CN102011573B - 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 evenly injecting multielement hot fluid in horizontal well

Technical field

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

Background technology

Offshore viscous oil field is being carried out multielement hot fluid (N at present ₂+ CO ₂+ steam) application test of handling up.Horizontal well field measurement and analog study both at home and abroad shows, the general steam injection mode of horizontal well easily causes that advance by leaps and bounds in net horizontal section gas part, oil reservoir is employed inhomogeneous, horizontal segment oil reservoir has been employed well section and has only been accounted for 1/3-1/2 of horizontal section length, and, horizontal segment oil reservoir is employed uneven can aggravation along with the increase in steam injection cycle, even causes local vapour to alter and water outlet.

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

Summary of the invention

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

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

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

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

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

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

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

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

H _mtotal energy flow for multielement hot fluid;

G _tolfor multielement hot fluid mass flow;

G is acceleration of gravity;

Z is well depth;

Wellbore pressure is:

$\frac{\mathrm{dp}}{\mathrm{dz}}={\mathrm{\ρ}}_{m}g\sin \mathrm{\θ}-\mathrm{\λ}\frac{{\mathrm{\ρ}}_m{u}_m^2}{2d}$

In above formula, p is pressure;

ρ _mfor multielement hot fluid density;

G is acceleration of gravity;

Z is well depth;

θ is hole angle;

λ is resistance coefficient;

U _mfor multielement hot fluid speed;

D is tubing diameter.

Mass dryness fraction design formulas:

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

In above formula, χ is steam quality;

Z is well depth;

for saturation water mass flow;

molal weight for water;

P is pressure;

P _wfor water saturation pressure;

T is multielement hot fluid temperature;

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

dQ＝2πr _toU _to(T _s-T _h)dz

In above formula, Q is 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 well depth.

Heat conduction from cement sheath outer rim to stratum is:

dQ＝2πλ _e(T _h-T _e)dz/f(t)

In above formula, Q is 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 well depth;

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

$d_i=2\sqrt{\frac{q}{{\mathrm{n\πv}}_{o\left(i\right)}}}$

In above formula, d _iit is i section discharge orifice diameter;

Q is multielement hot fluid flow;

N is horizontal segment segments;

V _{o (i)}it is i section discharge orifice discharge velocity.

I section discharge orifice number is:

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

In above formula, d _iit is i section discharge orifice diameter; ;

A ₁for preset discharge orifice area;

Q is multielement hot fluid flow;

N is horizontal segment segments;

V _{o (i)}it is i section discharge orifice discharge velocity;

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

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

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

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

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

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

Tool of the present invention has the following advantages:

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 tubing string in result of calculation correction horizontal well, to reach the object of even heated fluid injection in horizontal well, its oil reservoir wide accommodation, and technology is relatively simple, cost is low, do not need to change existing well head and steam injection pipe, can make 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 of the present invention is high, effective.

Accompanying drawing explanation

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

Fig. 1 shows Horizontal Well body structure schematic diagram;

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

The specific embodiment

The present invention includes following steps:

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

Horizontal Well body structure as shown in Figure 1, comprises well head 1, pit shaft 2 and horizontal segment 3, on horizontal segment 3 tubing strings 6, is provided with discharge orifice 4.Major length is horizontal section length herein, and in order to make horizontal segment can realize even injection, in Homogeneous Reservoir, general every 50-70 rice is divided into one section.

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

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

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

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

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

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

Because the calculating of heat waste relates to pressure, temperature and the mass dryness fraction of multielement hot fluid, so pressure, temperature and the mass dryness fraction distribution that must first calculate multielement hot fluid; And to determine pressure, temperature and the mass dryness fraction in shaft bottom, just must be according to heat waste and the Pressure Drop of the charge velocity of multielement hot fluid and shaft column calculation of parameter pit shaft.The calculating that this shows pit shaft multielement hot fluid pressure, temperature, mass dryness fraction and heat waste intercouples, and the calculating of each will could be determined through iteration.

