# What’s the oil extraction expertise

When there is a pressure difference in permeability, the property of the rock to allow liquid and gas to pass is called the permeability of the rock, and the permeability is the quantitative expression of the permeability of the rock. It characterizes the ability of oil and gas to flow through the formation rock to the bottom of the well, in square meters (or square micrometers). ·Absolute Permeability Absolute or physical permeability refers to the permeability obtained when only any one phase (gas or single liquid) flows in the pores of the rock and has no physical or chemical interaction with the rock. It is usually represented by gas permeability, also referred to as permeability. ·When multiphase (effective) permeability and relative permeability coexist and flow in the formation of multiphase fluids, the size of the passage capacity of a certain phase fluid in the rock, It is called the phase permeability or effective permeability of the phase fluid. The relative permeability of a certain phase fluid refers to the ratio of the effective permeability of the phase fluid to the absolute permeability. ·Formation pressure and original formation pressure The oil, gas layer itself and the oil, gas, and water in it all bear a certain pressure, which is called formation pressure. There are three types of formation pressure: original formation pressure, current formation pressure and static pressure of oil and gas layers. Before the oil field was put into development, the entire oil layer was in a state of equilibrium pressure and no flow occurred. In the early stage of oilfield development, the first or the first batch of oil wells were completed, and after blowout, the wells were shut in and pressure was measured. The pressure measured at this time is the original formation pressure. ·Formation pressure coefficient The formation pressure coefficient is equal to the increase in pressure when the formation depth increases by 10 meters from the ground. · Low pressure anomaly and high pressure anomaly Generally speaking, the deeper the reservoir, the greater the pressure. The pressure coefficient of most oil reservoirs is between 0.7-1.2, and the low pressure anomaly is greater than 1. 2 is abnormal high pressure. ·The purpose of acidification treatment of oil wells is to make the acid liquid penetrate into the formation generally along the radial direction of the oil well, thereby expanding the pore space under the action of the acid liquid, dissolving the particle blockages in the space, and eliminating the adverse effects of the formation permeability reduction near the wellbore. Achieve the effect of increasing production. ·Fracturing acidification The acid treatment process of squeezing acid out of the formation under the pressure sufficient to open the formation to form cracks or open the original fractures of the formation is called fracturing acidification. Fracturing acidification is mainly used to plug oil and gas wells in deep or low permeability areas. ·Fracturing The so-called fracturing is a method of using hydraulic action to form cracks in the oil layer, also known as oil layer hydraulic fracturing. The oil layer fracturing process is to use a fracturing truck to squeeze the high-pressure, large-displacement and certain viscosity liquid into the oil layer. When the oil layer has many cracks, proppant (such as quartz sand, etc.) is added to fill the cracks to improve the oil layer’s performance. Permeability to increase water injection (water injection well) or oil production (oil well). Commonly used fracturing fluids include five basic types: water-based fracturing fluid, oil-based fracturing fluid, emulsion fracturing fluid, foam fracturing fluid and acid-based fracturing fluid. ·Solid rocket propellant or liquid for high-energy gas fracturing, ignites and deflagrates (rather than explode) in the downhole oil layer, producing a large amount of high-pressure and high-temperature gas, and splitting the oil layer with multiple radiation within a few milliseconds to tens of milliseconds For cracks with a length of 2 to 5m, the cracks cannot be completely closed after the deflagration shock wave disappears, thereby removing partial blockage of the oil layer and improving the permeability of the formation near the bottom of the well. This process technology is high-energy gas fracturing. High-energy gas fracturing has many advantages, the main ones are as follows: no large fracturing equipment is needed; no large amount of fracturing fluid; no proppant injection; convenient and fast construction; little or no damage to the formation; low cost, etc. . ·Oilfield development Oilfield development refers to the rational distribution of oil wells and the order of production on the reservoir based on the understanding and mastery of the oilfield geology and its changing laws, as well as adjusting the working system of oil production wells and other technical measures to reduce underground petroleum resources. The whole process of mining to the ground. ·Oilfield development procedure The oilfield development procedure refers to the work sequence of the oilfield from detailed exploration to full development. 1. Deploy exploratory wells on the structural zone where the oil is seen to quickly control the oil-bearing area. 2. Drill data wells in the controlled oil-bearing area to understand the characteristics of the oil layer. 3. Partition and layered oil test to obtain the production capacity parameters of the oil layer. 