CN105672968A - Steam injection pipe for oil deposit exploitation and oil deposit exploitation method - Google Patents

Abstract

The invention discloses a steam injection pipe for oil deposit exploitation and an oil deposit exploitation method. The method comprises the following steps of: determining the length of each segment among multiple segments of a steam injection pipe; determining the material quality and size of each segment among the multiple segments under a condition that each segment among the multiple segments is equal in heat loss; generating the steam injection pipe according to the determined material quality and size of each segment among the multiple segments; and heating an oil deposit in which a steam injection well is positioned through the steam injection pipe. Through determining that the radial heat loss values of the segments of the steam injection pipe are equal, further determining the material quality and size of each segment of the steam injection pipe, generating the steam injection pipe according to the determined material quality and size and heating the oil deposit, the oil deposit is uniformly heated by each segment of the steam injection pipe, further the steam injection effect of the steam injection pipe is improved, a steam channeling phenomenon is reduced, and further the oil extraction efficiency is improved.

Description

A kind of oil reservoir exploitation steam inject tube and oil reservoir reoovery method

Technical field

The present invention relates to oil production technology, particularly relate to a kind of oil reservoir exploitation steam inject tube and oil reservoir reoovery method.

Background technology

SAGD (SteamAssistedGravityDrainage, steam assisted gravity lets out oil) is a super-heavy oil deposit development technique. This technology is by steam from being positioned at a bite straight well above the horizontal production well of oil reservoir near-bottom or a bite horizontal well injection oil reservoir, thus is heated by oil reservoir, the crude oil heated and steam condensate output from the horizontal well bottom oil reservoir. This technology has the advantage of high oil recovery ability, high gas oil ratio, high recovery rate and low inter-well interference, and this technology can effectively be avoided producing too early to alter logical problem between well.

At present, SAGD adopts the mode of injecting steam in steam inject tube to be heated by oil reservoir, then, because the oil reservoir area needing heating is generally bigger, so the horizontal steam injection section of steam inject tube is usually long. Can there is heat waste when flowing along steam inject tube in steam, if the design variable of steam inject tube is unreasonable, be so easy to cause the heat waste of each section of steam inject tube different, and heat waste difference can cause each region heating of oil reservoir uneven. For the region of over-heating, steam first directly can set up the longitudinal layer position of thermal communication through oil reservoir with recovery well, and then generation vapour is altered.

For the problems referred to above, effective solution is not yet proposed at present.

Summary of the invention

For the problems referred to above, it is an object of the invention to provide a kind of oil reservoir exploitation steam inject tube and oil reservoir reoovery method. The method can develop super-heavy oil deposit.

In order to realize above-mentioned purpose, a kind of oil reservoir exploitation steam inject tube provided by the invention, comprise: vertical section, horizontal section and connect the transition section of described vertical section and horizontal section, wherein, described horizontal section comprises multiple steam injection section, being provided with one or more steam injection hole in each steam injection section of described multiple steam injection section, in described multiple steam injection section, the thermosteresis of each steam injection section is equal.

Further, described oil reservoir reoovery method steam inject tube is arranged on top and/or the lower section of oil reservoir.

Further, in described horizontal section, the quantity of steam injection section is 3 or 4.

Further, in described horizontal section, the length of steam injection section is 9～11m.

In order to realize above-mentioned purpose, the present invention also provides a kind of oil reservoir reoovery method; Determine the length of each section in steam inject tube multiple sections; When in ensureing described multiple sections, the thermosteresis of each section is equal, determine material and the size of each section in described multiple sections, wherein, the radial thermosteresis of each section in described multiple sections of the radial entire thermal resistance decision of the length of each section described and each section, the radial entire thermal resistance of each section described is determined by the material of each section and size; Material and size according to each section in described multiple sections determined generate described steam inject tube; By described steam inject tube, steam injection well place oil reservoir is heated.

Further, the radial thermosteresis according to each section in described in following formulae discovery multiple sections:

$Q_m=\frac{T_s-T_e}{R_m}{\mathrm{dL}}_m$

Wherein, Q_mRepresent the radial thermosteresis of m section, R_mRepresent the radial entire thermal resistance of m section, T_eRepresent the near-bottom temperature steady state value after cyclic preheat, T_sRepresent the medial temperature of saturation steam, dL_mRepresent the length of m section.

