CN104153982A - Method and device for acquiring characteristic curve of rod-pumped well underground system - Google Patents

Abstract

The invention provides a method and a device for acquiring a characteristic curve of a rod-pumped well underground system. The method includes: using an underground lifting system below a polished rod as a whole, and giving parameters of the rod-pumped well underground system; acquiring the characteristic curve of a pump inlet and outlet pressure difference related to actual displacement of a pump, according to the parameters of the rod-pumped well underground system; further, acquiring a characteristic curve of the pump inlet and outlet pressure difference related to power of the rod-pumped well underground system and acquiring a characteristic curve of the pump inlet and outlet pressure difference related to efficiency of the rod-pumped well underground system.

Description

One is obtained the characteristic method of pumping well downhole system and device

Technical field

The present invention relates to oil field machinery oil technical field, particularly one is obtained the characteristic method of pumping well downhole system and device.

Background technique

Rod pumping system is the mechanical oil production model using the earliest, remains at present domestic and international topmost artificial lift mode.Rod pumping pump is a kind of reciprocating pump, it works under deep-well condition, there is the sucker rod of overlength, in the time of underground work, be subject to the impact of sucker rod and oil pipe resiliently deformable, pump full level etc. very large, make the downhole system that comprises sucker rod, oil pipe and oil well pump there is the reciprocal pump performance characteristic of the common ground of being different from.

For rod pumping system, lack the device characteristics curve that similar electric submersible pump, screw pump system have always, this has increased the complexity of rod pumped well in the time of node analysis and optimal design.Pumping well often adopts trial and error method in the time of optimal design, and iterations is many, long operational time.Owing to there is no the characteristic curve of pumping well downhole system, make the flow process of pumping well optimal design very complicated, and be unfavorable for realizing the optimal design of multiple artificial lifting way and the unification of node analysis method.

Summary of the invention

In order to solve the problem of prior art, the present invention proposes one and obtains the characteristic method of pumping well downhole system and device, set up pumping well downhole system characteristic curve, be conducive to realize the optimal design of multiple artificial lifting way and the unification of node analysis method.

For achieving the above object, the invention provides one and obtain the characteristic method of pumping well downhole system, described method comprises:

Down-hole hoisting system below polished rod is done as a whole, the parameter of given pumping well downhole system;

Utilize the parameter of described pumping well downhole system, obtain the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ.

Optionally, in an embodiment of the present invention, the characteristic step that the pump actual displacement that entrance pressure reduction is corresponding is pumped in described acquisition comprises:

Utilize the effective stroke S of plunger _pobtain loss of plunger stroke with ground stroke S and affect system η _s; Utilize gas liquid ratio R in clearance ratio K, pump to obtain pump full level coefficient η _c; Utilization enters the discharge capacity Q in pump barrel _{pump_in}, wastage q between plunger lining _lossobtain pump leakage influence coefficient η _q; Utilize the volume expansion coefficient B of fluid to obtain fluid volume effects coefficient η _b; Wherein, the effective stroke S of described plunger _p, wastage q between described plunger lining _lossbe and there is the representation that pumps entrance pressure differential deltap P;

Utilize loss of plunger stroke influence coefficient η _s, pump full level coefficient η _c, pump leakage influence coefficient η _qwith fluid volume effects coefficient η _bobtain pump efficiency η _v;

Utilize described pump efficiency η _vwith described theoretical displacement of pump Q _tobtain pump actual displacement Q, obtain pumping the characteristic curve of the pump actual displacement that entrance pressure differential deltap P is corresponding.

Optionally, in an embodiment of the present invention, described method further comprises: obtain the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

Optionally, in an embodiment of the present invention, the characteristic step of system power under the corresponding pumping well of entrance pressure reduction is pumped in described acquisition:

Utilize density p, gravity acceleration g and the effective head H` of pump actual displacement Q, fluid to obtain the useful horsepower N of polished rod _e; Utilize fluid the flow through flow Q of valve opening of resistance coefficient ζ, the density p of fluid, the fluid of valve ball that flows through ₁obtain hydraulic loss power N with pump valve valve seat orifice area A _loss-H; Utilize the wastage q between plunger lining _losswith pump entrance pressure differential deltap P and obtain Volume Loss power N _loss-V; Utilize length l, the plunger of pump footpath D, ground stroke S, jig frequency n, pump gap h, plunger eccentricity epsilon, pump entrance pressure differential deltap P and fluid viscosity μ obtains mechanical loss efficiency N _{loss_M};

Utilize the useful horsepower N of polished rod _e, hydraulic loss power N _loss-H, Volume Loss power N _loss-Vwith mechanical loss efficiency N _{loss_M}obtain polished rod horsepower N _rP, obtain pumping the characteristic curve of system power under the corresponding pumping well of entrance pressure differential deltap P.

