CN105370266A - In-situ combustion layered electric ignition gas injection well wellbore temperature distribution determining method and device - Google Patents

Abstract

The invention discloses an in-situ combustion layered electric ignition gas injection well wellbore temperature distribution determining method and a device. The method comprises the following steps: (1) dividing a section of wellbore from the top of an ignition gun to the bottom of an inner pipe into multiple wellbore units dl in the axial direction, and letting l=0 and k=1; (2) calculating the temperature of air in the inner pipe after heating through an electric igniter; (3) calculating the thermal resistance of a formation, the thermal resistance of a cement ring, the thermal resistance of the wall of a casing, the thermal resistance between the air in an oil sleeve annulus and the casing, the thermal resistance of the outer pipe wall of a heat insulation pipe, the thermal resistance of a heat insulation layer, the thermal resistance of the inner pipe wall of the heat insulation pipe, the thermal resistance of the wall of a screen pipe, the thermal resistance of the wall of an oil pipe, the thermal resistance of air in the annulus between the inner pipe and an outer pipe, the thermal resistance of the wall of the inner pipe, and the thermal resistance of air in the inner pipe; (4) calculating the total radial thermal resistance of the wellbore; (5) calculating the radial heat loss of the wellbore; (6) calculating the temperature of air in the inner pipe; (7) calculating the temperature of air in the annulus between the inner pipe and the outer pipe; and (8) letting l=l+dl and k=k+1, repeating steps (3) to (7) for iterative calculation, ending iteration until l>=L, thus obtaining a temperature curve of the inner pipe and the outer pipe. Calculation is simple, and the precision is high.

Description

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

Technical field

The present invention relates to combustion in situ field, particularly relate to a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method and device.

Background technology

Current domestic combustion in situ Partial Block is that multilayer is burnt, and layering igniting layered gas-injection, due to the tubing string limited space that layering is injected, layering igniting cannot be implemented with portable electric igniter, someone proposes a kind of demixing point ignition method, realizes, as shown in Figure 1 based on the structure shown in Fig. 1, two-layer oil pipe is had in sleeve pipe, wherein, pipe is plain tubing, and outer tube is divided into 3 sections, and (AB section is instlated tubular, and instlated tubular is sleeve structure, BC section is screen casing, and CD section is plain tubing).Dark under being deeply generally no more than instlated tubular under igniter.Air injects (as shown in the figure direction of arrow) from interior pipe, outer tube respectively, the air that interior pipe injects enters bottom oil layer from the bottom of interior pipe after igniter heats, and the air that outer tube injects enters top oil reservoir from screen casing after heat conducting effect heating.The layered gas-injection igniting of two sections oil reservoir can be realized by this ignition method.

Calculating well bore temperature distribution is the key realizing above-mentioned demixing point ignition method, but, the defining method of the gas injection well well bore temperature distribution for above-mentioned layering ignition structure and method is not yet proposed at present.

Summary of the invention

The invention provides a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method and device, at least to solve the problem not yet having demixing point ignition technique well-sinking thermal field defining method at present.

According to an aspect of the present invention, provide a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method, comprise: step 1, this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, and the length of each pit shaft unit is dl, makes l=0, k=1, wherein, l represents the length of current calculating, and k represents iterations; Step 2, calculates the temperature T of air after described electric igniter heating being injected into described interior pipe _s; Step 3, calculates the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, described gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and described outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and described gas injection well pit shaft outside is stratum; Step 4, according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically; Step 5, according to described temperature T _s, described entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically; Step 6, according to described temperature T _s, described heat waste and described electric igniter power, the air themperature of pipe in calculating; Step 7, according to described temperature T _s, described heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating; Step 8, make l=l+dl, k=k+1, according to the change of formation temperature, repeats above-mentioned steps 3 to step 7, carry out iterative computation, until l>=L, then iteration terminates, and obtains the temperature distribution history of described interior pipe and the temperature distribution history of described outer tube, wherein, L represents that well head arrives the length bottom interior pipe.

According to another aspect of the present invention, provide a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution determining device, comprise: division unit, for this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, the length of each pit shaft unit is dl, makes l=0, k=1, wherein, l represents the length of current calculating, and k represents iterations; First computing unit, for calculating the temperature T of air after described electric igniter heating being injected into described interior pipe _s; Second computing unit, for calculating the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, described gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and described outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and described gas injection well pit shaft outside is stratum; 3rd computing unit, for according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically; 4th computing unit, for according to described temperature T _s, described entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically; 5th computing unit, for according to described temperature T _s, described heat waste and described electric igniter power, the air themperature of pipe in calculating; 6th computing unit, for according to described temperature T _s, described heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating; Iterative computation unit, for making l=l+dl, k=k+1, according to the change of formation temperature, the second computing unit is utilized to carry out iterative computation, until l>=L to the 6th computing unit, then iteration terminates, obtain the temperature distribution history of described interior pipe and the temperature distribution history of described outer tube, wherein, L represents that well head arrives the length bottom interior pipe.

By combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method of the present invention and device, consider the change of the many factors such as well bore and tubing string structure, the heat transfer of pit shaft radial direction and stratum thermophysical property along well depth, pit shaft is divided into some sections, obtain the physical parameter of correspondent section, part physical parameter is the function of temperature, adopt solution by iterative method, calculate interior pipe Temperature Distribution and outer tube Temperature Distribution.Can in accurate Calculation demixing point ignition technique situation, any flow condition, any time are along the Temperature Distribution of gas injection well pit shaft.Meanwhile, computational process is simple and convenient, and have higher precision, iterations is low, and computational efficiency is high, has extraordinary stability and convergence.According to the Temperature Distribution of pit shaft, effectively can predict the air themperature arriving upper and lower oil reservoir, to adjust gas injection rate and igniter power, and then ensure the smooth enforcement of demixing point ignition method.

Accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, and form a application's part, schematic description and description of the present invention, for explaining the present invention, does not form limitation of the invention.In the accompanying drawings:

Fig. 1 is the electrically-fired structural representation of combustion in situ layering of the embodiment of the present invention;

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

Fig. 3 is the structured flowchart 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;

Fig. 4 is the temperature distributing curve diagram of the interior pipe 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.

Detailed description of the invention

Below in conjunction with the accompanying drawing in the embodiment of the present invention, be clearly and completely described the technical scheme in the embodiment of the present invention, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on embodiments of the invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to protection scope of the present invention.

Embodiments provide a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method, Fig. 2 is the flow chart of the combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method of the embodiment of the present invention, as shown in Figure 2, the method comprises following step S201 to step S208.

Step S201, this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, and the length of each pit shaft unit is dl, makes l=0, k=1, and wherein, l represents the length of current calculating, and k represents iterations.

Step S202, calculates the temperature T of air after electric igniter heating being injected into interior pipe _s.

