CN104239693A - Method and system for calculating daily fluid production rate in valve leakage state of oil pump - Google Patents

Abstract

The invention discloses a method and a system for calculating a daily fluid production rate in a valve leakage state of an oil pump. The calculation method comprises the following steps of determining an effective stroke of an underground plunger pump in the valve leakage state, i.e. the daily fluid production rate is calculated regardless of the influence of valve leakage within the effective stroke; calculating instantaneous leakage by virtue of a closing point, determined after the valve leakage of the plunger pump, of a fixed valve or a floating valve, and calculating daily valve leakage according to the instantaneous leakage; subtracting the daily valve leakage from the daily fluid production rate calculated regardless of the influence of valve leakage within the effective stroke to obtain the daily fluid production rate in the valve leakage state of the plunger pump. The calculation system comprises a module for calculating the daily fluid production rate regardless of the influence of valve leakage within the effective stroke, a daily valve leakage calculation module and a module for calculating the daily fluid production rate in the valve leakage state. According to the method and the system, the shortcomings of a conventional indicator diagram metering method are compensated, and the indicator diagram metering accuracy is improved.

Description

The computing method of daily fluid production rate and system thereof under oil well pump valve leakage state

Technical field

The present invention relates to a kind of rod-pumped well Liquid output computing technique field, particularly a kind of being applicable to utilizes actual indicator card to calculate method and the computing system of daily fluid production rate after valve leakage appears in walking-beam pumping unit well.

Background technology

In oilfield development process, enter into the machine instruction statement mining stage after oil well loses blowing ability, conventional oil production method is that oil pumping unit matching down-hole has bar reciprocating pump to produce, and be called for short oil well pump herein, Liquid output separation vessel measures.Power graph method measures and starts application the nineties in last century, instead of separation vessel metering Liquid output gradually; Compared with this technology is measured with separation vessel, because of its advanced technology, uphole equipment and supporting flow process are simple, run and maintenance cost low, oil field widespread use at home at present, but in actual applications, this technology exists following problem:

(1) when after the leakage of oil well pump generation valve, there is mistake in the result of calculation of Liquid output, even when because of valve leakage cause oil well reality not production fluid time, power graph method metering Liquid output result of calculation display oil well still there is certain liquid-producing capacity, be not inconsistent with practical condition.

(2) oil well pump valve leakage points of two kinds forms exist, one be foreign matter between valve ball and valve seat, valve can not be closed, and now actual indicator card and normal contrast change greatly, and distinguish and judgement than being easier to; Two is valve ball or the damage of valve seat surface of contact, valve seat is coordinated not tight with valve ball, the leakage of this situation aggravates gradually, initial stage is not easily found, along with valve leakage is serious gradually, now power graph method error in dipping is also increasing, well mouth of oil well Liquid output declines gradually, and measure Liquid output result and rise gradually and actually to run counter to, as non-early detection valve leakage problem, continue the Liquid output using power graph method metering, the mistake of oil well production trend can be caused, totally unfavorable to the analytical work of oil well and well group.

Summary of the invention

The present invention is directed to the deficiencies in the prior art, computing method and the system thereof of daily fluid production rate under oil well pump valve leakage state in the metering of a kind of power graph method are provided.

For achieving the above object, the technical solution used in the present invention is:

The computing method of daily fluid production rate under oil well pump valve leakage state, method is as follows:

Determine the effective stroke of oil well pump under valve leakage state, namely in effective stroke, do not consider the daily fluid production rate of valve leakage impact;

By the pass close point of determined standing valve or the pass close point of travelling valve after the leakage of oil well pump valve, calculate instantaneous wastage, then calculate day valve wastage according to instantaneous wastage;

With not considering in described effective stroke that the daily fluid production rate of valve leakage impact deducts described day valve wastage, namely draw the daily fluid production rate of oil well pump under valve leakage state.

