Basic oilfield mining knowledge

Permeability: when the pressure is poor, the nature of the rock that allows the passage of liquid and gas is called the permeability of the rock, and the permeability is the number of permeability of the rock. It represents the ability of oil and gas to flow to the bottom of the well through the formation rock, measured in square meters (or square micron ).
Absolute permeability: absolute or physical permeability refers to the permeability obtained when only one phase (gas or single liquid) flows in the pores of the rock and has no physical chemical effect on the rock. It is usually represented by the Gas Permeability, also referred to as the permeability.
Phase (effective) permeability and relative permeability: The pass capacity of a certain phase in the rock when the multi-phase fluid coexist and flows in the formation, it is called the phase or effective permeability of the phase fluid. The relative permeability of a certain phase fluid refers to the ratio of the effective permeability to the absolute permeability of the phase fluid.
Formation pressure and original formation pressure: The oil, gas layer itself and the oil, gas, and water in it all bear certain pressure, which is called formation pressure. Formation pressure can be divided into three types: original formation pressure, current formation pressure and oil, gas static pressure. Before the oilfield is put into development, the whole oil layer is in a balanced and compressed state, with no flow occurring. In the initial stage of oilfield development, the first or first batch of wells are completed, and after being sprayed, close the wells for pressure measurement. The measured pressure is the original formation pressure.
Formation Pressure Coefficient: The pressure coefficient of the formation is equal to the pressure increase from the ground, each increase of the formation depth of 10 meters.
Low Pressure Abnormality and High Pressure Abnormality: Generally, the larger the buried deep pressure of the oil layer, the pressure coefficient of most reservoirs is between 0.7-1.2. The lower pressure exception is less than 0.7, and the high pressure exception is greater than 1.2.
Oil Well acidification: the purpose of acidification is to make the acid roughly penetrate into the formation along the radial direction of the oil well, so as to expand the pore space and dissolve the particles in the space under the action of the acid, eliminate the adverse effect of lower formation permeability near the wellbore to increase production.
Fracturing and acidification: The Acid extrusion process for the formation under the pressure of sufficient pressure to open the formation to form cracks or open the original cracks of the formation is called fracturing and acidification. Fracturing and acidification are mainly used for oil and gas wells with a deep or low penetration area.
Fracturing: the so-called fracturing is a method that uses hydraulic action to create cracks in the oil layer, also known as hydraulic fracturing of the oil layer. In the oil layer fracturing process, the high-pressure large-displacement liquid with a certain viscosity is squeezed into the oil layer. When the oil layer is pressed out of many cracks, the support agent (such as Z sand) is added to fill the cracks, improve the penetration ability of the oil layer to increase the water injection (water injection well) or oil production (oil wells ). Common fracturing fluids include water-based fracturing fluids, oil-based fracturing fluids, milk fracturing fluids, foam fracturing fluids, and acid-based fracturing fluids.
High-Energy Gas Fracturing: the use of solid rocket propellant or liquid gunpowder, in the underground oil layer fire explosion (rather than explosion), produce a large number of high pressure and high temperature gas, the oil is laminated with multiple radiation records within several milliseconds to dozens of milliseconds, up to 2 ~ 5 m of cracks, explosion-proof Shock Wave disappears after the cracks cannot be completely closed, thus removing part of the oil block, improve the formation Penetration ability near the bottom hole, this technology is high energy gas fracturing. High-energy gas fracturing has many advantages, including the following: Large fracturing equipment is not needed; a large amount of fracturing fluid is not needed; support agents are not injected; construction operations are convenient and fast; formation damage is small or even harmless; low cost.
Oilfield development: oilfield development refers to the rational distribution of oil wells and production sequence in the reservoir on the basis of understanding and understanding of the oilfield geology and its change rules, it also adjusts the working system and other technical measures of the production wells to cover the whole process of underground oil resources from the ground.
Oilfield development procedures: oilfield development procedures refer to the sequence of work from detailed exploration to full development. 1. Arrange exploration wells on the construction belt of the oil to quickly control the oil-bearing area. 2. Drilling Data wells within the controlled oil-bearing area to understand the characteristics of the oil layer. 3. Partition layer test oil, and obtain the oil layer production capacity parameters. 4. Open up the production test area to further master the characteristics of the oil layer and its variation rules. 5. conduct comprehensive research based on core, logging, test oil, test data, and other data, make a layer comparison map, structure map, and fault distribution map of the oil layer, and determine the reservoir type. 6. oilfield development and design. 7. Drill a set of basic well networks based on the most reliable and stable oil layers. After drilling, the oil sands of all oil layers are compared and studied based on all the data of the wells. Then, the original scheme is modified and adjusted. 8. After the production wells and injection wells are put into operation, collect the actual output and pressure data for research, modify the original design indicators, and determine the specific production and injection schemes for each development period. The development procedure varies with the situation of each oilfield. .