4. Open up a production test area to further grasp the characteristics of the oil layer and its changing laws. 5. Conduct comprehensive research based on various data such as core, well logging, oil test, production test, etc., draw up layer comparison maps, structural maps, and fault distribution maps to determine the type of reservoir. 6. Oilfield development design. 7. Drill a basic well pattern based on the most reliable and stable oil layer. After drilling, it will not be put into production. According to all the data of the well, a comparative study of the oil sand bodies of all oil layers will be carried out, and then the original plan will be revised and adjusted. 8. After the production wells and water injection wells are put into production, the actual production and pressure data are collected for research, the original design indicators are modified, and the specific production and injection plans for each development period are determined. Due to the different conditions of each oil field, the development procedures are not exactly the same. ·Reservoir-driven type Reservoir-driven type refers to the main driving force for oil displacement when the oil layer is exploited. Different driving power means different driving methods. The driving modes of oil reservoirs can be divided into four categories: water pressure driving, air pressure driving, dissolved gas driving and gravity driving. In fact, there are different driving energies at different stages in the development of oil reservoirs, that is, there are several driving methods at the same time. ·Recoverable reserves Recoverable reserves refer to the amount of oil and gas that can be recovered from oil and gas reservoirs under the current economic and technical conditions. Recoverable reserves increase with the increase in oil and gas prices and the application of advanced mining technology. ·Oil production rate The ratio of the annual production of an oil field (oil reservoir) to its geological reserves, expressed as a percentage, called the oil production rate. ·Oil recovery intensity The oil recovery intensity is the daily oil production per unit thickness of the oil layer, which is the number of tons of oil produced per meter of oil layer per day. ·Oil Production Index The daily oil production of an oil well is divided by the pressure difference at the bottom of the well, and the quotient obtained is called the oil production index. The oil production index is equal to the daily oil production of an oil well with a unit production pressure difference. It is an important parameter indicating the productivity of an oil well. · Recovery factor The percentage of recoverable reserves in geological reserves is called recovery factor. ·Christmas tree Christmas tree is a wellhead device for self-blowing wells. It is mainly used to suspend the tubing string running into the well, seal the annular space of the tubing casing, control and regulate the production of oil wells, ensure operation, construction, record oil and casing pressure data, test and wax removal and other daily production management. ·Decline rate, natural decline rate, and comprehensive decline rate After a certain period of time in oil and gas fields, the production will decline according to a certain rule. The decline rate refers to the percentage of production decline per unit time. The natural decline rate refers to the ratio of the oil production in the next stage to the oil production in the previous stage after excluding the increase in production by various production-increasing measures. The comprehensive decline rate refers to the rate of decline including the increase in output from various production-increasing measures. ·Daily production level of the oil field The average value of the actual daily production of the oil field is called the daily production level. Since oil wells need to be overhauled in a short period of time or to increase production measures in a short period of time, not all oil wells are producing oil every day, so the daily production level is lower than the daily production capacity. ·Oil well gas logging Gas measurement is one of the most important tasks in oil well management. Only by mastering the accurate gas volume and gas-oil ratio can we correctly analyze and judge the underground changes of oil wells, grasp the relationship between oil field and oil well injection and production, and better manage oil wells. . At present, there are two types of gas measurement commonly used in the field: vent gas measurement and closed gas measurement. There are three commonly used gas measurement methods: (1) Gasketing flowmeter venting method (pressure difference gauge gas measurement); (2) Differential flowmeter (float type differential pressure gauge) airtight pressure measurement method; (3) Bellows Automatic gas measurement method. ·Split production allocation Stratified production allocation is based on the development requirements of the oilfield, the oil layer is divided into several production intervals in the downhole packer. For each different interval, the downhole nozzles of different diameters are installed to control the different production pressure difference to obtain different output. ·Mechanical oil recovery When the energy of the oil layer is not enough to maintain the spout, the energy must be artificially supplemented from the ground to lift the crude oil out of the wellhead. If the way to supplement energy is to use mechanical energy to extract oil from the ground, it is called mechanical oil extraction. At present, domestic and foreign mechanical oil extraction devices are mainly divided into two