System for locking interior door latches

Abstract

A method, system and apparatus for centralized thermal recovery based on an oil reservoir are disclosed. The steps of the method including treating the oil reservoir with edge and bottom water layers as a whole unit; providing horizontal wells extending into the upper part of the edge and bottom water layers with an electric heating system configured to be positioned in each horizontal well; continuously centralized electric heating the edge and bottom water until temperature of the whole oil reservoir rises to the flowing state of formation oil; and then centralized thermal recovery is carried out by several recovery mechanisms in addition to viscosity reduction and gravity-assisted oil recovery. An electric heating system is also disclosed including an inner liner, ferrite permanent magnet rods, waterproof spiral electric heaters, an insulation board and a sealing board.

1 . A centralized thermal recovery method based on an oil reservoir said the oil reservoir comprising at least one or more edge and bottom water layers, said the oil reservoir is at a first temperature and pressure comprising a quantity of in-place oil, said method comprising:
 the oil reservoir with edge and bottom water layers treated as a whole unit sealed by cap rocks and other barriers including anticline structure, fault, lithological change, edge and bottom water,   providing at least one or more horizontal wells extending into at least one or more water layers at a depth below the oil-water contact, each horizontal well comprising an electric thermal recovery system comprising:   an inner liner provided in a horizontal well wherein the upper half slotted and the lower half vacuum-sealed by a heat insulation plate and a sealing plate;   a heat insulation plate set at a horizontal diameter of the inner liner;   an electric heater configured to be positioned on the heat insulation plate in the upper part of the inner liner;   a plurality of ferrite permanent magnet rods fixed at the upper inner liner;   sealing plate together with heat insulation plate sealing the lower half of the inner liner;   centralized electric heating at least one or more edge and bottom water layers with the electric heaters until oil reservoir temperature rises to the state of all the formation crude oil becoming mobile and flowing; and   centralized recovering the mobilized oil with at least one or more production wells.   
     
     
         2 . The method according to  claim 1  wherein:
 the whole oil reservoir is treated as a sealed unit to be centralized heated; 
 the oil reservoir temperature and pressure integrally increased; 
 all the formation crude oil in the oil reservoir is mobilized. 
 
     
     
         3 . The method according to  claim 1  wherein:
 treating the whole oil reservoir with edge and bottom water layers as an integrated unit sealed by cap rocks, barriers including anticline structure and edge-bottom water; 
 the reason that thermal energy can be continuously transferred upward and accumulated gradually in the oil reservoir comprising
 reservoirs are well connected, and 
 heat conduction velocity of reservoir is higher than that of surrounding rocks; 
 the direction of heat transfer is mainly upward; 
 continuously electric heating edge and bottom water to keep thermal energy accumulated gradually in the oil reservoir. 
 the thermal insulation effect of surrounding rock is high. 
 
 
     
     
         4 . The method according to  claim 1  wherein
 the property of gravity differentiation between hot and cold water makes heat energy in edge and bottom water mainly transfer upwardly, and 
 the cold water moving downwards can be electrically heated continuously; 
 heat energy is mainly accumulated in upper edge and bottom water layers and oil reservoir along with a little heat energy emitting downwards. 
 
     
     
         5 . The method according to  claim 1  wherein
 the reservoir develop edge and bottom water, and 
 contain adequate formation water resources; 
 horizontal wells continuously electric heat edge and bottom water for a long time and supply substantial thermal energy to the oil reservoir. 
 
     
     
         6 . The method according to  claim 1  wherein
 horizontal wells can be sidetracking horizontal wells of original production wells, or meet water layers alone; 
 horizontal wells can be independent or multi-branch horizontal wells; 
 horizontal wells are equably arranged on a horizontal plane in the upper edge and bottom water layer; 
 the depth determination of horizontal wells depends on reservoir volume, the larger the volume, the deeper the depth; 
 the number, length and trend of horizontal wells are determined by the size of water body and reservoir volume. 
 
