CN102011573A - Method for uniformly injecting multi-component thermal fluid in horizontal well - Google Patents

Abstract

The invention provides a method for uniformly injecting a multi-component thermal fluid in a horizontal well. The method comprises the following steps: (1) segmenting horizontal segments in the horizontal well; (2) initially setting the size of each discharge orifice on a tubular column in each segment of the horizontal well and the number of discharge orifices at a tail end; (3) detecting the temperature, pressure and dryness of the multi-component thermal fluid; (4) obtaining the on-way temperature, pressure, dryness and heat loss of each shaft segment of the horizontal well by iterative calculation; (5) obtaining the actual number of the discharge orifices on the tubular column in each segment of the horizontal well and the size of each discharge orifice by iterative calculation; and (6) drilling the tubular column based on the calculation result, putting the tubular column subject to drilling down into the well, and injecting the multi-component thermal fluid in the tubular column. The invention has the advantages of wide oil pool application range, relatively simple technology and low cost, and ensures that the oil pool at the horizontal well segment can be subject to uniform steam injection without changing the traditional well orifices and steam injection pipes. Besides, by using the invention, the producing degree of the oil reservoir is improved and the optimal exploitation effect can be ensured by injecting the multi-component thermal fluid in the horizontal well of the exploited oil pool.

Description

A kind of method of in horizontal well, evenly injecting multielement hot fluid

Technical field

The present invention relates to the heavy crude heat extraction technology, relate in particular to a kind of method of in horizontal well, evenly injecting multielement hot fluid.

Background technology

Present marine viscous crude field is being carried out multielement hot fluid (N ₂+ CO ₂+ steam) application test of handling up.Horizontal well field measurement and analog study both at home and abroad shows, horizontal well is generally annotated way of steam and is caused easily that advance by leaps and bounds in net horizontal section gas part, oil reservoir is employed inhomogeneous, the horizontal segment oil reservoir has been employed the 1/3-1/2 that the well section only accounts for horizontal section length, and, the horizontal segment oil reservoir is employed uneven can the aggravation with the increase in the vapour cycle of showwing loving care for, even causes local vapour to scurry and water outlet.

External Canada and domestic Liaohe Oil Field primary study and used the two-tube steam injection technology technology of horizontal well, adopt the inner and outer pipes mode respectively horizontal well heel and end to be annotated vapour, steam injects from two passages, one is that 1.9 " integral joint tubing is injected into the horizontal segment tiptoe; one is that 41/2 " vacuum heat insulation tube and 1.9 " integral joint tubing annular space well is annotated heel from the bottom; carry out flow-control by ground flow mediation valve door, realize two controls that go out vapour point different displacements from top.Two-tube steam injection technology can realize annotating the dynamic adjustment of vapour amount at well head, and notes vapour utilization rate is improved, and has improved the horizontal well development effect to a certain extent, but technical requirements and cost height.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of oil reservoir wide accommodation, and application process is simple, cost is low, does not need the method for evenly injecting multielement hot fluid in horizontal well that changes existing well head and annotate steam pipe.

In order to address the above problem, the invention provides a kind of method of in horizontal well, evenly injecting multielement hot fluid, may further comprise the steps:

(1) measures the horizontal well entire length, and horizontal segment in the horizontal well is carried out segmentation according to measurement result;

(2) measure the horizontal well internal diameter, and discharge orifice size and terminal discharge orifice number on the tubing string in each section horizontal well are carried out initial setting according to measurement result;

(3) detect multielement hot fluid temperature, pressure and the mass dryness fraction of preparing injection;

(4) according to testing result in the step (3) and horizontal well along each section of journey characteristic iterative computation horizontal well pit shaft along Cheng Wendu, pressure, mass dryness fraction and heat waste, wherein, pit shaft is along the journey temperature loss:

$q^{\′}=-\frac{{\mathrm{dH}}_m}{\mathrm{dz}}+G_{\mathrm{tol}}g$

In the following formula, q ' is the heat waste of pit shaft unit length;

H _mTotal energy for multielement hot fluid;

G _TolBe the multielement hot fluid mass flow;

G is an acceleration of gravity;

Z is a well depth;

Wellbore pressure is:

$\frac{\mathrm{dp}}{\mathrm{dz}}={\mathrm{\&rho;}}_{m}g\sin \mathrm{\&theta;}-\mathrm{\&lambda;}\frac{{\mathrm{\&rho;}}_m{u}_{\mathrm{<figure-callout\; id="2"\; label="m"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">m</figure-callout>}}^2}{2d}$

In the following formula, p is a pressure;

ρ _mBe multielement hot fluid density;

G is an acceleration of gravity;

Z is a well depth;

θ is a hole angle;

λ is a resistance coefficient;

u _mBe multielement hot fluid speed;

D is a tubing diameter.

