CN105257279A - Method for measuring working fluid level of rod-pumped well - Google Patents

Abstract

The invention discloses a method for measuring the working fluid level of a rod-pumped well. The method comprises the following steps: according to a drag coefficient calculation model, obtaining a drag coefficient; according to the drag coefficient, a sucker-rod string displacement motion model and a sucker-rod string load calculation model, obtaining displacement parameters at different depths and load parameters of a sucker-rod string, and then obtaining displacement parameters and load parameters of a pump; according to the displacement parameters and the load parameters of the pump, obtaining a pump diagram of the pump; according to the pump diagram and a submergence pressure calculation model as well as a fluid property calculation model, obtaining working fluid level parameters of the rod-pumped well. Through adoption of the method, the measurement timeliness can be effectively improved under the circumstance that the calculation precision is ensured; besides, the method is further applicable to an oil well where casing pressure needs to be controlled for production, so that an error in calculation of the working fluid level can be reduced.

Description

A kind of measuring method of rod-pumped well producing fluid level

Technical field

The present invention relates to petroleum technology field, particularly relate to a kind of measuring method of rod-pumped well producing fluid level.

Background technology

Rod-pumped well producing fluid level is feed flow situation, the diagnosis oil well failure of understanding oil well, carries out the important parameter of oil production technology Adaptability Evaluation and optimization.The main method of testing of current well fluid level is Acoustic Reflection Method, and the subject matter that the method exists has: (1) rely on workman's manual operations; (2) there is certain unsafe factor in well head sounding device; (3) monthly test once, can not the change of on-line tracing producing fluid level; (4) dynamic oil level is greater than to the oil well of 1000 meters, be easily subject to the impact of some other operating modes, test error is larger.

In recent years, due to the development of indicator diagram measurement means, make to calculate producing fluid level technology according to indicator card to cross over from theory to application, the variation tendency tracking technique of producing fluid level is progressively set up and constantly perfect, but, when having by mapping actual measurement static load indicator card calculating well fluid level, effectively can eliminate inertial load, oscillating load, the impact of the factors such as frrction load, computational solution precision is relatively high, but simultaneously, the acquisition more complicated of upper and lower static load and loaded down with trivial details, and check difficulty, once oil well condition changes, also need to revise its static load indicator card, timeliness is poor, and when adopting the method to calculate well fluid level, do not consider the impact of casing pressure, for the oil well controlling casing pressure production, the producing fluid level calculated will there will be the higher problem of error.

Summary of the invention

The invention provides a kind of measuring method of rod-pumped well producing fluid level, when guaranteeing computational accuracy, can effectively improve its timeliness, and the oil well controlling casing pressure and produce can also be applied to, make the error-reduction of the producing fluid level calculated.

Embodiments provide a kind of measuring method of rod-pumped well producing fluid level, comprising:

According to resistance coefficient computation model, obtain the resistance coefficient corresponding with described rod-pumped well;

According to described resistance coefficient and rod string displacement motion model, obtain the displacement parameter of described rod string; And

According to described resistance coefficient and rod string LOAD FOR model, obtain the load parameter of described rod string;

According to the displacement parameter of described rod string, obtain the displacement parameter of the pump of described rod string bottom; And according to the load parameter of described rod string, obtain the load parameter of described pump;

According to the displacement parameter of described pump and the load parameter of described pump, obtain the pump dynagraoph of described pump;

According to described pump dynagraoph, obtain described pump intake pump intake pressure parameter;

According to Temperature Distribution and the calculation of property of fluid model of the pit shaft of described rod-pumped well, obtain the physical properties of fluids parameter of described pit shaft;

According to described intake pump intake pressure parameter and described physical properties of fluids parameter, obtain the pressure distribution parameter in the annular space between the oil pipe of described pumpingh well and sleeve pipe;

According to described pressure distribution parameter, obtain the producing fluid level parameter of described rod-pumped well.

Optionally, described resistance coefficient computation model, is specially:

$C=\frac{2\mathrm{\π}\mathrm{\μ}}{{\mathrm{\ρ}}_r{A}_r}\{\frac{1}{\ln m}+\frac{4}{B_2}(B_1+1)\{B_1+\frac{2}{\frac{\mathrm{\ω}L}{a}\frac{1}{sin\frac{\mathrm{\ω}l}{a}}+cos\frac{\mathrm{\ω}l}{a}}\left\}\right\};$

Wherein, $m=\frac{D_t}{D_r},B_1=\frac{m^2-1}{2\ln m}-1,B_2=m^4-1-\frac{{(m^2-1)}^2}{\ln m}$

μ express liquid viscosity in formula; ρ _rrepresent the density of sucker rod; A _rrepresent the sectional area of sucker rod; D _trepresent tubing diameter; D _rrepresent sucker rod diameter; L represents sucker rod length; C represents resistance coefficient.

Optionally, described according to described resistance coefficient and rod string displacement motion model, obtain the displacement parameter of described rod string, be specially:

Substituted in described rod string displacement motion model by described resistance coefficient, obtain the displacement parameter of described rod string, wherein, described rod string displacement motion model is specially:

$\frac{\∂U(x,t)}{\∂t^2}=a^2\frac{{\∂}^2(x,t)}{\∂x^2}-c\frac{\∂U(x,t)}{\∂t}$

In formula:

U (x, t) represents the displacement of t rod string x section part;

A represents the spread speed of sound wave in rod string.

Optionally, described according to described resistance coefficient and rod string LOAD FOR model, obtain the load parameter of described rod string, specifically comprise:

Described resistance coefficient is substituted in described rod string LOAD FOR model, obtain the load parameter of described rod string, wherein, described rod string LOAD FOR model comprises sucker rod Gravity calculation model, fluid column LOAD FOR model, fluid by drag evaluation model, the rod string inertial load computation model in valve hole, the frrction load computation model of fluid column inertial load computation model, pump barrel and plunger frrction load computation model, sucker rod and liquid, pipe liquid frrction load computation model and rod string uplift force computation model.