(A) wellbore pressure calculates

In pit shaft, the Pressure Drop of gas-liquid phase pipe is the synthesis result of friction loss, potential variation and kinetic energy change, and the momentum balance equation of following is (get is 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) pit shaft mass dryness fraction is calculated

Multielement hot fluid flowing for two-phase, multi-component Complex Flows in pit shaft, liquid phase is water, and gas phase is by saturated vapour, N ₂, CO ₂the mist forming, from law of partial pressure: the partial pressure of saturated vapour is directly proportional to shared mole percent:

$y_{H_{2}O}^{\&prime;\&prime;}=p_w\left(T\right)/p=\frac{G_{H_{2}O}^{\&prime;\&prime;}}{M_{H_{2}O}}/[\frac{G_{H_{2}O}^{\&prime;\&prime;}}{M_{H_{2}O}}+\frac{G_{{\mathrm{CO}}_2}}{M_{{\mathrm{CO}}_2}}+\frac{G_{N_2}}{M_{N_2}}]---\left(2\right)$

Wherein, steam saturation pressure p _wcan be tried to achieve by steam properties.

Order $c_1=[\frac{G_{{\mathrm{CO}}_2}}{M_{{\mathrm{CO}}_2}}+\frac{G_{N_2}}{M_{N_2}}]$

If now steam quality is x, have

substitution (2) formula arranges and can obtain:

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

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

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

(C) temperature in wellbore is calculated

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

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

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

To formula (5), differentiate obtains:

$\frac{{\mathrm{dH}}_m}{\mathrm{dz}}=G_{{\mathrm{CO}}_2}\frac{{\mathrm{dh}}_{{\mathrm{CO}}_2}}{\mathrm{dT}}+G_{N_2}\frac{{\mathrm{dh}}_{N_2}}{\mathrm{dT}}[(1-x)G_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}o}^{\&prime;}}{\mathrm{dT}}+{\mathrm{xG}}_{N_{2}O}\frac{{\mathrm{dh}}_{H_{2}O}^{\&prime;\&prime;}}{\mathrm{dT}}]\frac{\mathrm{dT}}{\mathrm{dZ}}+{\mathrm{rG}}_{H_{2}O}\frac{\mathrm{dx}}{\mathrm{dz}}---\left(6\right)$

Wherein, after being arranged, formula (6) substitution formula (5) can obtain temperature computation formula:

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

Wherein, $c_2=G_{{\mathrm{CO}}_2}\frac{{\mathrm{dh}}_{{\mathrm{CO}}_2}}{\mathrm{dT}}+G_{N_2}\frac{{\mathrm{dh}}_{N_2}}{\mathrm{dT}}+(1-x)G_{H_{2}O}\frac{{\mathrm{dh}}_{{H_{2}o}^{\&prime;}}^{\&prime;}}{\mathrm{dT}}+{\mathrm{xG}}_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}O}^{\&prime;\&prime;}}{\mathrm{dT}}{\mathrm{rc}}_{1}p\frac{M_{H_{2}O}}{{(p-p_w)}^2}\frac{{\mathrm{dp}}_w}{\mathrm{dT}}$

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

(D) wellbore heat loss calculation

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

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

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

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 bracket.

B) heat conduction from cement sheath outer rim to stratum

Owing to being unsettled heat conduction, the heat waste on stratum is started greatly, but along with the carrying out of steam injection, formation temperature increases, heat transfer power temperature difference T will reduce, and cause heat waste reduction.

Be formulated as:

dQ＝2πλ _e(T _h-T _e)dz/f(t) (9)

Wherein, $f\left(t\right)=0.982\ln [1+1.81\frac{\sqrt{\mathrm{at}}}{r_h}],$ For nondimensional time function.

