CN105370266B

CN105370266B - In-situ combustion layered electric ignition gas injection well shaft temperature distribution determination method and device

Info

Publication number: CN105370266B
Application number: CN201510862739.8A
Authority: CN
Inventors: 马振; 张洪君; 刘利; 李树全; 曲绍刚; 孙振宇; 屈振哲; 王智博; 杨宝春; 于晓聪; 张成博; 方梁锋; 刘红芹; 汪盈盈; 关志忠; 王河; 钟满发; 徐东; 夏进军; 吴超
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2015-12-01
Filing date: 2015-12-01
Publication date: 2018-06-01
Anticipated expiration: 2035-12-01
Also published as: CN105370266A

Abstract

the invention discloses a method and a device for determining the temperature distribution of a shaft of a layered electric ignition gas injection well in-situ combustion, wherein the method comprises the steps of 1, dividing a section of shaft from the top of an ignition gun to the bottom of an inner pipe into a plurality of shaft units dl in the axial direction, enabling L to be 0 and k to be 1, 2, calculating the temperature of air of the inner pipe after being heated by an electric igniter, 3, calculating formation thermal resistance, cement ring thermal resistance, sleeve wall thermal resistance, thermal resistance between oil sleeve annular air and a sleeve, outer pipe wall thermal resistance of a heat insulation pipe, thermal resistance of a heat insulation layer, inner pipe wall thermal resistance of the heat insulation pipe, screen wall thermal resistance, oil pipe wall thermal resistance, inner pipe and outer pipe annular air thermal resistance, inner pipe wall thermal resistance and inner pipe air thermal resistance, 4, calculating the total thermal resistance of the shaft in the radial direction, 5, calculating the heat loss of the shaft in the radial direction, 6, calculating the air temperature of the inner pipe, 7, calculating the air temperature of the inner pipe and outer pipe annular air, 8, enabling L to be L + dl and k +1, repeatedly executing 3-7, carrying out iterative.

Description

Combustion in situ layering electric ignition gas injection well well bore temperature distribution determines method and device

Technical field

The present invention relates to combustion in situ field more particularly to a kind of combustion in situ layering electric ignition gas injection well temperature in wellbore point Cloth determines method and device.

Background technology

Country's combustion in situ Partial Block is burnt for multilayer at present, layering igniting layered gas-injection, due to the pipe of layering injection Column space is limited, and portable electric igniter can not be used to implement layering igniting, it is thus proposed that a kind of layering ignition method, based on Fig. 1 Shown structure is realized, as shown in Figure 1, there is two layers of oil pipe in casing, wherein inner tube is plain tubing, and outer tube is divided into 3 sections (AB sections For instlated tubular, instlated tubular is sleeve structure, and BC sections are screen casing, and CD sections are plain tubing).It is usually no more than deeply under igniter heat-insulated Pipe is lower deep.Respectively from inner tube, outer tube injection (as shown in arrow direction in figure), the air of inner tube injection adds air by igniter Enter bottom oil layer from the bottom of inner tube after heat, the air that outer tube injects enters upper after the effect heating of heat transfer from screen casing Portion's oil reservoir.The layered gas-injection that can realize two sections oil reservoir by the ignition method is lighted a fire.

It is the key that realize above-mentioned layering ignition method to calculate well bore temperature distribution, still, is not yet proposed for upper at present State the definite method of the gas injection well well bore temperature distribution of layering igniting structures and methods.

The content of the invention

The present invention provides a kind of combustion in situ layering electric ignition gas injection well well bore temperature distributions to determine method and device, with It at least solves the problems, such as that there has been no layering ignition process well-sinking temperature fields at present to determine method.

According to an aspect of the invention, there is provided a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution is true Determine method, including：Step 1, will be in the axial direction divided into interior this section of pit shaft of bottom of the tube at the top of the burning torch of electric igniter multiple Pit shaft unit, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, k expressions change Generation number；Step 2, temperature T of the air for being injected into said inner tube after electric igniter heating is calculated_s；Step 3, divide Not Ji Suan stratum thermal resistance R₁, cement sheath thermal resistance R₂, thermal resistance R between casing inside and outside wall₃, air and set in oil jacket annular space Thermal resistance R between pipe₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, thermal insulation layer thermal resistance R₆, instlated tubular inner tube inside and outside Thermal resistance R between wall₇, thermal resistance R between screen casing inside and outside wall₈, thermal resistance R between oil pipe inside and outside wall₉, in inner tube and outer tube annular space Air thermal resistance R₁₀, thermal resistance R between inner tube inside and outside wall₁₁And the thermal convection current thermal resistance R of interior inner air tube₁₂；Wherein, the note Wellbore of Gas Wells radially includes successively from the inside to the outside：Inner tube, outer tube, casing and cement sheath, the outer tube is along well head to shaft bottom side To including successively：Instlated tubular, screen casing and oil pipe, the gas injection well shaft outside is stratum；Step 4, according to R₁To R₁₂Calculate well The diametrical entire thermal resistance of cylinder；Step 5, according to the temperature T_s, the entire thermal resistance and formation temperature, calculate pit shaft on the radial Heat loss；Step 6, according to the temperature T_s, the heat loss and the electric igniter power, calculate the Air Temperature of inner tube Degree；Step 7, according to the temperature T_s, the heat loss and R₁₀To R₁₂, calculate inner tube and the air themperature of outer tube annular space；Step 8, l=l+dl, k=k+1 are made, according to the variation of formation temperature, above-mentioned steps 3 is repeated to step 7, is iterated calculating, Until l >=L, then iteration terminates, and obtains the temperature distribution history of said inner tube and the temperature distribution history of the outer tube, wherein, L Represent well head to the length of interior bottom of the tube.

According to another aspect of the present invention, a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution is provided Determining device, including：Division unit, for will in the axial direction be drawn to interior this section of pit shaft of bottom of the tube at the top of the burning torch of electric igniter It is divided into multiple pit shaft units, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, K represents iterations；First computing unit, for calculating the air for being injected into said inner tube after electric igniter heating Temperature T_s；Second computing unit, for calculating the thermal resistance R on stratum respectively₁, cement sheath thermal resistance R₂, between casing inside and outside wall Thermal resistance R₃, thermal resistance R between air and casing in oil jacket annular space₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, it is heat-insulated The thermal resistance R of layer₆, instlated tubular inner tube inside and outside wall between thermal resistance R₇, thermal resistance R between screen casing inside and outside wall₈, oil pipe inside and outside wall it Between thermal resistance R₉, air thermal resistance R in inner tube and outer tube annular space₁₀, thermal resistance R between inner tube inside and outside wall₁₁And interior inner air tube Thermal convection current thermal resistance R₁₂；Wherein, the gas injection well shaft radially includes successively from the inside to the outside：Inner tube, outer tube, casing and cement Ring, the outer tube include successively along well head to shaft bottom direction：Instlated tubular, screen casing and oil pipe, the gas injection well shaft outside is ground Layer；3rd computing unit, for according to R₁To R₁₂Calculate the diametrical entire thermal resistance of pit shaft；4th computing unit, for basis The temperature T_s, the entire thermal resistance and formation temperature, calculate the diametrical heat loss of pit shaft；5th computing unit, for root According to the temperature T_s, the heat loss and the electric igniter power, calculate the air themperature of inner tube；6th computing unit, For according to the temperature T_s, the heat loss and R₁₀To R₁₂, calculate inner tube and the air themperature of outer tube annular space；Iterative calculation is single Member for making l=l+dl, k=k+1, according to the variation of formation temperature, is carried out using the second computing unit to the 6th computing unit Iterative calculation, until l >=L, then iteration terminates, obtain said inner tube temperature distribution history and the outer tube Temperature Distribution it is bent Line, wherein, L represents well head to the length of interior bottom of the tube.