Above-mentioned computing method, do not consider in described effective stroke that the daily fluid production rate computing method of valve leakage impact are:

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440;$

In formula: Q _y: the daily fluid production rate not considering valve leakage impact in effective stroke, m ³/ d; D: pump size, m; S _i: travelling valve closes close point or standing valve closes the distance of close point to bottom dead centre, m; S _k: travelling valve opening point or standing valve opening point to the distance of bottom dead centre, m; N: jig frequency, min ^-1.

Above-mentioned computing method, described day valve wastage computing method are:

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440;$

Q _l: day valve wastage, m ³/ d; D: pump size, m; ν _i: suspension point travelling speed when travelling valve or standing valve are closed, m/s; θ i: travelling valve or standing valve close the crank angle of close point, °; θ kq: the crank angle of travelling valve or standing valve opening point, °.

The computing system of daily fluid production rate under oil well pump valve leakage state, comprising:

First computing module, for determining the effective stroke of oil well pump under valve leakage state, draws in effective stroke the daily fluid production rate not considering valve leakage impact;

Second computing module, for by the pass close point of determined standing valve or the pass close point of travelling valve after the leakage of oil well pump valve, calculates instantaneous wastage, then calculates day valve wastage according to instantaneous wastage;

3rd computing module, for the daily fluid production rate and described day valve wastage of not considering leakage impact in described effective stroke being subtracted each other, draws the daily fluid production rate of oil well pump under valve leakage state.

Above-mentioned computing system, the first described computing module, for passing through following formulae discovery,

$Q_y=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440;$

In formula: Q _y: the daily fluid production rate not considering valve leakage impact in effective stroke, m ³/ d; D: pump size, m; S _i: travelling valve closes close point or standing valve closes the distance of close point to bottom dead centre, m; S _k: travelling valve opening point or standing valve opening point to the distance of bottom dead centre, m; N: jig frequency, min ^-1.

Above-mentioned computing system, the second described computing module, for passing through following formulae discovery,

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440;$

In formula: Q _l: day valve wastage, m ³/ d; D: pump size, m; ν _i: suspension point travelling speed when travelling valve or standing valve are closed, m/s; θ i: travelling valve or standing valve close the crank angle of close point, °; θ kq: the crank angle of travelling valve or standing valve opening point, °.

Under oil well pump valve leakage state provided by the invention, the computing method of daily fluid production rate and system thereof correctly determine the effective stroke of oil well pump under valve leakage state; According to the key point of leakage merit figure, calculate instantaneous wastage, thus calculate daily fluid production rate, compensate for the deficiency in the metering of current power graph method, improve the accuracy of power graph method metering.

Accompanying drawing explanation

Fig. 1 is rod-pumped well normal indicator diagram.

Fig. 2 is that travelling valve leakage or plunger and working barrel gap increase load-position diagram.

Fig. 3 is standing valve leakage load-position diagram.

In Fig. 1,2,3: A: travelling valve closes close point; B: standing valve opening point; C: standing valve closes close point; D: travelling valve opening point; P: load coordinate, KN; S: displacement coordinate, m.

Fig. 4 is conventional beam-pumping unit rough schematic.

A in Fig. 4: walking beam forearm, m; C: arm lengths after walking beam, m; P: length of connecting rod, m; R: crank length, m; I: walking beam centre of support to the horizontal range at reducer output shaft center, m; H: walking beam centre of support to the height of base bottom, m; G: reducer output shaft center to the height of base bottom, m; K: walking beam centre of support to the distance at reducer output shaft center, m; J: the distance between crank center to walking beam centre of support, m; θ: crank angle, is in 12 o ' clock positions as zero degree using crank, prolongs crank sense of rotation tolerance; φ: zero degree line and K wire clamp angle; The angle of β: C and P; The angle of α: P and R; The angle of χ: C and J; The angle of ρ: K and J; The angle of ψ: C and K; ψ _b: the ψ angle of polished rod when extreme lower position; ψ _t: the ψ angle of polished rod when extreme higher position; θ _k: the angle of K and R; ω: crank rotation angle speed, generally equals π N/30, S ^-1; N: jig frequency, min ^-1.

