Basic knowledge of oil production geology

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1 Darcy’s Law: When fluid flows through rock, the flow rate is directly proportional to permeability, cross-sectional area, and pressure difference, and inversely proportional to viscosity and distance. 2 rows of wells: The wells distributed in straight lines are called row-column well network. 3 area well network: According to a certain geometric shape, such as (triangle ； square ； Hexagons, etc.) wells evenly distributed on the oil field. 4 development layers: The purpose of combining oil layers with similar properties in a complete set of oil-bearing layers and developing them with a separate well pattern to separate the development layers is to reduce the interference of good oil layers and poor oil layers. Different water injection methods and well layout methods can be used according to the properties of the oil layers, which is beneficial to the oil production speed and ultimate recovery rate. 5 Principles for dividing development layers: ⑴An independent development layer must have certain reserves. ； ⑵1. There must be good separation between the upper and lower layers of each development layer. ； ⑶ The properties of oil reservoirs in the same development layer should be close to ； ⑷The structural shape, oil and water distribution, pressure system and crude oil properties of oil reservoirs in the same development layer should be similar. 6 Oil field development: The process of using a set of mining techniques to promote the flow of crude oil from the oil layer to the bottom of the well and to the surface. 7 development methods: Refers to what energy is used for development during the oil field development process. Fields developed in a manner conducive to natural energy, e.g.: Dissolved steam, edge water energy, etc. 8 Oilfield dynamic monitoring: ⑴Reservoir pressure monitoring, ⑵ flow rate monitoring, ⑶ fluid properties monitoring, ⑷ reservoir water flooding monitoring, ⑸ recovery rate monitoring, ⑹ downhole branching condition monitoring. 9 Dynamic analysis: It refers to the method of understanding the movement patterns of oil and water in underground oil layers through a large amount of primary data on oil and water wells. 10 "Six points and four clear": six points is: Layered water injection ； layered oil recovery ； Layered testing ； stratified research ； Stratified transformation and layered management. Four Cleansings are: Layered pressure clearing ； Clear layered water injection amount ； The stratification yield is clear and the stratification water yield is clear. 11 Dynamic analysis content: Includes three aspects: Production dynamics analysis ； Analysis of lifting conditions in wellbore ； Reservoir dynamic analysis. 12 Reservoir dynamic analysis: Distribution and movement of oil and water in various oil layers ； Pressure distribution and lifting conditions ； Changes in seepage resistance ； Water absorption, oil production and reserve utilization status ； Changes in production capacity ； Changes in oil layer structure and fluid properties, etc. 13 The current formation pressure is lower than the original force: For oil fields that rely on natural energy to develop, it is an energy consumption process, so the current formation pressure is always lower than the original formation pressure. 14 The role of total pressure difference in development: For oil fields developed by water injection, water is injected to maintain formation pressure. When the total pressure difference is positive, the injection volume is greater than the production volume, making the current formation pressure exceed the original formation pressure. When the total pressure difference is negative, the injection volume is less than the production volume, resulting in an underground deficit, making the current formation pressure lower than the original formation pressure. 15 The role of production pressure difference in development: Because under the same geological conditions, the greater the production pressure difference, the higher the oil well output. However, when the formation pressure is constant and the production pressure difference is large enough, when the flow pressure is lower than the saturation pressure, it will cause the oil layer to devaporize, produce sand, increase the oil-to-steam ratio, and reduce the oil well productivity. Therefore, it is important to establish a reasonable production pressure difference. 16 The role of flow-saturation pressure difference in development: The flow-saturation pressure difference is a condition for measuring the reasonable production status of an oil well. When the flow pressure is higher than the saturation pressure, the dissolved vapor in the crude oil cannot be separated at the bottom of the well. On the contrary, the dissolved vapor in the crude oil will separate prematurely at the bottom of the well, causing the crude oil viscosity to increase, the flow resistance to increase, and affecting production. Therefore, it is important to set a reasonable flow-saturation pressure difference boundary. 17 The role of subsurface pressure difference in development: The subsaturation pressure difference is a condition for measuring the reasonable production status of an oil layer. When the formation pressure is lower than the saturation pressure, the crude oil in the oil layer will devaporize and the viscosity of the crude oil will increase, thus reducing the recovery rate. Therefore, the injection-production ratio must be adjusted regularly to keep the formation energy reasonable. 18 Conditions affecting recovery rate: The level of recovery factor is mainly affected by geological conditions, quality of oil layers, properties of crude oil, oil field development methods and technological level. 19 The flow process of crude oil in self-injection development: It takes three processes: formation seepage ； vertical pipe flow ； Mouth flow. 20 main oil layer: Refers to the good oil layer with large thickness and high permeability, which is called the main oil layer. 21 Replacement of oil layer: When the main oil layer is produced to a certain extent, in order to make up for the reduction in production of the main oil layer, the development ； potential of low differential oil layers to achieve stable production. 22 water breakthrough level: It refers to the process in which the injected water advances toward the oil well along the connecting layer, making a certain layer in the oil well contain water. 23 Water direction: Because a well is affected by several water injection wells, due to differences in permeability, the injected water cannot advance uniformly to the oil well. The injected water from one of the wells must rush into the oil well. The water injection effect in this direction is called the incoming water direction. 