Electric ignition gas injection well well bore temperature distribution is layered by the combustion in situ of the present invention and determines method and device, synthesis is examined The radially variation of many factors along well depth such as heat transfer and stratum thermophysical property of well bore and oil pipe rod structure, pit shaft is considered, by pit shaft It is divided into several sections, the physical parameter of correspondent section is obtained, part physical parameter is the function of temperature, using solution by iterative method, is calculated Obtain inner tube Temperature Distribution and outer tube Temperature Distribution.It is arbitrary flow condition, arbitrary in the case of layering ignition process can accurately be calculated Temperature Distribution of the moment along gas injection well shaft.Meanwhile calculating process is simple and convenient, has higher precision, iterations is low, meter It is efficient, there is extraordinary stability and convergence.According to the Temperature Distribution of pit shaft, arrival oil up and down can be effectively predicted The air themperature of layer to adjust gas injection rate and igniter power, and then ensures the smooth implementation of layering ignition method.

Description of the drawings

Attached drawing described herein is used for providing a further understanding of the present invention, forms the part of the application, this hair Bright schematic description and description does not form limitation of the invention for explaining the present invention.In the accompanying drawings：

Fig. 1 is the structure diagram of the combustion in situ layering electric ignition of the embodiment of the present invention；

Wherein, casing -1, inner tube -11, outer tube -12, instlated tubular -121, screen casing -122, oil pipe -123, well head -2, manually Shaft bottom -3, air -4, igniter -5, bottom oil layer -6, top oil reservoir -7；

Fig. 2 is that the combustion in situ layering electric ignition gas injection well well bore temperature distribution of the embodiment of the present invention determines the flow of method Figure；

Fig. 3 is the knot of the determining device of the combustion in situ layering electric ignition gas injection well well bore temperature distribution of the embodiment of the present invention Structure block diagram；

Fig. 4 is the temperature distributing curve diagram of the inner tube of the embodiment of the present invention；

Fig. 5 is the temperature distributing curve diagram of the outer tube of the embodiment of the present invention.

Specific embodiment

With reference to the attached drawing in the embodiment of the present invention, the technical solution in the embodiment of the present invention is carried out clear, complete Ground describes, it is clear that described embodiment is only part of the embodiment of the present invention, instead of all the embodiments.Based on this The embodiment of invention, the every other implementation that those of ordinary skill in the art are obtained without making creative work Example, belongs to protection scope of the present invention.

An embodiment of the present invention provides a kind of combustion in situ layering electric ignition gas injection well well bore temperature distributions to determine method, schemes 2 be that the combustion in situ layering electric ignition gas injection well well bore temperature distribution of the embodiment of the present invention determines the flow chart of method, such as Fig. 2 institutes Show, this method includes steps S201 to step S208.

Step S201 will be divided into multiple wells in the axial direction at the top of the burning torch of electric igniter to interior this section of pit shaft of bottom of the tube Cylinder unit, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, k represents iteration Number.

Step S202 calculates temperature T of the air for being injected into inner tube after electric igniter heats_s。

Step S203 calculates the thermal resistance R on stratum respectively₁, cement sheath thermal resistance R₂, thermal resistance R between casing inside and outside wall₃, oil Thermal resistance R between lantern ring aerial air and casing₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, thermal insulation layer it is (i.e. heat-insulated Between the inner tube and outer tube of pipe) thermal resistance R₆, instlated tubular inner tube inside and outside wall between thermal resistance R₇, heat between screen casing inside and outside wall Hinder R₈, thermal resistance R between oil pipe inside and outside wall₉, air thermal resistance R in inner tube and outer tube annular space₁₀, thermal resistance between inner tube inside and outside wall R₁₁And the thermal convection current thermal resistance R of interior inner air tube₁₂；Wherein, gas injection well shaft radially includes successively from the inside to the outside：It is inner tube, outer Pipe, casing and cement sheath, outer tube include successively along well head to shaft bottom direction：Instlated tubular, screen casing and oil pipe, outside gas injection well shaft For stratum.

Step S204, according to R₁To R₁₂Calculate the diametrical entire thermal resistance of pit shaft.

Step S205, according to temperature T_s, entire thermal resistance and formation temperature, calculate the diametrical heat loss of pit shaft.

Step S206, according to temperature T_s, heat loss and electric igniter power, calculate the air themperature of inner tube.

Step S207, according to temperature T_s, heat loss and R₁₀To R₁₂, calculate inner tube and the air themperature of outer tube annular space.

Step S208, makes l=l+dl, k=k+1, according to the variation of formation temperature, repeats above-mentioned steps S203 to step Rapid S207 is iterated calculating, and until l >=L, then iteration terminates, and obtains the temperature distribution history of inner tube and the temperature point of outer tube Cloth curve, wherein, L represents well head to the length of interior bottom of the tube.

By the above method, well bore and oil pipe rod structure, pit shaft radially heat transfer and stratum thermophysical property etc. are considered Pit shaft is divided into several sections by variation of many factors along well depth, and the physical parameter (thermal resistance, heat transfer coefficient) of correspondent section, portion is obtained The function that physical parameter is divided to be temperature, using solution by iterative method, is calculated inner tube Temperature Distribution and outer tube Temperature Distribution.The party In the case of method can accurately calculate layering ignition process, the Temperature Distribution of arbitrary flow condition, any time along gas injection well shaft.Together When, this method is simple and convenient, has higher precision, and iterations is low, and computational efficiency is high, has extraordinary stability and receipts Holding back property.According to the Temperature Distribution of pit shaft, the air themperature for reaching oil reservoir up and down can be effectively predicted, to adjust gas injection rate and igniting Device power, and then ensure the smooth implementation of layering ignition method.

Main assumption condition in the embodiment of the present invention is：

(1) for fluid flow state to stablize one-way flow, fluid is gas single-phase flow；

(2) heat transfer is steady heat transfer in pit shaft；

(3) stratum heat transfer is unsteady heat transfer, and obeys the non dimensional time function of Ramey；

(4) casing programme is as shown in Figure 1：Inner oil tube-outer oil pipe-oil jacket annular space-casing-cement sheath-stratum；

(5) heat loss in pit shaft and surrounding formation is radial direction, while is also contemplated for biography of the air flow along well depth direction Heat；

(6) variation that air flows through temperature after cable is ignored；

(7) formation temperature presses linear change, it is known that geothermal gradient and surface temperature；

(8) tubing and casing is concentric.

Casing programme as shown in Figure 1 takes well head as coordinate origin, straight down for just.

In one embodiment, the thermal resistance R that the following formula calculates stratum may be employed₁：

Wherein, K_eRepresent formation thermal conductivity, unit is W/ (mK)；A represents that stratum is averaged coefficient of heat transfer, unit m²/ d；T represents the oil well production time；r_hRepresent wellbore radius (i.e. gas injection well central axes to the distance of cement sheath outer wall), unit m.

In one embodiment, the thermal resistance R that the following formula calculates cement sheath may be employed₂：

Wherein, K_cemRepresent cement sheath thermal conductivity factor, unit is W/ (mK)；r_hRepresent wellbore radius, unit m；r_coTable Show sleeve outer wall radius, unit m.