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

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

(A) assumed condition

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

A) horizontal Injection Section oil jacket annular space internal pressure equates, and is 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 injection rate of horizontal segment equates,

q ₁＝q ₂＝…＝q _i＝…＝q _n＝q/n (11)

(B) the even injection parameter of horizontal segment solves

Multielement hot fluid is when horizontal segment flows, and its fluidised form is turbulent flow, between venthole n-1 and n, along stroke pressure loss, is:

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

Wherein, $C=\frac{1}{j}{R}^{1/6},j=0.01~0.02,R=\frac{d}{4};$ υ _ibe multielement hot fluid flow velocity in i section ascending pipe, its design formulas:

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

, 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 end discharge orifice size, number, therefore according to counter the pushing away of formula (15), can obtain one by one every section of discharge orifice muzzle velocity.

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

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

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

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

Simultaneous formula (15), (16), (17), and the horizontal segment segments arranging in integrating step 1, end discharge orifice number and discharge orifice size, can try to achieve horizontal segment every section of required discharge orifice size, number and earial drainage speed.

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

According to every section of discharge orifice parameter, on 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 tubing string in result of calculation correction horizontal well, to reach the object of even heated fluid injection in horizontal well, its oil reservoir wide accommodation, and technology is relatively simple, cost is low, do not need to change existing well head and steam injection pipe, can make 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.

Below in conjunction with a specific embodiment, elaborate:

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, end discharge orifice number and size arrange

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

2, associating pressure, temperature and heat waste design formulas, every section of 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 journey parameter distribution

The degree of depth	Pressure	Temperature	Heat waste	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	129.726	7.95E+00	5.37E+02	0.827	GAP
							1085	13.4285	129.357	8.27E+00	5.36E+02	0.827	GAP
1129	13.5472	128.992	8.59E+00	5.35E+02	0.826	GAP
							1173	13.6108	128.634	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 of discharge orifice number of calculated level section, discharge orifice size and earial drainage speed, result of calculation is as shown in table 3, finally according to this uniform Design parameter, on horizontal segment injection string, 360 degree spiral punchings, just can realize multielement hot fluid and evenly inject in horizontal well.

Table 3 horizontal segment multielement hot fluid evenly injects design

Each parameter situation in the present invention below:

D-tubing diameter, m;

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 coefficient of friction resistance;

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

H _mthe total energy flow 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-sleeve pipe external diameter, m;

R _h-cement sheath external diameter, m;

λ _tub-oil pipe thermal transmittance, W/ (mK);

λ _cas-sleeve pipe thermal transmittance, W/ (mK);

λ _cem-cement sheath thermal transmittance, W/ (mK);

λ _e-stratum thermal transmittance, W/ (mK);

T _h-cement sheath outer rim temperature, ℃;

T _e-surface temperature, ℃;

T _s-multielement hot fluid temperature, ℃;

A-geothermal gradient, ℃/m, conventionally a=0.03～0.035 ℃;

The t-heat injection cumulative time, h;

Z-well depth, m;

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

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

θ-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;

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.

U _iflow velocity in-i section injection string, m/s; (i=1,2...n)

Q _i-i section flow, m ³/ s; (i=1,2...n)

Q-multielement hot fluid injects flow, m ³/ s;

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

C-constant;

ζ-local loss coefficient;

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

N _i-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 of the present invention is high, effective.

In sum; these are only preferred embodiment of the present invention, be not intended to limit protection scope of the present invention, therefore; all any modifications of doing within the spirit and principles in the present invention, be equal to replacement, improvement etc., within protection scope of the present invention all should be included in.

Claims (6)

1. in horizontal well, evenly inject a method for multielement hot fluid, it is characterized in that, comprise the following steps:

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

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

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

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

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

In above formula, q ' is the heat waste of pit shaft unit interval, unit length, unit watts/meter;

H _mfor the total energy flow of multielement hot fluid, unit watt;

G _tolfor multielement hot fluid mass flow, unit Kilograms Per Second;

G is acceleration of gravity, and unit is m/s ²;

Z is well depth, unit rice;

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 above formula, p is pressure, unit MPa;

ρ _mfor multielement hot fluid density, unit kilograms per cubic meter;

G is acceleration of gravity, and unit is m/s ²;

Z is well depth, unit rice;

θ is hole angle, unit radian;

λ is resistance coefficient;

U _mfor multielement hot fluid speed, unit meter per second;

D is tubing diameter, unit rice;