Reservoir driving type: the reservoir driving type refers to the main driving force for oil displacement during the start of the reservoir. The driving methods vary depending on the power of displacement. Reservoir driving methods can be divided into four categories: water pressure driving, pneumatic driving, pneumatic driving and gravity driving. In fact, different stages of the reservoir development process have different driving energy, that is, there are several driving methods at the same time.
Recoverable Reserves: this refers to the amount of oil and gas that can be produced from the reservoir in the current economic and technical conditions. The recoverable reserves increase with the rise in oil and gas prices and the application of advanced mining technology.
Production speed: the proportion of the annual production volume of an oilfield (reservoir) to its geological reserves, expressed as a percentage, indicating the production speed.
Oil production intensity: the oil production intensity is the daily production volume per unit of oil layer thickness, that is, the amount of tons of oil produced per meter of oil layer per day.
Oil production index: the daily production volume of an oil well is divided by the pressure difference at the bottom of the well. The oil production index equals the daily production volume of the oil wells with a unit production pressure difference. It is an important parameter for the productivity of the oil wells.
Recovery factor: the percentage of recoverable reserves in geological reserves.
Oil decision tree: it is a self-injection well wellhead device. It is mainly used to control and adjust the production of oil wells, ensure the operation, construction, and admission of oil and casing pressure data by hanging the oil column and sealing the annular space of oil casing, testing and wax cleaning and other daily production management.
Delivery rate, natural delivery rate, and overall delivery rate: after a certain period of time for the development of oil and gas fields, the production will decrease according to certain rules, and the delivery rate is the percentage of the production decline within the unit time. The natural progressive reduction rate refers to the ratio of the next-stage fuel consumption to the previous-stage fuel consumption after a variety of Increase measures are excluded. The overall delivery rate refers to the delivery rate that includes the increase of various yield measures.
Oilfield Nissan level: the average daily output of an oilfield is called the daily output level. Because the oil wells need to be repaired within a short period of time or the construction of production increase measures, not all oil wells are produced every day, so the daily production level is lower than the daily production capacity.
Oil Well gas measurement: gas measurement is one of the most important tasks in oil well management. Only by mastering the accurate gas volume and gas-to-oil ratio can we analyze and judge the underground change of the Oil Well correctly, master the relationships between oil fields and oil wells, so as to better manage the oil wells. Currently, on-site Gas Testing is commonly used in two categories: air testing and closed gas testing. There are three common gas measurement methods: (1) gasket flowmeter air outfall gas measurement method (Pressure Difference Meter gas measurement); (2) Differential flowmeter (Float Pressure Difference Meter) Closed Pressure Measurement Method; (3) bellows automatic gas measurement method.
Stratified production allocation: Stratified production refers to the division of the oil layers into several exploitation layers in the downhole packer according to the oilfield development requirements. For the distribution device under different layers, different diameter of the downhole nozzle is installed to control different production pressure difference, in order to obtain different output.
Mechanical Oil Production: when the energy in the oil layer is insufficient to maintain self-injection, it is necessary to manually supplement the energy from the ground to lift the crude oil out of the wellhead. If the energy is supplemented by mechanical energy, it is called Mechanical oil production. At present, domestic and foreign mechanical production units are mainly divided into two categories: Rod Pump and no rod pump. The rod pump ground power equipment drives the pumping unit, and drives the deep well pump through the sucker rod. The rod-less pump does not use a sucker rod to transmit power to the pumping equipment. There are many types of rod-less pumps, such as hydraulic piston pumps, electric submersible centrifugal pumps, jet pumps, vibration pumps, and screw pumps. The most widely used deep well pump unit is the walking beam pumping unit. This device has a reasonable structure, durability, convenient management, and a wide range of applicability.
Pump Efficiency: the ratio of the actual liquid production volume of the pumping well to the theoretical displacement of the pump is called pump efficiency. The formula is as follows: Medium-Well Pump Efficiency of the Q liquid/Q formula × 100%, and actual production of the Q liquid well (tons/day ); the Theoretical Displacement (ton/day) of Q pump reflects the pump performance and the selection of Pumping parameters. There are three factors that affect the pump efficiency: (1) geological factors: including Oil Well Sand Production, excessive gas, oil well wax, high viscosity of crude oil, corrosive water in the oil layer, hydrogen sulfide gas corrosion pump parts, etc.; (2) equipment factors: pump manufacturing quality, installation quality, the combination of the bushing and the piston gap is not proper, or the faner ball and the faner seat are not strict, will reduce the pump efficiency. (3) Impact of the working mode: improper selection of the pump parameters will also reduce the pump efficiency. If the parameter is too large, the theoretical displacement is far greater than the liquid supply capacity of the oil layer, resulting in short supply, and the pump efficiency is naturally very low. The pump efficiency is reduced because the oil is too late to enter the working cylinder of the pump. Pump hanging too deep, so that the stroke loss is too large, will also reduce the pump efficiency.