In one embodiment, the thermal resistance R between the following formula calculating casing inside and outside wall may be employed₃：

Wherein, K_casRepresent casing thermal conductivity factor, unit is W/ (mK)；r_ciRepresent internal surface of sleeve pipe radius, unit m； r_coRepresent sleeve outer wall radius, unit m.

In one embodiment, the thermal resistance between the air and casing in the following formula calculating oil jacket annular space may be employed R₄：

Wherein, h_c1Represent the free convection heat transfer coefficient of air in oil jacket annular space, unit is W/ (m²·K)；h_r1Represent oil The heat radiation heat transfer coefficient of the aerial air of lantern ring, unit are W/ (m²·K)；r_ciRepresent internal surface of sleeve pipe radius, unit m.

The following formula may be employed and calculate heat radiation heat transfer coefficient h_r1：

Wherein, δ represents Stefan-Boltzmann (this special fence-Boltzmann) constant, and value is 2.189 × 10^-8W/ (m²·K)；F_tciRepresent oil pipe or instlated tubular outer wall surface to internal surface of sleeve pipe surface emissivity coefficient of efficiency；T_toRepresent outer tube outer wall Temperature；T_ciRepresent internal surface of sleeve pipe temperature；ε_oRepresent heat-insulated pipe outer wall blackness；ε_ciRepresent internal surface of sleeve pipe blackness；r_toIt represents outside outer tube Wall radius.

The following formula may be employed and calculate free convection heat transfer coefficient h_c1：

Wherein, G_rRepresent Grashof numbers (grashof number)；P_rRepresent Prandtl numbers (Prandtl number)；K_haRepresent oil jacket The thermal conductivity factor of the air of annular space, unit are W/ (mK)；G represents acceleration of gravity, unit m/s²；ρ_anRepresent oil jacket annular space Air in mean temperature T_anUnder density, unit kg/m³；U_anRepresent the air of oil jacket annular space in mean temperature T_anUnder Viscosity, unit mPas；C_anRepresent the air of oil jacket annular space in mean temperature T_anUnder thermal capacitance, unit be J (m³·K)；β tables Show the thermal cubic expansion coefficient of air in oil jacket annular space, be a constant, value can be 1.78 × 10^-3。

The thermal resistance of outer tube can divide three sections to be calculated, as shown in Figure 1, AB sections are instlated tubular, BC sections are screen casing, and CD sections are Plain tubing.Include R with the relevant thermal resistance of outer tube₅To R₉, illustrate its calculating process individually below.

In one embodiment, the thermal resistance R between the outer tube inside and outside wall of the following formula calculating instlated tubular may be employed₅：

Wherein, K_tubRepresent oil pipe thermal conductivity factor, unit is W/ (mK)；r_oRepresent instlated tubular outer tube outer wall radius, unit For m；r_iRepresent instlated tubular outer tube wall radius, unit m.

In one embodiment, the thermal resistance R that the following formula calculates thermal insulation layer may be employed₆：

Wherein, K_insRepresent instlated tubular thermal conductivity factor, unit is W/ (mK)；r_iRepresent instlated tubular outer tube wall radius, it is single Position is m；r_{to_w}Represent instlated tubular outer wall of inner tube radius, unit m.

In one embodiment, the thermal resistance R between the inner tube inside and outside wall of the following formula calculating instlated tubular may be employed₇：

Wherein, K_tubRepresent oil pipe thermal conductivity factor, unit is W/ (mK)；r_{to_w}Represent instlated tubular outer wall of inner tube radius, it is single Position is m；r_{ti_w}Represent instlated tubular inner tube wall radius, unit m.

In one embodiment, the thermal resistance R between the following formula calculating screen casing inside and outside wall may be employed₈：

Wherein, K_sieRepresent screen casing thermal conductivity factor, unit is W/ (mK)；r_{to_s}Represent screen casing exterior radius, unit m； r_{ti_s}Represent screen casing inner wall radius, unit m.

In one embodiment, the thermal resistance R between the following formula calculating oil pipe inside and outside wall may be employed₉：

Wherein, K_tubRepresent oil pipe thermal conductivity factor, unit is W/ (mK)；r_{ti_t}Represent tube inner wall radius, unit m； r_{to_t}Represent oil-pipe external wall radius, unit m.

In one embodiment, the following formula may be employed and calculate inner tube and the air thermal resistance R in outer tube annular space₁₀：

Wherein, h_c2Represent inner tube and the free convection heat transfer coefficient of air in outer tube annular space, unit is W/ (m²·K)；h_r2 Represent inner tube and the heat radiation heat transfer coefficient of air in outer tube annular space, unit is W/ (m²·K)；r_{n_to}Represent outer wall of inner tube radius, Unit is m.

h_c2And h_r2Calculating it is similar with formula (6)~(11), specifically, may be employed the following formula calculate heat radiation pass Hot coefficient h_r2：

Wherein, δ represents Stefan-Boltzmann constants, and value is 2.189 × 10-8W/ (m²·K)；F_tciRepresent oil pipe Or instlated tubular outer wall surface is to internal surface of sleeve pipe surface emissivity coefficient of efficiency；T_{n_to}Represent outer wall of inner tube temperature；T_tiIt represents in outer tube Wall temperature；ε_{n_to}Represent outer wall of inner tube blackness；ε_tiRepresent outer tube wall blackness；r_tiRepresent outer tube wall radius.

The following formula may be employed and calculate free convection heat transfer coefficient h_c2：

Wherein, G_rRepresent Grashof numbers；P_rRepresent Prandtl numbers；K_haRepresent inner tube and the heat conduction of air in outer tube annular space Coefficient；G represents acceleration of gravity；ρ_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder density；U_anIn expression Pipe is with air in outer tube annular space in mean temperature T_anUnder viscosity；C_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder thermal capacitance；β represents inner tube and the thermal cubic expansion coefficient of air in outer tube annular space, is a constant, and value can be 1.78 ×10^-3。

In one embodiment, the thermal resistance R between the following formula calculating inner tube inside and outside wall may be employed₁₁：

Wherein, K_tubRepresent oil pipe thermal conductivity factor, unit is W/ (mK)；r_{n_ti}Represent inner tube wall radius, unit m； r_{n_to}Represent outer wall of inner tube radius, unit m.

In one embodiment, the thermal convection current thermal resistance R of inner air tube in the following formula calculating may be employed₁₂：

Wherein, h_fThe thermal conductivity factor coefficient of inner air tube in expression, value are 0.05W/ (mK)；r_{n_ti}It represents in inner tube Wall radius；r_{n_to}Represent outer wall of inner tube radius.

In one embodiment, according to R₁To R₁₂The diametrical entire thermal resistance of pit shaft is calculated, it is specific as follows：

The entire thermal resistance of first segment pit shaft (i.e. AB sections, corresponding this section of pit shaft of instlated tubular) is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₅+R₆+R₇+R₁₀+R₁₁+R₁₂ (26)

The entire thermal resistance of second segment pit shaft (i.e. BC sections, corresponding this section of pit shaft of screen casing) is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₈+R₁₀+R₁₁+R₁₂ (27)

The entire thermal resistance of the 3rd section of pit shaft (i.e. CD sections, from oil pipe top to interior bottom of the tube) is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₉+R₁₀+R₁₁+R₁₂ (28)

In fig. 1, it is assumed that depth L1 (i.e. AB segment length) under instlated tubular, the burning torch length of electric igniter is L2, and screen casing is long It spends for L3 (i.e. BC segment length), tubing length is L4 (i.e. CD segment length), then total length L=L1+L3+L4, on burning torch Portion position (cable length of L5, that is, electric igniter) at L5=L1-L2.Since cable is using sheathed structure, heat effect is very It is small, therefore can be without considering the heat effect of cable, it is assumed that air is begun to warm up at L5.By L5 to L sections of pit shaft in the axial direction It is divided into several pit shaft units, the initial temperature (temperature of the inner air tube after electric igniter heats in i.e.) of inner tube is to pass through The T that formula (34) is calculated_s, main heat loss is diametrical heat loss.