Optionally, in an embodiment of the present invention, described method further comprises: obtain the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

Optionally, in an embodiment of the present invention, the characteristic step that the corresponding pumping unit downhole system efficiency of entrance pressure reduction is pumped in described acquisition comprises:

Utilize the useful horsepower N of described polished rod _ewith described polished rod horsepower N _rPobtain pumping unit downhole system efficiency, obtain pumping the characteristic curve of the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

For achieving the above object, the present invention also provides one to obtain the characteristic device of pumping well downhole system, and described device comprises:

The given unit of systematic parameter, as a whole for the down-hole hoisting system below polished rod is done, the parameter of given pumping well downhole system; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ;

The first characteristic curve obtains unit, for utilizing the parameter of described pumping well downhole system, obtains the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump.

Optionally, in an embodiment of the present invention, described device further comprises: the second characteristic curve obtains unit;

Described the second characteristic curve obtains unit, for obtaining the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

Optionally, in an embodiment of the present invention, described device further comprises: the 3rd characteristic curve obtains unit;

Described the 3rd characteristic curve obtains unit, for obtaining the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

Technique scheme has following beneficial effect: obtained and obtained pumping well downhole system characteristic curve by the technical program, be convenient to rod pumping system to carry out node analysis and optimal design.And comprehensively in three characteristic curves, it can integrate and assist more existing theories and method effectively, is conducive to realize the optimal design of multiple artificial lifting way and the unification of node analysis method by the performance characteristic of rod pump downhole system.

Brief description of the drawings

In order to be illustrated more clearly in the embodiment of the present invention or technological scheme of the prior art, to the accompanying drawing of required use in embodiment or description of the Prior Art be briefly described below, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.

Fig. 1 is that one provided by the invention is obtained one of characteristic method flow diagram of pumping well downhole system;

Fig. 2 be one provided by the invention obtain the characteristic method flow diagram of pumping well downhole system two;

Fig. 3 be one provided by the invention obtain the characteristic method flow diagram of pumping well downhole system three;

Fig. 4 is that one provided by the invention is obtained one of characteristic device block diagram of pumping well downhole system;

Fig. 5 be one provided by the invention obtain the characteristic device block diagram of pumping well downhole system two;

Fig. 6 be one provided by the invention obtain the characteristic device block diagram of pumping well downhole system three;

Fig. 7 is discharge capacity composition schematic diagram in the present embodiment;

Fig. 8 is power composition schematic diagram in the present embodiment;

Fig. 9 is pumping well downhole system performance diagram in the present embodiment;

Figure 10 is Q～Δ P plotted curve that in the present embodiment, different PIPs are corresponding;

Figure 11 is that in the present embodiment, different swabbing parameters combine corresponding Q～△ P plotted curve;

Figure 12 is the inflow and outflow plotted curve that in the present embodiment, different swabbing parameters combine corresponding pump intake node.

Embodiment

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

Oil pipe, sucker rod, oil well pump and wellbore fluids influencing each other in the time producing considered in overall evaluation of a technical project of the present invention, down-hole hoisting system below polished rod is done as a whole, in order to predict pumping well downhole system characteristic curve, first want the parameter of given rod pump downhole system, then pump the way of entrance pressure reduction by change, calculate actual displacement and the downhole system power efficiency of the poor correspondence of different pump pressures, finally obtain that discharge capacity～pump pressure is poor, power～pump pressure is poor, efficiency～pump pressure differs from three characteristic curves.

As shown in Figure 1, for one provided by the invention is obtained the characteristic method flow diagram of pumping well downhole system.Described method comprises:

Step 101): the down-hole hoisting system below polished rod is done as a whole, the parameter of given pumping well downhole system;

Step 102): utilize the parameter of described pumping well downhole system, obtain the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ.