Step S203, calculates the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer (namely between the interior pipe of instlated tubular and outer tube) thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and gas injection well pit shaft outside is stratum.

Step S204, according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically.

Step S205, according to temperature T _s, entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically.

Step S206, according to temperature T _s, heat waste and electric igniter power, the air themperature of pipe in calculating.

Step S207, according to temperature T _s, heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating.

Step S208, make l=l+dl, k=k+1, according to the change of formation temperature, repeats above-mentioned steps S203 to step S207, carry out iterative computation, until l >=L, then iteration terminates, and obtains the temperature distribution history of interior pipe and the temperature distribution history of outer tube, wherein, L represents that well head arrives the length bottom interior pipe.

Pass through said method, consider the change of the many factors such as well bore and tubing string structure, the heat transfer of pit shaft radial direction and stratum thermophysical property along well depth, pit shaft is divided into some sections, obtain the physical parameter (thermal resistance, thermal transmittance) of correspondent section, part physical parameter is the function of temperature, adopt solution by iterative method, calculate interior pipe Temperature Distribution and outer tube Temperature Distribution.In the method energy accurate Calculation demixing point ignition technique situation, any flow condition, any time are along the Temperature Distribution of gas injection well pit shaft.Meanwhile, the method is simple and convenient, and have higher precision, iterations is low, and computational efficiency is high, has extraordinary stability and convergence.According to the Temperature Distribution of pit shaft, effectively can predict the air themperature arriving upper and lower oil reservoir, to adjust gas injection rate and igniter power, and then ensure the smooth enforcement of demixing point ignition method.

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

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

(2) in pit shaft, heat transfer is steady state heat conduction;

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

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

(5) heat waste in pit shaft and surrounding formation is radial, also considers the heat transfer of air flowing along well depth direction simultaneously;

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

(7) formation temperature linearly changes, known geothermal gradient and surface temperature;

(8) tubing and casing is concentric.

Casing programme as shown in Figure 1, getting well head is the origin of coordinates, is just straight down.

In one embodiment, the thermal resistance R on following formulae discovery stratum can be adopted ₁:

$R_1=\frac{f\left(t\right)}{2{\mathrm{\πK}}_e}---\left(1\right)$

$f\left(t\right)=ln\left(\frac{2\sqrt{at}}{r_h}\right)-0.29---\left(2\right)$

Wherein, K _erepresent formation thermal conductivity, unit is W/ (mK); A represents the average coefficient of heat transfer in stratum, and unit is m ²/ d; T represents the oil well production time; r _hrepresent wellbore radius (namely gas injection well axis is to the distance of cement sheath outer wall), unit is m.

In one embodiment, the thermal resistance R of following formulae discovery cement sheath can be adopted ₂:

$R_2=\frac{1}{2{\mathrm{\πK}}_{cem}}ln\frac{r_h}{r_{co}}---\left(3\right)$

Wherein, K _cemrepresent cement sheath coefficient of thermal conductivity, unit is W/ (mK); r _hrepresent wellbore radius, unit is m; r _corepresent sleeve outer wall radius, unit is m.

In one embodiment, the thermal resistance R between following formulae discovery sleeve pipe inside and outside wall can be adopted ₃:

$R_3=\frac{1}{2{\mathrm{\πK}}_{cas}}ln\frac{r_{co}}{r_{ci}}---\left(4\right)$

Wherein, K _casrepresent sleeve pipe coefficient of thermal conductivity, unit is W/ (mK); r _cirepresent internal surface of sleeve pipe radius, unit is m; r _corepresent sleeve outer wall radius, unit is m.

In one embodiment, the thermal resistance R between air in following formulae discovery oil jacket annular space and sleeve pipe can be adopted ₄:

$R_4=\frac{1}{2\mathrm{\π}(h_{c1}+h_{r1})r_{ci}}---\left(5\right)$

Wherein, h _c1represent the free convection heat transfer coefficient of air in oil jacket annular space, unit is W/ (m ²k); h _r1represent the heat radiation thermal transmittance of air in oil jacket annular space, unit is W/ (m ²k); r _cirepresent internal surface of sleeve pipe radius, unit is m.

Following formulae discovery heat radiation thermal transmittance h can be adopted _r1:

$h_{r1}={\mathrm{\δF}}_{tci}(T_{to}^{*2}+T_{ci}^{*2})(T_{to}^{*}+T_{ci}^{*})---\left(6\right)$

$T_{to}^{*}=T_{to}+273.15,T_{ci}^{*}=T_{ci}+273.15---\left(7\right)$

$\frac{1}{F_{tci}}=\frac{1}{{\mathrm{\ϵ}}_o}+\frac{r_{to}}{r_{ci}}(\frac{1}{{\mathrm{\ϵ}}_{ci}}-1)---\left(8\right)$

Wherein, δ represents Stefan-Boltzmann (this special fence-Boltzmann) constant, and value is 2.189 × 10 ^-8w/ (m ²k); F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 instlated tubular outer wall blackness; ε _cirepresent internal surface of sleeve pipe blackness; r _torepresent outer tube outer wall radius.

Following formulae discovery free convection heat transfer coefficient h can be adopted _c1:

$h_{c1}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{ro}\ln \frac{r_{ci}}{r_{to}}}---\left(9\right)$

$G_r=\frac{{(r_{ci}-r_{to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{to}-T_{ci})}{U_{an}^2}---\left(10\right)$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}}---\left(11\right)$

Wherein, G _rrepresent Grashof number (grashof number); P _rrepresent Prandtl number (Prandtl number); K _harepresent the coefficient of thermal conductivity of the air of oil jacket annular space, unit is W/ (mK); G represents acceleration of gravity, and unit is m/s ²; ρ _anrepresent that the air of oil jacket annular space is at average temperature T _anunder density, unit is kg/m ³; U _anrepresent that the air of oil jacket annular space is at average temperature T _anunder viscosity, unit is mPas; C _anrepresent that the air of oil jacket annular space is at average temperature T _anunder thermal capacitance, unit is J (m ³k); β represents the thermal cubic expansion coefficient of air in oil jacket annular space, is a constant, and value can be 1.78 × 10 ^-3.

The thermal resistance of outer tube can divide three sections to calculate, and as shown in Figure 1, AB section is instlated tubular, and BC section is screen casing, and CD section is plain tubing.The thermal resistance relevant to outer tube comprises R ₅to R ₉, below its computational process is described respectively.

In one embodiment, the thermal resistance R between the outer tube inside and outside wall that can adopt following formulae discovery instlated tubular ₅:

$R_5=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_o}{r_i}---\left(12\right)$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity, unit is W/ (mK); r _orepresent instlated tubular outer tube outer wall radius, unit is m; r _irepresent instlated tubular outer tube wall radius, unit is m.