     
     
         7 . The method according to  claim 1  wherein an electric heating system comprising:
 an inner liner positioned in the horizontal well comprising
 the upper half of the inner liner slotted to allow formation water flowing freely; 
 and the lower half of the inner liner vacuum-sealed to prevent thermal energy from transferring downwards; 
 the whole inner liner provided to support the ferrite permanent magnet rods, the waterproof spiral electric immersion heater and the heat insulation board; 
 
 a heat insulation board set at a horizontal diameter of the inner liner to prevent thermal energy from transferring downwards; 
 several ferrite permanent magnet rods fixed on the inner wall of the upper half inner liner to prevent scale; 
 a waterproof spiral electric immersion heater connected in series provided on the heat insulation board in the middle of the upper liner to generate resistant heat and directly heats the edge-bottom water; 
 a sealing board set at two sides of the lower half of the inner liner in cooperation with the heat insulation board to prevent thermal energy from transferring downwards, and 
 keep the stability of the lower half of the inner liner. 
 
     
     
         8 . The method according to  claim 1  wherein the edge and bottom water plays a prominent roles in centralized thermal recovery based on an oil reservoir comprising:
 the edge and bottom water is treated as heat transfer medium; 
 the edge and bottom water is treated as a coolant of the immersion heaters; 
 the edge and bottom water is treated as a sort of protection for petrophysical characteristics of porosity and permeability for its relatively stable salinity similar to that of pore water in the oil reservoir; 
 the edge and bottom water protects crude oil from heat damage because of its relative lower boiling temperature under certain pressure; 
 the edge and bottom water has capacity of heat storage, and can keep preheated reservoir warm throughout the whole process of centralized thermal recovery; 
 the edge and bottom water is treated as one of sources of steam flooding energy in the process of centralized oil production; 
 the edge and bottom water coning is treated as a resource of hot edge and bottom water driving energy in the process of centralized oil production: 
 because of the strong fluidity and high thermal conductivity of water, it can decrease the well pattern density of electric heating horizontal wells; 
 the edge and bottom water flowing up and down is treated as a source of induced heat provided the electric immersion heater passes current which induces induced current in water due to its electrical conductivity; 
 Influenced by geothermal gradient, the deeper the formation water is buried, the higher the formation water temperature is, and the more energy-saving electric heating the edge and bottom water is; 
 because of the direction of heat transferring mainly upward, the gravity differentiation of hot and cold water, as well as the fact that thermal conductivity of surrounding rock is worse than that of reservoir, the thermal energy in edge and bottom water mainly transfers upward with less heat loss and most accumulates in the oil reservoir and the edge bottom water layer above the horizontal wells plane; 
 edge and bottom water resources are abundant and environmentally friendly, therefore the method of electric heating edge and bottom water can be recycled. 
 
     
     
         9 . The method according to  claim 1 ,  7  and  8  wherein the electric heating system positioned in the horizontal well comprising:
 the electric heaters generate resistance heat, and directly heats the edge-bottom water; 
 the formation water moving up and down generate induced current and induced heat due to the electrical conductivity of water provided that the electric heaters connect with current; 
 
     
     
         10 . The method according to  claim 1  wherein
 the electric immersion heater preferably includes a thermocouple operatively connected to the surface power unit for monitoring heating time and the temperature of the edge-bottom water; and 
 further to control the pressure of the oil reservoir according to the congruent relationship between boiling point and pressure of water. 
 
     
     
         11 . The method according to  claim 1  comprising
 the gradually accumulated reservoir pressure and temperature can be released with some production wells to prevent cracking in closed reservoirs; 
 the electric immersion heater preferably includes a thermocouple operatively connected to the surface power unit for monitoring heating time and heating temperature, accordingly, further to control the pressure of the oil reservoir according to the congruent relationship between boiling point and pressure of water. 
 under a certain pressure below the reservoir fracture pressure, continuously electric heating the upper part of edge and bottom water at a higher temperature for a long time. 
 under a certain pressure below the reservoir fracture pressure, continuously electric heating the upper part of edge and bottom water layers by pressure relief through production wells at a higher temperature for a long time. 
 