categories: rod pumps and rodless pumps. Rod pumps and ground power equipment drive pumping units, and deep well pumps are driven by sucker rods. Rodless pump, pumping equipment that does not use sucker rods to transmit power. There are many types of rodless pumps, such as hydraulic piston pumps, electric submersible centrifugal pumps, jet pumps, vibration pumps, screw pumps and so on. At present, the most widely used beam pumping unit and deep well pump device. Because this device has a reasonable structure, is durable, easy to manage, and has a wide range of applications. ·The ratio of the actual liquid production of a pumping well to the theoretical displacement of the pump is called the pump efficiency. The calculation formula is: η=Q liquid/Q rationale×100% where η is deep well pump efficiency; Q liquid and actual oil well production (tons/day); Q rational pump’s theoretical displacement (tons/day) ), the pump efficiency reflects the pump performance and whether the selection of pumping parameters is appropriate. There are three factors that affect pump efficiency: (1) Geological factors: including sand production in oil wells, excessive gas, waxing in oil wells, high crude oil viscosity, corrosive water in the oil layer, gas corrosion of pump components, etc.; (2) equipment Factors: pump manufacturing quality, installation quality, improper selection of bushing and piston clearance fit, or loose valve ball and valve seat, etc. will reduce pump efficiency. (3) The influence of working mode: improper selection of pump working parameters will also reduce pump efficiency. If the parameter is too large, the theoretical displacement is far greater than the oil supply capacity of the oil layer, causing the supply to fall short of demand, and the pump efficiency is naturally very low. If the stroke is too fast, the oil will not get into the pump working cylinder in time, and the pump efficiency will be reduced. If the pump hangs too deep, the stroke loss will be too large, and the pump efficiency will also be reduced. ·Methods to improve pump efficiency of oil well pump (1) Improve water injection effect, maintain formation energy, stabilize formation pressure, and improve liquid supply capacity. (2) Reasonably select deep well pumps, improve the quality of the pumps (overhaul), and ensure the matching clearance and valve leakage of the pumps. (3) Reasonably select the working parameters of the pumping well. (4) Reduce stroke loss. (5) Prevent damage to the pump by sand, wax, water and corrosive media.
When the energy supplied by the gas lift formation is not enough to lift the crude oil from the bottom of the well to the surface, the oil well stops spontaneous blowout. In order to make the oil well continue to produce oil, it is necessary to artificially press the gas (natural gas) into the bottom of the well to make the crude oil spray out of the ground. This oil recovery method is called gas lift oil extraction. Offshore oil production, exploratory wells, inclined wells, oil wells that contain sand, gas, and corrosive components that are not suitable for other mechanical oil production methods can all use gas lift to produce oil. The advantages of gas lift production are simple wellhead and downhole equipment, and convenient management and adjustment. The disadvantage is that the ground equipment system is complex, the investment is large, and the utilization rate of gas energy is low. ·Oilfield water injection The measure of using water injection wells to inject water into the oil layer to supplement and maintain the pressure of the oil layer is called water injection. After the oil field is put into development, as the exploitation time increases, the energy of the oil layer itself will continue to be consumed, causing the pressure of the oil layer to continue to drop. A large amount of dead oil cannot be recovered. In order to make up for the underground deficit caused by crude oil recovery, maintain or increase the pressure of the oil layer, achieve high and stable production of the oil field, and obtain a higher recovery rate, it is necessary to inject water into the oil field. ·Oilfield water injection method The water injection method is the injection-production system, which refers to the position of the water injection well in the oil reservoir and the arrangement relationship between the water injection well and the production well. The water injection method can be selected according to the characteristics of the oil field: ①Edge water injection, its classification There are three types of water injection outside the edge, water injection on the edge, and water injection inside the edge; ②cutting water injection; ③area water injection, which can be divided into five-point injection, seven-point injection, oblique seven-point injection, four-point injection and nine-point injection Wait. ·Laminar injection is installed in the lower packer in the water injection well to separate the oil layer into several water injection intervals. The water injection process of installing water nozzles of different diameters under the water distributor is called layered injection. In order to solve the contradiction between layers, the water injection should be distributed to each layer reasonably, the formation pressure is maintained, the water injection is controlled for the layers with good permeability and strong water absorption; and the water injection is strengthened for the layers with poor permeability and weak water absorption. So that high, medium, low, and permeable formations can play the role of water injection