The mass dryness fraction design formulas:

$\frac{\mathrm{dx}}{\mathrm{dz}}=\frac{c_1{M}_{H_{2}O}}{G_{H_{2}O}}\frac{1}{{\left({p-p}_w\right)}^2}(p\frac{{\mathrm{dp}}_w}{\mathrm{dT}}\frac{\mathrm{dT}}{\mathrm{dz}}-p_w\frac{\mathrm{dp}}{\mathrm{dz}})$

In the following formula, χ is a steam quality;

Z is a well depth;

Be the saturation water mass flow;

Molal weight for water;

P is a pressure;

p _wBe water saturation pressure;

T is the multielement hot fluid temperature;

Steam to the heat output of cement sheath outer rim in the dz section is in the oil pipe:

dQ＝2πr _toU _to(T _s-T _h)dz

In the following formula, Q is the pit shaft radial flow heat;

r _To-oil pipe external diameter;

U _To-overall coefficient of heat transfer;

T _h-cement sheath outer rim temperature;

T _s-multielement hot fluid temperature;

Z is a well depth.

Heat conduction from the cement sheath outer rim to the stratum is:

dQ＝2πλ _e(T _h-T _e)dz/f(t)

In the following formula, Q is the pit shaft radial flow heat;

λ _e-stratum thermal transmittance;

T _e-surface temperature;

T _h-cement sheath outer rim temperature;

F (t)-nondimensional time function;

Z is a well depth;

(5) according to initial set value in result of calculation in the step (4) and step (1), (2) and evenly inject the principle iteration and calculate actual discharge orifice number and discharge orifice size on every section horizontal well tubing string, wherein, i section discharge orifice diameter is:

$d_i=2\sqrt{\frac{q}{{\mathrm{n\&pi;v}}_{o\left(i\right)}}}$

In the following formula, d _iIt is i section discharge orifice diameter;

Q is the multielement hot fluid flow;

N is the horizontal segment segments;

v _{O (i)}It is i section discharge orifice discharge velocity.

I section discharge orifice number is:

$N_i=\frac{\mathrm{\&pi;}{\left(\frac{d_i}{2}\right)}^2}{A_1}=\frac{q}{{\mathrm{nv}}_{o\left(i\right)}{A}_1}$

In the following formula, d _iIt is i section discharge orifice diameter;

A ₁For presetting the discharge orifice area;

Q is the multielement hot fluid flow;

N is the horizontal segment segments;

v _{O (i)}It is i section discharge orifice discharge velocity;

(6) according to result of calculation in the step (5) tubing string is punched, will punch in the tubing string lower going-into-well of back, then multielement hot fluid is injected this tubing string.

Further, according to the principle of one section in every 50-70 rice horizontal well is carried out segmentation in the described step (1).

Further, setting the discharge orifice size in the described step (2) is 1-2 centimetre.

Further, set terminal discharge orifice number according to the maximum speed limit of discharge orifice in the described step (2).

Further, adopt thermometer, pressure to take into account temperature, pressure and mass dryness fraction that hygrometer detects the multielement hot fluid of preparing injection in the described step (3) respectively.

Further, on tubing string, carry out 360 degree spiral punchings in the described step (5).

The present invention has following advantage:

1, the present invention is according to horizontal well and each parameter measurements of multielement hot fluid are calculated along Cheng Wendu, pressure, mass dryness fraction and heat waste horizontal well, and according to discharge orifice size and number on the tubing string in the result of calculation correction horizontal well, to reach the purpose of even heated fluid injection in horizontal well, its oil reservoir wide accommodation, and technology is simple relatively, cost is low, do not need to change existing well head and annotate steam pipe, can make the net horizontal section oil reservoir evenly inhale vapour, improve the development degree of oil reservoir, guarantee that horizontal well injects multi-element fluid exploitation oil reservoir and reaches best exploitation effect.

2, application process of the present invention is simple, reliable, can realize automation mechanized operation, and the present invention and can using in multiple different occasions only needs to adjust measurement parameter, and dependability height of the present invention is effective.

Description of drawings

Below in conjunction with accompanying drawing embodiments of the present invention are described further:

Fig. 1 shows horizontal well casing programme schematic diagram;

Fig. 2 shows horizontal segment and evenly injects schematic diagram.

The specific embodiment

The present invention includes following steps:

(1) measures the horizontal well entire length, and horizontal segment in the horizontal well is carried out segmentation according to measurement result.

The horizontal well casing programme comprises well head 1, pit shaft 2 and horizontal segment 3 as shown in Figure 1, and horizontal segment 3 tubing strings 6 are provided with discharge orifice 4.Major length is a horizontal section length herein, can realize even injection in order to make horizontal segment, and in the homogeneous oil reservoir, general every 50-70 rice is divided into one section.

