In the case of a deep well pump, the initial step involves assembling the outer cylinder and the bushing on the ground. These components are then connected to the lower part of the tubing. After this, the assembled unit is lowered into the well. Once in place, the fixed valve is fitted, ensuring a secure connection. Finally, the plunger is linked to the lower end of the sucker rod string, which is then inserted into the pump.
Let's take a closer look at the tube pump and its structure. There are two main types of tube pumps: the combined oil pump and the whole barrel oil pump. The combined oil pump is made up of an outer working cylinder, a bushing embedded in the outer working cylinder, a plunger with upstream and downstream moving valves, and a fixed valve. On the other hand, the whole barrel oil pump consists of a pump barrel, plunger with upper and lower moving valves, and a fixed valve.
The whole barrel oil pump has several advantages over the combined oil pump. First of all, it has a simpler structure and is much lighter. It also does not require a bushing, which means there is no risk of dislocation during transportation or when going down the well. Additionally, the length of the pump barrel can be increased, making it better suited for use in long stroke oil well pumps.
Overall, the tube pump is an essential tool for extracting oil from the ground. Whether you are using a combined oil pump or a whole barrel oil pump, it is important to choose the right type of pump for the job at hand.
Take a look at the rod-type pump, which is assembled on the ground before being connected to the sucker rod string's lower end. With the circlip pre-installed on the oil pipe's predetermined position, the entire pump is lowered into the working cylinder through the oil pipe. This pump has the advantage of not needing to remove the oil outlet pipe, making pump inspection convenient. However, the rod pump is complex in structure and has a high manufacturing cost. Due to its smaller diameter, the pump's allowed size to operate under the same oil pipe diameter is smaller than that of the tube pump, resulting in lower displacement. For this reason, rod pumps are ideal for wells with large pumping depths but low production.
The downhole unit of the deep well pump consists of several essential parts, namely the submersible motor, protector, separator, and multi-stage centrifugal pump. Let's take a closer look at each component.
Starting with the submersible motor, it is a remarkable piece of equipment that employs a two-pole, three-phase squirrel-cage asynchronous induction motor design. This motor type ensures efficient and reliable operation even in challenging downhole conditions.
Moving on to the protector, this crucial device plays a vital role in safeguarding the submersible motor. It operates by exploiting the disparity in density between the well fluid and the motor oil. By utilizing this difference, the protector prevents any well fluid from infiltrating the motor and causing potential short circuits or motor burnout.
Another indispensable component is the oil and gas separator. Its primary function is to separate any free gas present in the well fluid. The separator effectively minimizes the occurrence of gas entering the pump, which could disrupt its normal functioning. By preventing gas intrusion, it ensures optimal performance of the multi-stage centrifugal pump.
Lastly, we have the multi-stage centrifugal pump, which is responsible for transforming the well fluid's characteristics. This pump operates in a step-by-step manner, progressively intensifying pressure and velocity. Through this process, the pump generates sufficient force to lift the fluid to the surface, achieving the desired head.
In summary, the deep well pump's downhole unit comprises the submersible motor, protector, separator, and multi-stage centrifugal pump. Each component contributes significantly to the pump's overall efficiency and functionality, ensuring the successful extraction of fluid from the deep well.