Optionally, described according to described pump dynagraoph, obtain described pump intake pump intake pressure parameter, specifically comprise:

Choose the point of load up and down in described pump dynagraoph;

According to the described upper and lower point of load and Pump Suction Nozzle pump intake pressure computation model, obtain described intake pump intake pressure parameter.

Optionally, described Pump Suction Nozzle pump intake pressure computation model is specially:

$P_n=\frac{2P_h(f_p-f_r)}{f_p}+2\mathrm{\Δ}P+\frac{W_l}{f_p},$

Wherein, Δ P represents the Pressure Drop that oil reservoir production fluid produces through standing valve and travelling valve opening; W _lrepresent well liquid column load.

By an embodiment or multiple embodiment, the present invention has following beneficial effect or advantage:

Due to the measuring method of the rod-pumped well producing fluid level in the embodiment of the present application, according to resistance coefficient computation model, rod string displacement motion model and rod string LOAD FOR model, obtain the displacement parameter of described rod string and the load parameter of described rod string, according to the displacement parameter of described rod string, obtain the displacement parameter of the pump of described rod string bottom, and according to the load parameter of described rod string, obtain the load parameter of described pump, according to the displacement parameter of described pump and the load parameter of described pump, obtain the pump dynagraoph of described pump, according to described pump dynagraoph, obtain described pump intake pump intake pressure parameter, according to Temperature Distribution and the calculation of property of fluid model of the pit shaft of described rod-pumped well, obtain the physical properties of fluids parameter of described pit shaft, according to described intake pump intake pressure parameter and described physical properties of fluids parameter, obtain the pressure distribution parameter in the annular space between the oil pipe of described pumpingh well and sleeve pipe, according to described pressure distribution parameter, obtain the producing fluid level parameter of described rod-pumped well, so, resistance coefficient computation model can be passed through, inertia eliminated by rod string displacement motion model and rod string LOAD FOR model, the impact of vibration and frrction load, and solve the static load obtaining pump dynagraoph, make the accuracy of the static load of the pump dynagraoph obtained higher, and make to carry out producing fluid level according to the static load of pump dynagraoph again and calculate the accuracy of producing fluid level parameter obtained and be also improved, and by above-mentioned computation model can Real-time Obtaining to producing fluid level face parameter, so, can effectively improve its timeliness, and the measuring method that the application provides obtains when producing fluid level parameter according to the pressure distribution parameter in described annular space, so, the measuring method that the application is provided can also be applied to the oil well controlling casing pressure and produce, make the error-reduction of the producing fluid level calculated.

Accompanying drawing explanation

Fig. 1 is the fundamental diagram of pump in the embodiment of the present invention;

Fig. 2 is wellbore fluids distribution map in the embodiment of the present invention.

In figure, appended with drawings mark is as follows:

10---pump letter, 11---plunger, 12---travelling valve, 13---standing valve, 14---sucker rod, 20---gas column section, 21---gassiness oil column section, 22---mixed liquor section.

Detailed description of the invention

The invention provides a kind of measuring method of rod-pumped well producing fluid level, when guaranteeing computational accuracy, can effectively improve its timeliness, and the oil well controlling casing pressure and produce can also be applied to, make the error-reduction of the producing fluid level calculated.

In order to better understand technique scheme, below in conjunction with Figure of description and concrete embodiment, technique scheme is described in detail.

Before the measuring method describing a kind of rod-pumped well producing fluid level of the present invention, first the operating principle understanding pump is needed, lower mask body is for sucker rod pump, concrete, see Fig. 1, pump comprises pump letter 10, plunger 11, travelling valve 12, standing valve 13 and sucker rod 14, in pump work process, in pump barrel 10, pressure P (t) is with the change in plunger motion direction, by suction pressure P _irise to discharge pressure P _por by P _pbe down to P _i, plunger 11 completes unloading or loads: after standing valve 13 is opened, and liquid sucks pump chamber through the hole of standing valve 13, now P (t)=P _i, plunger 11 has loaded, and pump carries and remains unchanged; After travelling valve 12 is opened, liquid discharges pump chamber through the hole of travelling valve 12, now P (t)=P _p, plunger 11 has unloaded, and pump carries and remains unchanged.

If ignore the inertia force of plunger and liquid, then the equilibrium equation acted on plunger should be:

Upstroke:

F _p(t)=P _p(f _p-f _r)-P (t) f _p+ W _p+ f formula 1

Down stroke:

F _p(t)=P _pf _r-P (t) f _p+ W _p-f formula 2

In formula 1 and formula 2, F _pt () represents the load of pump, unit: N; P _prepresent the pressure on travelling valve 12 top, unit: Pa; P (t) represents pressure in pump barrel 10, unit: Pa; W _prepresent plunger 11 weight, unit: N; F represents the frictional resistance between plunger 11 and pump barrel 10, unit: N; f _prepresent the sectional area of plunger 11, unit: m ²; f _rrepresent the sectional area of sucker rod 14, unit: m ².

Wherein, when the Pump Suction Nozzle pump intake pressure parameter that pump submergence is corresponding and upstroke pump suction pressure between existence determine relation, therefore described Pump Suction Nozzle pump intake pressure parameter can be obtained by indicator card, then the pressure distribution parameter in the annular space utilizing pit shaft multiphase flow model to calculate between the oil pipe of described pumpingh well and sleeve pipe, the intersection point of described Pump Suction Nozzle pump intake pressure parameter and described pressure distribution parameter is the degree of depth of producing fluid level, so, the measuring method of the application is for obtaining described Pump Suction Nozzle pump intake pressure parameter and described pressure distribution parameter, producing fluid level face parameter is obtained with this, described producing fluid level face parameter comprises the degree of depth in producing fluid level face.