Fig. 5 is the normal actual indicator card of certain well.

Fig. 6 is certain well travelling valve leakage actual indicator card.

Fig. 7 is the pumping unit hanging point displacement of CYJY12-6-73HF type and crank angle relation curve.

Fig. 8 is CYJY12-6-73HF type pumping unit hanging spot speed and crank angle relation curve.

Embodiment

Discuss in detail below at present power graph method correctly can not calculate the problem that actual daily fluid production rate after valve leakage appears in oil well pump, the present invention, by the fusion with existing measurement technology, improves the process of power graph method accurate measurement degree.

(1) basic calculation of power graph method metering at present.

Composition graphs 1, power graph method metering carries out daily fluid production rate calculating according to actual indicator card application oil well pump discharge capacity formula in conjunction with effective stroke.Effective stroke is judged actual indicator card geometric properties and Curvature varying analysis by power graph method measuring software, and obtain the opening point D of ram pump travelling valve and close close point A, namely D A is effective stroke at the projector distance of merit figure displacement coordinate.

(2) reason that under valve leakage state, power graph method metering Liquid output is inaccurate.

When oil well pump normally works, travelling valve and standing valve alternately open and close, complete feed liquor, discharge opeing process.When wherein leakage appears in any one group of valve, normal closedown and the unlatching of another group valve all can be affected.

There is leakage in Fig. 2 travelling valve, namely defined travelling valve and can not realize closing, in this case, D A truly can not reflect effective stroke, and still apply current method and calculate, its result of calculation is obviously incorrect.

There is leakage in Fig. 3 standing valve, though now D A can reflect effective stroke, in the whole service of pump, valve leakage phenomena exists thereupon, directly by current computing method, consequently inaccurate.

(3) redefine oil well pump there is valve leakage after effective stroke, i.e. the plunger useful volume abdicating at work or compress.Contrast main descriptive geometry from rod-pumped well typical case travelling valve leakage load-position diagram Fig. 2 and normal indicator diagram Fig. 1 to be characterized as: it is that increment of load line AB and abscissa axis angle diminish that increment of load slows down, unload i.e. unloading line CD and abscissa axis angle in advance to increase, increment of load line AB is not parallel with unloading line CD, and it is larger that wastage larger increment of load line AB and unloading line CD extend the angle formed.

Reflect in travelling valve leakage merit figure, standing valve is opened B point in B point and normal merit figure Fig. 1 and is contrasted and move to right, close close point C to move to left, namely the shift length of standing valve opening in each stroke shortens than normal merit figure (Fig. 1), external agency just must can enter working barrel under standing valve opening, therefore, when travelling valve is missed, standing valve opening point B is to the distance of closing close point C, and namely BC could as the effective stroke under travelling valve leakage state.Plunger and working barrel wearing clearance increase misses that miss the graphic feature of merit figure Fig. 2 with travelling valve basically identical, takes same method calculating effective stroke.

Standing valve leakage merit figure Fig. 3, also can cause same impact because standing valve leaks to the open and close of travelling valve, therefore when standing valve is missed, and effective stroke when travelling valve opening point D is standing valve leakage to the absolute distance closing close point A.

(4) determination of wastage key point is calculated.

Because travelling valve is not closed completely, in the whole course of work of oil well pump, certain media in plunger upper part oil pipe is flow backwards by ball and ball seat blow-by place and enters in the working barrel of below oil pump plunger piston, the size of its wastage depends on plunger upper part fluid column pressure, the sectional area size of liquid viscosity and leakage points, fluid column pressure is larger, leakage points sectional area is larger, wastage is larger, when there is leakage in travelling valve, if on plunger fluid column pressure and leakage points sectional area constant time, wastage is invariable in the whole course of work of oil well pump, namely the leakage volume (m in the unit interval ³/ s).