24 Inter-layer conflicts: In the development of heterogeneous and multi-layer oil fields, due to the different permeabilities between layers, there are differences. After water injection development, there are differences in water absorption capacity, water line advancement speed, and formation pressure. There are differences between layers in terms of oil production rate, water flooding conditions, etc. This difference is called interlayer contradiction. 25 Planar Contradiction: Due to different permeability and connectivity of an oil layer on the plane, the well network controls the oil layer differently. After water injection, the water line advances at different speeds in one direction, causing the water content, production, and pressure to be different between wells in the same oil layer. This is enough to cause differences between wells in the same oil layer. This difference is called plane contradiction. 26 Intra-layer conflicts: Within an oil layer, due to the different particles that make up the oil sand body, the permeability is different. After water injection, the high permeability zone with small propagation resistance of the injected water bursts in. In addition, the viscosity of oil and water ； Surface tension, differences in rock surface properties, etc., form intra-layer contradictions. 27 area water injection: A method in which water injection wells and oil production wells are evenly distributed according to a certain geometric shape and used for water injection and oil production. 28 Layered water injection: According to the characteristics of the sections, similar sections are combined into one water injection section, and separators are used to separate each layer. Corresponding water nozzles are configured according to different water absorption capacities to control the amount of water injection to achieve the purpose of layered water distribution. 29 General water injection: Under the same water injection pressure, the smooth oil pipe water injection method is used without layering. 30 Conditions affecting the direction of incoming water: Since a well is affected by several water injection wells, the injected water cannot advance uniformly to the oil well due to differences in permeability. The injected water from one of the wells must rush into the oil well. Therefore, the main direction of water inflow is affected by geological conditions. 31 Consumption of production pressure difference: Can be divided into three types of consumption: ⑴Well wall resistance consumption, ⑵ pressure consumption in the near-wellbore zone, ⑶ pressure consumption in the oil layer. 32 Eccentric water distributor: The eccentric water distributor is a movable water distribution tool, mainly composed of a working barrel and a plug. 33 packer: It is an important downhole tool for implementing the 'six points and four cleans' oil production technology. Its function is to separate the oil layers to achieve the purpose of layered oil recovery and water injection. 34 The function of the trumpet: The bell mouth is installed at the lower part of the oil pipe of a self-injection or general water injection well, more than 5 meters away from the top of the oil layer. It is the main channel for the instrument to be lifted up and unobstructed. 35 blocked: It is to squeeze a selective plugging agent into the water-producing layer in the oil well, so that it interacts with the water in the water-producing layer to produce a solid or colloidal obstruction. Two packers are used to clamp the upper and lower parts of the pressure-selection layer, and then the pressure-selection layer is fractured. 36 Non-selective water blocking: In the process of oil field mining, due to the water layer troughing or the sudden intrusion of injected water, the oil well will encounter water prematurely or be flooded. In order to avoid the above situation, underground technological measures are taken. 37 Packer to block water: Use packer to separate the water layer and oil layer to achieve the purpose of blocking water. 38 Reasons for sudden rise in water content: ⑴The packer with the plugging layer fails, ⑵ the plugging layer breaks open, ⑶ the casing is damaged, and ⑷ the water layer penetrates into the single layer and causes flooding. 39 Reasons for sudden drop in water injection volume: ⑴The water injection pressure drops or there is a problem with the water meter, ⑵ the water injection pipeline is blocked, ⑶ dirt blocks the oil layer pores, ⑷ the downhole nozzle is clogged. 40 Reasons for sudden increase in water injection volume: ⑴The water injection pressure rises or there is a problem with the water meter, ⑵ the water nozzle is large or falls off, ⑶ the bottom ball is not tight or falls off, ⑷ the oil pipe falls off or the thread is leaking, ⑸ the pipe is grooved outside, the casing is broken or broken, etc. 41 Mechanical oil recovery: Various mechanical methods are used to extract oil to the surface. Mechanical oil extraction is used for wells with low formation pressure that cannot spontaneously blow out. Currently, the machines used include oil pumps and electric submersible pumps. 42 Main components of oil pump: It is mainly composed of a working cylinder, a fixed valve and a hollow piston with a traveling valve. 43 Briefly describe the working principle of the oil pump: When the piston moves up, the swimming valve closes, the fixed valve opens, and liquid enters the pump. When the piston moves downward, the fixed valve closes and the traveling valve opens, allowing the liquid in the pump to enter the oil pipe. 44 Downhole tools for electric submersible pump wells: It is composed of motor, rotary separator, electric pump (different stages), valve, pressure measuring valve, etc. 45 Reasons for sudden drop in output of pumping wells: ⑴Verka. ⑵The sucker rod is broken, ⑶ vapor lock, ⑷ The oil layer has insufficient liquid supply capacity. 46 The role of electric pump underground pressure measurement: When starting the pressure measurement, the downhole pressure gauge and connector are placed on the pressure measuring logging rod to measure the annular pressure of the oil casing. 47 The role of electric pump underground valve: When the oil well is in normal production, the pressure difference between the bottom of the well and the oil pipe will push up the valve, allowing the crude oil to pass smoothly. When the oil well is shut down for pressure measurement, the wellbore pressure is higher than the pressure in front of the pump, so the valve is closed, so that oil cannot flow back, so as not to damage the motor. 48 Impact of flow pressure on oil and water well productivity: The oil that flows into the bottom of the well is lifted to the surface by flowing pressure. Generally, the level of flowing pressure can reflect the production capacity of oil and water wells. Oil and water wells with high flowing pressure have strong production capabilities. This post was last edited by majingkunmail on 2009-2-24 17:13 ]