Wherein, the measuring method of a kind of rod-pumped well producing fluid level provided by the invention, comprises the following steps:

Step 100: according to resistance coefficient computation model, obtains the resistance coefficient corresponding with described rod-pumped well.

In specific implementation process, the actual stroke of pump can be obtained by pump dynagraoph, but first must know resistance coefficient before accurately calculating pump dynagraoph.In this case, can obtain described resistance coefficient by gibbs resistance coefficient computation model, wherein, described gibbs resistance coefficient computation model is specially:

$C=\frac{2\mathrm{\π}\mathrm{\μ}}{{\mathrm{\ρ}}_r{A}_r}\{\frac{1}{\ln m}+\frac{4}{B_2}(B_1+1)\{B_1+\frac{2}{\frac{\mathrm{\ω}L}{a}\frac{1}{sin\frac{\mathrm{\ω}l}{a}}+cos\frac{\mathrm{\ω}l}{a}}\left\}\right\}$ Formula 3

$m=\frac{D_t}{D_r}$

$B_1=\frac{m^2-1}{2\ln m}-1$

$B_2=m^4-1-\frac{{(m^2-1)}^2}{\ln m}$

In equation 3, μ express liquid viscosity, unit: Pas; ρ _rrepresent the density of sucker rod, unit: Kg/m ³; A _rrepresent the sectional area of sucker rod, unit: m ²; D _trepresent tubing diameter, unit: m; D _rrepresent sucker rod diameter, unit: m; L represents sucker rod length, unit: m; A represents the spread speed of sound wave in rod string (sound wave spread speed in carbon steel is roughly 4900m/s); ω represents crank angular velocity; M represents pipe aperture and sucker rod diameter ratio.

Concrete, formula 3 is single rod string computation model, is only applicable to single-stage sucker rod roofbolt, and multistage sucker rod roofbolt can be divided into multistage calculating by solving, and the endian data of every one-level is carried out multistage solving as the fringe conditions that next stage calculates and can be obtained.

Step 101: according to described resistance coefficient and rod string displacement motion model, obtain the displacement parameter of described rod string.

In specific implementation process, rod string displacement motion model can describe with the wave equation of band damping, specific as follows:

$\frac{\∂U(x,t)}{\∂t^2}=a^2\frac{{\∂}^2(x,t)}{\∂x^2}-c\frac{\∂U(x,t)}{\∂t}$ Formula 4

In formula 4, U (x, t) represents the displacement of t rod string x section part; A represents the spread speed of sound wave in rod string (sound wave spread speed in carbon steel is roughly 4900m/s); C represents damped coefficient. so, after the value being got c by step 100, bring the value of described c into described rod string displacement motion model, the displacement parameter obtaining described rod string specifically can represent with U (x, t).

Wherein, the fringe conditions of formula 4 is suspension point dynamic load function D (t) and polished rod displacement function U (t), and two equations all use the mode of truncation Fourier space to be provided by formula:

$D\left(t\right)=\frac{{\mathrm{\σ}}_0}{2}+\underset{n=1}{\overset{\stackrel{\‾}{n}}{\Σ}}({\mathrm{\σ}}_n\cos n\mathrm{\ω}t+{\mathrm{\τ}}_n\sin n\mathrm{\ω}t)$ Formula 5

$U\left(t\right)=\frac{{\mathrm{\ν}}_0}{2}+\underset{n=1}{\overset{\stackrel{\‾}{n}}{\Σ}}({\mathrm{\ν}}_n\cos n\mathrm{\ω}t+{\mathrm{\δ}}_n\sin n\mathrm{\ω}t)$ Formula 6

Because do not consider rod string gravity in equation 4, so actual dynamic loading function D (t) should be polished rod load deduct sucker rod gravity, and with the fringe conditions of dynamic load function as model.The Fourier coefficient σ of D (t) and U (t) ₀, σ _n, τ _nand ν ₀, ν _n, δ _nsolving equation is as follows:

${\mathrm{\σ}}_n=\frac{\mathrm{\ω}}{\mathrm{\π}}{\∫}_0^{T}D\left(t\right)\cos n\mathrm{\ω}tdt,(n=0,1,2......\stackrel{\‾}{n})$ Formula 7

${\mathrm{\τ}}_n=\frac{\mathrm{\ω}}{\mathrm{\π}}{\∫}_0^{T}D\left(t\right)\sin n\mathrm{\ω}tdt,(n=0,1,2......\stackrel{\‾}{n})$ Formula 8

$v_n=\frac{\mathrm{\ω}}{\mathrm{\π}}{\∫}_0^{T}U\left(t\right)\cos n\mathrm{\ω}tdt(n=0,1,2......\stackrel{\‾}{n})$ Formula 9

${\mathrm{\δ}}_n=\frac{\mathrm{\ω}}{\mathrm{\π}}{\∫}_0^{T}U\left(t\right)\sin n\mathrm{\ω}tdt,(n=0,1,2......\stackrel{\‾}{n})$ Formula 10

Wherein, in above-mentioned formula, ω represents crank angular velocity; T represents the pumping cycle.

