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Oil field------a combination of reservoirs within the same area, controlled by a single structural feature. Gas field------a collection of several or a dozen gas reservoirs controlled by a single structure. Oil------a brown substance whose main component is a mixture of hydrocarbons with different structures. Dark green or black liquid. Natural gas----a flammable mixture of gases primarily composed of hydrocarbons. Oil-bearing layer----a rock layer that once produced oil in ancient times. Oil and gas migration -- the process by which oil and gas move anywhere within the Earth’s crust under the influence of pressure differences and concentration differences. Vertical migration -- namely, the upward and downward movement of oil and gas in a direction that is nearly perpendicular to the strata plane. Directional migration – namely, the lateral movement of oil and gas in a direction that is nearly parallel to the strata planes. Reservoir ----- a rock layer that allows oil and gas to flow, accumulate, and be stored in its pores and fractures. Oil reservoir-----A reservoir that contains oil and gas. Trap ---- Any area that is capable of preventing oil and gas from flowing in the reservoir and concentrating them there. Cap rock——an impermeable rock layer located immediately above and below the reservoir, preventing the spread of oil and gas. Barrier layer——an impermeable rock layer placed between two adjacent reservoirs to prevent communication between them. Obstruction----Conditions or objects that prevent the migration of oil and gas. Oil-bearing area----the area enclosed by the inner boundary of the oil-bearing zone. Oil-water interface----the boundary where oil and water come into contact. Oil storage area-----In an oil storage structure, it refers to the planar area within the oil-bearing boundary. Industrial oil and gas reservoirs-----oil and gas reservoirs that are valuable for exploitation under current technical conditions. Structural oil and gas reservoirs-----traps formed by the deformation and displacement of rock layers due to tectonic movements. Stratigraphic oil and gas reservoirs-----traps formed by obstruction conditions caused by stratigraphic factors. Lithologic oil and gas reservoirs-----traps formed due to changes in the lithology of the reservoir rock. Oil reservoir structure-----Any geological structure that is capable of storing oil and gas. Geological structure-----The patterns remaining as a result of deformation and displacement caused by crustal movements within the Earth’s crust. Depositional facies refers to the sum of depositional characteristics formed in a specific depositional environment. Depositional environment-----refers to the physical and geographical conditions, climate conditions, biological development status, as well as the physical and chemical properties and geochemical characteristics of the sedimentary medium in which rocks are deposited and lithified. Simple medium-----A medium that has only one type of pore structure is called a simple medium. Such as porous media, fractured media, etc. Multiple media----A medium in which two or more types of pore structures exist simultaneously is called a multiple media. Homogeneous reservoir ----- The entire reservoir has the same properties. Heterogeneous reservoirs-----reservoirs with different properties, including dual-media reservoirs and fractured reservoirs ； In multi-layer reservoirs, elastic drive occurs – when a well is brought online and pressure drops, the liquid in the reservoir expands elastically, increasing in volume and thus pushing the crude oil toward the bottom of the well. Hydraulic drive——driven by water at the reservoir edge. The pressure of the bottom water or injected water pushes the crude oil toward the bottom of the well. Geological reserves ---- the total amount of crude oil stored in reservoirs with oil and gas generation capacity under the original conditions of the strata. Extractable reserves——the amount of oil that can be extracted from an oil reservoir under the current technological and economic conditions. Remaining recoverable reserves ---- the difference between the recoverable reserves of an oil field and the cumulative amount extracted after it begins to be developed. Oil recovery rate-----The percentage of oil produced from an oil field compared to its geological reserves. Final recovery rate----the percentage of total oil produced by the end of oilfield development relative to the geological reserve. Extraction degree---the ratio of the total oil produced by an oil field at a certain point in time to its geological reserves. Oil production rate----the ratio of annual oil output to geological reserves. Crude oil density----refers to the mass of crude oil per cubic meter under standard conditions (20 degrees, 0.1 MPa). Relative density of crude oil ---- refers to the ratio of the density of crude oil under standard surface conditions (20 degrees Celsius, 0.1 MPa) to the density of pure water at 4 degrees Celsius. Crude