In one embodiment, the thermal resistance R of following formulae discovery isolation layer can be adopted ₆:

$R_6=\frac{1}{2{\mathrm{\πK}}_{ins}}ln\frac{r_i}{r_{to\_w}}---\left(13\right)$

Wherein, K _insrepresent instlated tubular coefficient of thermal conductivity, unit is W/ (mK); r _irepresent instlated tubular outer tube wall radius, unit is m; r _{to_w}represent instlated tubular outer wall of inner tube radius, unit is m.

In one embodiment, the thermal resistance R between the interior pipe inside and outside wall that can adopt following formulae discovery instlated tubular ₇:

$R_7=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_w}}{r_{ti\_w}}---\left(14\right)$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity, unit is W/ (mK); r _{to_w}represent instlated tubular outer wall of inner tube radius, unit is m; r _{ti_w}represent instlated tubular inner tube wall radius, unit is m.

In one embodiment, the thermal resistance R between following formulae discovery screen casing inside and outside wall can be adopted ₈:

$R_8=\frac{1}{2{\mathrm{\πK}}_{sie}}ln\frac{r_{to\_s}}{r_{ti\_s}}---\left(15\right)$

Wherein, K _sierepresent screen casing coefficient of thermal conductivity, unit is W/ (mK); r _{to_s}represent screen casing exterior radius, unit is m; r _{ti_s}represent screen casing inwall radius, unit is m.

In one embodiment, the thermal resistance R between following formulae discovery oil pipe inside and outside wall can be adopted ₉:

$R_9=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_t}}{r_{ti\_t}}---\left(16\right)$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity, unit is W/ (mK); r _{ti_t}represent tube inner wall radius, unit is m; r _{to_t}represent oil-pipe external wall radius, unit is m.

In one embodiment, pipe and the air thermal resistance R in outer tube annular space in following formulae discovery can be adopted ₁₀:

$R_{10}=\frac{1}{2\mathrm{\π}(h_{c2}+h_{r2})r_{n\_to}}---\left(17\right)$

Wherein, h _c2manage the free convection heat transfer coefficient with air in outer tube annular space in representing, unit is W/ (m ²k); h _r2manage the heat radiation thermal transmittance with air in outer tube annular space in representing, unit is W/ (m ²k); r _{n_to}represent outer wall of inner tube radius, unit is m.

H _c2and h _r2calculating and formula (6) ~ (11) similar, concrete, following formulae discovery heat radiation thermal transmittance h can be adopted _r2:

$h_{r2}={\mathrm{\δF}}_{tci}(T_{n\_to}^{*2}+T_{ti}^{*2})(T_{n\_to}^{*}+T_{ti}^{*})---\left(18\right)$

$T_{n\_to}^{*}=T_{n\_to}+273.15,T_{ti}^{*}=T_{ti}+273.15---\left(19\right)$

$\frac{1}{F_{tci}}=\frac{1}{{\mathrm{\ϵ}}_{n\_to}}+\frac{r_{n\_to}}{r_{ti}}(\frac{1}{{\mathrm{\ϵ}}_{ti}}-1)---\left(20\right)$

Wherein, δ represents Stefan-Boltzmann constant, and value is 2.189 × 10-8W/ (m ²k); F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 outer wall of inner tube blackness; ε _tirepresent outer tube wall blackness; r _tirepresent outer tube wall radius.

Following formulae discovery free convection heat transfer coefficient h can be adopted _c2:

$h_{c2}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{n\_to}\ln \frac{r_{ti}}{r_{n\_to}}}---\left(21\right)$

$G_r=\frac{{(r_{ti}-r_{n\_to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{n\_to}-T_{ti})}{U_{an}^2}---\left(22\right)$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}}---\left(23\right)$

Wherein, G _rrepresent Grashof number; P _rrepresent Prandtl number; K _hathe coefficient of thermal conductivity with air in outer tube annular space is managed in representing; G represents acceleration of gravity; ρ _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder density; U _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder viscosity; C _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder thermal capacitance; β represents the thermal cubic expansion coefficient of air in interior pipe and outer tube annular space, is a constant, and value can be 1.78 × 10 ^-3.

In one embodiment, the thermal resistance R in following formulae discovery between pipe inside and outside wall can be adopted ₁₁:

$R_{11}=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{n\_to}}{r_{n\_ti}}---\left(24\right)$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity, unit is W/ (mK); r _{n_ti}represent inner tube wall radius, unit is m; r _{n_to}represent outer wall of inner tube radius, unit is m.

In one embodiment, the thermal convection current thermal resistance R of inner air tube in following formulae discovery can be adopted ₁₂:

$R_{12}=\frac{r_{n\_to}}{2{\mathrm{\πh}}_f{r}_{n\_ti}}---\left(25\right)$

Wherein, h _fthe coefficient of thermal conductivity coefficient of inner air tube in representing, value is 0.05W/ (mK); r _{n_ti}represent inner tube wall radius; r _{n_to}represent outer wall of inner tube radius.

In one embodiment, according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically, specific as follows:

Adopt the entire thermal resistance of following formulae discovery first paragraph pit shaft (i.e. AB section, this section of pit shaft that instlated tubular is corresponding):

R＝R ₁+R ₂+R ₃+R ₄+R ₅+R ₆+R ₇+R ₁₀+R ₁₁+R ₁₂(26)

Adopt the entire thermal resistance of following formulae discovery second segment pit shaft (i.e. BC section, this section of pit shaft that screen casing is corresponding):

R＝R ₁+R ₂+R ₃+R ₄+R ₈+R ₁₀+R ₁₁+R ₁₂(27)

Adopt the entire thermal resistance at following formulae discovery the 3rd section of pit shaft (i.e. CD section, bottom from oil pipe top to interior pipe):

R＝R ₁+R ₂+R ₃+R ₄+R ₉+R ₁₀+R ₁₁+R ₁₂(28)

In FIG, dark L1 (i.e. AB segment length) under supposing instlated tubular, the burning torch length of electric igniter is L2, screen casing length is L3 (i.e. BC segment length), tubing length is L4 (i.e. CD segment length), so total length is L=L1+L3+L4, and burning torch upper position is at L5=L1-L2 place (cable length of L5 and electric igniter).Because cable adopts sheathed structure, heat effect is very little, therefore can not consider the heat effect of cable, supposes that air starts heating at L5 place.L5 to L section pit shaft is divided into several pit shaft unit in the axial direction, and the initial temperature (namely the temperature of inner air tube after electric igniter heating) of interior pipe is the T calculated by formula (34) _s, main heat waste is heat waste diametrically.

In one embodiment, according to temperature T _s, entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically, comprising: according to law of conservation of energy, adopt following formulae discovery heat waste:

$Q=\frac{T_s-T_e}{R}dl---\left(29\right)$

Wherein, Q represents pit shaft unit radial heat waste, and unit is W; T _erepresent formation temperature, unit is DEG C; R represents pit shaft unit radial entire thermal resistance.Such as, in AB section, the entire thermal resistance that in formula (29), pit shaft unit radial entire thermal resistance R uses formula (26) to calculate; In BC section, the entire thermal resistance that in formula (29), pit shaft unit radial entire thermal resistance R uses formula (27) to calculate; In CD section, the entire thermal resistance that in formula (29), pit shaft unit radial entire thermal resistance R uses formula (28) to calculate.