Optionally, in an embodiment of the present invention, the characteristic step that the pump actual displacement that entrance pressure reduction is corresponding is pumped in described acquisition comprises:

Utilize the effective stroke S of plunger _p, ground stroke S obtain loss of plunger stroke affect system η _s; Utilize gas liquid ratio R in clearance ratio K, pump to obtain pump full level coefficient η _c; Utilization enters the discharge capacity Q in pump barrel _{pump_in}, wastage q between plunger lining _lossobtain pump leakage influence coefficient η _q; Utilize the volume expansion coefficient B of fluid to obtain fluid volume effects coefficient η _b; Wherein, the effective stroke S of described plunger _p, wastage q between described plunger lining _lossbe and there is the representation that pumps entrance pressure differential deltap P;

Utilize loss of plunger stroke influence coefficient η _s, pump full level coefficient η _c, pump leakage influence coefficient η _qwith fluid volume effects coefficient η _bobtain pump efficiency η _v;

Utilize described pump efficiency η _vwith described theoretical displacement of pump Q _tobtain pump actual displacement Q, obtain pumping the characteristic curve of the pump actual displacement that entrance pressure differential deltap P is corresponding.

As shown in Figure 2, for one provided by the invention is obtained two of the characteristic method flow diagram of pumping well downhole system.On the basis of Fig. 1, described method further comprises:

Step 103): obtain the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

Optionally, in an embodiment of the present invention, the characteristic step that system power under the corresponding pumping well of entrance pressure reduction is pumped in described acquisition comprises:

Utilize density p, gravity acceleration g and the effective head H` of pump actual displacement Q, fluid to obtain the useful horsepower N of polished rod _e; Utilize fluid the flow through flow Q of valve opening of resistance coefficient ζ, the density p of fluid, the fluid of valve ball that flows through ₁obtain hydraulic loss power N with pump valve valve seat orifice area A _loss-H; Utilize the wastage q between plunger lining _losswith pump entrance pressure differential deltap P and obtain Volume Loss power N _loss-V; Utilize length l, the plunger of pump footpath D, ground stroke S, jig frequency n, pump gap h, plunger eccentricity epsilon, pump entrance pressure differential deltap P and fluid viscosity μ obtains mechanical loss efficiency N _{loss_M};

Utilize the useful horsepower N of polished rod _e, hydraulic loss power N _loss-H, Volume Loss power N _loss-Vwith mechanical loss efficiency N _{loss_M}obtain polished rod horsepower N _rP, obtain pumping the characteristic curve of system power under the corresponding pumping well of entrance pressure differential deltap P.

As shown in Figure 3, for one provided by the invention is obtained three of the characteristic method flow diagram of pumping well downhole system.On the basis of Fig. 2, described method further comprises:

Step 104): obtain the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

Optionally, in an embodiment of the present invention, the characteristic step that the corresponding pumping unit downhole system efficiency of entrance pressure reduction is pumped in described acquisition comprises:

Utilize the useful horsepower N of described polished rod _ewith described polished rod horsepower N _rPobtain pumping unit downhole system efficiency, obtain pumping the characteristic curve of the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

As shown in Figure 4, for one provided by the invention is obtained one of characteristic device block diagram of pumping well downhole system.Described device comprises:

The given unit 401 of systematic parameter, as a whole for the down-hole hoisting system below polished rod is done, the parameter of given pumping well downhole system; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ;

The first characteristic curve obtains unit 402, for utilizing the parameter of described pumping well downhole system, obtains the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump.

As shown in Figure 5, for one provided by the invention is obtained two of the characteristic device block diagram of pumping well downhole system.On the basis of Fig. 4, described device further comprises: the second characteristic curve obtains unit 403;

Described the second characteristic curve obtains unit 403, for obtaining the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

As shown in Figure 6, for one provided by the invention is obtained three of the characteristic device block diagram of pumping well downhole system.On the basis of Fig. 5, described device further comprises: the 3rd characteristic curve obtains unit 404;

Described the 3rd characteristic curve obtains unit 404, for obtaining the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

Below by drawing for example system performance curve under rod pumped well, basic calculating parameter is as follows: pit shaft is vertical, well depth 2500m, lower pump degree of depth 2000m, taper of rod is (25mm*700m+22mm*600m+19mm*700m), pipe aperture 0.062m, oil pipe external diameter 0.073m, tubing anchor, pump gap 0.1mm, pump footpath 44mm, stroke 4.5m, jig frequency 4min-1, PIP is 3MPa, production gas-oil ratio 20m3/m3, moisture content is 0 etc.