oil freezing point----the highest temperature at which it loses its fluidity under certain conditions. Crude oil viscosity----The frictional resistance generated between molecules as the crude oil flows. Crude oil volume factor----the ratio of the volume of crude oil under formation conditions to the volume of the same amount of crude oil after degassing under standard surface conditions. Crude oil compressibility coefficient----the change in pressure per unit volume of crude oil in the formation when the pressure changes by 0. The rate of change of volume at 1 MPa. Solubility coefficient----the amount of natural gas that dissolves in unit volume of crude oil per 0.1 MPa increase in pressure at a constant temperature. Porosity----the ratio of the volume of pores in a rock to the total volume of the rock. Absolute porosity----the ratio of the volume of all pores in a rock to the total volume of the rock. Effective porosity-----the ratio of the volume of interconnected pores in a rock to the total volume of the rock. Oil saturation-----In an oil reservoir, it is the ratio of the volume of pores occupied by crude oil to the total pore volume of the rock. Water saturation-----In an oil reservoir, it is the ratio of the volume of pores occupied by water to the total volume of pores in the rock. Steady seepage-----During the seepage process, if all moving elements such as pressure and flow velocity are independent of time, it is referred to as steady. Unstable seepage-----During the seepage process, if the various moving elements are dependent on time, it is considered unstable seepage. Isobaric lines----Lines that connect points in a stratum where the pressure is equal are called isobaric lines. Streamlines-----Lines that are perpendicular to isobars are called streamlines. Flow field diagram----A graph composed of a set of isobars and a set of streamlines is called a flow field diagram. Single-phase flow-----A flow in which there is only one type of fluid is called single-phase flow. Multiphase flow------When two or more fluids flow simultaneously, it is called two-phase or multiphase flow. Permeability----The ability of a rock to allow liquids to pass through it under a certain pressure difference is known as permeability, and the magnitude of this ability is expressed in terms of permeability values. Absolute permeability ---- the permeability of an oil layer as determined by air. Effective permeability----the permeability of a particular phase of fluid as measured when two or more fluids pass through the rock. Relative permeability----the ratio of effective permeability to absolute permeability. Oil in water – a form in which tiny oil droplets are present in an aqueous medium. Water-in-oil – a form in which tiny oil droplets are present in a water-based medium. Fuel supply radius-----the radius of the circle obtained by converting the fuel supply area of the oil well into a circular area. Formation coefficient----the product of the effective thickness of the formation and its effective permeability. Flow coefficient——the ratio of the formation coefficient to the viscosity of underground crude oil, indicating the ease with which fluid flows through the rock formations. Pressure transmission coefficient-----a parameter that indicates the quality of a reservoir’s ability to transmit pressure. Backflow-----After the wellhead is closed on an oil well, oil still continues to flow from the formation into the wellbore; this phenomenon is known as backflow. Wellbore storage effect-----a phenomenon that occurs when a oil well is just shut down. Equivalent radius——It converts the effects of various factors in an actual well (imperfections or excess perfection) on pressure into an equivalent effect on pressure caused by a certain well diameter; this equivalent radius is known as the equivalent radius. Degree of perfection-----refers to the ratio of the working pressure difference of an ideally perfect well to that of an actual well. Improved index-----the ratio of the actual operating pressure difference of the oil well to the slope of the limiting line segment for pressure recovery. Epidermal effect-----the ratio of the additional pressure caused by various imperfections in the actual well to the permeability resistance of the oil layer. It is a phenomenon in which a pressure drop occurs when crude oil flows from the oil reservoir into the wellbore. Inter-well interference-----The dynamic effects that occur between wells. Oil recovery index----the increase in oil production for every 0.1 MPa increase in the production pressure difference of an oil well. Bar graph-------shows the lithology in various directions of the oil layer, the variations in lithofacies, as well as the connectivity between layers and between wells. Primary oil reservoir-----An oil reservoir with large thickness and high permeability, which is a high-quality oil reservoir. Successor layer-----An oil layer that plays a role in maintaining stable production in an oil field. Water-bearing horizon – The injected water moves along