(2) measure the horizontal well internal diameter, and discharge orifice size and terminal discharge orifice number on the tubing string in each section horizontal well are carried out initial setting according to measurement result.

Horizontal segment evenly injects as shown in Figure 2, and multielement hot fluid 5 injection strings 6 are provided with discharge orifice 4 on the tubing string 6, and multielement hot fluid 5 enters annular space 8 between tubing string 6 and the screen casing 7 by discharge orifice 4, also piles up layer of gravel 10 between screen casing 7 and the stratum 9.

Discharge orifice size too conference influences the injection string structural performance; The discharge orifice size is too little, and the discharge orifice chock pressure difference is big, effluxvelocity is big, and screen casing is caused certain impact, and therefore, general discharge orifice size dimension is arranged on 1-2 centimetre.Terminal discharge orifice number will according to the injection string end whether opening, the maximum speed limit of discharge orifice (＜30m/s) be provided with.

(3) detect multielement hot fluid temperature, pressure and the mass dryness fraction of preparing injection.

Adopt thermometer, pressure to take into account temperature, pressure and mass dryness fraction that hygrometer detects the multielement hot fluid of preparing injection respectively.

(4) according to testing result in the step (3) and horizontal well along each section of journey characteristic iterative computation horizontal well pit shaft along Cheng Wendu, pressure, mass dryness fraction and heat waste.

Because Calculation of Heat loss relates to pressure, temperature and the mass dryness fraction of multielement hot fluid, pressure, temperature and the mass dryness fraction that therefore must calculate multielement hot fluid earlier distribute; And to determine pressure, temperature and the mass dryness fraction in shaft bottom, just must fall according to the charge velocity of multielement hot fluid and the heat waste and the pressure of shaft column calculation of parameter pit shaft.This shows that pit shaft multielement hot fluid pressure, temperature, mass dryness fraction and Calculation of Heat loss intercouple, the calculating of each will could be determined through iteration.

(A) wellbore pressure calculates

It is the synthesis result of friction loss, potential variation and kinetic energy change that the pressure of the interior gas-liquid phase pipe of pit shaft falls, and the momentum balance equation of being followed is (get and to be positive direction vertically downward):

$\frac{\mathrm{dp}}{\mathrm{dz}}={\mathrm{\&rho;}}_{m}g\sin \mathrm{\&theta;}-\mathrm{\&lambda;}\frac{{\mathrm{\&rho;}}_m{u}_m^2}{2d}---\left(1\right)$

(B) the pit shaft mass dryness fraction is calculated

Multielement hot fluid flowing in pit shaft for two-phase, multi-component complexity flow, liquid phase is a water, and gas phase is by saturated vapour, N ₂, CO ₂The mist of forming, by law of partial pressure as can be known: the partial pressure of saturated vapour is directly proportional with shared mole percent:

$y_{H_{2}O}^{\&prime;\&prime;}=p_w\left(T\right)/p=\frac{G_{H_{2}O}^{\&prime;\&prime;}}{M_{H_{2}O}}/[\frac{G_{H_{2}O}^{\&prime;\&prime;}}{M_{H_{2}O}}+\frac{G_{{\mathrm{CO}}_2}}{{\mathrm{<figure-callout\; id="2"\; label="M\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{\mathrm{CO}}_{}}}+\frac{G_{N_2}}{M_{N_2}}]---\left(2\right)$

Wherein, steam saturation pressure p _wCan try to achieve by water vapour character.

Order $c_1=[\frac{G_{{\mathrm{CO}}_2}}{{\mathrm{<figure-callout\; id="2"\; label="M\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">M</figure-callout>}}_{{\mathrm{CO}}_{}}}+\frac{G_{N_2}}{M_{N_2}}]$

If this moment, steam quality was x, then have

The arrangement of substitution (2) formula can get:

$\frac{p_w\left(T\right)}{p}=\frac{{\mathrm{xG}}_{H_{2}O}}{M_{H_{2}O}{c}_1}---\left(3\right)$

Because T is the function of z, x, p also are the functions of z, p _wBe the function of T,, can obtain the mass dryness fraction design formulas formula (3) differentiate:

$\frac{\mathrm{dx}}{\mathrm{dz}}=\frac{c_1{M}_{H_{2}O}}{G_{H_{2}O}}\frac{1}{{\left({p-p}_w\right)}^2}(p\frac{{\mathrm{dp}}_w}{\mathrm{dT}}\frac{\mathrm{dT}}{\mathrm{dz}}-p_w\frac{\mathrm{dp}}{\mathrm{dz}})---\left(4\right)$

(C) temperature in wellbore is calculated

According to energy-balance equation, the heat waste in the pit shaft unit interval, on the unit length equals in the unit interval, the minimizing of multielement hot fluid energy on the unit length, promptly (ignores kinetic energy rejection):