In one embodiment, according to temperature T _s, heat waste and electric igniter power, the air themperature of pipe in calculating, comprising:

Following formulae discovery is adopted to be in the air themperature of the interior pipe of first paragraph pit shaft (i.e. AB section):

CmT _s-Q/1000+0.6P＝CmT' _s(30)

Following formulae discovery is adopted to be in the air themperature of the interior pipe of second segment pit shaft and the 3rd section of pit shaft (i.e. BD section):

CmT _s-Q/1000＝CmT' _s(31)

Wherein, T' _sair themperature in representing in pipe after change, 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, and unit is kg/s; P represents the power of electric igniter.

In one embodiment, the air themperature (also can be described as the air themperature of outer tube) of pipe and outer tube annular space in following formulae discovery can be adopted:

T _H＝T _s-(R ₁₀+R ₁₁+R ₁₂)×Q/dl(32)

Wherein, T _hpipe and the air themperature of outer tube annular space in representing, unit is DEG C.

In one embodiment, the change of following formulae discovery formation temperature can be adopted in step S208:

T _e＝T _ins+αdl(33)

Wherein, T _insrepresent surface temperature, unit is DEG C; α represents geothermal gradient, and unit is DEG C/m; T _erepresent formation temperature, unit is DEG C.

In one embodiment, consider that electric igniter cable probably has 40% along journey heat waste, following formulae discovery can be adopted to be injected into the temperature T of air after electric igniter heating of interior pipe _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 mass flow of air; P represents the power of electric igniter.

Based on same inventive concept, the embodiment of the present invention additionally provides a kind of determining device of combustion in situ layering electric ignition gas injection well well bore temperature distribution, may be used for the method realized described by above-described embodiment, repeats part and repeats no more.Following used, term " unit " can realize the software of predetermined function and/or the combination of hardware.Although the system described by following examples preferably realizes with software, hardware, or the realization of the combination of software and hardware also may and conceived.

Fig. 3 is the structured flowchart 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, as shown in Figure 3, this device comprises: division unit 31, first computing unit 32, second computing unit 33, the 3rd computing unit 34, the 4th computing unit 35, the 5th computing unit 36, the 6th computing unit 37 and iterative computation unit 38.Below this structure is specifically described.

Division unit 31, for this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, the length of each pit shaft unit is dl, makes l=0, k=1, and wherein, l represents the length of current calculating, and k represents iterations;

First computing unit 32, for calculating the temperature T of air after electric igniter heating being injected into interior pipe _s;

Second computing unit 33, for calculating the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and gas injection well pit shaft outside is stratum;

3rd computing unit 34, for according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically;

4th computing unit 35, for according to temperature T _s, entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically;

5th computing unit 36, for according to temperature T _s, heat waste and electric igniter power, the air themperature of pipe in calculating;

6th computing unit 37, for according to temperature T _s, heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating;

Iterative computation unit 38, for making l=l+dl, k=k+1, according to the change of formation temperature, the second computing unit 33 is utilized to carry out iterative computation, until l >=L to the 6th computing unit 37, then iteration terminates, obtain the temperature distribution history of interior pipe and the temperature distribution history of outer tube, wherein, L represents that well head arrives the length bottom interior pipe.

Pass through said apparatus, consider the change of the many factors such as well bore and tubing string structure, the heat transfer of pit shaft radial direction and stratum thermophysical property along well depth, pit shaft is divided into some sections, obtain the physical parameter (thermal resistance, thermal transmittance) of correspondent section, part physical parameter is the function of temperature, adopt solution by iterative method, calculate interior pipe Temperature Distribution and outer tube Temperature Distribution.In this device energy accurate Calculation demixing point ignition technique situation, any flow condition, any time are along the Temperature Distribution of gas injection well pit shaft.Meanwhile, computational process is simple and convenient, and have higher precision, iterations is low, and computational efficiency is high, has extraordinary stability and convergence.According to the Temperature Distribution of pit shaft, effectively can predict the air themperature arriving upper and lower oil reservoir, to adjust gas injection rate and igniter power, and then ensure the smooth enforcement of demixing point ignition method.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R on following formulae discovery stratum ₁:

$R_1=\frac{f\left(t\right)}{2{\mathrm{\πK}}_e},$

$f\left(t\right)=ln\left(\frac{2\sqrt{at}}{r_h}\right)-0.29,$

Wherein, K _erepresent formation thermal conductivity; A represents the average coefficient of heat transfer in stratum; T represents the oil well production time; r _hrepresent wellbore radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R of following formulae discovery cement sheath ₂:

$R_2=\frac{1}{2{\mathrm{\πK}}_{cem}}ln\frac{r_h}{r_{co}},$

Wherein, K _cemrepresent cement sheath coefficient of thermal conductivity; r _hrepresent wellbore radius; r _corepresent sleeve outer wall radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R between following formulae discovery sleeve pipe inside and outside wall ₃:

$R_3=\frac{1}{2{\mathrm{\πK}}_{cas}}ln\frac{r_{co}}{r_{ci}},$

Wherein, K _casrepresent sleeve pipe coefficient of thermal conductivity; r _cirepresent internal surface of sleeve pipe radius; r _corepresent sleeve outer wall radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R between air in following formulae discovery oil jacket annular space and sleeve pipe ₄:

$R_4=\frac{1}{2\mathrm{\π}(h_{c1}+h_{r1})r_{ci}},$

Wherein, h _c1represent the free convection heat transfer coefficient of air in oil jacket annular space; h _r1represent the heat radiation thermal transmittance of air in oil jacket annular space; r _cirepresent internal surface of sleeve pipe radius;

Adopt following formulae discovery heat radiation thermal transmittance h _r1:

$h_{r1}={\mathrm{\δF}}_{tci}(T_{to}^{*2}+T_{ci}^{*2})(T_{to}^{*}+T_{ci}^{*}),$

$T_{to}^{*}=T_{to}+273.15,T_{ci}^{*}=T_{ci}+273.15,$

$\frac{1}{F_{ci}}=\frac{1}{{\mathrm{\ϵ}}_o}+\frac{r_{to}}{r_{ci}}(\frac{1}{{\mathrm{\ϵ}}_{ci}}-1),$

Wherein, δ represents Stefan-Boltzmann constant; F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 instlated tubular outer wall blackness; ε _cirepresent internal surface of sleeve pipe blackness; r _torepresent outer tube outer wall radius;

Adopt following formulae discovery free convection heat transfer coefficient h _c1:

$h_{c1}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{to}\ln \frac{r_{ci}}{r_{to}}},$

$G_r=\frac{{(r_{ci}-r_{to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{to}-T_{ci})}{U_{an}^2},$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}},$

Wherein, G _rrepresent Grashof number; P _rrepresent Prandtl number; K _harepresent the coefficient of thermal conductivity of the air of oil jacket annular space; G represents acceleration of gravity; ρ _anrepresent that the air of oil jacket annular space is at average temperature T _anunder density; U _anrepresent that the air of oil jacket annular space is at average temperature T _anunder viscosity; C _anrepresent that the air of oil jacket annular space is at average temperature T _anunder thermal capacitance; β represents the thermal cubic expansion coefficient of air in oil jacket annular space.