the interconnected layers toward the oil well, causing a certain horizon in the well to become water-bearing. Water inflow direction-----The dynamic change in an oil production well as a result of the injection effects from wells injecting water in a certain direction is referred to as the water inflow direction. Oil sweep area coefficient-----refers to the ratio of the area of the oil layer that has been flooded in a production well cluster to the total area under control. Injection-production balance----The volume of water injected into the reservoir is equal to the volume of oil produced. Injection-production ratio ----- the ratio of the volume of fluids injected into an oil field (water, gas) to the volume of fluids produced (oil, gas, water). Water absorption index----the daily water injection volume of an injection well under a unit injection pressure difference. Water injection intensity----The daily water injection volume of an injection well into an oil layer per unit effective thickness. Pressure balance-----The pressure in the reservoir supplied by the water injection well and the oil produced. The pressure consumed by water is equal. Underground deficit----the area where the volume of water injected is less than the volume of fluid extracted. Water content----For oil wells with water, the percentage of daily water production relative to the total daily liquid production. Well types——Wells are classified into different categories based on drilling objectives and development requirements. Exploration wells – wells drilled in geological structures that have been shown to be promising through geophysical surveys, in order to understand the conditions underground and locate oil and gas fields. Data well-----A core drilling well drilled to obtain the data required for preparing an oil field development plan. Production well——a well used for extracting oil. Water injection well----a well used to inject water into the oil reservoir. Observation well——a well specifically used to monitor the underground conditions in an oil field. Inspection well——a well drilled to assess the effectiveness of oil layer development. Renovation wells-----To improve the injection and production system, it is necessary to drill new wells, and these newly drilled wells are called renovation wells. Adjustment wells – additional wells that are drilled, either individually or in groups or rows, on top of the existing well network in order to improve the efficiency of oil field development. Injection well—a well that injects water into the formation through the tubing is called an injection well. Backflow well—a well that injects water from the casing into the formation is called a backflow well. Well pattern----the arrangement and distribution of oil, gas, and water wells in an oil field. Accuracy----reflects the degree of error in testing instruments, meters, and measuring devices. Error----the difference between the measured value and the true value. Oil makeup distance — the distance from the plane of the tubing hanger to the drill bit center. Compensation distance — the distance from the upper surface of the last collar on the casing to the drill bit center. Hydrostatic column pressure-----the pressure of the water column from the wellhead to the middle of the oil reservoir. Original formation pressure-----the pressure in the middle of the oil layer, as measured in exploration wells, before the oil field is put into development. Current formation pressure-----the pressure in the middle of the oil layer measured at a certain stage after the oil field begins to be developed. Oil pressure----the remaining pressure of crude oil as it flows from the bottom of the well to the wellhead. Gauge pressure – the pressure of the compressed gas in the annular space between the oil and casing. Flow pressure ---- the pressure in the middle of the oil layer measured during normal production of an oil well. Static pressure----the pressure in the middle of the oil layer, measured after a well comes online by shutting it down for a short period of time until the pressure at the bottom of the well stabilizes. Saturation pressure----the pressure at which natural gas dissolved in crude oil begins to separate. Reference level pressure----During oil field development, in order to accurately compare the levels of pressure between different wells, the pressures are adjusted to the same elevation depth for comparison; the pressure at that same elevation depth is known as reference level pressure. Pressure coefficient----refers to the ratio of the original formation pressure to the hydrostatic pressure. Total pressure difference-----the difference between the current formation pressure and the original formation pressure. Production pressure difference------the current difference between formation pressure and flow pressure. Flow saturation pressure difference----refers to the difference between flow pressure and saturation pressure. Ground saturation pressure difference ---- refers to the difference between the current formation