$q^{\&prime;}=-\frac{{\mathrm{dH}}_m}{\mathrm{dz}}+\mathrm{Gg}---\left(5\right)$

Wherein, $H_m=G_{{\mathrm{CO}}_2}{h}_{{\mathrm{CO}}_2}\left(T\right)+G_{N_2}{h}_{N_2}\left(T\right)+(1-x)G_{H_{2}O}{h}_{H_{2}o}^{\&prime;}\left(T\right)+x{G}_{H_{2}O}{h}_{H_{2}O}^{\&prime;\&prime;}\left(T\right)$

Differentiate gets to formula (5):

$\frac{{\mathrm{dH}}_m}{\mathrm{dz}}={\mathrm{<figure-callout\; id="2"\; label="G\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_{{\mathrm{CO}}_{}}\frac{{\mathrm{<figure-callout\; id="2"\; label="dh\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">dh</figure-callout>}}_{{\mathrm{CO}}_{}}}{\mathrm{dT}}+{\mathrm{<figure-callout\; id="2"\; label="G\; N"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_{N_{}}\frac{{\mathrm{<figure-callout\; id="2"\; label="dh\; N"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">dh</figure-callout>}}_{N_{}}}{\mathrm{dT}}+[(1+x)G_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}o}^{\&prime;}}{\mathrm{dT}}+x{G}_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}O}^{\&prime;\&prime;}}{\mathrm{dT}}]\frac{\mathrm{dT}}{\mathrm{dZ}}+r{G}_{H_{2}O}\frac{\mathrm{dx}}{\mathrm{dz}}---\left(6\right)$

Wherein, r=h " (T)-h ' (T), will can obtain the temperature computation formula after formula (6) substitution formula (5) arrangement:

$\frac{\mathrm{dT}}{\mathrm{dz}}=[{\mathrm{rc}}_1\frac{M_{H_{2}O}}{{\left({p-p}_w\right)}^2}{p}_w\frac{\mathrm{dp}}{\mathrm{dz}}+\mathrm{Gg}-q_1]/c_2---\left(7\right)$

Wherein, ${\mathrm{<figure-callout\; id="2"\; label="c"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">c</figure-callout>}}_2={\mathrm{<figure-callout\; id="2"\; label="G\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_{{\mathrm{CO}}_{}}\frac{{\mathrm{<figure-callout\; id="2"\; label="dh\; CO"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">dh</figure-callout>}}_{{\mathrm{CO}}_{}}}{\mathrm{dT}}+{\mathrm{<figure-callout\; id="2"\; label="G\; N"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">G</figure-callout>}}_{N_{}}\frac{{\mathrm{<figure-callout\; id="2"\; label="dh\; N"\; filenames="HDA0000039417350000011.png"\; state="\{\{state\}\}">dh</figure-callout>}}_{N_{}}}{\mathrm{dT}}+(1-x)G_{H_{2}O}\frac{{\mathrm{dh}}_{H_2{o}^{\&prime;}}^{\&prime;}}{\mathrm{dT}}+x{G}_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}O}^{\&prime;\&prime;}}{\mathrm{dT}}+r{c}_{1}p\frac{M_{H_{2}O}}{{\left({p-p}_w\right)}^2}\frac{{\mathrm{dp}}_w}{\mathrm{dT}}$

Simultaneous formula (1), (4), (7) have promptly constituted multielement hot fluid two phase flow temperature, pressure and mass dryness fraction Mathematical Modeling.

(D) wellbore heat loss calculation

Adopt the method for Ramey (1962 by U.S. professor Ramey proposition) and Satter (nineteen sixty-five Satter improves and promotes) on the basis of Ramey method, regard by of the one dimension steady state heat conduction of oil pipe center radially conducting heat of heat waste as the cement sheath outer rim formed to the one dimension unsteady heat transfer two parts between the stratum to the cement sheath outer rim; And radially heat waste is along the well depth direction, and time dependent; Suppose that in the unit interval heat waste on the pit shaft segment length dz is dQ.

A) the oil pipe center is to the heat transfer of cement sheath outer rim

Steam to the heat output of cement sheath outer rim in the dz section is in the oil pipe:

dQ＝2πr _toU _to(T _s-T _h)dz (8)

Wherein, $U_{\mathrm{to}}=r_{\mathrm{to}}[\frac{1}{r_{\mathrm{ti}}{h}_f}+\frac{\ln \frac{r_{\mathrm{to}}}{r_{\mathrm{ti}}}}{{\mathrm{\&lambda;}}_{\mathrm{tub}}}+\frac{\ln \frac{r_i}{r_{\mathrm{to}}}}{{\mathrm{\&lambda;}}_{\mathrm{ins}}}+\frac{1}{r_i(h_c+h_r)}+\frac{\ln \frac{r_{\mathrm{co}}}{r_{\mathrm{ci}}}}{{\mathrm{\&lambda;}}_{\mathrm{cas}}}+\frac{\ln \frac{r_h}{r_{\mathrm{co}}}}{{\mathrm{\&lambda;}}_{\mathrm{cem}}}]$

Every thermal resistance that is respectively thermal resistance, casing wall thermal resistance and the cement sheath of tube inner wall Forced Convection Heat Transfer thermal resistance, tubing wall thermal resistance, annulus fluid or gas in the bracket.