Further, the radial entire thermal resistance according to each section in described in following formulae discovery multiple sections:

R_m=R_m1+R_m2+R_m3+R_m4+R_m5+R_m6+R_m7+R_m8

R_m1Represent the thermal convection thermal resistance value between steam and steam inject tube inwall, R_m2Represent the thermally conductive heat resistance between the inwall of steam inject tube and outer wall, R_m3Represent the thermally conductive heat resistance of thermofin, R_m4Represent the thermally conductive heat resistance of instlated tubular tube wall, R_m5Represent annular space thermal convection thermal resistance value, R_m6Represent the thermally conductive heat resistance of casing wall, R_m7Represent the thermally conductive heat resistance of cement mantle, R_m8Represent the thermally conductive heat resistance of oil reservoir.

Further, the medial temperature according to following formulae discovery saturation steam:

T_s=195.94P^0.225-17.8

Wherein, T_sRepresenting the medial temperature of saturation steam, P is vapour pressure, and unit is Pa.

Further, according to following formulae discovery vapour pressure:

$\frac{dP}{dl}=-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]gsin\mathrm{\θ}+\frac{\mathrm{\λ}Gv}{2{\mathrm{DA}}_p}}{1-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]{\mathrm{vv}}_{sg}}{P}}$

Wherein, P is vapour pressure, and unit is Pa; L represents the distance of axial flow, and unit is m; ρ_lFor density of liquid phase, unit is kg/m³; ρ_gFor gas phase density, unit is kg/m³; H_lFor liquid holdup, unit is m³/m³; G is universal gravity constant, and unit is m/s²; θ is the angle of pipeline and horizontal direction; λ is the frictional resistant coefficient of two-phase flow; G is the mass rate of mixture, and unit is kg/s; V is the flow velocity of mixture, and unit is m/s; v_sgFor the conversion speed of gas phase, unit is m/s; D is pipe diameter, and unit is m; A_pFor pipeline section amasss, unit is m²。

A kind of oil reservoir exploitation steam inject tube of the present invention and oil reservoir reoovery method, by adjusting material and the length of this steam inject tube each section of steam injection section, make the heat waste value of each section of steam injection section on this steam inject tube horizontal section identical, and then heated by oil reservoir by this tubing string, and then can ensure that each section of steam inject tube is to the even heating of oil reservoir; Improve the steam injection efficiency of steam inject tube, decrease vapour and alter phenomenon, it is to increase oil-production efficiency.

Accompanying drawing explanation

Fig. 1 is the structural plan of the oil reservoir exploitation steam inject tube in the present embodiment in well;

Fig. 2 is the radial thermal resistance schematic diagram of the oil reservoir exploitation steam inject tube in the present embodiment;

The schema of the oil reservoir reoovery method that Fig. 3 provides for the present embodiment.

Above accompanying drawing illustrates: 1, recovery well; 2, steam injection well; 3, steam inject tube; 31, vertical section; 32, horizontal section; 321, steam injection section; 4, steam injection hole; 5, sleeve pipe; 6, oil reservoir.

Embodiment

In prior art, the conventional pattern shape for SAGD horizontal well mainly divides straight flat combination and dual horizontal well combination, and namely at oil reservoir top layout straight well steam injection well, bottom is arranged horizontal well or all arranged horizontal well at top and bottom. For, in the operation process of the SAGD horizontal well of reality, generally temporally order divides two stages: the first stage is the cyclic preheat stage, is namely heated by oil reservoir top crude oil. The little discharge capacity injecting steam of steam inject tube in steam injection well, evenly heats oil reservoir, makes the crude oil on oil reservoir top have certain mobility. Subordinate phase is the steam injection gravity drainage stage, namely to Oil extraction bottom oil reservoir, owing to steam injection well and producing well after unified longitudinal region cyclic preheat for some time are set up thermal communication, being affected by gravity the crude oil with mobility can enter the recovery well bottom oil reservoir from the steam injection well stream at oil reservoir top.