pressure and the saturation pressure. Water injection pressure difference-----refers to the difference between the flow pressure and static pressure at the bottom of the water injection well. Flow pressure gradient----the pressure generated per meter of liquid column during the normal operation of an oil well. Hydrostatic gradient-----The pressure generated per meter of liquid column once the well pressure stabilizes after the well is shut in. Mechanical oil extraction-----a method of bringing oil to the surface using various machines. A pump jack is a surface machine that drives the downhole pumping pump. The sucker rod is the elongated rod in a pump jack well; it is connected to the polished rod at the top and to the pump at the bottom, serving to transmit power. The bare rod is a circular steel rod that connects the pump at the top and the sucker rod at the bottom, serving to transmit power. The suspension device is the component that connects the donkey head to the bare shaft. Pumping pump-----A downhole device driven by a pump to lift crude oil from the well to the surface. Casing – a steel pipe fixed to the wellbore with cement, which serves to separate oil, gas, and water layers, reinforce the oil layer, and stabilize the wellbore. Casing pipe----a seamless steel pipe inserted into the middle of the casing. Hydrostatic level ---- The level of the fluid in the annulus that gradually rises after the pump is installed in the well and then stabilizes at a certain level. Moving liquid level – the distance from the wellhead to the liquid level during normal pumping operation. Pump efficiency----the ratio of the actual displacement of the pumping pump to its theoretical displacement. Submersion depth-----the difference between the pump depth and the liquid level. Stroke ---- The distance between the high and low points of the motion of the rod, as caused by the back-and-forth movement of the donkey’s head. Pulses per minute----the number of times the piston of the pumping pump moves back and forth within the working cylinder per minute. Fill factor----the ratio of the volume of oil that enters the pump during one stroke of the pump piston to the volume displaced by the piston. Air lock-----A phenomenon in which a deep well pump is unable to extract oil when gas enters it. Pump curve----a closed curve measured by a dynamometer during one pumping cycle of a pump. Fracturing-----A method that uses hydraulic force to create fractures in oil reservoirs. Co-layer fracturing refers to the simultaneous fracturing of various sub-layers within the same production layer group in one well. Single-layer fracturing-----involves selecting a small layer or a specific section within a layer group for fracturing. Formation fracture pressure-----refers to the pressure at which the formation fractures or the pressure when the formation begins to absorb water. Polluted well—a reservoir with a pollution coefficient greater than zero is considered a polluted well. Perfect well—a reservoir with a pollution coefficient of zero is considered a perfect well. Super-perfect well—a reservoir with a pollution coefficient less than zero is considered a super-perfect well. Acidized wells——Oil layers with a pollution coefficient of less than -3 are acidized wells. Water absorption start pressure——The pressure at which the oil layer begins to absorb water is known as the water absorption start pressure. Driving mechanism——The method by which force is applied to drive crude oil toward the bottom of the well is called the driving mechanism. Water injection intensity-----The daily water injection volume per unit of effective thickness is referred to as water injection intensity. Water content-----The ratio of daily water production to daily liquid production is called the water content. Tunneling – communication between various sections along the oil well casing and the cement ring, or between the cement ring and the wellbore wall. Completed well depth----the distance from the bottom of the completed well to the top surface of the square plug. Cement rise – the height to which the cement rises between the casing and the wellbore wall. Artificial bottom of well – the surface of the layer of cement that remains at the lowest part of the casing after cementing is completed. Cement plug——the cement column from the bottom of the completed well to the artificial bottom of the well. Fluidity-----The ratio of the number of formation pores to the viscosity of underground crude oil is called fluidity. Mechanical oil extraction – The method of using various machines to bring crude oil to the surface is called mechanical oil extraction. Epidermal factor-----The severity of the epidermal effect properties is referred to as the epidermal factor. Mid-depth of the oil layer ---- 1/2 of the distance from the wellhead of the oil-water well to the perforated section (from top to bottom). Oil supply radius—In multi-well production, the radius within which oil wells control the oil-bearing area underground is referred to as the oil supply radius.