B) heat conduction from the cement sheath outer rim to the stratum

Owing to be unsettled conduction of heat, the heat waste on stratum is begun greatly, but with the carrying out of the vapour of showwing loving care for, formation temperature increases, heat transfer power temperature difference T will reduce, and cause the heat waste reduction.

Be formulated as:

dQ＝2πλ _e(T _h-T _e)dz/f(t) (9)

Wherein,

Be the nondimensional time function.

(5) according to initial set value in result of calculation in the step (4) and step (1), (2) and evenly inject the principle iteration and calculate actual discharge orifice number and discharge orifice size on every section horizontal well tubing string.

Distribute along Cheng Wendu, pressure and mass dryness fraction according to the pit shaft of trying to achieve,, evenly be injected to prerequisite, anti-horizontal segment every section required discharge orifice size, number and discharge velocity of pushing away with every section in conjunction with horizontal segment segments and terminal discharge orifice size, number.

(A) assumed condition

In order to make multielement hot fluid evenly inject the stratum, must satisfy 2 conditions along whole horizontal segment:

A) a level injection section oil jacket annular space internal pressure equates, and more than or equal to strata pressure+injecting multielement hot fluid pressure reduction, i.e. (n is that horizontal segment evenly injects segments):

p _o1＝p _o2＝…＝p _oi＝…＝p _on＝p _o (10)

B) each section of horizontal segment injection rate equates, promptly

q ₁＝q ₂＝…＝q _i＝…＝q _n＝q/n (11)

(B) the even injection parameter of horizontal segment is found the solution

When multielement hot fluid flowed at horizontal segment, its fluidised form was a turbulent flow, between venthole n-1 and the n along the stroke pressure loss was:

$p_{i-1}-p_i=\frac{8\mathrm{gl}}{C^{2}R}\frac{{\mathrm{\&upsi;}}_i^2}{2g}{\mathrm{\&rho;}}_{m}g$ (i＝1、2...n) (12)

Wherein,

J=0.01～0.02,

υ _iBe multielement hot fluid flow velocity in the i section ascending pipe, its design formulas:

Simultaneously by the local pressure loss formula:

$p_{i-1}-p_i=\mathrm{\&lambda;}\frac{l}{4R}\frac{{\mathrm{\&upsi;}}_i^2}{2g}{\mathrm{\&rho;}}_{m}g---\left(13\right)$

Therefore, $\mathrm{\&zeta;}\frac{v_{o(i-1)}^2}{2g}{\mathrm{\&rho;}}_{m}g=\mathrm{\&zeta;}\frac{v_{o\left(i\right)}^2}{2g}{\mathrm{\&rho;}}_{m}g+\frac{8\mathrm{gl}}{C^{2}R}\frac{{\mathrm{\&upsi;}}_i^2}{2g}{\mathrm{\&rho;}}_{m}g---\left(14\right)$

Then, i-1 section discharge orifice discharge velocity is:

$v_{o(i-1)}=\sqrt{\frac{\mathrm{\&zeta;}{v}_{o(i}^2)+\frac{8\mathrm{gl}}{C^{2}R}{\mathrm{\&upsi;}}_i^2}{\mathrm{\&zeta;}}}---\left(15\right)$

Wherein, v _{O (n)}Can try to achieve according to terminal discharge orifice size, number,, can obtain every section discharge orifice muzzle velocity one by one therefore according to counter the pushing away of formula (15).

Because every section is evenly injected (injection rate is known), then by i section discharge orifice discharge velocity formula, can try to achieve the diameter of this section discharge orifice:

$d_i=2\sqrt{\frac{q}{\mathrm{n\&pi;}{v}_{o\left(i\right)}}}---\left(16\right)$

According to presetting the discharge orifice area A ₁, the required discharge orifice number of i section then:

$N_i=\frac{\mathrm{\&pi;}{\left(\frac{d_i}{2}\right)}^2}{A_1}=\frac{q}{{\mathrm{nv}}_{o\left(i\right)}{A}_1}---\left(17\right)$

Horizontal segment every section required discharge orifice size, number and earial drainage speed can be tried to achieve in simultaneous formula (15), (16), (17), and the horizontal segment segments, terminal discharge orifice number and the discharge orifice size that are provided with in the integrating step 1.