What one, provided the present embodiment asks the computational methods of pumping well downhole system three characteristic curve Q～Δ p, N～Δ p, η～Δ p based on decomposition method, simultaneously, utilize discharge capacity constitutional diagram, the power constitutional diagram of the pumping well downhole system that Q～Δ p characteristic curve, N～Δ p characteristic curve, η～Δ p characteristic curve provide, can assist characteristic curve is analyzed and explained.

(1) the poor relation of pump displacement and pump pressure

The poor relation curve (Q～Δ P) of discharge capacity and pump pressure is in characteristic curve most important one.Provide and affect each factor of pumping efficiency of oil pump and the poor relation of pump pressure, obtained the pump efficiency under different pressure reduction, thereby further obtain the poor relation with actual displacement of pump pressure.

Given each group device parameter: pump footpath D, ground stroke S and jig frequency n, utilize following formula (0) can obtain Theoretical flowing capacity Q _t, the actual displacement Q of pump is less than Theoretical flowing capacity Q _t, both ratio is called pump efficiency η _v, the influence factor of pump efficiency mainly contains the resiliently deformable of sucker rod, oil pipe, and liquid is in underground and difference ground volume, and the hydraulic slip in pump barrel between full level and the plunger lining of liquid, can be calculated by following formula:

Q _t＝1440*(πD ²/4)*S*n (0)

η _V＝η _Sη _Cη _qη _B (1)

${\mathrm{\η}}_S=\frac{S_p}{S}---\left(2\right)$

$\begin{array}{c}{S}_p=S+e_p-(e_r+e_t)\\ =S+2.076\×{10}^{-10}{\mathrm{Sn}}^2{L}^2-\frac{\mathrm{\ΔP}\·f_p}{E}(\frac{L_i}{f_{\mathrm{ri}}}+\frac{L}{f_i})\end{array}---\left(3\right)$

${\mathrm{\η}}_c=\frac{1-\mathrm{KR}}{1+R}---\left(4\right)$

${\mathrm{\η}}_q=\frac{Q_{\mathrm{pump}\_\mathrm{in}}-q_{\mathrm{loss}}}{Q_{\mathrm{pump}\_\mathrm{in}}}=1-\frac{q_{\mathrm{loss}}}{Q_{\mathrm{pump}\_\mathrm{in}}}---\left(5\right)$

$q_{\mathrm{loss}}=\mathrm{\πD}[(1+{1.5\mathrm{\ϵ}}^2)\frac{h^3\mathrm{\ΔP}}{12\mathrm{v\ρl}}-\frac{U}{2}h]---\left(6\right)$

${\mathrm{\η}}_B=\frac{1}{B}---\left(7\right)$

In formula: η _sfor loss of plunger stroke influence coefficient; η _cfor pump full level coefficient; η _qfor pump leakage influence coefficient; η _bfor fluid volume effects coefficient; S _pfor the effective stroke of plunger, m; e _pfor overtravel, m; e _r, e _tbe respectively the loss of plunger stroke that sucker rod, oil pipe elastic telescopic cause, m; L is rod string overall length, m; Δ P is for pumping entrance pressure reduction, Pa; E is the Young's modulus of steel, Pa; L _ifor each grade pumping rod length, m; f _rifor each grade pumping rod cross-section area, m ²; f _ifor tubing wall cross-section area, m ²; K is clearance ratio; R is gas liquid ratio in pump; q _lossfor the wastage between plunger lining, m ³/ s; Q _{pump_in}for entering the discharge capacity in pump barrel, m ³/ s; D is pump footpath, m; ε is the eccentricity of plunger; H is pump gap, m; The kinematical viscosity of ν fluid, m ²/ s; The density of ρ fluid, kg/m ³; The length of l plunger, m; U is the mean velocity of plunger, m/s; B is the volume expansion coefficient of fluid.