In one embodiment, the second computing unit 33 specifically for adopt following formulae discovery instlated tubular outer tube inside and outside wall between thermal resistance R ₅:

$R_5=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_o}{r_i},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; 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 for adopting the thermal resistance R of following formulae discovery isolation layer ₆:

$R_6=\frac{1}{2{\mathrm{\πK}}_{ins}}ln\frac{r}{r_{to\_w}},$

Wherein, K _insrepresent instlated tubular coefficient of thermal conductivity; r _irepresent instlated tubular outer tube wall radius; r _{to_w}represent instlated tubular outer wall of inner tube radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R in following formulae discovery instlated tubular between pipe inside and outside wall ₇:

$R_7=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_w}}{r_{ti\_w}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _{to_w}represent instlated tubular outer wall of inner tube radius; r _{ti_w}represent instlated tubular inner tube wall radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R between following formulae discovery screen casing inside and outside wall ₈:

$R_8=\frac{1}{2{\mathrm{\πK}}_{sie}}ln\frac{r_{to\_s}}{r_{ti\_s}},$

Wherein, K _sierepresent screen casing coefficient of thermal conductivity; r _{to_s}represent screen casing exterior radius; r _{ti_s}represent screen casing inwall radius.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R between following formulae discovery oil pipe inside and outside wall ₉:

$R_9=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_t}}{r_{ti\_t}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; 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 for adopting pipe and the air thermal resistance R in outer tube annular space in following formulae discovery ₁₀:

$R_{10}=\frac{1}{2\mathrm{\π}(h_{c2}+h_{r2})r_{n\_to}},$

Wherein, h _c2the free convection heat transfer coefficient with air in outer tube annular space is managed in representing; h _r2the heat radiation thermal transmittance with air in outer tube annular space is managed in representing; r _{n_to}represent outer wall of inner tube radius;

Adopt following formulae discovery heat radiation thermal transmittance h _r2:

$h_{r2}={\mathrm{\δF}}_{tci}(T_{n\_to}^{*2}+T_{ti}^{*2})(T_{n\_to}^{*}+T_{ti}^{*}),$

$T_{n\_to}^{*}=T_{n\_to}+273.15,T_{ti}^{*}=T_{ti}+273.15,$

$\frac{1}{F_{tci}}=\frac{1}{{\mathrm{\ϵ}}_{n\_to}}+\frac{r_{n\_to}}{r_{ti}}(\frac{1}{{\mathrm{\ϵ}}_{ti}}-1),$

Wherein, δ represents Stefan-Boltzmann constant; F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 outer wall of inner tube blackness; ε _tirepresent outer tube wall blackness; r _tirepresent outer tube wall radius;

Adopt following formulae discovery free convection heat transfer coefficient h _c2:

$h_{c2}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{n\_to}\ln \frac{r_{ti}}{r_{n\_to}}},$

$G_r=\frac{{(r_{ti}-r_{n\_to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{n\_to}-T_{ti})}{U_{an}^2},$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}},$

Wherein, G _rrepresent Grashof number; P _rrepresent Prandtl number; K _hathe coefficient of thermal conductivity with air in outer tube annular space is managed in representing; G represents acceleration of gravity; ρ _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder density; U _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder viscosity; C _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder thermal capacitance; β represents the thermal cubic expansion coefficient of air in interior pipe and outer tube annular space.

In one embodiment, the second computing unit 33 is specifically for adopting the thermal resistance R in following formulae discovery between pipe inside and outside wall ₁₁:

$R_{11}=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{n\_to}}{r_{n\_ti}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _{n_ti}represent inner tube wall radius; r _{n_to}represent outer wall of inner tube radius.

In one embodiment, the second computing unit 33 can adopt the thermal convection current thermal resistance R of inner air tube in following formulae discovery ₁₂:

$R_{12}=\frac{r_{n\_to}}{2{\mathrm{\πh}}_f{r}_{n\_ti}},$

Wherein, h _fthe coefficient of thermal conductivity coefficient of inner air tube in representing; r _{n_ti}represent inner tube wall radius; r _{n_to}represent outer wall of inner tube radius.

In one embodiment, the 3rd computing unit 34 is specifically for adopting the entire thermal resistance of following formulae discovery first paragraph pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₅+R ₆+R ₇+R ₁₀+R ₁₁+R ₁₂，

Adopt the entire thermal resistance of following formulae discovery second segment pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₈+R ₁₀+R ₁₁+R ₁₂，

Adopt the entire thermal resistance of following formulae discovery the 3rd section of pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₉+R ₁₀+R ₁₁+R ₁₂，

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

In one embodiment, the 4th computing unit 35 specifically for according to law of conservation of energy, adopts following formulae discovery heat waste:

$Q=\frac{T_s-T_e}{R}dl,$

Wherein, Q represents pit shaft unit radial heat waste; T _erepresent formation temperature; R represents pit shaft unit radial entire thermal resistance.

In one embodiment, the air themperature of the 5th computing unit 36 specifically for adopting following formulae discovery to be in pipe in first paragraph pit shaft:

CmT _s-Q/1000+0.6P＝CmT' _s，

Following formulae discovery is adopted to be in the air themperature of the interior pipe of second segment pit shaft and the 3rd section of pit shaft:

CmT _s-Q/1000＝CmT' _s，

Wherein, T' _sair themperature in representing in pipe after change; C represents the specific heat capacity of air; M represents the mass flow of air; P represents the power of electric igniter; Q represents pit shaft unit radial heat waste; First paragraph pit shaft is this section of pit shaft that instlated tubular is corresponding; Second segment pit shaft is this section of pit shaft that screen casing is corresponding; 3rd section of pit shaft from oil pipe top to interior pipe bottom.

In one embodiment, the 6th computing unit 37 is specifically for adopting the air themperature of pipe and outer tube annular space in following formulae discovery:

T _H＝T _s-(R ₁₀+R ₁₁+R ₁₂)×Q/dl，

Wherein, T _hthe air themperature of pipe and outer tube annular space in representing; Q represents pit shaft unit radial heat waste.

In one embodiment, iterative computation unit 38 is specifically for adopting the change of following formulae discovery formation temperature:

T _e＝T _ins+αdl，

Wherein, T _insrepresent surface temperature; α represents geothermal gradient; T _erepresent formation temperature.

