We have compiled "100 Q&As on Oil Production Basics," which uses a question-and-answer format to organize and summarize key knowledge points about oil and gas fields. This is Part 1, covering questions 1-50. The content covers core knowledge such as the basic concepts of oil and gas fields, production wells and oil production methods, pumping unit and progressive cavity pump operation, water injection and flooding methods, and oil well operation and maintenance.
1. What is an oil and gas field?
Answer: An accumulation primarily of oil is called an oil field, a primarily gas field is called a gas field, and a field containing both oil and a significant amount of gas is called an oil and gas field.
2. What is a source layer?
Answer: In a broad sense, a source layer refers to a rock formation capable of generating oil and natural gas.
3. What is oil and gas migration?
Answer: Oil and gas migration refers to the movement of oil and gas within the Earth's crust.
4. What is a trap?
Answer: A trap is a location suitable for oil and gas to accumulate and form an oil and gas reservoir.
5. What is an oil and gas reservoir?
Answer: When a certain amount of oil and gas accumulates within a trap, an oil and gas reservoir is formed.
6. What are the types of oil and gas reservoirs?
A: There are four types of oil and gas reservoirs: structural oil and gas reservoirs, fault oil and gas reservoirs, stratigraphic oil and gas reservoirs, and lithologic oil and gas reservoirs.
7. What is sedimentary facies?
A: It refers to the combination of sedimentary characteristics of sedimentary rocks formed in a specific sedimentary environment.
8. What is petroleum?
A: Petroleum is a combustible, organic, liquid mineral, a complex mixture primarily composed of liquid hydrocarbons.
9. What is waterflooding?
A: Waterflooding involves artificially injecting water into an oil reservoir to maintain reservoir energy and displace crude oil, thereby increasing oil production and recovery.
10. What principles should be used to determine the well flushing rate?
A: The well flushing rate should be gradually increased and then decreased, slowly increasing and decreasing the water volume until the well is completely flushed.
11. What are the three major underground contradictions associated with waterflooding oilfields?
A: The three major underground contradictions encountered in waterflooding oilfield development are inter-layer contradictions, planar contradictions, and intra-layer contradictions.
12. What is a production well?
A: A production well is a well used to produce crude oil.
13. What is an infill adjustment well?
A: Wells drilled to tap untapped oil reserves, improve dead oil zones not reached by waterflooding, and adjust for poor horizontal and vertical oil production and development results are called infill adjustment wells.
14. What is a cluster well?
A: Due to topographical factors, a group of wells is drilled within a certain area of unused land, directional deviated wells are drilled to align the completion point coordinates with the specified well pattern, without affecting development results.
15. What is mechanical oil recovery?
A: Mechanical oil recovery is the process of bringing oil to the surface using mechanical lifting.
16. How many types of mechanical oil recovery are there?
A: There are four types of mechanical oil production methods: (1) deep well pump; (2) submersible electric pump; (3) screw pump; (4) hydraulic piston pump.
17. What is a pumping unit?
A: A pumping unit is a ground device of a rod pumping equipment system. It consists of a power machine, a reducer, a frame and a four-bar linkage.
18. What is an electric pump well? How does an electric pump well lift the well fluid to the surface?
A: An electric pump well is a multi-stage centrifugal pump that works underground. It is lowered into the well together with the oil pipe. The ground power supply transmits electricity to the underground submersible motor through a transformer, a control panel and a power cable, so that the submersible motor drives the multi-stage centrifugal pump to rotate, converting the electrical energy into mechanical energy and lifting the well fluid in the oil well to the surface.
19. What is a screw pump?
A: The underground device that lifts the fluid in the well is called a screw pump. The ground drive device drives the rotor to rotate through the underground sucker rod. The power is transmitted by the sucker rod string.
20. How many types of reservoir drive methods are there?
Answer: Five: elastic drive, solution gas drive, hydraulic drive, air pressure drive, and gravity drive.
21. What is the function of a Christmas tree?
Answer: The primary function of a Christmas tree is to control and regulate well production, facilitate the tripping and testing of downhole tools, instruments, and meters, and perform well repair operations.
22. What are the main components of a Christmas tree?
Answer: It consists of gates, tees, and crosses.
23. How does the production process flow in a pumping well work?
Answer: From the reservoir (fixed valves and floating valves in the pump), to the wellhead (oil flowline), to the metering station or transfer station, and then to the external station.
24. How does the production process flow in a screw pump well work?
Answer: From the reservoir (screw pump, sucker rod, power source drive head), to the wellhead (oil flowline), to the metering station, to the transfer station, and then to the external station.
25. What is casing pressure?
Answer: The residual pressure of oil and gas at the wellhead within the annular space between the tubing and casing is called casing pressure, or simply casing pressure.
26. What is back pressure?
Answer: The frictional pressure of oil flowing in the tubing is called back pressure.
27. What is the stroke of a pumping well?
Answer: Generally speaking, the distance between the top and bottom dead centers of the sucker rod is called the stroke.
28. What is the stroke rate of a pumping well?
Answer: The number of times the pumping rod moves up and down per minute is called the stroke rate.
29. What is the stroke utilization rate of a pumping well?
Answer: It represents the ratio of the actual stroke rate of the pumping unit to the maximum stroke rate on the pumping unit nameplate.
30. What is the stroke utilization rate of a pumping well?
A: It represents the ratio of the actual stroke rate of the pumping unit to the maximum stroke rate on the pumping unit nameplate.