Methods to Improve Pump Efficiency of pumping oil pump: (1) improve the effect of water injection, maintain formation energy, stabilize formation pressure, and improve the liquid supply capability. (2) reasonably choose the deep well pump, improve the quality of the pump (overhaul), and ensure that the pump's cooperation gap and alivol are not leaked. (3) reasonably select the pump well operating parameters. (4) Reduce Stroke losses. (5) prevent the infringement of sand, wax, water and corrosive media on the pump.
Gas Production: when the energy provided by the local layer is insufficient to lift the crude oil from the bottom of the well to the ground, the oil well stops self-spraying. In order to allow the oil well to continue to output oil, it is necessary to manually Push the gas (natural gas) into the bottom hole so that the crude oil can be sprayed out of the ground. This method is called gas lift. Offshore oil production, exploration wells, inclined shafts, sand-bearing, and gas wells with more corrosive components are not suitable for other mechanical oil wells. The advantage of gas production is that the wellhead and downhole equipment are relatively simple, and the management and adjustment are convenient. The disadvantage is that the ground equipment system is complex, with a large investment and low gas energy utilization.
Oilfield Water Injection: water injection is used to inject water into the oil layer to supplement and maintain the oil layer pressure. After the oilfield is put into development, with the increase of the exploitation time, the energy of the oil layer itself will be continuously consumed, resulting in the oil layer pressure decreasing constantly. A large amount of Underground crude oil is deprecated, the viscosity increases, and the production of the oil wells is greatly reduced, it may even stop spraying and stop production, resulting in a large amount of dead oil left in the ground. In order to make up for the underground loss caused by crude oil production, maintain or increase the oil layer pressure, achieve high and stable production of the oil field, and obtain high recovery, the oil field must be injected with water.
Oilfield water injection method: the water injection method refers to the injection-production system, which refers to the location of the injection well in the reservoir and the arrangement between the injection well and the production well. The following water injection methods can be selected based on the characteristics of the oilfield: ① edge water injection, it can be divided into three types: External Water Injection, on-edge water injection and intra-edge water injection; ② cutting water injection; ③ area water injection, which can be divided into five-point water injection, seven-point water injection, and seven-point water injection, four-point water injection and nine-point water injection.
Stratified injection: the lower packer in the water injection well separates the oil layers into several water injection layers. The water dispenser is installed with different diameter nozzle. The water injection process is called stratified injection. In order to solve the conflicts between layers, water injection is allocated to each layer reasonably to maintain formation pressure and control water injection for layers with good permeability and high water absorption ability; strengthen water injection for layers with poor permeability and weak water absorption ability. This allows High, Medium, Low, and permeability strata to play the role of water injection to achieve long-term high and stable production of the oilfield and improve the final recovery.
Downhole Operation: In the process of oilfield development, a set of equipment and tools on the ground and underground are used according to the needs of oilfield adjustment, transformation, improvement, and tapping potential, various downhole technical measures are taken for oil and water wells to increase the injection and production volume, improve the seepage conditions of oil layers and the technical conditions of oil and water wells, and increase the production speed and final recovery. This series of underground construction techniques are collectively referred to as underground operations.
Type of oil layer damage: oil layer Damage refers to the loss of oil layer permeability caused by some reason. Oil Layer damage includes mechanical particle damage, Clay expansion damage, oil-water emulsion damage, paraffin, colloid, asphalt, resin deposition damage, chemical scaling precipitation damage, oil-water interface tension (capillary force) change damage, damage caused by rock wetting changes, damage caused by biological bacteria blockage, etc. The most basic method to prevent damage to the oil layer is to conduct the water compatibility test between the fluid and the oil layer, crude oil and oil layer to avoid unexpected changes in the oil layer. The proper density of the pressure well fluid should be selected, avoid Leaking a large volume of downhole fluid to damage the oil layer.
Well Test: Testing analyzes the characteristics of oil and gas layers by changing the operating system of oil, gas, and water wells and testing the parameters such as output, pressure, and temperature, A method for studying the different development and change rules of oil and gas reservoirs. It is an important means to grasp the dynamics of oil and gas reservoirs, and is an important basis for formulating a reasonable mining system and development plan.
Stable well test: stable well test gradually changes the operating system of the oil well (for self-injection wells, the diameter of the oil nozzle is changed; for gas-lift wells, the gas injection volume is changed; for pumping wells, the stroke and punch volume are changed ), then, the bottom hole pressure, oil, gas, and aquaculture volume, sand content and oil/gas ratio under each working system are measured. The so-called stability means that the output basically does not change with time.
Unstable well test: the unstable well test changes the operating system of the well to change the bottom hole pressure, based on these pressure changes, the formation parameters and reserves within the oil well control range, the degree of perfection of the oil well, the calculation of the current formation pressure and the judgment of the boundary condition of the reservoir are analyzed and studied. The bottom hole pressure change is an unstable process, so it is called an unstable test.
Production Dynamic Logging: the main task of production dynamic logging is to determine the production profile of the oil and gas wells, the injection profile of the water injection and steam injection wells, determine the water flooding layer, and find the missing oil and gas layers; determine the engineering and technical status of the well, and determine the porosity, permeability, and oil saturation of the oil-producing gas layer.