     
     
         12 . The method according to  claim 1  wherein
 temperatures in all oil layers rise to the point needed by continuously electric heating the edge and bottom water layers, and wherein 
 the temperature of the oil reservoir for effective oil thermal recovery increases at least to the rang of 80° C. to 150° C.; 
 continuously centralized electric heating the edge and bottom water at a temperature of the edge and bottom water around the immersion heater lower than 450° C. 
 
     
     
         13 . The method according to  claim 1  wherein the greater the depth of the edge and bottom water layer, less electrical energy required to heat the edge and bottom water layer, due to the reasons comprising,
 the smaller the temperature difference between temperature of formation water and boiling point, less heat energy needed; 
 the greater the temperature difference between the temperature of formation water and surface water, less heat energy required; 
 no heat loss of wellbore and pipeline, the greater the depth of the reservoir, the less energy needed; 
 less electric energy needed in secondary oil recovery due to high reservoir temperature. 
 
     
     
         14 . The method according to  claim 1  comprising centralized excavating the crude oil with at least one or more production wells wherein the production wells can be horizontal wells or vertical wells or a combination of vertical and horizontal wells. 
     
     
         15 . The method according to  claim 1  including during centralized recovering the mobilized oil with at least one or more production wells, a variety of thermal recovery mechanisms are used consisting of:
 the thermal expansion pressure from water formations and oil layers; 
 the effect of synthesis steam flooding produced by water soluble gas overflow, steam coming from edge and bottom water as well as pore water, and pyrolysis gas from crude oil in bottom oil reservoirs; 
 hot water flooding due to edge and bottom hot water coning; 
 the viscosity-reduction effect/wax-precipitation effect of in-place oil under high temperature; 
 gravity drainage of the heated crude oil; 
 gravity differentiation among fluids after primary-centralized thermal recovery of oil for another times, and 
 combinations thereof. 
 
     
     
         16 . The method according to  claim 1  comprising
 after the completion of primary oil recovery, the residual oil and water in reservoir can be separated by gravity differentiation over time, and 
 the formation water can be re-heated for secondary oil recovery. 
 
     
     
         17 . An electric heating system comprising,
 an inner liner divided by a heat insulation board comprising upper half of the inner liner slotted and lower half of the inner liner vacuum-sealed; and   the heat insulation board is set at a horizontal diameter of the inner liner,   a sealing board is provided on either side of the lower liner;   wherein the lower liner, in cooperation with the heat insulation board, insulates heat, and   the lower part of the liner is vacuum-sealed by the sealing board and the heat insulation board to reduce downward transmission of thermal energy;   waterproof spiral electric heaters in series connection are provided on the heat insulation board in the middle part of the upper part slotted of the liner;   several ferrite permanent magnet rods are fixed at the inner top of the upper liner;   
     
     
         18 . The system according to  claim 17  wherein
 the upper half of the inner liner slotted allowing fluids to transfer freely, and 
 supporting the pressure of overlying formations; 
 suspending the ferrite permanent magnet rods. 
 
     
     
         19 . The system according to  claim 17  wherein
 electric heaters connected in series generate resistance heat, and 
 directly heat edge-bottom water; 
 the electric heaters connected with current generate electromagnetic field, together with ferrite permanent magnetic field, which makes the formation water moving up and down generate induced current and induced heat due to the electrical conductivity of water. 
 
     
     
         20 . The system according to  claim 17  wherein at least one ferrite permanent magnet-rod is arranged to reduce scaling of the electric heater. 
     
     
         21 . The system according to  claim 17  wherein
 the lower half of the inner liner vacuum-sealed to prevent thermal energy from transferring downwards; 
 a heat insulation board set at a horizontal diameter of the inner liner to prevent thermal energy from transferring downwards; 
 a sealing board set at two sides of the lower half of the inner liner in cooperation with the heat insulation board to prevent thermal energy from transferring downwards, and 
 keep the stability of the lower half of the inner liner.