Actual displacement Q can be calculated by Theoretical flowing capacity and pump efficiency, thereby actual displacement and the relation of pump pressure between poor can be obtained.

Q＝Q _tη _V

Utilize technique scheme can draw out following discharge capacity constitutional diagram, it has reflected that actual displacement and every discharge capacity lose along with the poor Changing Pattern of pump pressure visually, supposes that viscosity of crude is 5mPas when calculating.As shown in Figure 7, " " discharge capacity loss that Regional Representative's stroke causes, it increases along with the poor increase of pump pressure; " " the discharge capacity loss that causes of Regional Representative's pump full level; " " leakage causes between Regional Representative's plunger and lining discharge capacity loss, it increases along with the poor increase of pump pressure; " " region is the discharge capacity loss that bulk effect causes, its numerical value is smaller; Below white portion represents actual displacement.In figure, black arrow indication curve is exactly the poor characteristic curve of discharge capacity～pump pressure (Q～Δ P).

(2) the poor relation of polished rod horsepower and pump pressure

After obtaining the poor relation of pump displacement and pump pressure, can further calculate according to the poor and actual displacement of pump pressure input power and the efficiency of downhole system.Polished rod horsepower is the power that pumping unit passes to polished rod, is the input power of downhole system.The method of calculating polished rod horsepower is as follows: obtain polished rod horsepower by calculating useful horsepower, mechanical loss power, Volume Loss power, hydraulic loss power sum, that is:

N _RP＝N _e+N _{Loss_H}+N _{Loss_V}+N _{Loss_M} (8)

N _e＝H'Qρg (9)

$N_{L\_H\_\mathrm{volve}}=\mathrm{\ζ\ρ}\frac{{Q_1}^3}{{2A}^2}---\left(10\right)$

N _{V_L}＝ΔPq _loss (11)

$N_{L\_M\_\mathrm{pump}}=\frac{1}{60}\mathrm{\πDnS}[\frac{\mathrm{\ΔPh}}{2}+\frac{1}{15}\frac{\mathrm{\μl}}{\sqrt{{1-\mathrm{\ϵ}}^2}}\·\frac{\mathrm{nS}}{h}]---\left(12\right)$

In formula: N _rPfor polished rod horsepower, w; N _{loss_H}for hydraulic loss power, w; N _{loss_V}for Volume Loss power, w; N _{loss_M}for mechanical loss power, w.N _efor useful horsepower, w; Q is actual displacement, m ³/ s; H' is effective head, m; The density of ρ fluid, kg/m ³; G is gravity accleration, m ²/ s.ζ is the flow through resistance coefficient (ζ=2.5) of valve ball of fluid; A is pump valve valve seat orifice area, m ²; Q ₁for the flow through flow of valve opening of fluid, m ³/ s.

Utilize the poor relation of polished rod horsepower and pump pressure can obtain power constitutional diagram, it has reflected that available power discharge capacity and every power loss are along with the poor Changing Pattern of pump pressure visually, and when calculating, former oil viscosity is 50mPas.As shown in Figure 8, mechanical loss power is smaller.The impact of the large generation of viscosity of crude is two aspects, has caused hydraulic loss power ratio larger on the one hand, on the other hand by the wastage reducing between plunger and lining.Poor when smaller when pump pressure, Volume Loss is little, and hydraulic loss is preponderated; Poor when larger when pump pressure, Volume Loss starts to account for certain advantage.In figure, black arrow indication curve is exactly the poor characteristic curve of power～pump pressure (N～Δ P).

(3) the poor relation of polished rod efficiency and pump pressure

Utilize following formula can calculate the efficiency of downhole system:

$\mathrm{\η}=\frac{N_e}{N_{\mathrm{RP}}}---\left(13\right)$

According to the ratio of available power and total output, can calculate the poor characteristic curve of efficiency～pump pressure (η～Δ P).

Two, by the performance characteristic of pumping well downhole system comprehensively in three characteristic curves, can effectively integrate output and the efficiency calculation model of sucker-rod pumping system.