Concrete, in real work, D (t) and U (t) provides with the form of indicator card data point, can can be determined with approximate area integral by Fourier coefficient, described Fourier space n maximum occurrences can be 6, and Integration Solving adopts dividing method to be divided into by integral image 144 pieces of wide holding to carry out approximate solution.Carry out abbreviation by the method for variables separation to equation to solve, the change in displacement relation obtaining t rod string x section part is shown below:

$U(x,t)=\frac{\mathrm{\σ}}{2{\mathrm{EA}}_r}x+\frac{{\mathrm{\ν}}_0}{2}+\underset{n=1}{\overset{\stackrel{\‾}{n}}{\Σ}}\[O_n\left(x\right)\cos n\mathrm{\ω}t+P_n\left(x\right)\sin n\mathrm{\ω}t\]$ Formula 46

The variation relation of the dynamic load function of t rod string x section part is such as formula shown:

$F(x,t)={\mathrm{EA}}_r\[\frac{{\mathrm{\σ}}_0}{2{\mathrm{EA}}_r}+\underset{n=1}{\overset{\stackrel{\‾}{n}}{\Σ}}\[\frac{\∂O_n\left(x\right)}{\∂x}\cos n\mathrm{\ω}t+\frac{\∂P_n\left(x\right)}{\∂x}\sin n\mathrm{\ω}t\]$ Formula 47

In t, the roofbolt Weight computation model below the full payload on rod string x section=F (x, t)+rod string x section is as follows:

O _n(x)=(K _nch β _nx+ δ _nsh β _nx) sina _nx+ (μ _nsh β _nx+ ν _nch β _nx) cosa _nx formula 48

P _n(x)=(K _nsh β _nx+ δ _nch β _nx) cosa _nx+ (μ _nch β _nx+ ν _nsh β _nx) sina _nx formula 49

${\mathrm{\α}}_n=\frac{n\mathrm{\ω}}{a\sqrt{2}}\sqrt{1+\sqrt{1+{\left(\frac{C}{n\mathrm{\ω}}\right)}^2}}$

${\mathrm{\β}}_n=\frac{n\mathrm{\ω}}{a\sqrt{2}}\sqrt{-1+\sqrt{+{\left(\frac{C}{n\mathrm{\ω}}\right)}^2}}$

$K_n=\frac{{\mathrm{\σ}}_n{\mathrm{\α}}_n+{\mathrm{\τ}}_n{\mathrm{\β}}_n}{{\mathrm{EA}}_r({{\mathrm{\α}}^2}_n+{\mathrm{\β}}_n^2)}$

${\mathrm{\μ}}_n=\frac{{\mathrm{\σ}}_n{\mathrm{\β}}_n-{\mathrm{\τ}}_n{\mathrm{\α}}_n}{{\mathrm{EA}}_r({\mathrm{\α}}_n^2+{\mathrm{\β}}_n^2)}$

Step 102: according to described resistance coefficient and rod string LOAD FOR model, obtain the load parameter of described rod string.

In specific implementation process, described resistance coefficient is substituted in described rod string LOAD FOR model, obtain the load parameter of described rod string, wherein, described rod string LOAD FOR model comprises sucker rod Gravity calculation model, fluid column LOAD FOR model, fluid by drag evaluation model, the rod string inertial load computation model in valve hole, the frrction load computation model of fluid column inertial load computation model, pump barrel and plunger frrction load computation model, sucker rod and liquid, pipe liquid frrction load computation model and rod string uplift force computation model.

Concrete, described sucker rod Gravity Models is for eliminating the impact of rod string gravity, and in the polished rod load that segmentation calculates, directly deduct the gravity of corresponding length rod string, computation model is as follows:

F _r=q _rgL formula 11

In formula 11, F _rrepresent the aerial gravity of rod string, unit: N; L represents rod string length, unit: m; q _rrepresent every meter of quality of rod string, unit: kg/m.

Concrete, described fluid column LOAD FOR model is specially:

F _l=(A _p-A _m) × P _out-A _p× P _informula 12

In formula 12, F _lrepresent the fluid column load acted on plunger, unit: N; A _mrepresent most next stage sucker rod sectional area, unit: m2; A _prepresent oil pump piston sectional area, m2; P _outrepresent pump discharge place pressure, unit: Pa; P _inrepresent Pump Suction Nozzle place pressure, unit: Pa.

Concrete, described fluid is specially by the drag evaluation model in valve hole

$F_v=\frac{1.5\×2\×{\mathrm{\ρ}}_l}{729\×{\mathrm{\μ}}^2}\×\frac{A_p^3}{f_0^2}\×{(S_p\×N)}^2$ Formula 13

In formula 13, F _vrepresent the resistance of fluid by valve hole, unit: N; ρ _lrepresent fluid density, kg/m ³; f ₀represent valve hole area of passage, unit: m ²; S _prepresent piston effective stroke, unit: m; N represents strokes per minute, unit: rpm; μ represents by testing the valve discharge coefficient determined, is calculated by following formula:

$\left\{\begin{array}{cc}\mathrm{\&mu;}=0.225+0.325\&times;{({\mathrm{lgN}}_{\mathrm{Re}}-4)}^{1.7}& N_{\mathrm{Re}}\&GreaterEqual;{10}^4\\ \mathrm{\&mu;}=0.225\&times;{({\mathrm{lgN}}_{\mathrm{Re}}-3)}^{0.6}& N_{\mathrm{Re}}<{10}^4\end{array}\right.$ Formula 14

$N_{\mathrm{Re}}=\frac{d_{Vo}\&times;A_p\&times;S_p\&times;N\&times;{\mathrm{\&rho;}}_l}{19\&times;f_0\&times;{\mathrm{\&mu;}}_l}$ Formula 15

In formula 14 and formula 15, d _v0represent valve bore dia, unit: m; μ _lrepresent fluid viscosity, unit: Pa.S.

Concrete, described rod string inertial load computation model is specially:

formula 16

formula 17

In formula 16 and formula 17, F _rirepresent rod string inertial load, unit: N; S represents stroke, unit: m; R represents oil pumping machine crank radius, unit: m; L represents pumping unit connecting bar length, unit: m.