In one embodiment, according to temperature T_s, entire thermal resistance and formation temperature, calculate the diametrical heat loss of pit shaft, Including：According to law of conservation of energy, heat loss is calculated using the following formula：

Wherein, Q represents pit shaft unit radial heat loss, unit W；T_eRepresent formation temperature, unit is DEG C；R represents well Cylinder unit radial entire thermal resistance.For example, pit shaft unit radial entire thermal resistance R uses formula (26) to count in AB sections, formula (29) Obtained entire thermal resistance；Pit shaft unit radial entire thermal resistance R uses what formula (27) was calculated in BC sections, formula (29) Entire thermal resistance；Pit shaft unit radial entire thermal resistance R uses the entire thermal resistance that formula (28) is calculated in CD sections, formula (29).

In one embodiment, according to temperature T_s, heat loss and electric igniter power, calculate the air themperature of inner tube, Including：

The air themperature of the inner tube in first segment pit shaft (i.e. AB sections) is calculated using the following formula：

CmT_s- Q/1000+0.6P=CmT_s' (30)

The air themperature of the inner tube in second segment pit shaft and the 3rd section of pit shaft (i.e. BD sections) is calculated using the following formula：

CmT_s- Q/1000=CmT_s' (31)

Wherein, T_s' representing the air themperature after variation in inner tube, unit is DEG C；C represents the specific heat capacity of air, and value is 1.0069kJ/ (kg ﹒ DEG C)；M represents the mass flow of air, unit kg/s；P represents the power of electric igniter.

In one embodiment, the following formula calculating inner tube may be employed and the air themperature of outer tube annular space (is alternatively referred to as The air themperature of outer tube)：

T_H=T_s-(R₁₀+R₁₁+R₁₂)×Q/dl (32)

Wherein, T_HRepresent inner tube and the air themperature of outer tube annular space, unit is DEG C.

In one embodiment, the variation that the following formula calculates formation temperature may be employed in step S208：

T_e=T_ins+αdl (33)

Wherein, T_insRepresent surface temperature, unit is DEG C；α represent geothermal gradient, unit for DEG C/m；T_eRepresent stratum temperature Degree, unit are DEG C.

In one embodiment, it is contemplated that electric igniter cable probably has 40% along journey heat loss, and following public affairs may be employed Formula calculating is injected into temperature T of the air of inner tube after electric igniter heats_s：

CmT+0.6P=CmT_s (34)

Wherein, T represents the initial temperature of air, and unit is DEG C；C represents the specific heat capacity of air；M represents the quality stream of air Amount；P represents the power of electric igniter.

Based on same inventive concept, the embodiment of the present invention additionally provides a kind of combustion in situ layering electric ignition gas injection well shaft The determining device of Temperature Distribution can be used to implement the described method of above-described embodiment, and overlaps will not be repeated.Following institute It uses, term " unit " can realize the combination of the software and/or hardware of predetermined function.Although following embodiment is described System is preferably realized with software, but the realization of the combination of hardware or software and hardware is also what may and be contemplated.

Fig. 3 is the knot of the determining device of the combustion in situ layering electric ignition gas injection well well bore temperature distribution of the embodiment of the present invention Structure block diagram, as shown in figure 3, the device includes：Division unit 31, the first computing unit 32, the second computing unit the 33, the 3rd calculate Unit 34, the 4th computing unit 35, the 5th computing unit 36, the 6th computing unit 37 and iterative calculation unit 38.Below to this Structure is specifically described.

Division unit 31, for will be in the axial direction divided into interior this section of pit shaft of bottom of the tube at the top of the burning torch of electric igniter Multiple pit shaft units, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, k tables Show iterations；

First computing unit 32, for calculating temperature T of the air for being injected into inner tube after electric igniter heats_s；

Second computing unit 33, for calculating the thermal resistance R on stratum respectively₁, cement sheath thermal resistance R₂, between casing inside and outside wall Thermal resistance R₃, thermal resistance R between air and casing in oil jacket annular space₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, every The thermal resistance R of thermosphere₆, instlated tubular inner tube inside and outside wall between thermal resistance R₇, thermal resistance R between screen casing inside and outside wall₈, oil pipe inside and outside wall Between thermal resistance R₉, air thermal resistance R in inner tube and outer tube annular space₁₀, thermal resistance R between inner tube inside and outside wall₁₁It is and empty in inner tube The thermal convection current thermal resistance R of gas₁₂；Wherein, gas injection well shaft radially includes successively from the inside to the outside：Inner tube, outer tube, casing and cement Ring, outer tube include successively along well head to shaft bottom direction：Instlated tubular, screen casing and oil pipe, gas injection well shaft outside are stratum；

3rd computing unit 34, for according to R₁To R₁₂Calculate the diametrical entire thermal resistance of pit shaft；

4th computing unit 35, for according to temperature T_s, entire thermal resistance and formation temperature, calculate the diametrical heat waste of pit shaft It loses；

5th computing unit 36, for according to temperature T_s, heat loss and electric igniter power, calculate the Air Temperature of inner tube Degree；

6th computing unit 37, for according to temperature T_s, heat loss and R₁₀To R₁₂, calculate inner tube and the air of outer tube annular space Temperature；

Unit 38 is iterated to calculate, for making l=l+dl, k=k+1, according to the variation of formation temperature, is calculated using second single First 33 to the 6th computing units 37 are iterated calculatings, and until l >=L, then iteration terminates, obtain the temperature distribution history of inner tube with The temperature distribution history of outer tube, wherein, L represents well head to the length of interior bottom of the tube.

By above device, well bore and oil pipe rod structure, pit shaft radially heat transfer and stratum thermophysical property etc. are considered Pit shaft is divided into several sections by variation of many factors along well depth, and the physical parameter (thermal resistance, heat transfer coefficient) of correspondent section, portion is obtained The function that physical parameter is divided to be temperature, using solution by iterative method, is calculated inner tube Temperature Distribution and outer tube Temperature Distribution.The dress It puts in the case of accurately calculating layering ignition process, the Temperature Distribution of arbitrary flow condition, any time along gas injection well shaft.Together When, calculating process is simple and convenient, has higher precision, and iterations is low, and computational efficiency is high, have extraordinary stability and Convergence.According to the Temperature Distribution of pit shaft, the air themperature for reaching oil reservoir up and down can be effectively predicted, to adjust gas injection rate and point Firearm power, and then ensure the smooth implementation of layering ignition method.

In one embodiment, the second computing unit 33 is specifically used for the thermal resistance R that stratum is calculated using the following formula₁：

Wherein, K_eRepresent formation thermal conductivity；A represents that stratum is averaged coefficient of heat transfer；T represents the oil well production time；r_hIt represents Wellbore radius.

In one embodiment, the second computing unit 33 is specifically used for the thermal resistance R that cement sheath is calculated using the following formula₂：

Wherein, K_cemRepresent cement sheath thermal conductivity factor；r_hRepresent wellbore radius；r_coRepresent sleeve outer wall radius.