Oil well pump to-and-fro movement under sucker rod drives, the characteristics of motion of oil pumper is due to the constraint by four-bar mechanism, the motion of horse head suspension point is in speed change state all the time, its characteristics of motion is similar to simple harmonic motion, when upper and lower dead point, travelling speed is the slowest, and runs the fastest when the half way of upstroke and down stroke, when plunger is upwards run by bottom dead centre, because initial velocity is slow, wastage is greater than the up space abdicated of plunger, the fluid column pressure of plunger upper part still can be delivered in the working barrel of plunger bottom, standing valve can not be opened by fluid column pressure effect, along with the travelling speed of plunger is accelerated gradually, when plunger is up, when the instantaneous space abdicated is greater than instantaneous leakage volume, pressure drop in the working barrel of plunger bottom, standing valve fall under stress with oil sets annular space fluid column pressure double action under open, medium in annular space just can enter, therefore when standing valve is opened instantaneously, the space that plunger travelling speed is abdicated, just equal because travelling valve misses the leakage medium volume of filling, namely the projected position of standing valve opening point B on displacement coordinate S on travelling valve leakage load-position diagram, but due to transmit motion sucker rod in the course of the work bearing load change and there is elastic deformation, i.e. stroke loss, the time causing plunger to be moved up by bottom dead centre is more delayed than the traveling time of suspension point, therefore plunger is different from suspension point initial stage translational speed by the move upward speed at initial stage of bottom dead centre, and in polished rod upstroke the second half, translational speed declines gradually, and the variable motion of plunger translational speed now substantially in suspension point is synchronous, the speed moved upward along with plunger declines gradually, the space abdicated when plunger is up, equal travelling valve bleed space that medium fills time, standing valve is closed by self gravitation effect, manage outer medium no longer to enter in working barrel, the key point that therefore during travelling valve leakage, instantaneous wastage calculates should be the pass close point of standing valve, plunger and working barrel wear and tear to cause gap to increase to miss and also take same method to calculate.In like manner, the key point that during standing valve leakage, the pass close point of travelling valve calculates as wastage.

(5) calculating of the instantaneous travelling speed of suspension point.

The instantaneous travelling speed of suspension point, by the impact of multiple factors, comprising the geometric relationship of the stroke of oil pumper, jig frequency, oil pumper four-bar mechanism and size, the impact providing motor four some factors of power, wherein motor is in the practical application of rod-pumped well, constant speed run motor accounts for the overwhelming majority, the impact that motor gear box operates is not considered in this research, thinks that motor is constant speed running.Therefore accurately to calculate suspension point travelling speed during key point, just must consider the structure of ground pumping unit oil pumper Fig. 4.

In sum, the present invention is the method that after valve leakage appears in oil well pump, application actual indicator card calculates daily fluid production rate, is the improvement to current power graph method measurement technology.On the basis that current power graph method measures, upgrading continuous data storehouse, adds oil pumper geometrical characteristic parameter, strengthens the identification of typical merit figure vector characteristic, still adopts current method to calculate Liquid output during normal condition.Using computing method of the present invention as alternative, when software determine oil well pump exist valve leakage time, automatically select these computing method to carry out Liquid output calculating.

Specifically described below.

(1) computing method:

The computing method of the typical merit figure that oil well pump is working properly.

Oil well pump typical merit figure working properly comprises normal merit figure Fig. 1,5, typical feed flow deficiency merit figure, wax deposition type merit figure, viscous crude effect type merit figure.This quasi-representative merit figure graphic feature be not occurs because oil well pump existing problems with the graphic difference of normal merit figure, the reason affecting its change is that external force is done, and therefore applies the calculating that computing method that current power graph method measures carry out Liquid output.

In addition Pumping with gushing type merit figure, this type of merit figure is also had to be not suitable for applying the calculating that power graph method carries out Liquid output.

The computing method of oil well pump operation irregularity merit figure.