(6) according to result of calculation in the step (5) tubing string is punched, will punch in the tubing string lower going-into-well of back, then multielement hot fluid is injected this tubing string.

According to every section discharge orifice parameter, on the horizontal segment injection string, carry out 360 degree spiral punchings, be lowered to the even injection that this tubing string just can be realized multielement hot fluid.

The present invention is according to horizontal well and each parameter measurements of multielement hot fluid are calculated along Cheng Wendu, pressure, mass dryness fraction and heat waste horizontal well, and according to discharge orifice size and number on the tubing string in the result of calculation correction horizontal well, to reach the purpose of even heated fluid injection in horizontal well, its oil reservoir wide accommodation, and technology is simple relatively, cost is low, do not need to change existing well head and annotate steam pipe, can make the net horizontal section oil reservoir evenly inhale vapour, improve the development degree of oil reservoir, guarantee that horizontal well injects multi-element fluid exploitation oil reservoir and reaches best exploitation effect.

Elaborate below in conjunction with a specific embodiment:

One horizontal well implementing plan multielement hot fluid injects operation, and its well head injection parameter (temperature: 140 ℃, pressure: 8MPa), multielement hot fluid component (N ₂: 687Nm ³/ h, CO ₂: 147Nm ³/ h and water: 6.9t/h), heat injection pipe string combination and heat insulation mode: " vacuum heat-insulation oil pipe+annular space fills nitrogen, well vertical section: 500m, inclination section: 700, horizontal segment: 310m (horizontal segment end openings) to adopt 4-1/2.

1, horizontal segment segments, terminal discharge orifice number and size are provided with

Every section product degree of horizontal segment is set to 62m, and then the horizontal segment segments is: the 310m/62m=5 section; Terminal discharge orifice number is set to 40, and its size is 10mm.

2, associating pressure, temperature and heat waste design formulas, every section pressure of iterative computation pit shaft, temperature, heat waste, enthalpy, thermal transmittance, fluidised form distribute, and result of calculation is as shown in table 2.

Table 2 pit shaft is along the journey parameter distribution

The degree of depth	Pressure	Temperature	Heat waste	The steam enthalpy	Thermal transmittance	Fluidised form
							0	7.9178	139.136	0.00E+00	5.72E+02	0.836	GAP
41.64	8.0847	138.742	2.29E-01	5.70E+02	0.836	GAP
							71.08	8.2103	138.464	4.58E-01	5.69E+02	0.836	GAP
100.52	8.3371	138.187	6.87E-01	5.68E+02	0.835	GAP

129.96	8.4649	137.912	9.14E-01	5.67E+02	0.835	GAP
							159.4	8.5939	137.637	1.14E+00	5.66E+02	0.835	GAP
188.84	8.7239	137.362	1.37E+00	5.65E+02	0.835	GAP
							218.28	8.8551	137.089	1.59E+00	5.64E+02	0.834	GAP
247.72	8.9873	136.816	1.82E+00	5.63E+02	0.834	GAP
							277.16	9.1207	136.544	2.04E+00	5.62E+02	0.834	GAP
306.6	9.2551	136.273	2.27E+00	5.61E+02	0.834	GAP
							336.04	9.3905	136.003	2.49E+00	5.60E+02	0.833	GAP
365.48	9.527	135.733	2.71E+00	5.59E+02	0.833	GAP
							394.92	9.6646	135.465	2.94E+00	5.58E+02	0.833	GAP
424.36	9.8032	135.197	3.16E+00	5.57E+02	0.833	GAP
							453.8	9.9428	134.929	3.38E+00	5.56E+02	0.832	GAP
483.24	10.0834	134.663	3.60E+00	5.55E+02	0.832	GAP
							512.68	10.2251	134.397	3.82E+00	5.54E+02	0.832	GAP
542.12	10.3678	134.132	4.04E+00	5.53E+02	0.831	GAP
							571.56	10.5115	133.868	4.26E+00	5.52E+02	0.831	GAP
601	10.6562	133.605	4.64E+00	5.51E+02	0.831	GAP
							645	10.8742	133.213	4.97E+00	5.50E+02	0.831	GAP
689	11.123	132.82	5.31E+00	5.49E+02	0.83	GAP
							733	11.3994	132.426	5.64E+00	5.47E+02	0.83	GAP
777	11.6907	132.033	5.98E+00	5.46E+02	0.829	GAP