By Q～Δ P, N～Δ P, tri-Drawing of Curves of η～Δ P to three characteristic curves that just can obtain rod pump downhole system on a width figure.As shown in Figure 9, three curves are exactly viscosity of crude corresponding characteristic curve while being 5mPas, and other three curves are viscosity of crude corresponding characteristic curve while being 50mPas.Be integrated with like this and be beneficial to optimal design and the analytic process of simplifying rod pumping system, improved speed and the precision of program operation, realize the normalization of various artificial lifting way optimization and analysis.

Three, utilize pumping well downhole system characteristic curve to be convenient to rod pumping system to carry out node analysis and optimal design.

Utilize pumping well downhole system characteristic curve can carry out node analysis and the optimal design of rod pumped well, below taking node analysis as example, introduce this characteristic application.Solution node can be placed on the positions such as shaft bottom, Pump Suction Nozzle, pump discharge.When node analysis, select Vogel method to describe the percolation law of fluid in oil reservoir, describe the flowing law of heterogeneous fluid in pit shaft by Beggs-Brill correlation, describe the performance characteristic of downhole system with above-mentioned characteristic curve.

As taking pump intake as node, calculation procedure is: first given a series of production Q, then, from system two ends, calculate respectively feed pressure and outflow pressure that under different output, pump intake node is corresponding, and wherein the formula of feed pressure is as follows:

P _inflow＝P _wf(Q)－ΔP _dnow(Q) (14)

In formula: P _inflowrepresent feed pressure, P _wf(Q) represent the flowing bottomhole pressure (FBHP) under different output, Δ P _dnow(Q) represent the internal drop of pump well-sinking, need to calculate by well casing multiphase pipe flow Pressure Drop Model.

Outflow pressure is calculated as follows:

P _outflow＝P _wh+ΔP _up(Q)－ΔP _pump(Q) (15)

In formula: P _outflowrepresent outflow pressure, P _whrepresent well head pressure, Δ P _up(Q) represent that well head is to the internal drop of pump discharge oil pipe.Δ P _pump(Q) represent the pressure reduction that pump provides, calculate by characteristic curve.

In the time of node analysis, mainly use Q～Δ P curve, another two curves (N～Δ P, η～Δ P) are mainly used in optimal design.For the ease of contrast and explanation, below each figure only draw Q～Δ P curve.

Rod pump is in the time of actual production, and PIP is often lower than bubble point pressure, and PIP is larger on characteristic curve impact, so need to proofread and correct characteristic curve with PIP in the time of application.As shown in figure 10, provided the Q～Δ P curve after different PIPs are proofreaied and correct.As can be seen from Figure 10,, along with the decline of PIP, it is more and more obvious on characteristic impact.

Figure 11 has provided different stroke jig frequency pumps footpath and has combined corresponding Q～Δ P curve.In figure, 3*4*44 represents that swabbing parameter is combined as: stroke 3m, jig frequency 4min ^-1, pump footpath 44mm.Figure 11 has provided the Q～Δ P characteristic curve under the process data conditions such as different stroke jig frequency pumps footpath, by this suite line, illustrate that ground stroke S, jig frequency n and pump footpath D are on the characteristic impact of Q～Δ P, effectively show the industry characteristics of rod pumping system, and contrast the difference between characteristic curve under different process data conditions.

Figure 12 provides the inflow and outflow curve of pump intake node under several groups of swabbing parameter conditions, and this curve is to utilize the Q～Δ P curve calculation in Figure 11 to obtain according to formula 15.Utilize the intersection point of inflow and outflow curve can obtain the coordinate production under current conditions of manufacture.

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

Claims (9)

1. obtain the characteristic method of pumping well downhole system, it is characterized in that, described method comprises:

Down-hole hoisting system below polished rod is done as a whole, the parameter of given pumping well downhole system;

Utilize the parameter of described pumping well downhole system, obtain the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ.

