1. Oil well (pump inspection) operation:
The methods of extracting oil from the formation can be divided into two categories: one is to use the energy of the formation itself to lift crude oil, which is called self-flowing oil production; the other is that due to the lack of energy in the formation itself, it is necessary to artificially use mechanical equipment to supplement the energy of the liquid in the well in order to lift the crude oil to the ground, which is called artificial lifting oil production or mechanical oil production. At present, the main artificial lifting methods in oil fields are gas lift, insert rod pump oil production and rodless pump oil production.
insert rod pump oil production includes pumping unit insert rod pump and ground driven screw pump (generally not used). Rodless pump oil production includes electric submersible pumps, hydraulic piston pumps, jet pumps, etc. Regardless of the lifting oil production method used, due to adjustments to the oil field development plan, equipment failures, etc., pump inspection (replacement) operations are required.
2.Check (replace) the insert rod pump:
The insert rod pump is a method of producing oil by transferring the reciprocating motion of the pumping unit suspension point to the pumping pump through the sucker rod, and the insert rod pump piston moves up and down to take out the liquid in the well. insert rod pump is currently the most widely used artificial lift oil production method in various oil fields, accounting for about 90% of the number of artificial lift wells. The insert rod pump is mainly composed of a pumping unit, a pumping pump, a sucker rod and supporting tools.
The pump should be inspected due to a failure of the insert rod pump downhole. The time interval between two pump inspections is called the pump inspection cycle. Many factors such as the production of the oil well, the oil layer pressure, the oil layer temperature, the gas and water discharge, the sand and wax deposition of the oil well, the corrosiveness of the crude oil, and the management system of the oil well will affect the length of the pump inspection cycle.
3.The reasons for the pump inspection of the pumping well due to accidents are generally the following:
1. Waxing of the oil well causes piston jamming and valve jamming, which makes the insert rod pump unable to work normally or blocks the oil pipe.
2. Sand jamming and sand blockage pump inspection.
3. insert rod pump inspection due to the disengagement of the sucker rod.
4. insert rod pump inspection due to the breakage of the sucker rod.
5. The wear and leakage of the insert rod pump continues to increase, resulting in a decrease in the production volume and reduced pump efficiency, and pump inspection construction is required.
6. The sucker rod and the oil pipe are eccentrically worn, the oil pipe is worn out or the coupling and rod body are worn off, and pump inspection construction is required.
7. The dynamic liquid level of the oil well changes, and the production changes. In order to find out the cause, pump inspection construction is required.
8. According to the requirements of the oil field development plan, it is necessary to change the working system and replace the pump or deepen or lift the pump hanging depth.
9. Other reasons: such as inspection construction caused by oil pipe disengagement, pump barrel disengagement, bushing disorder, large pump disconnector disconnection, etc.
4.The pump inspection operation mainly includes the following construction procedures:
Construction preparation, well washing, well pressure, pumping rod string, pipe string, wax scraping, well clearance, sand surface exploration, sand flushing, pipe string, pipe string, pumping rod string, test well handover, writing construction summary, etc.
5.The system of a typical submersible electric pump well mainly consists of three parts:
(1) Ground part: The ground part includes transformer, control cabinet, junction box and special wellhead device, etc.
(2) Middle part: The middle part mainly includes oil pipe and cable.
(3) Downhole part: The downhole part mainly includes multi-stage centrifugal pump, oil-gas separator, submersible motor and protector.
The core of the above three parts is the seven major components of centrifugal pump, oil-gas separator, submersible motor, protector, submersible cable, transformer and control cabinet.
6.Explanation of terms:
Sand surface exploration: Sand surface exploration is the construction of the sand surface depth in the well by actually exploring the sand surface depth in the well. By actually exploring the sand surface depth in the well, a reference basis can be provided for other pipes to be lowered in the next step, and the sand production of the formation can also be understood by actually exploring the sand surface depth. If the sand surface in the well is too high, burying the oil layer or affecting other pipes to be lowered in the next step, sand flushing construction is required.
Sand flushing: Sand flushing is the process of injecting liquid into the well at high speed, dispersing the sand at the bottom of the well by hydraulic action, and bringing the dispersed sand to the ground by using the carrying capacity of the liquid circulation. There are generally three types of sand flushing methods: positive sand flushing, reverse sand flushing, and positive and reverse sand flushing.
Well washing： Well washing is the process of injecting a well washing working fluid with certain properties into the wellbore on the ground, and bringing a mixture of wax, dead oil, rust, impurities and other dirt on the well wall and tubing to the ground through the working fluid. Well washing is a regular project in underground operations. When constructing pumping wells, heavy oil wells, water injection wells and wells with severe wax deposition, well washing is generally required.
Positive well washing: The well washing working fluid is injected into the tubing and returned from the casing annulus. Positive well washing is generally used in wells with severe wax deposition in the tubing. Gas lift wells require positive washing.
Backwash wells：well washing working fluid is injected into the casing annulus and returned from the tubing. Backwash wells are generally used in pumping wells, water injection wells, and wells with severe casing wax deposition.