Concrete, described fluid column inertial load computation model is specially:

$F_{li}=\frac{F_l\&times;S\&times;N^2}{1790}\&times;(1+r/l)\&times;\frac{A_p-A_r}{A_t-A_r}$ Formula 18

In formula 18, F _lirepresent fluid column inertial load, unit: N; A _trepresent oil pipe sectional area, unit: m ².

Concrete, described pump barrel and plunger frrction load computation model are specially:

$F_p=0.94\&times;\frac{d_p}{d_e}-140$ Formula 19

In formula 19, F _prepresent the frrction load of pump barrel and plunger, unit: N; d _prepresent pump plunger diameter, unit: m; d _erepresent the gap of plunger and lining, unit: m;

Concrete, the frrction load computation model of described sucker rod and liquid is specially:

$F_{rl}=2{\mathrm{\&pi;}}^2{\mathrm{SN\&mu;}}_{l}L\&lsqb;\frac{m^2-1}{(m^2+1)\ln \left(m\right)-(m^2-1)}\&rsqb;$ Formula 20

In formula 20, F _rlindication rod liquid frrction load, unit: N; L represents sucker rod length, unit: m; M represents pipe aperture and sucker rod diameter ratio, d _trepresent pipe aperture, unit: m; d _rrepresent sucker rod internal diameter, unit: m.

Concrete, described pipe liquid frrction load computation model is specially

$F_{tl}=\frac{F_{rl}}{1.3}$ Formula 21

In formula 21, F _tlrepresent pipe liquid frrction load, unit: N.

Concrete, described rod string uplift force computation model is specially

F _rxj=P _j× (A _rj-A _rj+1) (j=1,2 ... m) formula 22

In formula 22, F _rxjrepresent the fluid uplift force that jth grade pumping rod lower surface place is subject to, unit: N; P _jrepresent the fluid pressure that jth grade pumping rod lower surface place is subject to, unit: Pa; A _rjrepresent jth grade pumping rod sectional area, unit: m ²; A _rj+1represent jth+1 grade pumping rod sectional area, unit: m ²; M represents sucker rod progression.

Step 103: according to the displacement parameter of described rod string, obtains the displacement parameter of the pump of described rod string bottom.

In specific implementation process, because the displacement parameter of described rod string is corresponding with the displacement parameter of described pump, so, after the displacement parameter being got described rod string by step 101, the displacement parameter of described pump can be obtained according to the displacement parameter of described rod string, wherein, the displacement parameter of described rod string is identical with the displacement parameter of described pump.

Step 104: according to the load parameter of described rod string, obtains the load parameter of described pump.

In specific implementation process, because the load parameter of described rod string is corresponding with the load parameter of described pump, so, after the load parameter being got described rod string by step 102, the load parameter of described pump can be obtained according to the load parameter of described rod string, wherein, the load parameter of described rod string is identical with the load parameter of described pump.

Step 105: according to the displacement parameter of described pump and the load parameter of described pump, obtain the pump dynagraoph of described pump.

In specific implementation process, after the load parameter of the displacement parameter and described pump that get described pump, directly according to the displacement parameter of described pump and the load parameter of described pump, the pump dynagraoph of described pump can be obtained.

Specifically, calculated by founding mathematical models, eliminate sucker rod dynamic load, the impact that roofbolt stretches etc., obtain shape regular, can the pump dynagraoph of accurate reflected pump practical working situation.Carry out owing to utilizing pump dynagraoph data calculating can effectively eliminate sucker rod dynamic load, roofbolt stretches and the impact of roofbolt frictional resistance etc., so, effectively can reduce error of calculation, makes the producing fluid level parameter that calculates according to described pump dynagraoph also more accurate.

Step 106: according to described pump dynagraoph, obtains described pump intake pump intake pressure parameter.

In specific implementation process, choose the point of load up and down in described pump dynagraoph; According to the described upper and lower point of load and Pump Suction Nozzle pump intake pressure computation model, obtain described intake pump intake pressure parameter.

Specifically, choose the point of load up and down in described pump dynagraoph, described intake pump intake pressure parameter is calculated again according to described Pump Suction Nozzle pump intake pressure computation model, oil reservoir production fluid all can produce a Pressure Drop Δ P through standing valve and travelling valve opening, wherein, described Pump Suction Nozzle pump intake pressure computation model is specially:

$\mathrm{\&Delta;}P=\frac{1}{729}\&CenterDot;\frac{{\mathrm{\&rho;}}_l}{{\mathrm{\&xi;}}^2}\&CenterDot;{\left(\frac{f_p}{f_o}\right)}^2\&CenterDot;{(s\&CenterDot;n)}^2$ Formula 23

In formula 23: ρ _lrepresent the density of crude oil, unit: kg/m ³; ξ represents valve discharge coefficient (and valve opening diameter, liquid viscosity, there is clear and definite functional relation between flow rate of liquid three, can calculate according to described functional relation) f _orepresent valve opening sectional area, unit: m ².

$N_{\mathrm{Re}}=\frac{d_o{V}_f}{\mathrm{\&nu;}}$ Formula 24

In formula 24, N _rerepresent Reynolds number; d _orepresent valve aperture, unit: m; V _frepresent flow stream velocity, unit: m/s; ν express liquid kinematic viscosity, unit: m ²/ s.