31. What is the submergence of a pumping well?
A: Submergence refers to the difference between the pump's hanging depth and the dynamic liquid level when the pump is lowered into the well.
32. What does the submergence reflect?
A: A low submergence will reduce the pump's filling coefficient and oil production. A high submergence will increase the pump's load.
33. What is the balance rate of a pumping well?
A: The ratio of the pumping unit's downstroke current to its upstroke current is called the balance rate of the pumping well.
34. What type of pumping unit is commonly used in oil fields?
A: The beam pumping unit is a common pumping unit in oil fields.
35. What are the main components of a beam pumping unit?
A: A beam pumping unit consists of four main parts: a walking beam, connecting rod, crank mechanism, reduction gearbox, power unit, and auxiliary devices.
36. What are the different structural types of beam pumping units?
A: Beam pumping units are classified into conventional, out-of-phase, and front-mounted types based on their structural form.
37. How many balancing methods are there for beam pumping units?
A: Balancing methods include mechanical balancing (including beam balancing, crank balancing, and compound balancing) and gas balancing.
38. What are the main components of a progressive cavity pump production system?
A: The main equipment of a progressive cavity pump production system consists of two parts: surface and underground. The underground equipment includes the progressive cavity pump and anchoring tools, while the surface part mainly includes the drive head, driving force equipment, and the wellhead.
39. What is gas lock?
A: Gas lock occurs when gas enters a deep well pump, preventing it from pumping out.
40. Why can releasing casing gas reduce and prevent the effects of gas?
A: During production in a pumping well, excessive casing pressure forces the dynamic liquid level to drop. When the dynamic fluid level drops to the pump suction port, gas can enter the deep well pump, causing gas intrusion and reducing pump efficiency. In severe cases, this can lead to gas lock and shut down the well. At this point, the pressure should be released slowly and appropriately to release the casing gas, reducing the casing pressure and raising the dynamic fluid level to prevent gas from entering the pump.
41. Why does wax deposit in oil wells?
Answer: After crude oil flows into the wellbore, as it rises from the bottom of the well to the wellhead, the temperature and pressure decrease, and as gas precipitates, dissolved paraffin crystals precipitate. As the temperature drops further, the paraffin continues to precipitate, and the crystals grow, aggregate, and deposit on the pipe wall, resulting in wax deposition.
42. What are the hazards of wax deposition in oil wells?
Answer: Wax deposition in the tubing reduces the tubing diameter and increases oil flow resistance, reducing well production. In severe cases, it can even block the well. Wax deposition in oil well pumps can easily cause pump leakage, reduce the pump's fill factor, and reduce the well's production.
43. What are the factors that affect wax deposition in oil wells?
Answer: The factors that affect wax deposition in oil wells are:
(1) the composition of crude oil (including the content of wax, colloid and asphalt);
(2) mining conditions (including temperature, pressure, gas-oil ratio and production);
(3) impurities in crude oil (mud, sand and water);
(4) the smoothness and surface properties of the pipe wall.
44. What are the main technical measures for wax removal and wax prevention in oil wells?
A: There are five main methods for wax removal and wax prevention in oil wells:
(1) mechanical wax removal technology, (2) thermal wax removal and wax prevention technology, (3) surface wax removal and wax prevention technology, (4) strong magnetic wax prevention technology, and (5) chemical wax removal and wax prevention technology.
45. What are the requirements for hot washing quality?
Answer: The requirements for hot washing quality are: the incoming water (oil) temperature cannot be lower than 75℃, the outlet return oil temperature cannot be lower than 60℃, and it must be stable for more than 40 minutes. The motor current returns to the working current when it was normal last time, the dynamometer diagram is normal, and the production returns to normal level.
46. Why does sand appear in the oil layer?
Answer: Sand appears in the oil layer due to the destruction of the rock structure near the bottom of the well. It is related to the cementation strength, stress state and mining conditions of the rock.
47. What are the hazards of sand appearing in the oil layer of the oil well to production?
Answer: Sand appearing in the oil layer of the oil well can easily cause sand accumulation in the oil-producing layer, surface manifolds and storage tanks. For pumping wells with serious sand production, sand often enters the pump, causing wear of the pump valves, plungers, bushings, etc., thereby reducing pump efficiency and production. In severe cases, the well is forced to shut down due to sand jam.
48. What is polymer flooding?
Answer: Polymer flooding is a method of adding a hydrolyzed high molecular polymer (mainly polyacrylamide) to the injected water to achieve the purpose of increasing crude oil recovery.
49. What steps should be taken to analyze the production dynamics of oil wells?
A: The production dynamics analysis of oil wells is generally carried out in the following four steps:
(1) Collection and organization of relevant information.
(2) Comparison and analysis of data.
(3) Analysis and demonstration of causes.
(4) Identify existing problems and propose corresponding next steps.
50. What does the daily production of an oil well include?
A: The daily production of an oil well includes daily liquid production, daily oil production, and daily water production.
The above 50 questions basically cover the most common basic knowledge and operating procedures in oil and gas field production. In the next article "100 Questions and Answers on Basic Knowledge of Oil Production (Part 2)", we will continue to explore questions 51-100, covering oil well dynamic analysis, water injection and flooding technology, oil production equipment operation and maintenance, oil well fault diagnosis, and optimized production management methods. Interested friends can follow our website for more information!