells is very difficult. The reasons are:
1). The process of sand production cannot be directly observed. Oil field development is carried out deep in the formation and cannot be directly observed on the ground;
②The rock’s mechanical properties are complex. The mechanical properties of formation
rocks may vary in a relatively large range. Deep formation coring is not only expensive but also has certain contingencies and limitations. For example, it is difficult to maintain the water content, temperature, and pressure conditions of deep formation on the ground, and these factors Have a great influence on the mechanical properties of the stratum rock;
③The reservoir conditions are complex. With the progress of production and the implementation of various stimulation measures, the reservoir has become very complicated, which also brings difficulties to the study of the sand production mechanisms.
④ There are many factors affecting sand production in oil wells. Sand production in oil wells is affected by many complex factors, such as geological conditions, rock mechanical properties, production parameters, etc.
During the production process of a well, it is very important to accurately predict whether it will produce sand because no matter what sand control measures are taken, the cost will be high. Therefore, unnecessary sand control measures will not only increase production costs, but also pollute oil and gas. Layers, reducing production efficiency. But for those wells that were abandoned or unable to continue development due to sand production, taking sand control measures is the only way to make oil wells worthwhile.
About the existing bottom-fixed sealing rod type downhole pump, its locking sleeve of the sealing locking device is directly connected to tubing, and after the tubing is fixed and sealed down the well, a sealed space is formed between the sucker rod pump pump barrel and the tubing. When pump is working or off, the sand particles in the oil well are deposited in this space, which causes the sand to bury the pump barrel and cause sand jamming, thus affecting the normal pump inspection work.
This patent introduces a bottom-fixed sealing anti-sand stuck sucker rod pump, which can prevent the sand from burying pump barrel after going down the well and prevent sand stuck. It is especially suitable for the exploitation of a small amount of sand-containing crude oil in deep wells. Moreover, the manufacturing process is simple, the success rate of the downhole block seal is high, and sand jamming is prevented, and the operation and maintenance are convenient.
The structure of the oil pump is as follows:
- The special structure has reduced the resistance on the plunger, suitable for heavy oil recovery.
The sand-settling centralizing and locating device can prevent
from sand stuck.
- The sealing & rotary device can relieve the reverse torque of making up or breaking out the tubing, making the operation easy.
- It can drain the oil when need lifting and inspecting the pump.
- Suitable for wells with viscosity of crude oil≤4000Mpa.s;
- Suitable for wells with sand cut≤1.2%；
- Not apply to the wells which has high gas cut and frequent gas locking.
The utility model is composed of a pump barrel assembly
1, a plunger assembly
2, and a sealing and locking device
3. The sealing and locking device 3 is provided with a sand trap assembly
4, and the sand trap assembly 4 is composed of a sand trap barrel 7, an annular joint 8. The locking sleeve 5 of the sealing and locking device 3 is connected to the upper end of the inner core of the annular joint 8. An annular channel between the sealing and locking device 3 and the sand trap assembly 4 is formed. The annular joint 8 inner core of the sand trap assembly is a blind hole. And there are 1 – 4 through holes in the radial direction. This through hole communicates with the blind hole and does not communicate with the annular space. The lower end of the annular joint 8 is connected with sand trap tubing
9. When pump is sent down, connect the sand trap assembly 4 and the locking sleeve 5 of the sealing locking device 3 to the tubing string. When pump reaches the design depth, the sealing locking head 6 of the sealing locking device 3 and the pump is at the predetermined depth. Then the seal locking device 3 and the locking head 6 are fixed into the locking sleeve 5, locks and seals.
When the pump is turned on, the crude oil enters the pumping through the radial through hole of the annular joint 8 and the oil pump is lifted to the wellhead. and the sand in the crude oil in the oil well sinks into the sand trap tubing 9 through the annular channel, to avoid the deposit of large stinging sand between the seal locking device 3 and the pump barrel and the tubing, which prevents the pump barrel from being buried by sand and sand stuck.