821	11.981	131.642	6.31E+00	5.44E+02	0.829	GAP
							865	12.2572	131.254	6.64E+00	5.43E+02	0.829	GAP
909	12.521	130.869	6.97E+00	5.42E+02	0.828	GAP
							953	12.7936	130.485	7.29E+00	5.40E+02	0.828	GAP
997	13.0702	130.102	7.62E+00	5.39E+02	0.828	GAP
							1041	13.2781	129726	7.95E+00	5.37E+02	0.827	GAP
1085	13.4285	129357	8.27E+00	5.36E+02	0.827	GAP
							1129	13.5472	128992	8.59E+00	5.35E+02	0.826	GAP
1173	13.6108	128634	8.91E+00	5.33E+02	0.826	GAP
							1200	13.6309	128.28	9.23E+00	5.32E+02	0.826	SLUG

3, according to the even injection parameter design formulas of horizontal segment, every section discharge orifice number of calculated level section, discharge orifice size and earial drainage speed, result of calculation is as shown in table 3, at last according to this uniform Design parameter, 360 degree spiral punchings can realize that just multielement hot fluid evenly injects in horizontal well on the horizontal segment injection string.

Table 3 horizontal segment multielement hot fluid evenly injects design

Be each parameter situation among the present invention below:

The d-tubing diameter, m;

The Z-well depth, m;

u _m-multielement hot fluid average speed, m/s;

ρ _m-multielement hot fluid averag density, kg/m ³

θ-hole angle, radian;

χ-steam quality, %;

P-multielement hot fluid pressure, MPa;

p _w-water saturation pressure, MPa;

T-multielement hot fluid temperature, ℃;

λ-two phase flow the coefficient of friction resistance;

The heat waste of q '-pit shaft unit length, W/m;

H _mThe total energy of-multielement hot fluid, W;

G _Tol-multielement hot fluid mass flow, kg/s;

-CO ₂, N ₂, saturation water, saturated vapour mass flow, kg/s;

-CO ₂, N ₂, saturation water, saturated vapour heat content, kJ/kg;

-water, CO ₂, N ₂Molal weight, kg/mol;

r _Ti-pipe aperture, m;

r _To-oil pipe external diameter, m;

r _Ci-casing inner diameter, m;

r _Co-cover external diameter of pipe, m;

r _h-cement sheath external diameter, m;

λ _Tub-oil pipe thermal transmittance, W/ (m ²K);

λ _Cas-sleeve pipe thermal transmittance, W/ (m ²K);

λ _Cem-cement sheath thermal transmittance, W/ (m ²K);

λ _e-stratum thermal transmittance, W/ (m ²K);

T _h-cement sheath outer rim temperature, ℃;

T _e-surface temperature, ℃;

T _s-multielement hot fluid temperature, ℃;

The a-geothermal gradient, ℃/m, common a=0.03～0.035 ℃;

The t-heat injection cumulative time, h;

The Z-well depth, m;

u _m-multielement hot fluid average speed, m/s;

ρ _m-multielement hot fluid averag density, kg/m ³

-stratum thermal diffusion coefficient, m ²/ h;

Q-pit shaft radial flow heat, W;

U _To-overall coefficient of heat transfer, W/ (m ²K);

F (t)-nondimensional time function;

The n-horizontal segment evenly injects segments;

The every segment length of l-, m;

p _i-horizontal segment i section oil pipe internal pressure, MPa; (i=1,2...n)

p _Oi-horizontal segment i section oil jacket annular pressure, MPa; (i=1,2...n)

p _o-horizontal segment oil jacket annular pressure, MPa;

A-injection string sectional area, m ²

υ _iFlow velocity in the-Di i section injection string, m/s; (i=1,2...n)

q _i-Di i section flow, t/s; (i=1,2...n)

The q-multielement hot fluid injects total amount, t/s;

d _i-Di i section discharge orifice diameter, m; (i=1,2...n)

The C-constant;

ζ-local losses coefficient;

v _{O (i)}-Di i section discharge orifice discharge velocity, m/s; (i=1,2...n)

N _i-Di i section earial drainage hole count; (i=1,2...n)

A ₁-preset discharge orifice area, m ²

Application process of the present invention is simple, reliable, can realize automation mechanized operation, and the present invention and can using in multiple different occasions only needs to adjust measurement parameter, and dependability height of the present invention is effective.

In sum; being preferred embodiment of the present invention only below, is not to be used to limit protection scope of the present invention, therefore; all any modifications of being done within the spirit and principles in the present invention, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (6)

1. a method of evenly injecting multielement hot fluid in horizontal well is characterized in that, may further comprise the steps:

(1) measures the horizontal well entire length, and horizontal segment in the horizontal well is carried out segmentation according to measurement result;

(2) measure the horizontal well internal diameter, and discharge orifice size and terminal discharge orifice number on the tubing string in each section horizontal well are carried out initial setting according to measurement result;

(3) detect multielement hot fluid temperature, pressure and the mass dryness fraction of preparing injection;