Wherein, the pressure P on travelling valve top _pcomputation model is as follows:

P _p=P _h+ ρ _lgL formula 25

Upstroke pump LOAD FOR model, according to formula 3 to formula 22, is specially:

P (t)=P _n-Δ P formula 26

F _pu=P _p(f _p-f _r)-(P _n-Δ P) f _p+ W _p+ f formula 27

Travelling valve down stroke can by following formulae discovery to closing front pump load after opening:

P (t)=P _n+ Δ P formula 28

F _pd=P _pf _r-(P _p+ Δ P) f _p+ W _p-f formula 29

According to formula 28 and formula 29, described intake pump intake pressure parameter can be obtained, specific as follows:

$P_n=\frac{2P_p(f_p-f_r)}{f_p}+2\mathrm{\&Delta;}P+\frac{2f}{f_p}-\frac{f_{pu}-f_{pd}}{f_p}$ Formula 30

Neglect the frictional resistance f between plunger and pump barrel, f _pu-f _pdbe well liquid column load W _l, can be obtained by indicator card data, described intake pump intake pressure parameter is specially:

$P_n=\frac{2P_h(f_p-f_r)}{f_p}+2\mathrm{\&Delta;}P+\frac{W_l}{f_p}$ Formula 31

Well liquid column load W is obtained according to oil well indicator card _l, formula 31 can be utilized to calculate described intake pump intake pressure parameter.

Step 107: according to Temperature Distribution and the calculation of property of fluid model of the pit shaft of described rod-pumped well, obtain the physical properties of fluids parameter of described pit shaft.

In specific implementation process, because subsurface temperature pressure can produce certain influence to wellbore fluids physical parameter, so must consider that in computational process the impact of temperature, pressure convection cell physical parameter and the distribution of temperature in wellbore gradient are described temperature distribution parameter.

Wherein, the density calculation model of crude oil is as follows:

${\mathrm{\&rho;}}_o=\frac{1000({\mathrm{\&gamma;}}_o+1.206\&times;{10}^{-3}{R}_s{\mathrm{\&gamma;}}_g)}{B_o}$ Formula 32

In formula 32, ρ _orepresent the oil density under average pressure and average temperature condition, unit: kg/m ³; γ _orepresent the relative oil density under ground condition; γ _grepresent the gas relative density under ground condition; R _srepresent the dissolved gas oil ratio under average pressure and average temperature condition, unit: m ³/ m ³; B _orepresent the oil volume factor under average pressure and average temperature condition.

Specifically, the computation model of described crude oil API degree is as follows:

${\mathrm{\&gamma;}}_{API}=\frac{141.5}{{\mathrm{\&gamma;}}_o}-131.5$ Formula 33

Concrete, the volume factor of crude oil is specially:

B _o=0.972+0.000147F ^1.175formula 34

Wherein:

$F=5.615R_s\sqrt{\frac{{\mathrm{\&gamma;}}_g}{{\mathrm{\&gamma;}}_o}}+2.25T+40$ Formula 35

Wherein, dissolved gas oil ratio:

$R_s=\frac{{\mathrm{\&gamma;}}_g{(1.404\&times;{10}^{-4}p)}^{1.0937}}{27.64}\&times;{10}^{\frac{11.172{\mathrm{\&gamma;}}_{API}}{1.8T+32+459.67}}({\mathrm{\&gamma;}}_{API}\&le;30)$ Formula 36

$R_s=\frac{{\mathrm{\&gamma;}}_g{(1.404\&times;{10}^{-4}p)}^{1.0937}}{56.06}\&times;{10}^{\frac{10.393{\mathrm{\&gamma;}}_{API}}{1.8T+32+459.67}}({\mathrm{\&gamma;}}_{API}>30)$ Formula 37

In formula 36 and formula 37, T represents average temperature, unit: DEG C; P represents average pressure, unit: Pa.

Concrete, the density of oil mixing with water liquid is specially:

ρ _l=ρ _o(1-f _w)+ρ _wf _wformula 38

In formula 38, f _wrepresent volumetric water content, unit: %.

Concrete, the density of natural gas is specially:

${\mathrm{\&rho;}}_g=3.4844\&times;{10}^{-3}\&times;\frac{{\mathrm{\&gamma;}}_{g}p}{Z(T+273.15)}$ Formula 39

In formula 39, ρ _grepresent the density of natural gas under given temperature and pressure conditions, unit: kg/m ³.

Concrete, described Wellbore Temperature Field computation model is as follows:

Because the change of formation temperature along with the degree of depth constantly changes, and the change of temperature can cause the change of wellbore fluids physical parameter, so diverse location place formation temperature must be calculated in the design, according to temperature layer fluid physical parameter definitely, rule of thumb formula can calculate the Temperature Distribution along pit shaft:

$G=\frac{Q_l\&times;1000}{24}$ Formula 40

$K_P=\frac{1}{1.1573+5.246\&times;e^{-\frac{G}{1000}}}$ Formula 41

$B_{ATA}=\frac{2{\mathrm{\&pi;K}}_P}{G(1+f_w)}$ Formula 42

$t=t_0+\frac{t_r-t_0}{B_{ATA}H}\&lsqb;B_{ATA}L+1-e^{-B_{ATA}(H-L)}\&rsqb;$ Formula 43

In formula 40, formula 41, formula 42 and formula 43, Q _lrepresent oilwell produced fluid amount, unit: t/d; f _wrepresent quality moisture content, unit: %; t ₀represent earth's surface thermostat layer temperature, unit: DEG C; t _rrepresent reservoir temperature, unit: DEG C; H represents midpoint of pay zone, unit: m; L represents the calculation level degree of depth, unit: m.

Step 108: according to described intake pump intake pressure parameter and described physical properties of fluids parameter, obtain the pressure distribution parameter in the annular space between the oil pipe of described pumpingh well and sleeve pipe.