In one embodiment, the second computing unit 33 is specifically used for using between the following formula calculating casing inside and outside wall Thermal resistance R₃：

Wherein, K_casRepresent casing thermal conductivity factor；r_ciRepresent internal surface of sleeve pipe radius；r_coRepresent sleeve outer wall radius.

In one embodiment, the second computing unit 33 is specifically used for calculating the air in oil jacket annular space using the following formula Thermal resistance R between casing₄：

Wherein, h_c1Represent the free convection heat transfer coefficient of air in oil jacket annular space；h_r1Represent the heat of air in oil jacket annular space Radiation heat transfer coefficient；r_ciRepresent internal surface of sleeve pipe radius；

Heat radiation heat transfer coefficient h is calculated using the following formula_r1：

Wherein, δ represents Stefan-Boltzmann constants；F_tciRepresent oil pipe or instlated tubular outer wall surface to internal surface of sleeve pipe Surface emissivity coefficient of efficiency；T_toRepresent outer tube outer wall temperature；T_ciRepresent internal surface of sleeve pipe temperature；ε_oRepresent heat-insulated pipe outer wall blackness； ε_ciRepresent internal surface of sleeve pipe blackness；r_toRepresent outer tube outer wall radius；

Free convection heat transfer coefficient h is calculated using the following formula_c1：

Wherein, G_rRepresent Grashof numbers；P_rRepresent Prandtl numbers；K_haRepresent the thermal conductivity factor of the air of oil jacket annular space；g Represent acceleration of gravity；ρ_anRepresent the air of oil jacket annular space in mean temperature T_anUnder density；U_anRepresent the air of oil jacket annular space In mean temperature T_anUnder viscosity；C_anRepresent the air of oil jacket annular space in mean temperature T_anUnder thermal capacitance；β represents oil jacket annular space The thermal cubic expansion coefficient of middle air.

In one embodiment, the second computing unit 33 is specifically used for calculating using the following formula inside and outside the outer tube of instlated tubular Thermal resistance R between wall₅：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_oRepresent instlated tubular outer tube outer wall radius；r_iRepresent instlated tubular outer tube wall Radius.

In one embodiment, the second computing unit 33 is specifically used for the thermal resistance R that thermal insulation layer is calculated using the following formula₆：

Wherein, K_insRepresent instlated tubular thermal conductivity factor；r_iRepresent instlated tubular outer tube wall radius；r_{to_w}Represent instlated tubular inner tube Exterior radius.

In one embodiment, the second computing unit 33 is specifically used for calculating using the following formula inside and outside the inner tube of instlated tubular Thermal resistance R between wall₇：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_{to_w}Represent instlated tubular outer wall of inner tube radius；r_{ti_w}Represent instlated tubular inner tube Inner wall radius.

In one embodiment, the second computing unit 33 is specifically used for using between the following formula calculating screen casing inside and outside wall Thermal resistance R₈：

Wherein, K_sieRepresent screen casing thermal conductivity factor；r_{to_s}Represent screen casing exterior radius；r_{ti_s}Represent screen casing inner wall radius.

In one embodiment, the second computing unit 33 is specifically used for using between the following formula calculating oil pipe inside and outside wall Thermal resistance R₉：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_{ti_t}Represent tube inner wall radius；r_{to_t}Represent oil-pipe external wall radius.

In one embodiment, the second computing unit 33 is specifically used for calculating in inner tube and outer tube annular space using the following formula Air thermal resistance R₁₀：

Wherein, h_c2Represent inner tube and the free convection heat transfer coefficient of air in outer tube annular space；h_r2Represent inner tube and outer pipe ring The heat radiation heat transfer coefficient of aerial air；r_{n_to}Represent outer wall of inner tube radius；

Heat radiation heat transfer coefficient h is calculated using the following formula_r2：

Wherein, δ represents Stefan-Boltzmann constants；F_tciRepresent oil pipe or instlated tubular outer wall surface to internal surface of sleeve pipe Surface emissivity coefficient of efficiency；T_{n_to}Represent outer wall of inner tube temperature；T_tiRepresent outer tube wall temperature；ε_{n_to}Represent that outer wall of inner tube is black Degree；ε_tiRepresent outer tube wall blackness；r_tiRepresent outer tube wall radius；

Free convection heat transfer coefficient h is calculated using the following formula_c2：

Wherein, G_rRepresent Grashof numbers；P_rRepresent Prandtl numbers；K_haRepresent inner tube and the heat conduction of air in outer tube annular space Coefficient；G represents acceleration of gravity；ρ_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder density；U_anIn expression Pipe is with air in outer tube annular space in mean temperature T_anUnder viscosity；C_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder thermal capacitance；β represents inner tube and the thermal cubic expansion coefficient of air in outer tube annular space.

In one embodiment, the second computing unit 33 is specifically used for using between the following formula calculating inner tube inside and outside wall Thermal resistance R₁₁：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_{n_ti}Represent inner tube wall radius；r_{n_to}Represent outer wall of inner tube radius.

In one embodiment, the thermal convection current heat of inner air tube in the following formula calculating may be employed in the second computing unit 33 Hinder R₁₂：

Wherein, h_fThe thermal conductivity factor coefficient of inner air tube in expression；r_n__tiRepresent inner tube wall radius；r_n__toRepresent inner tube Exterior radius.

In one embodiment, the 3rd computing unit 34 is specifically used for the total heat that first segment pit shaft is calculated using the following formula Resistance：

R=R₁+R₂+R₃+R₄+R₅+R₆+R₇+R₁₀+R₁₁+R₁₂,

The entire thermal resistance of second segment pit shaft is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₈+R₁₀+R₁₁+R₁₂,

The entire thermal resistance of the 3rd section of pit shaft is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₉+R₁₀+R₁₁+R₁₂,

Wherein, first segment pit shaft is corresponding this section of pit shaft of instlated tubular；Second segment pit shaft is corresponding this section of pit shaft of screen casing； 3rd section of pit shaft is from oil pipe top to interior bottom of the tube.

In one embodiment, the 4th computing unit 35 is specifically used for according to law of conservation of energy, using the following formula meter Calculate heat loss：

Wherein, Q represents pit shaft unit radial heat loss；T_eRepresent formation temperature；R represents pit shaft unit radial entire thermal resistance.

In one embodiment, the 5th computing unit 36 is specifically used for calculating in first segment pit shaft using the following formula The air themperature of inner tube：

CmT_s- Q/1000+0.6P=CmT_s',

The air themperature of the inner tube in second segment pit shaft and the 3rd section of pit shaft is calculated using the following formula：

CmT_s- Q/1000=CmT_s',

Wherein, T_s' represent the air themperature after variation in inner tube；C represents the specific heat capacity of air；M represents the quality of air Flow；P represents the power of electric igniter；Q represents pit shaft unit radial heat loss；First segment pit shaft is this corresponding section of instlated tubular Pit shaft；Second segment pit shaft is corresponding this section of pit shaft of screen casing；3rd section of pit shaft is from oil pipe top to interior bottom of the tube.

In one embodiment, the 6th computing unit 37 is specifically used for calculating inner tube and outer tube annular space using the following formula Air themperature：

T_H=T_s-(R₁₀+R₁₁+R₁₂) × Q/dl,

Wherein, T_HRepresent inner tube and the air themperature of outer tube annular space；Q represents pit shaft unit radial heat loss.