In order to prevent oil reservoir generation vapour from altering, propose a kind of oil reservoir exploitation steam inject tube in this example, as shown in Figure 1, this steam inject tube comprises vertical section, horizontal section and connects the transition section of vertical section and horizontal section, wherein, described horizontal section comprises multiple steam injection section, and each steam injection section of described multiple steam injection section is provided with one or more steam injection hole, and in described multiple steam injection section, the thermosteresis of each steam injection section is equal. The extension downwards from well head of vertical section is connected with transition section.

The horizontal section 32 of the steam inject tube 3 in Fig. 1 can comprise multistage steam injection section 321, and multistage steam injection section 321 is arranged in order. steam injection section 321 can be provided with in the horizontal direction and multiple join vapour hole. steam inject tube 3 carrys out heating in crude oil by steam injection hole 4 by steam injection to oil reservoir. the crude oil heated under gravity, enters recovery well 1 downwards. consider and need the oil reservoir area of heating bigger, so the horizontal section 32 of steam inject tube 3 generally arrange long, heat waste can be there is in steam when flowing along steam inject tube 3, if the radial thermal resistance value parameter of steam inject tube 3 is unreasonable, that easily causes that each section of horizontal well heats is uneven, and then each region heating causing oil reservoir is uneven, the steam in over-heating region first through oil reservoir directly and recovery well 1 set up the longitudinal layer position of thermal communication, and then occur vapour to alter, in this example, thermosteresis by each steam injection section 321 arranged in multiple steam injection section 321 is equal, effectively prevent the generation of the problems referred to above.

Concrete, oil reservoir reoovery method is can be SAGD dual horizontal well technology. SAGD dual horizontal well comprises recovery well 1 and steam injection well 2. Recovery well 1 is the main well section of oil producing operation, and steam injection well 2 comprises straight well section and branch's section, in the straight well section that the steam inject tube 3 of above-mentioned oil reservoir reoovery method is arranged on steam injection well 2 and branch's section. Wherein, straight well section and branch's section can be provided with sleeve pipe 5, the upper end of sleeve pipe 5 arranged in straight well section is connected with the well head of oil well, and the diameter of the sleeve pipe 5 of straight well section is greater than the diameter of the sleeve pipe 5 of branch's section, and this is mainly because the tubing string of straight well section setting is more than branch's section. Concrete, by filling mixed earth, sleeve pipe 5 permanent sleeve can be located in oil well between sleeve pipe 5 and the borehole wall.

Above-mentioned oil reservoir exploitation steam inject tube 3 can be arranged in the sleeve pipe 5 of steam injection well 2, concrete, and this steam inject tube 3 can comprise the vertical section 31 being arranged on straight well section, is arranged on the horizontal section 32 of branch's section and connects the transition section of vertical section 31 and horizontal section 32. The length of horizontal section 32 can be determined according to the concrete size of oil reservoir.Preferably, the horizontal section 32 of steam inject tube 3 can be corresponding with the horizontal length of oil reservoir. Transition section can be set directly at the lower end of vertical section 31, and the other end of transition section is connected with horizontal section 32.

Wherein, horizontal section 32 comprises multiple steam injection section 321, and each steam injection section 321 of multiple steam injection section 321 can be provided with one or more steam injection hole 4, and in multiple steam injection section 321, the thermosteresis of each steam injection section 321 is equal. Concrete, in steam injection section 321, the influence factor of the thermosteresis of each steam injection section 321 is the radial thermal resistance value R of steam injection section 321 tubing string_m, radial thermal resistance value R_mMore big, the thermosteresis Q of steam injection section 321 is more big. Thermosteresis Q is more big, just shows that the steam of this section is more many to the heat of external diffusion, and then the heating intensity of oil reservoir is more big.

Concrete, radial thermal resistance value R_mCan represent and be:

R_m=R_m1+R_m2+R_m3+R_m4+R_m5+R_m6+R_m7+R_m8

Wherein, m represents the label of steam injection section 321. R_m1Represent the thermal convection thermal resistance value between steam and steam inject tube inwall, R_m2Represent the thermally conductive heat resistance between the inwall of steam inject tube and outer wall, R_m3Represent the thermally conductive heat resistance of thermofin, R_m4Represent the thermally conductive heat resistance of instlated tubular tube wall, R_m5Represent annular space thermal convection thermal resistance value, R_m6Represent the thermally conductive heat resistance of casing wall, R_m7Represent the thermally conductive heat resistance of cement mantle, R_m8Represent the thermally conductive heat resistance of oil reservoir. Wherein, R_m1、R_m2、R_m3、R_m4For the thermal resistance of steam inject tube 3 steam injection section 321. It is illustrated in figure 2 the schematic diagram of above-mentioned each resistance.