Mass dryness fraction design formulas:

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

In above formula, χ is steam quality, unit percentage;

Z is well depth, unit rice;

$c_1=[\frac{G_{{\mathrm{CO}}_2}}{M_{{\mathrm{CO}}_2}}+\frac{G_{N_2}}{M_{N_2}}];$

for saturation water mass flow, unit Kilograms Per Second;

for the molal weight of water, unit kg/mol;

for the mass flow of carbon dioxide, unit Kilograms Per Second;

for the mass flow of nitrogen, unit Kilograms Per Second;

for the molal weight of carbon dioxide, unit kg/mol;

for the molal weight of nitrogen, unit kg/mol;

P is pressure, unit MPa;

P _wfor water saturation pressure, unit MPa;

T is multielement hot fluid temperature, unit ℃;

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

dQ=2πr _toU _to(T _s-T _h)dz

In above formula, Q is pit shaft radial flow heat, unit watt;

R _to-oil pipe external diameter, unit rice;

U _to-overall coefficient of heat transfer, the W/ (m of unit ²k);

T _h-cement sheath outer rim temperature, unit ℃;

T _svapor (steam) temperature in-oil pipe, unit ℃;

Z is well depth, unit rice;

Heat conduction from cement sheath outer rim to stratum is:

dQ=2πλ _e(T _h-T _e)dz/f(t)

In above formula, Q is pit shaft radial flow heat, unit watt;

λ _e-stratum thermal transmittance, the W/ of unit (mK);

T _e-surface temperature, unit ℃;

T _h-cement sheath outer rim temperature, unit ℃;

F (t)-nondimensional time function, $f\left(t\right)=0.982\ln [1+1.81\frac{\sqrt{\mathrm{at}}}{r_h}];$

R _hfor cement sheath external diameter, unit rice;

A is geothermal gradient, unit ℃/m;

T is the heat injection cumulative time, unit hour;

Z is well depth, unit rice;

Temperature computation formula:

$\frac{\mathrm{dT}}{\mathrm{dz}}=[{\mathrm{rc}}_1\frac{M_{H_{2}O}}{{(p-p_w)}^2}{p}_w\frac{\mathrm{dp}}{\mathrm{dz}}+\mathrm{Gg}-q_1]{/c}_2$

Wherein, $c_2=G_{{\mathrm{CO}}_2}\frac{{\mathrm{dh}}_{{\mathrm{CO}}_2}}{\mathrm{dT}}+G_{N_2}\frac{{\mathrm{dh}}_{N_2}}{\mathrm{dT}}+(1-x)G_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}O\text{'}}^{\text{'}}}{\mathrm{dT}}+x{G}_{H_{2}O}\frac{{\mathrm{dh}}_{H_{2}O}^{\&prime;\&prime;}}{\mathrm{dT}}+{\mathrm{rc}}_{l}p\frac{M_{H_{2}O}}{{(p-p_w)}^2}\frac{{\mathrm{dp}}_w}{\mathrm{dT}}$

ql＝q/n；

$r=h_{H_{2}O}\text{'}\text{'}\left(T\right)-h_{H_{2}O}\text{'}\left(T\right);$

be respectively the heat content of carbon dioxide, nitrogen, saturation water, saturated vapour, unit be kJ (kilojoule)/kilogram;

(5) according to initial set value in result of calculation in step (4) and step (1), (2) and evenly inject principle iteration and calculate actual discharge orifice number and discharge orifice diameter on every section of 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 above formula, d _ibe i section discharge orifice diameter, unit rice;

Q is multielement hot fluid flow, the m of unit ³/ s;

N is horizontal segment segments;

V _{o (i)}be i section discharge orifice discharge velocity, meter per second;

I section discharge orifice number is:

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

In above formula, d _ibe i section discharge orifice diameter, unit rice;

A ₁for preset discharge orifice area, unit square rice;

Q is multielement hot fluid flow, the t/s of unit;

N is horizontal segment segments;

V _{o (i)}be i section discharge orifice discharge velocity, unit meter per second;

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

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

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

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

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

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

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