In one embodiment, iterate to calculate unit 38 and be specifically used for the variation that formation temperature is calculated using the following formula：

T_e=T_ins+ α dl,

Wherein, T_insRepresent surface temperature；α represents geothermal gradient；T_eRepresent formation temperature.

In one embodiment, the first computing unit 32 is specifically used for the air that inner tube is injected into using the following formula calculating Temperature T after electric igniter heats_s：

CmT+0.6P=CmT_s,

Wherein, T represents the initial temperature of air；C represents the specific heat capacity of air；M represents the mass flow of air；P is represented The power of electric igniter.

Certainly, said units division simply a kind of signal division, the present invention is not limited thereto.As long as it can realize the present invention Purpose module division, be within the scope of protection of the invention.

In order to determine that method and device carries out more to above-mentioned combustion in situ layering electric ignition gas injection well well bore temperature distribution It clearly explains, is illustrated with reference to specific embodiment, however, it should be noted that the embodiment is merely to more Illustrate the present invention well, do not form and the present invention is improperly limited.

(1) L5~L sections of pit shafts are divided into several pit shaft units in the longitudinal direction, each pit shaft element length is dl, from L5 Place starts to calculate, and makes l=0, k=1.

(2) temperature T of the air after electric igniter heats is calculated by formula (34)_s。

(3) R is calculated₁, R₂, R₃, R₅, R₆, R₇, R₈, R₉, R₁₁, R₁₂, make R₄=0, R₁₀=0 (due to R₄、R₁₀With heat transfer coefficient Related, heat transfer coefficient is related with the temperature of pipe, and does not know channel temp value initially, therefore, first sets R₄、R₁₀It is worth 0), to lead to It crosses formula (26)~(28) and calculates entire thermal resistance R.

(4) heat loss is calculated by formula (29)

(5) outer wall of inner tube temperature T is calculated_n__tO=T_s-(R₁₁+R₁₂)×Q/dl。

(6) outer tube wall temperature is calculated, it is necessary to be segmented calculating：

AB sections：T_ti=T_e+(R₁+R₂+R₃+R₄+R₅+R₆+R₇)×Q/dl；

BC sections：T_ti=T_e+(R₁+R₂+R₃+R₈)×Q/dl；

CD sections：T_ti=T_e+(R₁+R₂+R₃+R₉)×Q/dl。

(7) R is calculated by formula (17)~(23)₁₀。

(8) internal surface of sleeve pipe temperature T is calculated_ci=T_e+(R₁+R₂+R₃)×Q/dl。

(9) outer tube outer wall temperature is calculated, it is necessary to be segmented calculating：

AB sections：T_to=T_s-(R₅+R₆+R₇+R₁₀+R₁₁+R₁₂)×Q/dl；

BC sections：T_to=T_s-(R₅+R₁₀+R₁₁+R₁₂)×Q/dl；

CD sections：T_to=T_s-(R₉+R₁₀+R₁₁+R₁₂)×Q/dl。

(10) R is calculated by formula (5)~(11)₄。

(11) outer tube wall temperature is calculated again, it is necessary to be segmented calculating：

AB sections：T_ti=T_e+(R₁+R₂+R₃+R₄+R₅+R₆+R₇)×Q/dl；

BC sections：T_ti=T_e+(R₁+R₂+R₃+R₄+R₈)×Q/dl；

CD sections：T_ti=T_e+(R₁+R₂+R₃+R₄+R₉)×Q/dl。

(12) R is calculated again by formula (17)~(23)₁₀。

(13) entire thermal resistance R is calculated again by formula (26)~(28).

(14) heat loss is calculated again

(15) the temperature T of inner tube air is calculated by formula (30)~(31)_s'。

(16) inner tube and the air themperature of outer tube annular space are calculated by formula (32).

(17) k=k+1, l=l+dl are made, calculating formation temperature by formula (33) changes T_e=T_ins+ adl returns to the (3) step continues to iterate to calculate；If l >=L, iteration terminates.Obtain the temperature distribution history of inner tube and the Temperature Distribution song of outer tube Line, as shown in Figure 4 and Figure 5.

In conclusion the embodiment of the present invention to determine method for there has been no layering ignition process well-sinking temperature fields at present Problem, it is proposed that a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution determines method and device, considers well Body and the radially variation of many factors along well depth such as heat transfer and stratum thermophysical property of oil pipe rod structure, pit shaft, pit shaft is divided into Several sections, the physical parameter of correspondent section is obtained, part physical parameter is the function of temperature, can be simultaneously using solution by iterative method Inner tube gas injection Temperature Distribution and outer tube gas injection Temperature Distribution is calculated.According to the Temperature Distribution of pit shaft, can effectively predict Up to the air themperature of upper and lower oil reservoir, to adjust gas injection rate and igniter power, and then ensure the smooth implementation of layering ignition method.

The present invention establishes corresponding mathematical model using thermal conduction study method, and has carried out computer programming to this method. When establishing temperature distribution model, it is assumed that heat transfer in pit shaft is steady state heat transfer, and the heat transfer in pit shaft surrounding formation is unstable state Heat transfer not only allows for heat loss radially when calculating well bore temperature distribution, it is also considered that air flow is along well depth direction The influence conducted heat to well bore temperature distribution, segmentation calculating is carried out according to each section of tubing string difference of the tubular column structure of outer tube.Calculating process It is simple and convenient, there is higher precision, iterations is low, and computational efficiency is high, has extraordinary stability and convergence, more It is suitble to computer programming.In the case of layering ignition process can accurately be calculated, arbitrary flow condition, any time are along gas injection well shaft Temperature Distribution.

Any process described otherwise above or method description are construed as in flow chart or herein, represent to include Module, segment or the portion of the code of the executable instruction of one or more the step of being used to implement specific logical function or process Point, and the scope of the preferred embodiment of the present invention includes other realization, wherein can not press shown or discuss suitable Sequence, including according to involved function by it is basic simultaneously in the way of or in the opposite order, carry out perform function, this should be of the invention Embodiment person of ordinary skill in the field understood.

It should be appreciated that each several part of the present invention can be realized with hardware, software, firmware or combination thereof.Above-mentioned In embodiment, software that multiple steps or method can in memory and by suitable instruction execution system be performed with storage Or firmware is realized.If for example, with hardware come realize in another embodiment, can be under well known in the art Any one of row technology or their combination are realized：With for the logic gates to data-signal realization logic function Discrete logic, have suitable combinational logic gate circuit application-specific integrated circuit, programmable gate array (PGA), scene Programmable gate array (FPGA) etc..

Particular embodiments described above has carried out the purpose of the present invention, technical solution and advantageous effect further in detail Describe in detail it is bright, it should be understood that the above is only a specific embodiment of the present invention, the guarantor being not intended to limit the present invention Scope is protected, within the spirit and principles of the invention, any modification, equivalent substitution, improvement and etc. done should be included in this Within the protection domain of invention.