By adjusting the radial entire thermal resistance R of each steam injection section 321 of steam inject tube 3_m, it is possible to make the radial steam heat loss of every section of steam injection section 321 identical, thus ensure every section of steam injection section 321 to oil reservoir to add heat identical.

In the present embodiment, oil reservoir reoovery method steam inject tube 3 is arranged on top and/or the lower section of oil reservoir, arranges position and quantity according to what the structure of steam injection amount He actual oil reservoir determined steam inject tube 3.

In the present embodiment, in horizontal section 32, the quantity of steam injection section 321 can be 3 or 4, and the direction that each steam injection section 321 can be threaded connection is connected. The length of each section of steam inject tube 3 can be generally 9～11m.

In one preferred embodiment, the length of steam injection section is 800mm to 1000mm, and the diameter of steam injection section is 73mm. Present embodiment not length and size to steam injection section do concrete restriction, the length of steam injection section and size can be determined according to the service requirements of reality.

Preferably, the aperture of steam injection section is 4mm.

Another preferred embodiment in, steam injection section comprises pipe and steam injection outer tube in steam injection, and steam injection outer tube sleeve is located in steam injection on pipe.

Preferably, it is provided with vacuum heat-insulating layer between pipe and steam injection outer tube in steam injection.

In one preferred embodiment, in steam injection, pipe and steam injection outer tube can be cast iron pipe or stainless steel tube.

In the present embodiment, in horizontal section 32, the quantity of steam injection section 321 can be 3 or 4, and the direction that each steam injection section 321 can be threaded connection is connected. The length of each section of steam inject tube 3 can be generally 9～11m.

Based on the oil reservoir exploitation steam inject tube 3 shown in Fig. 1, additionally provide a kind of oil reservoir reoovery method in this example, as shown in Figure 3, it is possible to comprise the following steps:

Step S301: the length determining each steam injection section 321 in multiple steam injection section 321 in the horizontal section 32 of steam inject tube 3;

Step S302: when the thermosteresis of each section is equal in ensureing described multiple sections, determine material and the size of each section in described multiple sections, wherein, the radial thermosteresis of each section in described multiple sections of the radial entire thermal resistance decision of the length of each section described and each section, the radial entire thermal resistance of each section described is determined by the material of each section and size;

Step S303: generate described steam inject tube according to the material of each section in described multiple sections determined and size;

Step S304: steam injection well 2 place oil reservoir is heated by described steam inject tube 3.

That is, using equal material and the size determining each section as principle of the thermosteresis of each section, thus generate steam inject tube, carry out oil reservoir heating based on this kind of steam inject tube, so that it may oil reservoir occurs vapour alter effectively to prevent.

Assume that the horizontal section 32 of above-mentioned steam inject tube 3 has m steam injection section 321, radial steam heat loss Q_mRepresent be steam when moving in steam inject tube 3 to the heat of external diffusion. If the radial steam heat loss Q of every section of steam inject tube_mIdentical, then mean that every section of steam inject tube is identical to the heat of external diffusion, and then represent that the heat that adds of oil reservoir is identical by every section of steam inject tube.

The pit shaft unit radial steam heat loss Q of heating phase_mCan represent and be:

$Q_m=\frac{T_s-T_e}{R_m}{\mathrm{dL}}_m$

Wherein, R_mRepresenting the entire thermal resistance of pit shaft unit radial, unit is (m k)/w; DL_mRepresenting steam inject tube 3 unit length axially, unit is m; T_sRepresenting the temperature of saturation steam in pit shaft, unit is DEG C.