In specific implementation process, see Fig. 2, fluid in annular space between oil pipe and sleeve pipe is due to gravitational differentiation, general formation three sections: gas column section 20, gassiness oil column section 21 and oil, gas, water carry out the mixed liquor section 22 mixed, and described intake pump intake pressure parameter is gas column section 20 and gassiness oil column section 21 two sections of pressure sums:

P _n=P _d+ Δ P _oformula 44

In formula 44, P _nrepresent intake pump intake pressure, unit: Pa; P _drepresent the pressure at producing fluid level place, unit: Pa; Δ P _orepresent the pressure that producing fluid level produces to the oil column at pump place, unit: Pa.

Wherein, annular space gas column pressure P _daccount form is as follows:

Because rod-pumped well annular space flow section is relatively large, and throughput in general can not be very large, therefore the negligible pressure loss caused due to frictional resistance and kinetic energy.Consider that the density of gas column changes with the change of pressure, temperature, the pressure at producing fluid level place is obtained by following formula:

$P_D\left(X\right)=P_{so}\exp \left(\frac{{\mathrm{\&rho;}}_{go}{\mathrm{gxT}}_0}{P_0{T}_{av}{Z}_{av}}\right)$ Formula 45

In formula 45, x represents the degree of depth counted from well head, unit: m; G represents acceleration of gravity, unit: m/s2; T ₀, P ₀represent the temperature and pressure under the status of criterion, unit: K and MPa; ρ _g0represent the gas density under the status of criterion, unit: kg/m3; T _avrepresent the Gas Compression Factor under average temperature; Z _avrepresent the Gas Compression Factor under average temperature and pressure; P _sorepresent surface casing pressure (getting its absolute value), unit: MPa; P _dx () represents the gas column pressure (getting its absolute value) at x place, unit: MPa.

Further, the pressure Δ P that produces to the oil column at pump place of producing fluid level _oaccount form is as follows:

Concrete, the pressure Δ P that producing fluid level produces to the oil column at pump place _o, oil gradient distribution in oil jacket annular space can be calculated by multiphase flow model and obtain.

Step 109: according to described pressure distribution parameter, obtains the producing fluid level parameter of described rod-pumped well.

In specific implementation process, can by drawing the indicator card of rod-pumped well; First fluid column load is determined; Then calculate pump dynagraoph, determine that liquid carries; Then described entrance pump intake pressure parameter is calculated; Calculate the pressure distribution parameter of annular space fluid column again; And then calculate the pressure distribution parameter in annular space, finally determine that the intersection point of the pressure distribution parameter in annular space head of liquid distributed constant and annular space is producing fluid level parameter, wherein, the parameter in present specification all can represent by use curve.

In actual application, shown in the contrast table table 1 specific as follows of the producing fluid level parameter obtained by the measuring method of the application and actual dynamic oil level.

Table 1

Wherein, by setting up rod-pumped well producing fluid level forecast model, ground merit figure is converted into pump dynagraoph, then quantitative Treatment is carried out to pump dynagraoph, and then calculate well fluid level in conjunction with the basic data of oil well and crude oil property parameter.Through field trial, precision of prediction about 3%, has that precision is high, the advantage of good reliability, and can predict in real time, improves the real-time of its prediction.

In actual application, the measurement of fluid level depth of oil well has been carried out by the measuring method of the application for certain actual production oil well, first the correlation technique data of this oil well described is gathered, comprise the basic means of production that oil well is normally produced, the data such as oil-extractor polish-rod stroke, jig frequency and pump size, lower-continuous mapping, oil density, moisture content.Also should comprise the long and grade of steel information of the diameter of rod string at different levels, bar for tapered rod string combined system, indicator card data are load displacement data, and the concrete well data that obtains is as shown in table 2 and table 3.

Dark/m in oil reservoir	1921.95	Pump footpath/mm	44
				Gas relative density	0.7	Pump is dark/m	1696.3
Relative oil density	0.9	Stroke/m	6
				Formation temperature/DEG C	60	Jig frequency	1.8
Moisture content	0.633	Liquid output/t	8.04
				Viscosity of crude/mPa.s	640	Oil production/t	2.95
Produce steam oil ratio (SOR)	10	Oil pressure/MPa	0.86
				Pipe aperture/mm	62.0	Casing pressure/MPa	1.83
Casing inner diameter/mm	139.7	Back pressure/MPa	0.83

Table 2

Table 3

Concrete, according to the data in table 2 and table 3, measured described oil well by the measuring method of the application, the pump dynagraoph data obtaining described oil well are as shown in table 4.

Table 4

Further, namely from table 4, Maximal loading and load minimum value is chosen from the pump dynagraoph of prediction, then producing fluid level prediction is carried out in conjunction with basic data, wherein, in table 4, pump dynagraoph Maximal loading is 24.1KN and minimum value is-1.12KN, and load difference is 25.22KN, calculating PIP is 0.13MPa, the producing fluid level parameter measuring described oil well in conjunction with the indicator card of described oil well is again 1668m, and actual dynamic oil level is 1680m, and error is-0.714%.