2. the method for claim 1, is characterized in that, the characteristic step that the pump actual displacement that entrance pressure reduction is corresponding is pumped in described acquisition comprises:

Utilize the effective stroke S of plunger _pobtain loss of plunger stroke with ground stroke S and affect system η _s; Utilize gas liquid ratio R in clearance ratio K, pump to obtain pump full level coefficient η _c; Utilization enters the discharge capacity Q in pump barrel _{pump_in}, wastage q between plunger lining _lossobtain pump leakage influence coefficient η _q; Utilize the volume expansion coefficient B of fluid to obtain fluid volume effects coefficient η _b; Wherein, the effective stroke S of described plunger _p, wastage q between described plunger lining _lossbe and there is the representation that pumps entrance pressure differential deltap P;

Utilize loss of plunger stroke influence coefficient η _s, pump full level coefficient η _c, pump leakage influence coefficient η _qwith fluid volume effects coefficient η _bobtain pump efficiency η _v;

Utilize described pump efficiency η _vwith described theoretical displacement of pump Q _tobtain pump actual displacement Q, obtain pumping the characteristic curve of the pump actual displacement that entrance pressure differential deltap P is corresponding.

3. method as claimed in claim 2, is characterized in that, described method further comprises: obtain the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

4. method as claimed in claim 3, is characterized in that, the characteristic step of system power under the corresponding pumping well of entrance pressure reduction is pumped in described acquisition:

Utilize density p, gravity acceleration g and the effective head H` of pump actual displacement Q, fluid to obtain the useful horsepower N of polished rod _e; Utilize fluid the flow through flow Q of valve opening of resistance coefficient ζ, the density p of fluid, the fluid of valve ball that flows through ₁obtain hydraulic loss power N with pump valve valve seat orifice area A _loss-H; Utilize the wastage q between plunger lining _losswith pump entrance pressure differential deltap P and obtain Volume Loss power N _loss-V; Utilize length l, the plunger of pump footpath D, ground stroke S, jig frequency n, pump gap h, plunger eccentricity epsilon, pump entrance pressure differential deltap P and fluid viscosity μ obtains mechanical loss efficiency N _{loss_M};

Utilize the useful horsepower N of polished rod _e, hydraulic loss power N _loss-H, Volume Loss power N _loss-Vwith mechanical loss efficiency N _{loss_M}obtain polished rod horsepower N _rP, obtain pumping the characteristic curve of system power under the corresponding pumping well of entrance pressure differential deltap P.

5. method as claimed in claim 4, is characterized in that, described method further comprises: obtain the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

6. method as claimed in claim 5, is characterized in that, the characteristic step that the corresponding pumping unit downhole system efficiency of entrance pressure reduction is pumped in described acquisition comprises:

Utilize the useful horsepower N of described polished rod _ewith described polished rod horsepower N _rPobtain pumping unit downhole system efficiency, obtain pumping the characteristic curve of the corresponding pumping unit downhole system efficiency of entrance pressure reduction.

7. obtain the characteristic device of pumping well downhole system, it is characterized in that, described device comprises:

The given unit of systematic parameter, as a whole for the down-hole hoisting system below polished rod is done, the parameter of given pumping well downhole system; Wherein, the parameter of described pumping well downhole system comprises: gas liquid ratio R in clearance ratio K, pump, enter the discharge capacity Q in pump barrel _{pump_in}, volume expansion coefficient B, the jig frequency n of fluid, rod string overall length L, the elastic modulus E of steel, each grade pumping rod length L _i, each grade pumping rod cross-section area f _ri, tube wall cross-section area f produces oil _i, pump footpath D, the eccentricity epsilon of plunger, pump gap h, the kinematical viscosity ν of fluid, the density p of fluid, the length l of plunger, mean velocity U, the effective head H` of plunger, gravity acceleration g, fluid the flow through flow Q of valve opening of resistance coefficient ζ, the fluid of valve ball that flows through ₁, pump valve valve seat orifice area A and fluid viscosity μ;

The first characteristic curve obtains unit, for utilizing the parameter of described pumping well downhole system, obtains the characteristic curve of the actual displacement that pumps entrance pressure reduction respective pump.

8. device as claimed in claim 7, is characterized in that, described device further comprises: the second characteristic curve obtains unit;

Described the second characteristic curve obtains unit, for obtaining the characteristic curve that pumps system power under the corresponding pumping well of entrance pressure reduction.

9. device as claimed in claim 7, is characterized in that, described device further comprises: the 3rd characteristic curve obtains unit;

Described the 3rd characteristic curve obtains unit, for obtaining the characteristic curve that pumps the corresponding pumping unit downhole system efficiency of entrance pressure reduction.