At above-mentioned calculation of steam thermosteresis Q_mFormula in, T_eFormation temperature after expression cyclic preheat is a steady state value. Saturation steam medial temperature T_sCan try to achieve according to following formula:

T_s=195.94P^0.225-17.8

Wherein, pressure P can be tried to achieve according to following Beggs-Bill algorithm:

$\frac{dP}{dl}=-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]gsin\mathrm{\θ}+\frac{\mathrm{\λ}Gv}{2{\mathrm{DA}}_p}}{1-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]{\mathrm{vv}}_{sg}}{P}}$

Wherein, P is vapour pressure, and unit is Pa; L represents the distance of axial flow, and unit is m; ρ_lFor density of liquid phase, unit is kg/m³; ρ_gFor gas phase density, unit is kg/m³; H_lFor liquid holdup, unit is m³/m³; G is universal gravity constant, and unit is m/s²; θ is the angle of pipeline and horizontal direction; λ is the frictional resistant coefficient of two-phase flow; G is the mass rate of mixture, and unit is kg/s; V is the flow velocity of mixture, and unit is m/s; v_sgFor the conversion speed of gas phase, unit is m/s; D is pipe diameter, and unit is m; A_pFor pipeline section amasss, unit is m²。

Therefore, above-mentioned pressure P is also a steady state value.

Above-mentioned R_mCan be tried to achieve by following formula:

R_m=R_m1+R_m2+R_m3+R_m4+R_m5+R_m6+R_m7+R_m8

Wherein, R_m1Represent the thermal convection thermal resistance value between steam and steam inject tube inwall, R_m2Represent the thermally conductive heat resistance between the inwall of steam inject tube and outer wall, R_m3Represent the thermally conductive heat resistance of thermofin, R_m4Represent the thermally conductive heat resistance of instlated tubular tube wall, R_m5Represent annular space thermal convection thermal resistance value, R_m6Represent the thermally conductive heat resistance of casing wall, R_m7Represent the thermally conductive heat resistance of cement mantle, R_m8Representing the thermally conductive heat resistance of oil reservoir, unit is (m k)/w.

Therefore, according to several formula just can in the hope of dL any in pit shaft above_mThermosteresis in length.

In order to make the Q of each section_mEqual, because of T_eAnd T_sIt is constant, so just needs to make dL_m/R_mIt is all equal for each section.

In a specific embodiment, before determining the radial entire thermal resistance parameter of steam inject tube 3, as shown in Figure 3, it is possible to first get the length dL on two sections of steam inject tube 3 unit axles₁、dL₂。dL₁、dL₂Can be adjacent two segment distances, it is also possible to be non-conterminous two sections. In order to determine a comparatively accurate R_mParameter, dL₁、dL₂Value can get a segment steam inject tube 3 as far as possible. In order to make two sections of evenly distribute heats, only need the Q of its correspondence another_m1=Q_m2, because of T_eAnd T_sIt is constant, therefore, it is only necessary to the corresponding dL of adjustment₁And dL₂The radial entire thermal resistance R of section, for same level section 32, R₄To R₈For the value outside steam inject tube 3, it is all identical, only need to adjust material and the size of steam inject tube 3, i.e. adjustable R₁To R₄, and then make Q_m1=Q_m2。

Q_m1=Q_m2Just mean that the radial steam heat loss of two distances that the axis of steam inject tube 3 is selected is identical, can ensure that steam inject tube 3 is when heating oil reservoir by ensure the radial steam heat loss of two segment distances selected identical, to the every segment distance of oil reservoir to add heat identical.

From above description, can find out, the embodiment of the present invention achieves following technique effect: provide a kind of oil reservoir exploitation steam inject tube 3 and a kind of oil reservoir reoovery method, by adjusting material and the length of this steam inject tube 3 each sections of steam injection sections 321, make the heat waste value of each section of steam injection section 321 on the horizontal section 32 of this steam inject tube 3 identical, and then can ensure that each section of steam inject tube 3 is to the even heating of oil reservoir; Improve the steam injection efficiency of steam inject tube 3, decrease vapour and alter phenomenon, it is to increase oil-production efficiency.

Describe it is to be understood that above is to carry out illustrating instead of in order to limit. By reading foregoing description, many enforcement modes and many application outside the example provided will be all apparent for a person skilled in the art. Therefore, the scope of this instruction should do not determined with reference to foregoing description, but should determine with reference to whole scopes of the Equivalent that claims and these claims have. For comprehensive object, all articles and with reference to comprising the open all by reference to being combined in herein of patent application and bulletin. Aforementioned claim is omitted theme disclosed herein any in be not to abandon this body matter, also should not be considered as the part that this theme is not thought of as disclosed subject matter by contriver.