In one embodiment, the air temperature T through electric igniter heating after of the first computing unit 32 specifically for adopting following formulae discovery to be injected into interior pipe _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 the power of electric igniter.

Certainly, said units divides just a kind of signal and divides, and the present invention is not limited thereto.As long as the Module Division of object of the present invention can be realized, protection scope of the present invention all should be belonged to.

In order to more clearly explain above-mentioned combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method and device, be described below in conjunction with specific embodiment, but it should be noted that this embodiment is only to better the present invention is described, do not form and the present invention is limited improperly.

(1) L5 ~ L section pit shaft is divided into several pit shaft unit in the vertical, each pit shaft element length is dl, calculates, make l=0, k=1 from L5 place.

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

(3) R is calculated ₁, R ₂, R ₃, R ₅, R ₆, R ₇, R ₈, R ₉, R ₁₁, R ₁₂, make R ₄=0, R ₁₀=0 (due to R ₄, R ₁₀relevant with thermal transmittance, thermal transmittance is relevant with the temperature of pipe, and does not know temperature value at first, therefore, first arranges R ₄, R ₁₀value is 0), calculate entire thermal resistance R by formula (26) ~ (28).

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

(5) outer wall of inner tube temperature T is calculated _{n_to}=T _s-(R ₁₁+ R ₁₂) × Q/dl.

(6) calculate outer tube wall temperature, need segmentation to calculate:

AB section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₄+ R ₅+ R ₆+ R ₇) × Q/dl;

BC section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₈) × Q/dl;

CD section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₉) × Q/dl.

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

(8) internal surface of sleeve pipe temperature T is calculated _ci=T _e+ (R ₁+ R ₂+ R ₃) × Q/dl.

(9) calculate outer tube outer wall temperature, need segmentation to calculate:

AB section: T _to=T _s-(R ₅+ R ₆+ R ₇+ R ₁₀+ R ₁₁+ R ₁₂) × Q/dl;

BC section: T _to=T _s-(R ₅+ R ₁₀+ R ₁₁+ R ₁₂) × Q/dl;

CD section: T _to=T _s-(R ₉+ R ₁₀+ R ₁₁+ R ₁₂) × Q/dl.

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

(11) again calculate outer tube wall temperature, need segmentation to calculate:

AB section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₄+ R ₅+ R ₆+ R ₇) × Q/dl;

BC section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₄+ R ₈) × Q/dl;

CD section: T _ti=T _e+ (R ₁+ R ₂+ R ₃+ R ₄+ R ₉) × Q/dl.

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

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

(14) again heat waste is calculated

(15) the temperature T' of interior pipe air is calculated by formula (30) ~ (31) _s.

(16) air themperature of interior pipe and outer tube annular space is calculated by formula (32).

(17) k=k+1 is made, l=l+dl, by formula (33) fo pination temperature change T _e=T _ins+ adl, returns (3) step and continues iterative computation; If l>=L, then iteration terminates.Obtain the temperature distribution history of interior pipe and the temperature distribution history of outer tube, as shown in Figure 4 and Figure 5.

In sum, the embodiment of the present invention is for the problem not yet having demixing point ignition technique well-sinking thermal field defining method at present, propose a kind of combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method and device, consider well bore and tubing string structure, the many factors such as the heat transfer of pit shaft radial direction and stratum thermophysical property are along the change of well depth, pit shaft is divided into some sections, obtain the physical parameter of correspondent section, part physical parameter is the function of temperature, adopt solution by iterative method, interior pipe gas injection Temperature Distribution and outer tube gas injection Temperature Distribution can be calculated simultaneously.According to the Temperature Distribution of pit shaft, effectively can predict the air themperature arriving upper and lower oil reservoir, to adjust gas injection rate and igniter power, and then ensure the smooth enforcement of demixing point ignition method.

The present invention adopts the corresponding Mathematical Modeling of thermal conduction study method establishment, and has carried out computer programming to the method.When setting up temperature distribution model, suppose that the heat transfer in pit shaft is steady state heat transfer, heat transfer in pit shaft surrounding formation is unsteady-state heat transfer, the heat waste in radial direction is not only considered when calculating well bore temperature distribution, have also contemplated that the heat transfer of air flowing along well depth direction is on the impact of well bore temperature distribution, carries out segmentation calculating according to the tubular column structure of outer tube each section of tubing string difference.Computational process is simple and convenient, and have higher precision, iterations is low, and computational efficiency is high, has extraordinary stability and convergence, is more applicable to computer programming.Can in accurate Calculation demixing point ignition technique situation, any flow condition, any time are along the Temperature Distribution of gas injection well pit shaft.

Describe and can be understood in flow chart or in this any process otherwise described or method, represent and comprise one or more for realizing the module of the code of the executable instruction of the step of specific logical function or process, fragment or part, and the scope of the preferred embodiment of the present invention comprises other realization, wherein can not according to order that is shown or that discuss, comprise according to involved function by the mode while of basic or by contrary order, carry out n-back test, this should understand by embodiments of the invention person of ordinary skill in the field.

Should be appreciated that each several part of the present invention can realize with hardware, software, firmware or their combination.In the above-described embodiment, multiple step or method can with to store in memory and the software performed by suitable instruction execution system or firmware realize.Such as, if realized with hardware, the same in another embodiment, can realize by any one in following technology well known in the art or their combination: the discrete logic with the logic gates for realizing logic function to data-signal, there is the special IC of suitable combinational logic gate circuit, programmable gate array (PGA), field programmable gate array (FPGA) etc.

Above-described specific embodiment; object of the present invention, technical scheme and beneficial effect are further described; be understood that; the foregoing is only specific embodiments of the invention; the protection domain be not intended to limit the present invention; within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (20)

1. a combustion in situ layering electric ignition gas injection well well bore temperature distribution defining method, is characterized in that, comprising:

Step 1, this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, and the length of each pit shaft unit is dl, makes l=0, k=1, and wherein, l represents the length of current calculating, and k represents iterations;

Step 2, calculates the temperature T of air after described electric igniter heating being injected into described interior pipe _s;

Step 3, calculates the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, described gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and described outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and described gas injection well pit shaft outside is stratum;

Step 4, according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically;

Step 5, according to described temperature T _s, described entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically;

Step 6, according to described temperature T _s, described heat waste and described electric igniter power, the air themperature of pipe in calculating;

Step 7, according to described temperature T _s, described heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating;

Step 8, make l=l+dl, k=k+1, according to the change of formation temperature, repeats above-mentioned steps 3 to step 7, carry out iterative computation, until l >=L, then iteration terminates, and obtains the temperature distribution history of described interior pipe and the temperature distribution history of described outer tube, wherein, L represents that well head arrives the length bottom interior pipe.