Claims

1. a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution determines method, which is characterized in that including：

Step 1, multiple pit shaft units will be divided into the axial direction to interior this section of pit shaft of bottom of the tube at the top of the burning torch of electric igniter, The length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, k represents iterations；

Step 2, temperature T of the air for being injected into said inner tube after electric igniter heating is calculated_s；

Step 3, the thermal resistance R on stratum is calculated respectively₁, cement sheath thermal resistance R₂, thermal resistance R between casing inside and outside wall₃, oil jacket annular space In air and casing between thermal resistance R₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, thermal insulation layer thermal resistance R₆, it is heat-insulated Thermal resistance R between the inner tube inside and outside wall of pipe₇, thermal resistance R between screen casing inside and outside wall₈, thermal resistance R between oil pipe inside and outside wall₉, inner tube With the air thermal resistance R in outer tube annular space₁₀, thermal resistance R between inner tube inside and outside wall₁₁And the thermal convection current thermal resistance R of interior inner air tube₁₂； Wherein, the gas injection well shaft radially includes successively from the inside to the outside：Inner tube, outer tube, casing and cement sheath, the outer tube is along well Mouth includes successively to shaft bottom direction：Instlated tubular, screen casing and oil pipe, the gas injection well shaft outside is stratum；

Step 4, according to R₁To R₁₂Calculate the diametrical entire thermal resistance of pit shaft；

Step 5, according to the temperature T_s, the entire thermal resistance and formation temperature, calculate the diametrical heat loss of pit shaft；

Step 6, according to the temperature T_s, the heat loss and the electric igniter power, calculate the air themperature of inner tube；

Step 7, according to the temperature T_s, the heat loss and R₁₀To R₁₂, calculate inner tube and the air themperature of outer tube annular space；

Step 8, l=l+dl, k=k+1 are made, according to the variation of formation temperature, above-mentioned steps 3 is repeated to step 7, changes In generation, calculates, and until l >=L, then iteration terminates, obtain said inner tube temperature distribution history and the outer tube Temperature Distribution it is bent Line, wherein, L represents well head to the length of interior bottom of the tube.

2. according to the method described in claim 1, it is characterized in that, the thermal resistance R on stratum is calculated using the following formula₁：

Wherein, K_eRepresent formation thermal conductivity；A represents that stratum is averaged coefficient of heat transfer；T represents the oil well production time；r_hRepresent pit shaft Radius.

3. according to the method described in claim 1, it is characterized in that, the thermal resistance R of cement sheath is calculated using the following formula₂：

4. according to the method described in claim 1, it is characterized in that, the thermal resistance between casing inside and outside wall is calculated using the following formula R₃：

5. according to the method described in claim 1, it is characterized in that, the air and set in oil jacket annular space are calculated using the following formula Thermal resistance R between pipe₄：

Wherein, h_c1Represent the free convection heat transfer coefficient of air in oil jacket annular space；h_r1Represent the heat radiation of air in oil jacket annular space Heat transfer coefficient；r_ciRepresent internal surface of sleeve pipe radius；

<mrow> <msub> <mi>h</mi> <mrow> <mi>r</mi> <mn>1</mn> </mrow> </msub> <mo>=</mo> <msub> <mi>&delta;F</mi> <mrow> <mi>t</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> <mrow> <mo>(</mo> <msubsup> <mi>T</mi> <mrow> <mi>t</mi> <mi>o</mi> </mrow> <mrow> <mo>*</mo> <mn>2</mn> </mrow> </msubsup> <mo>+</mo> <msubsup> <mi>T</mi> <mrow> <mi>c</mi> <mi>i</mi> </mrow> <mrow> <mo>*</mo> <mn>2</mn> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <msubsup> <mi>T</mi> <mrow> <mi>t</mi> <mi>o</mi> </mrow> <mo>*</mo> </msubsup> <mo>+</mo> <msubsup> <mi>T</mi> <mrow> <mi>c</mi> <mi>i</mi> </mrow> <mo>*</mo> </msubsup> <mo>)</mo> </mrow> <mo>,</mo> </mrow>

<mrow> <mfrac> <mn>1</mn> <msub> <mi>F</mi> <mrow> <mi>t</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mo>=</mo> <mfrac> <mn>1</mn> <msub> <mi>&epsiv;</mi> <mi>o</mi> </msub> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>r</mi> <mrow> <mi>t</mi> <mi>o</mi> </mrow> </msub> <msub> <mi>r</mi> <mrow> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mrow> <mo>(</mo> <mfrac> <mn>1</mn> <msub> <mi>&epsiv;</mi> <mrow> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>,</mo> </mrow>

Wherein, δ represents Stefan-Boltzmann constants；F_tciRepresent oil pipe or instlated tubular outer wall surface to internal surface of sleeve pipe surface Radiate coefficient of efficiency；T_toRepresent outer tube outer wall temperature；T_ciRepresent internal surface of sleeve pipe temperature；ε_oRepresent heat-insulated pipe outer wall blackness；ε_ciTable Show internal surface of sleeve pipe blackness；r_toRepresent outer tube outer wall radius；

Wherein, G_rRepresent Grashof numbers；P_rRepresent Prandtl numbers；K_haRepresent the thermal conductivity factor of the air of oil jacket annular space；G is represented Acceleration of gravity；ρ_anRepresent the air of oil jacket annular space in mean temperature T_anUnder density；U_anRepresent the air of oil jacket annular space flat Equal temperature T_anUnder viscosity；C_anRepresent the air of oil jacket annular space in mean temperature T_anUnder thermal capacitance；β represents that oil jacket annular space is hollow The thermal cubic expansion coefficient of gas.

6. according to the method described in claim 1, it is characterized in that, using the following formula calculate instlated tubular outer tube inside and outside wall it Between thermal resistance R₅：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_oRepresent instlated tubular outer tube outer wall radius；r_iRepresent instlated tubular outer tube wall half Footpath.

7. according to the method described in claim 1, it is characterized in that, the thermal resistance R of thermal insulation layer is calculated using the following formula₆：

Wherein, K_insRepresent instlated tubular thermal conductivity factor；r_iRepresent instlated tubular outer tube wall radius；r_{to_w}Represent instlated tubular outer wall of inner tube Radius.

8. according to the method described in claim 1, it is characterized in that, using the following formula calculate instlated tubular inner tube inside and outside wall it Between thermal resistance R₇：

Wherein, K_tubRepresent oil pipe thermal conductivity factor；r_{to_w}Represent instlated tubular outer wall of inner tube radius；r_{ti_w}Represent instlated tubular inner tube wall Radius.

9. according to the method described in claim 1, it is characterized in that, the thermal resistance between screen casing inside and outside wall is calculated using the following formula R₈：

10. according to the method described in claim 1, it is characterized in that, the heat between oil pipe inside and outside wall is calculated using the following formula Hinder R₉：

11. it according to the method described in claim 1, it is characterized in that, is calculated using the following formula in inner tube and outer tube annular space Air thermal resistance R₁₀：

Wherein, h_c2Represent inner tube and the free convection heat transfer coefficient of air in outer tube annular space；h_r2It represents in inner tube and outer tube annular space The heat radiation heat transfer coefficient of air；r_{n_to}Represent outer wall of inner tube radius；

<mrow> <msub> <mi>h</mi> <mrow> <mi>r</mi> <mn>2</mn> </mrow> </msub> <mo>=</mo> <msub> <mi>&delta;F</mi> <mrow> <mi>t</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> <mrow> <mo>(</mo> <msubsup> <mi>T</mi> <mrow> <mi>n</mi> <mo>_</mo> <mi>t</mi> <mi>o</mi> </mrow> <mrow> <mo>*</mo> <mn>2</mn> </mrow> </msubsup> <mo>+</mo> <msubsup> <mi>T</mi> <mrow> <mi>t</mi> <mi>i</mi> </mrow> <mrow> <mo>*</mo> <mn>2</mn> </mrow> </msubsup> <mo>)</mo> </mrow> <mrow> <mo>(</mo> <msubsup> <mi>T</mi> <mrow> <mi>n</mi> <mo>_</mo> <mi>t</mi> <mi>o</mi> </mrow> <mo>*</mo> </msubsup> <mo>+</mo> <msubsup> <mi>T</mi> <mrow> <mi>t</mi> <mi>i</mi> </mrow> <mo>*</mo> </msubsup> <mo>)</mo> </mrow> <mo>,</mo> </mrow>