Claims (9)

1. an oil reservoir exploitation steam inject tube, it is characterized in that, comprise: vertical section, horizontal section and connect the transition section of described vertical section and described horizontal section, wherein, described horizontal section comprises multiple steam injection section, being provided with one or more steam injection hole in each steam injection section of described multiple steam injection section, in described multiple steam injection section, the thermosteresis of each steam injection section is equal.

2. oil reservoir exploitation steam inject tube according to claim 1, it is characterised in that, described oil reservoir exploitation steam inject tube is arranged on top and/or the lower section of oil reservoir.

3. oil reservoir exploitation steam inject tube according to claim 1, it is characterised in that, in described horizontal section, the quantity of steam injection section is 3 or 4.

4. oil reservoir exploitation steam inject tube according to claim 3, it is characterised in that, in described horizontal section, the length of steam injection section is 9～11m.

5. an oil reservoir reoovery method, it is characterised in that,

Determine the length of each steam injection section in multiple steam injection section in steam inject tube horizontal section;

When in ensureing described multiple sections, the thermosteresis of each section is equal, determine material and the size of each section in described multiple sections, wherein, the radial thermosteresis of each section in described multiple sections of the radial entire thermal resistance decision of the length of each section described and each section, the radial entire thermal resistance of each section described is determined by the material of each section and size;

Material and size according to each section in described multiple sections determined generate described steam inject tube;

By described steam inject tube, steam injection well place oil reservoir is heated.

6. method according to claim 5, it is characterised in that, the radial thermosteresis according to each section in described in following formulae discovery multiple sections:

$Q_m=\frac{T_s-T_e}{R_m}{\mathrm{dL}}_m$

Wherein, Q_mRepresent the radial thermosteresis of m section, R_mRepresent the radial entire thermal resistance of m section, T_eRepresent the near-bottom temperature steady state value after cyclic preheat, T_sRepresent the medial temperature of saturation steam, dL_mRepresent the length of m section.

7. method according to claim 6, it is characterised in that, the radial entire thermal resistance according to each section in described in following formulae discovery multiple sections:

R_m=R_m1+R_m2+R_m3+R_m4+R_m5+R_m6+R_m7+R_m8

R_m1Represent the thermal convection thermal resistance value between steam and steam inject tube inwall, R_m2Represent the thermally conductive heat resistance between the inwall of steam inject tube and outer wall, R_m3Represent the thermally conductive heat resistance of thermofin, R_m4Represent the thermally conductive heat resistance of instlated tubular tube wall, R_m5Represent annular space thermal convection thermal resistance value, R_m6Represent the thermally conductive heat resistance of casing wall, R_m7Represent the thermally conductive heat resistance of cement mantle, R_m8Represent the thermally conductive heat resistance of oil reservoir.

8. method according to claim 5, it is characterised in that, the medial temperature according to following formulae discovery saturation steam:

T_s=195.94P^0.225-17.8

Wherein, T_sRepresenting the medial temperature of saturation steam, P is vapour pressure, and unit is Pa.

9. method according to claim 8, it is characterised in that, according to following formulae discovery vapour pressure:

$\frac{dP}{dl}=-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]gsin\mathrm{\θ}+\frac{\mathrm{\λ}Gv}{2{\mathrm{DA}}_p}}{1-\frac{\[{\mathrm{\ρ}}_l{H}_l+{\mathrm{\ρ}}_g(1-H_l)\]{\mathrm{vv}}_{sg}}{P}}$

Wherein, P is vapour pressure, and unit is Pa; L represents the distance of axial flow, and unit is m; ρ_lFor density of liquid phase, unit is kg/m³; ρ_gFor gas phase density, unit is kg/m³; H_lFor liquid holdup, unit is m³/m³; G is universal gravity constant, and unit is m/s²; θ is the angle of pipeline and horizontal direction; λ is the frictional resistant coefficient of two-phase flow; G is the mass rate of mixture, and unit is kg/s; V is the flow velocity of mixture, and unit is m/s; v_sgFor the conversion speed of gas phase, unit is m/s; D is pipe diameter, and unit is m; A_pFor pipeline section amasss, unit is m²。