By an embodiment or multiple embodiment, the present invention has following beneficial effect or advantage:

Due to the measuring method of the rod-pumped well producing fluid level in the embodiment of the present application, according to resistance coefficient computation model, rod string displacement motion model and rod string LOAD FOR model, obtain the displacement parameter of described rod string and the load parameter of described rod string, according to the displacement parameter of described rod string, obtain the displacement parameter of the pump of described rod string bottom, and according to the load parameter of described rod string, obtain the load parameter of described pump, according to the displacement parameter of described pump and the load parameter of described pump, obtain the pump dynagraoph of described pump, according to described pump dynagraoph, obtain described pump intake pump intake pressure parameter, according to Temperature Distribution and the calculation of property of fluid model of the pit shaft of described rod-pumped well, obtain the physical properties of fluids parameter of described pit shaft, according to described intake pump intake pressure parameter and described physical properties of fluids parameter, obtain the pressure distribution parameter in the annular space between the oil pipe of described pumpingh well and sleeve pipe, according to described pressure distribution parameter, obtain the producing fluid level parameter of described rod-pumped well, so, resistance coefficient computation model can be passed through, inertia eliminated by rod string displacement motion model and rod string LOAD FOR model, the impact of vibration and frrction load, and solve the static load obtaining pump dynagraoph, make the accuracy of the static load of the pump dynagraoph obtained higher, and make to carry out producing fluid level according to the static load of pump dynagraoph again and calculate the accuracy of producing fluid level parameter obtained and be also improved, and by above-mentioned computation model can Real-time Obtaining to producing fluid level face parameter, so, can effectively improve its timeliness, and the measuring method that the application provides obtains when producing fluid level parameter according to the pressure distribution parameter in described annular space, so, the measuring method that the application is provided can also be applied to the oil well controlling casing pressure and produce, make the error-reduction of the producing fluid level calculated.

To the above-mentioned explanation of the disclosed embodiments, professional and technical personnel in the field are realized or uses the present invention.Apparent, defined herein General Principle will be made for those skilled in the art when not departing from the spirit or scope of invention, can to realize in other embodiments the multiple amendment of these embodiments.Therefore, the present invention can not be limited and these embodiments shown in this article, but will meet the widest scope consistent with principle disclosed herein and novel features.

Claims (6)

1. a measuring method for rod-pumped well producing fluid level, is characterized in that, comprising:

According to resistance coefficient computation model, obtain the resistance coefficient corresponding with described rod-pumped well;

According to described resistance coefficient and rod string displacement motion model, obtain the displacement parameter of described rod string; And

According to described resistance coefficient and rod string LOAD FOR model, obtain the load parameter of described rod string;

According to the displacement parameter of described rod string, obtain the displacement parameter of the pump of described rod string bottom; And

According to the load parameter of described rod string, obtain the load parameter of described pump;

According to the displacement parameter of described pump and the load parameter of described pump, obtain the pump dynagraoph of described pump;

According to described pump dynagraoph, obtain described pump intake pump intake pressure parameter;

According to Temperature Distribution and the calculation of property of fluid model of the pit shaft of described rod-pumped well, obtain the physical properties of fluids parameter of described pit shaft;

According to described intake pump intake pressure parameter and described physical properties of fluids parameter, obtain the pressure distribution parameter in the annular space between the oil pipe of described pumpingh well and sleeve pipe;

According to described pressure distribution parameter, obtain the producing fluid level parameter of described rod-pumped well.

2. the method for claim 1, is characterized in that, described resistance coefficient computation model, is specially:

$C=\frac{2\mathrm{\&pi;}\mathrm{\&mu;}}{{\mathrm{\&rho;}}_r{A}_r}\{\frac{1}{\ln m}+\frac{4}{B_2}(B_1+1)\{B_1+\frac{2}{\frac{\mathrm{\&omega;}L}{a}\frac{1}{sin\frac{\mathrm{\&omega;}l}{a}}+cos\frac{\mathrm{\&omega;}l}{a}}\left\}\right\};$

Wherein, $m=\frac{D_t}{D_r},B_1=\frac{m^2-1}{2\ln m}-1,B_2=m^4-1-\frac{{(m^2-1)}^2}{1nm}$

μ express liquid viscosity in formula; ρ _rrepresent the density of sucker rod; A _rrepresent the sectional area of sucker rod; D _trepresent tubing diameter; D _rrepresent sucker rod diameter; L represents sucker rod length; C represents resistance coefficient.

3. method as claimed in claim 2, is characterized in that, described according to described resistance coefficient and rod string displacement motion model, obtains the displacement parameter of described rod string, is specially:

Substituted in described rod string displacement motion model by described resistance coefficient, obtain the displacement parameter of described rod string, wherein, described rod string displacement motion model is specially:

$\frac{\&part;U(x,t)}{\&part;t^2}=a^2\frac{{\&part;}^2(x,t)}{\&part;x^2}-c\frac{\&part;U(x,t)}{\&part;t}$

In formula:

U (x, t) represents the displacement of t rod string x section part;

A represents the spread speed of sound wave in rod string.

4. method as claimed in claim 3, is characterized in that, described according to described resistance coefficient and rod string LOAD FOR model, obtains the load parameter of described rod string, specifically comprises:

Described resistance coefficient is substituted in described rod string LOAD FOR model, obtain the load parameter of described rod string, wherein, described rod string LOAD FOR model comprises sucker rod Gravity calculation model, fluid column LOAD FOR model, fluid by drag evaluation model, the rod string inertial load computation model in valve hole, the frrction load computation model of fluid column inertial load computation model, pump barrel and plunger frrction load computation model, sucker rod and liquid, pipe liquid frrction load computation model and rod string uplift force computation model.

5. method as claimed in claim 4, is characterized in that, described according to described pump dynagraoph, obtains described pump intake pump intake pressure parameter, specifically comprises:

Choose the point of load up and down in described pump dynagraoph;

According to the described upper and lower point of load and Pump Suction Nozzle pump intake pressure computation model, obtain described intake pump intake pressure parameter.

6. method as claimed in claim 5, it is characterized in that, described Pump Suction Nozzle pump intake pressure computation model is specially:

$P_n=\frac{2P_h(f_p-f_r)}{f_p}+2\mathrm{\&Delta;}P+\frac{W_l}{f_p},$

Wherein, Δ P represents the Pressure Drop that oil reservoir production fluid produces through standing valve and travelling valve opening; W _lrepresent well liquid column load.