2. method according to claim 1, is characterized in that, adopts the thermal resistance R on following formulae discovery stratum ₁:

$R_1=\frac{f\left(t\right)}{2{\mathrm{\πK}}_e},$

$f\left(t\right)=ln\left(\frac{2\sqrt{at}}{r_h}\right)-0.29,$

Wherein, K _erepresent formation thermal conductivity; A represents the average coefficient of heat transfer in stratum; T represents the oil well production time; r _hrepresent wellbore radius.

3. method according to claim 1, is characterized in that, adopts the thermal resistance R of following formulae discovery cement sheath ₂:

$R_2=\frac{1}{2{\mathrm{\πK}}_{cem}}ln\frac{r_h}{r_{co}},$

Wherein, K _cemrepresent cement sheath coefficient of thermal conductivity; r _hrepresent wellbore radius; r _corepresent sleeve outer wall radius.

4. method according to claim 1, is characterized in that, adopts the thermal resistance R between following formulae discovery sleeve pipe inside and outside wall ₃:

$R_3=\frac{1}{2{\mathrm{\πK}}_{cas}}ln\frac{r_{co}}{r_{ci}},$

Wherein, K _casrepresent sleeve pipe coefficient of thermal conductivity; r _cirepresent internal surface of sleeve pipe radius; r _corepresent sleeve outer wall radius.

5. method according to claim 1, is characterized in that, adopts the thermal resistance R between air in following formulae discovery oil jacket annular space and sleeve pipe ₄:

$R_4=\frac{1}{2\mathrm{\π}(h_{c1}+h_{r1})r_{ci}},$

Wherein, h _c1represent the free convection heat transfer coefficient of air in oil jacket annular space; h _r1represent the heat radiation thermal transmittance of air in oil jacket annular space; r _cirepresent internal surface of sleeve pipe radius;

Adopt following formulae discovery heat radiation thermal transmittance h _r1:

$h_{r1}={\mathrm{\δF}}_{tci}(T_{to}^{*2}+T_{ci}^{*2})(T_{to}^{*}+T_{ci}^{*}),$

$T_{to}^{*}=T_{to}+273.15,T_{ci}^{*}=T_{ci}+273.15,$

$\frac{1}{F_{tci}}=\frac{1}{{\mathrm{\ϵ}}_o}+\frac{r_{to}}{r_{ci}}(\frac{1}{{\mathrm{\ϵ}}_{ci}}-1),$

Wherein, δ represents Stefan-Boltzmann constant; F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 instlated tubular outer wall blackness; ε _cirepresent internal surface of sleeve pipe blackness; r _torepresent outer tube outer wall radius;

Adopt following formulae discovery free convection heat transfer coefficient h _c1:

$h_{c1}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{to}\ln \frac{r_{ci}}{r_{to}}},$

$G_r=\frac{{(r_{ci}-r_{to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{to}-T_{ci})}{U_{an}^2},$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}},$

Wherein, G _rrepresent Grashof number; P _rrepresent Prandtl number; K _harepresent the coefficient of thermal conductivity of the air of oil jacket annular space; G represents acceleration of gravity; ρ _anrepresent that the air of oil jacket annular space is at average temperature T _anunder density; U _anrepresent that the air of oil jacket annular space is at average temperature T _anunder viscosity; C _anrepresent that the air of oil jacket annular space is at average temperature T _anunder thermal capacitance; β represents the thermal cubic expansion coefficient of air in oil jacket annular space.

6. method according to claim 1, is characterized in that, the thermal resistance R between the outer tube inside and outside wall adopting following formulae discovery instlated tubular ₅:

$R_5=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_o}{r_i},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _orepresent instlated tubular outer tube outer wall radius; r _irepresent instlated tubular outer tube wall radius.

7. method according to claim 1, is characterized in that, adopts the thermal resistance R of following formulae discovery isolation layer ₆:

$R_6=\frac{1}{2{\mathrm{\πK}}_{ins}}ln\frac{r_i}{r_{to\_w}},$

Wherein, K _insrepresent instlated tubular coefficient of thermal conductivity; r _irepresent instlated tubular outer tube wall radius; r _{to_w}represent instlated tubular outer wall of inner tube radius.

8. method according to claim 1, is characterized in that, the thermal resistance R between the interior pipe inside and outside wall adopting following formulae discovery instlated tubular ₇:

$R_7=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_w}}{r_{ti\_w}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _{to_w}represent instlated tubular outer wall of inner tube radius; r _{ti_w}represent instlated tubular inner tube wall radius.

9. method according to claim 1, is characterized in that, adopts the thermal resistance R between following formulae discovery screen casing inside and outside wall ₈:

$R_8=\frac{1}{2{\mathrm{\πK}}_{sie}}ln\frac{r_{to\_s}}{r_{ti\_s}},$

Wherein, K _sierepresent screen casing coefficient of thermal conductivity; r _{to_s}represent screen casing exterior radius; r _{ti_s}represent screen casing inwall radius.

10. method according to claim 1, is characterized in that, adopts the thermal resistance R between following formulae discovery oil pipe inside and outside wall ₉:

$R_9=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{to\_t}}{r_{ti\_t}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _{ti_t}represent tube inner wall radius; r _{to_t}represent oil-pipe external wall radius.

11. methods according to claim 1, is characterized in that, adopt pipe and the air thermal resistance R in outer tube annular space in following formulae discovery ₁₀:

$R_{10}=\frac{1}{2\mathrm{\π}(h_{c2}+h_{r2})r_{n\_to}},$

Wherein, h _c2the free convection heat transfer coefficient with air in outer tube annular space is managed in representing; h _r2the heat radiation thermal transmittance with air in outer tube annular space is managed in representing; r _{n_to}represent outer wall of inner tube radius;

Adopt following formulae discovery heat radiation thermal transmittance h _r2:

$h_{r2}={\mathrm{\δF}}_{tci}(T_{n\_to}^{*2}+T_{ti}^{*2})(T_{n\_to}^{*}+T_{ti}^{*}),$

$T_{n\_to}^{*}=T_{n\_to}+273.15,T_{ti}^{*}=T_{ti}+273.15,$

$\frac{1}{F_{tci}}=\frac{1}{{\mathrm{\ϵ}}_{n\_to}}+\frac{r_{n-to}}{r_{ti}}(\frac{1}{{\mathrm{\ϵ}}_{ti}}-1),$

Wherein, δ represents Stefan-Boltzmann constant; F _tcirepresent that oil pipe or instlated tubular outer wall surface are 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 outer wall of inner tube blackness; ε _tirepresent outer tube wall blackness; r _tirepresent outer tube wall radius;

Adopt following formulae discovery free convection heat transfer coefficient h _c2:

$h_{c2}=\frac{0.049{\left(G_r{P}_r\right)}^{0.33}{P}_r^{0.074}{K}_{ha}}{r_{n\_to}\ln \frac{r_{ti}}{r_{n\_to}}},$

$G_r=\frac{{(r_{ti}-r_{n\_to})}^3{\mathrm{g\ρ}}_{an}^2\mathrm{\β}(T_{n\_to}-T_{ti})}{U_{an}^2},$

$P_r=\frac{C_{an}-U_{an}}{K_{ha}},$

Wherein, G _rrepresent Grashof number; P _rrepresent Prandtl number; K _hathe coefficient of thermal conductivity with air in outer tube annular space is managed in representing; G represents acceleration of gravity; ρ _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder density; U _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder viscosity; C _anin representing, pipe and air in outer tube annular space are at average temperature T _anunder thermal capacitance; β represents the thermal cubic expansion coefficient of air in interior pipe and outer tube annular space.