<mrow> <mfrac> <mn>1</mn> <msub> <mi>F</mi> <mrow> <mi>t</mi> <mi>c</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mo>=</mo> <mfrac> <mn>1</mn> <msub> <mi>&epsiv;</mi> <mrow> <mi>n</mi> <mo>_</mo> <mi>t</mi> <mi>o</mi> </mrow> </msub> </mfrac> <mo>+</mo> <mfrac> <msub> <mi>r</mi> <mrow> <mi>n</mi> <mo>-</mo> <mi>t</mi> <mi>o</mi> </mrow> </msub> <msub> <mi>r</mi> <mrow> <mi>t</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mrow> <mo>(</mo> <mfrac> <mn>1</mn> <msub> <mi>&epsiv;</mi> <mrow> <mi>t</mi> <mi>i</mi> </mrow> </msub> </mfrac> <mo>-</mo> <mn>1</mn> <mo>)</mo> </mrow> <mo>,</mo> </mrow>

Wherein, δ represents Stefan-Boltzmann constants；F_tciRepresent oil pipe or instlated tubular outer wall surface to internal surface of sleeve pipe surface Radiate coefficient of efficiency；T_{n_to}Represent outer wall of inner tube temperature；T_tiRepresent outer tube wall temperature；ε_{n_to}Represent outer wall of inner tube blackness；ε_ti Represent outer tube wall blackness；r_tiRepresent outer tube wall radius；

Wherein, G_rRepresent Grashof numbers；P_rRepresent Prandtl numbers；K_haRepresent inner tube and the thermal conductivity factor of air in outer tube annular space； G represents acceleration of gravity；ρ_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder density；U_anRepresent inner tube with Air is in mean temperature T in outer tube annular space_anUnder viscosity；C_anRepresent inner tube with air in outer tube annular space in mean temperature T_anUnder Thermal capacitance；β represents inner tube and the thermal cubic expansion coefficient of air in outer tube annular space.

12. according to the method described in claim 1, it is characterized in that, the heat between inner tube inside and outside wall is calculated using the following formula Hinder R₁₁：

13. according to the method described in claim 1, it is characterized in that, using the following formula calculate in inner air tube thermal convection current Thermal resistance R₁₂：

Wherein, h_fThe thermal conductivity factor coefficient of inner air tube in expression；r_{n_ti}Represent inner tube wall radius；r_{n_to}Represent outer wall of inner tube Radius.

14. according to the method described in claim 1, it is characterized in that, according to R₁To R₁₂The diametrical entire thermal resistance of pit shaft is calculated, Including：

The entire thermal resistance of first segment pit shaft is calculated using the following formula：

R=R₁+R₂+R₃+R₄+R₅+R₆+R₇+R₁₀+R₁₁+R₁₂,

R=R₁+R₂+R₃+R₄+R₈+R₁₀+R₁₁+R₁₂,

R=R₁+R₂+R₃+R₄+R₉+R₁₀+R₁₁+R₁₂,

Wherein, the first segment pit shaft is corresponding this section of pit shaft of the instlated tubular；The second segment pit shaft is the screen casing pair This section of pit shaft answered；The 3rd section of pit shaft is at the top of the oil pipe to said inner tube bottom.

15. according to the method described in claim 1, it is characterized in that, according to the temperature T_s, the entire thermal resistance and formation temperature, The diametrical heat loss of pit shaft is calculated, including：

According to law of conservation of energy, the heat loss is calculated using the following formula：

16. according to the method described in claim 1, it is characterized in that, according to the temperature T_s, the heat loss and the electric point The power of firearm calculates the air themperature of inner tube, including：

The air themperature of the inner tube in first segment pit shaft is calculated using the following formula：

CmT_s- Q/1000+0.6P=CmT_s',

CmT_s- Q/1000=CmT_s',

Wherein, T_s' represent the air themperature after variation in inner tube；C represents the specific heat capacity of air；M represents the mass flow of air；P Represent the power of electric igniter；Q represents pit shaft unit radial heat loss；The first segment pit shaft be the instlated tubular it is corresponding this Section pit shaft；The second segment pit shaft is corresponding this section of pit shaft of the screen casing；The 3rd section of pit shaft at the top of the oil pipe to Said inner tube bottom.

17. according to the method described in claim 1, it is characterized in that, inner tube and the sky of outer tube annular space are calculated using the following formula Temperature degree：

T_H=T_s-(R₁₀+R₁₁+R₁₂) × Q/dl,

18. according to the method described in claim 1, it is characterized in that, the change of formation temperature is calculated in step 8 using the following formula Change：

T_e=T_ins+ α dl,

19. according to the method described in claim 1, it is characterized in that, the sky of said inner tube is injected into using the following formula calculating Temperature T of the gas after electric igniter heating_s：

CmT+0.6P=CmT_s,

Wherein, T represents the initial temperature of air；C represents the specific heat capacity of air；M represents the mass flow of air；P represents electric point The power of firearm.

20. a kind of combustion in situ is layered electric ignition gas injection well well bore temperature distribution determining device, which is characterized in that including：

Division unit, for multiple wells will to be divided into the axial direction to interior this section of pit shaft of bottom of the tube at the top of the burning torch of electric igniter Cylinder unit, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, the length that l expressions currently calculate, k represents iteration Number；

First computing unit, for calculating temperature T of the air for being injected into said inner tube after electric igniter heating_s；

Second computing unit, for calculating the thermal resistance R on stratum respectively₁, cement sheath thermal resistance R₂, thermal resistance between casing inside and outside wall R₃, thermal resistance R between air and casing in oil jacket annular space₄, instlated tubular outer tube inside and outside wall between thermal resistance R₅, thermal insulation layer Thermal resistance R₆, instlated tubular inner tube inside and outside wall between thermal resistance R₇, thermal resistance R between screen casing inside and outside wall₈, between oil pipe inside and outside wall Thermal resistance R₉, air thermal resistance R in inner tube and outer tube annular space₁₀, thermal resistance R between inner tube inside and outside wall₁₁And the heat of interior inner air tube Thermal-convection resistance R₁₂；Wherein, the gas injection well shaft radially includes successively from the inside to the outside：Inner tube, outer tube, casing and cement sheath, The outer tube includes successively along well head to shaft bottom direction：Instlated tubular, screen casing and oil pipe, the gas injection well shaft outside is stratum；

3rd computing unit, for according to R₁To R₁₂Calculate the diametrical entire thermal resistance of pit shaft；

4th computing unit, for according to the temperature T_s, the entire thermal resistance and formation temperature, calculate the diametrical heat of pit shaft Loss；

5th computing unit, for according to the temperature T_s, the heat loss and the electric igniter power, calculate inner tube Air themperature；

6th computing unit, for according to the temperature T_s, the heat loss and R₁₀To R₁₂, calculate inner tube and the sky of outer tube annular space Temperature degree；

Unit is iterated to calculate, for making l=l+dl, k=k+1, according to the variation of formation temperature, utilizes the second computing unit to the Six computing units are iterated calculating, and until l >=L, then iteration terminates, and obtain the temperature distribution history of said inner tube and described outer The temperature distribution history of pipe, wherein, L represents well head to the length of interior bottom of the tube.