(4) according to testing result in the step (3) and horizontal well along each section of journey characteristic iterative computation horizontal well pit shaft along Cheng Wendu, pressure, mass dryness fraction and heat waste, wherein, pit shaft is along the journey temperature loss:

$q^{\&prime;}=-\frac{{\mathrm{dH}}_m}{\mathrm{dz}}+G_{\mathrm{tol}}g$

In the following formula, q ' is the heat waste of pit shaft unit length;

H _mTotal energy for multielement hot fluid;

G _TolBe the multielement hot fluid mass flow;

G is an acceleration of gravity;

Z is a well depth;

Wellbore pressure is:

$\frac{\mathrm{dp}}{\mathrm{dz}}={\mathrm{\&rho;}}_{m}g\sin \mathrm{\&theta;}-\mathrm{\&lambda;}\frac{{\mathrm{\&rho;}}_m{u}_m^2}{2d}$

In the following formula, p is a pressure;

ρ _mBe multielement hot fluid density;

G is an acceleration of gravity;

Z is a well depth;

θ is a hole angle;

λ is a resistance coefficient;

u _mBe multielement hot fluid speed;

D is a tubing diameter.

The mass dryness fraction design formulas:

$\frac{\mathrm{dx}}{\mathrm{dz}}=\frac{c_1{M}_{H_{2}O}}{G_{H_{2}O}}\frac{1}{{\left({p-p}_w\right)}^2}(p\frac{{\mathrm{dp}}_w}{\mathrm{dT}}\frac{\mathrm{dT}}{\mathrm{dz}}-p_w\frac{\mathrm{dp}}{\mathrm{dz}})$

In the following formula, χ is a steam quality;

Z is a well depth;

Be the saturation water mass flow;

Molal weight for water;

P is a pressure;

p _wBe water saturation pressure;

T is the multielement hot fluid temperature;

Steam to the heat output of cement sheath outer rim in the dz section is in the oil pipe:

dQ＝2πr _toU _to(T _s-T _h)dz

In the following formula, Q is the pit shaft radial flow heat;

r _To-oil pipe external diameter;

U _To-overall coefficient of heat transfer;

T _h-cement sheath outer rim temperature;

T _s-multielement hot fluid temperature;

Z is a well depth.

Heat conduction from the cement sheath outer rim to the stratum is:

dQ＝2πλ _e(T _h-T _e)dz/f(t)

In the following formula, Q is the pit shaft radial flow heat;

λ _e-stratum thermal transmittance;

T _e-surface temperature;

T _h-cement sheath outer rim temperature;

F (t)-nondimensional time function;

Z is a well depth;

(5) according to initial set value in result of calculation in the step (4) and step (1), (2) and evenly inject the principle iteration and calculate actual discharge orifice number and discharge orifice size on every section horizontal well tubing string, wherein, i section discharge orifice diameter is:

$d_i=2\sqrt{\frac{q}{{\mathrm{n\&pi;v}}_{o\left(i\right)}}}$

In the following formula, d _iIt is i section discharge orifice diameter;

Q is the multielement hot fluid flow;

N is the horizontal segment segments;

v _{O (i)}It is i section discharge orifice discharge velocity.

I section discharge orifice number is:

$N_i=\frac{\mathrm{\&pi;}{\left(\frac{d_i}{2}\right)}^2}{A_1}=\frac{q}{{\mathrm{nv}}_{o\left(i\right)}{A}_1}$

In the following formula, d _iIt is i section discharge orifice diameter;

A ₁For presetting the discharge orifice area;

Q is the multielement hot fluid flow;

N is the horizontal segment segments;

v _{O (i)}It is i section discharge orifice discharge velocity;

(6) according to result of calculation in the step (5) tubing string is punched, will punch in the tubing string lower going-into-well of back, then multielement hot fluid is injected this tubing string.

2. the method for evenly injecting multielement hot fluid in horizontal well as claimed in claim 1 is characterized in that: according to the principle of one section in every 50-70 rice horizontal well is carried out segmentation in the described step (1).

3. the method for evenly injecting multielement hot fluid in horizontal well as claimed in claim 1 is characterized in that: set the discharge orifice size in the described step (2) for 1-2 centimetre.

4. the method for evenly injecting multielement hot fluid in horizontal well as claimed in claim 1 is characterized in that: set terminal discharge orifice number according to the maximum speed limit of discharge orifice in the described step (2).

5. the method for evenly injecting multielement hot fluid in horizontal well as claimed in claim 1 is characterized in that: adopt thermometer, pressure to take into account temperature, pressure and mass dryness fraction that hygrometer detects the multielement hot fluid of preparing injection in the described step (3) respectively.

6. the method for evenly injecting multielement hot fluid in horizontal well as claimed in claim 1 is characterized in that: carry out 360 degree spiral punchings in the described step (5) on tubing string.

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