12. methods according to claim 1, is characterized in that, adopt the thermal resistance R between pipe inside and outside wall in following formulae discovery ₁₁:

$R_{11}=\frac{1}{2{\mathrm{\πK}}_{tub}}ln\frac{r_{n\_to}}{r_{n\_ti}},$

Wherein, K _tubrepresent oil pipe coefficient of thermal conductivity; r _{n_ti}represent inner tube wall radius; r _{n_to}represent outer wall of inner tube radius.

13. methods according to claim 1, is characterized in that, adopt the thermal convection current thermal resistance R of inner air tube in following formulae discovery ₁₂:

$R_{12}=\frac{r_{n\_to}}{2{\mathrm{\πh}}_f{r}_{n\_ti}},$

Wherein, h _fthe coefficient of thermal conductivity coefficient of inner air tube in representing; r _{n_ti}represent inner tube wall radius; r _{n_to}represent outer wall of inner tube radius.

14. methods according to claim 1, is characterized in that, according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically, comprising:

Adopt the entire thermal resistance of following formulae discovery first paragraph pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₅+R ₆+R ₇+R ₁₀+R ₁₁+R ₁₂，

Adopt the entire thermal resistance of following formulae discovery second segment pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₈+R ₁₀+R ₁₁+R ₁₂，

Adopt the entire thermal resistance of following formulae discovery the 3rd section of pit shaft:

R＝R ₁+R ₂+R ₃+R ₄+R ₉+R ₁₀+R ₁₁+R ₁₂，

Wherein, described first paragraph pit shaft is this section of pit shaft that described instlated tubular is corresponding; Described second segment pit shaft is this section of pit shaft that described screen casing is corresponding; Described 3rd section of pit shaft from described oil pipe top to described interior pipe bottom.

15. methods according to claim 1, is characterized in that, according to described temperature T _s, described entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically, comprising:

According to law of conservation of energy, adopt heat waste described in following formulae discovery:

$Q=\frac{T_s-T_e}{R}dl,$

Wherein, Q represents pit shaft unit radial heat waste; T _erepresent formation temperature; R represents pit shaft unit radial entire thermal resistance.

16. methods according to claim 1, is characterized in that, according to described temperature T _s, described heat waste and described electric igniter power, the air themperature of pipe in calculating, comprising:

Following formulae discovery is adopted to be in the air themperature of the interior pipe of first paragraph pit shaft:

CmT _s-Q/1000+0.6P＝CmT _s'，

Following formulae discovery is adopted to be in the air themperature of the interior pipe of second segment pit shaft and the 3rd section of pit shaft:

CmT _s-Q/1000＝CmT _s'，

Wherein, T _s' represent the air themperature after change in interior pipe; C represents the specific heat capacity of air; M represents the mass flow of air; P represents the power of electric igniter; Q represents pit shaft unit radial heat waste; Described first paragraph pit shaft is this section of pit shaft that described instlated tubular is corresponding; Described second segment pit shaft is this section of pit shaft that described screen casing is corresponding; Described 3rd section of pit shaft from described oil pipe top to described interior pipe bottom.

17. methods according to claim 1, is characterized in that, adopt the air themperature of pipe and outer tube annular space in following formulae discovery:

T _H＝T _s-(R ₁₀+R ₁₁+R ₁₂)×Q/dl，

Wherein, T _hthe air themperature of pipe and outer tube annular space in representing; Q represents pit shaft unit radial heat waste.

18. methods according to claim 1, is characterized in that, adopt the change of following formulae discovery formation temperature in step 8:

T _e＝T _ins+αdl，

Wherein, T _insrepresent surface temperature; α represents geothermal gradient; T _erepresent formation temperature.

19. methods according to claim 1, is characterized in that, adopt following formulae discovery to be injected into the temperature T of air after described electric igniter heating of described interior pipe _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 the power of electric igniter.

20. 1 kinds of combustion in situ layering electric ignition gas injection well well bore temperature distribution determining devices, is characterized in that, comprising:

Division unit, for this section of pit shaft bottom the burning torch top of electric igniter to interior pipe is divided into multiple pit shaft unit in the axial direction, the length of each pit shaft unit is dl, makes l=0, k=1, and wherein, l represents the length of current calculating, and k represents iterations;

First computing unit, for calculating the temperature T of air after described electric igniter heating being injected into described interior pipe _s;

Second computing unit, for calculating the thermal resistance R on stratum respectively ₁, cement sheath thermal resistance R ₂, thermal resistance R between sleeve pipe inside and outside wall ₃, air in oil jacket annular space and the thermal resistance R between sleeve pipe ₄, instlated tubular outer tube inside and outside wall between thermal resistance R ₅, isolation layer thermal resistance R ₆, instlated tubular interior pipe inside and outside wall between thermal resistance R ₇, thermal resistance R between screen casing inside and outside wall ₈, thermal resistance R between oil pipe inside and outside wall ₉, air thermal resistance R in interior pipe and outer tube annular space ₁₀, thermal resistance R between interior pipe inside and outside wall ₁₁and the thermal convection current thermal resistance R of interior inner air tube ₁₂; Wherein, described gas injection well pit shaft radially comprises from the inside to the outside successively: interior pipe, outer tube, sleeve pipe and cement sheath, and described outer tube comprises along well head successively to direction, shaft bottom: instlated tubular, screen casing and oil pipe, and described gas injection well pit shaft outside is stratum;

3rd computing unit, for according to R ₁to R ₁₂calculate pit shaft entire thermal resistance diametrically;

4th computing unit, for according to described temperature T _s, described entire thermal resistance and formation temperature, calculate pit shaft heat waste diametrically;

5th computing unit, for according to described temperature T _s, described heat waste and described electric igniter power, the air themperature of pipe in calculating;

6th computing unit, for according to described temperature T _s, described heat waste and R ₁₀to R ₁₂, the air themperature of pipe and outer tube annular space in calculating;

Iterative computation unit, for making l=l+dl, k=k+1, according to the change of formation temperature, the second computing unit is utilized to carry out iterative computation, until l >=L to the 6th computing unit, then iteration terminates, obtain the temperature distribution history of described interior pipe and the temperature distribution history of described outer tube, wherein, L represents that well head arrives the length bottom interior pipe.