Oil well pump operation irregularity merit figure comprises travelling valve leakage merit figure Fig. 2, standing valve leakage merit figure Fig. 3, and plunger and working barrel gap increase merit figure (basically identical with Fig. 2).This type of merit figure makes because of oil well pump existing problems itself graphic difference that merit figure feature and normal contrast occur, is applicable to the calculating carrying out daily fluid production rate by computing method of the present invention.

(2) calculating of the present invention to Liquid output is illustrated

By reference to the accompanying drawings 2,4, with travelling valve leakage, ground pumping unit is rear-mounted beam-pumping unit is that example is described.

Still exist because missing in effective stroke, instantaneous wastage is constant, and the discharge capacity formula therefore calculated under travelling valve leakage state is:

Q＝Q _y-Q _L

Q: daily fluid production rate, (m ³/ d),

Q _y: the daily fluid production rate not considering valve leakage impact in effective stroke, (m ³/ d),

Q _l: day valve wastage, (m ³/ d),

$Q_y=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440$

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440$

$t_L=\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{360}\×60\÷N$

In formula: ν _i: suspension point speed, suspension point travelling speed when this formula refers to that standing valve is closed, namely misses liquid instantaneous liquid-column height in working barrel, m/s;

T _l: suspension point working time in effective stroke, s;

θ i: standing valve closes the crank angle of close point, °;

θ kq: the crank angle of standing valve opening point, °;

S _i: standing valve closes the distance of close point to bottom dead centre, m;

S _k: standing valve opening point is to the distance of bottom dead centre; M;

Due to ν _iand t _lonly not relevant with stroke (S), jig frequency (N), also there are much relations with used ground pumping unit simultaneously, the oil pumper of different model, when stroke, jig frequency are identical, the instantaneous velocity of its same suspension point position is different, reason is that the physical dimension difference of four-bar mechanism and sense of rotation determined, will calculate accurately, must consider this factor of actual movement rule of four-bar mechanism.

First the crank angle when suspension point is in bottom dead centre is obtained.

That is: S _ithe crank angle θ of=0, S _i=A (ψ b-ψ), works as S _iwhen=0, ψ b-ψ=0, therefore ψ b=ψ;

Calculate standing valve turn-off transient plunger translational speed (instantaneous height of leakage fluid column):

this formula is applicable to the correlation computations of rear-mounted (comprising out-phase) oil pumper.

Example: certain producing well uphole equipment adopts CYJY12-6-73HF type oil pumper, and working system is S=6 rice, and N=3.27 beat/min, φ 44mm oil well pump is produced; Adopt power graph method metering Liquid output, production in early stage merit figure is characterized as oil well pump (Fig. 5) working properly, and daily fluid production rate is 36.5m ³/ d, mobile separation vessel is examined as 35.3m ³/ d.Later stage merit figure changes, load-position diagram feature instantiation travelling valve leakage (Fig. 6), and power graph method metering daily fluid production rate is 38.5m ³/ d, daily fluid production rate 25.4m examined by mobile separation vessel ³/ d, current power graph method metric results and actual Liquid output are not inconsistent.

Apply the present invention below and to calculate under oil well pump valve leakage state this well daily fluid production rate under Liquid output:

First associ-ated motion parameters is calculated according to CYJY12-6-73HF oil pumper physical dimension and working system:

CYJY12-6-73HF type oil pumper kinematic parameter abridged table

Working system 6m/3.27n

S is worked as in table _iwhen=0, θ=11.851 °, Ψ b=81.276 °.

S is obtained from Fig. 6 _i=5.95m, S _k=0.9m, N=3.27n/min

CYJY12-6-73HF type oil pumper kinematic parameter table generates Fig. 7 and checks in θ _i=189 °, θ _kq=53 °, parameter list generates Fig. 8 and checks in ν _i=0.203m/s

Bring formula into:

$Q_y=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440=36.14m^3/d$

$Q_L=\frac{{\mathrm{\π}}^{D^2}}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440=10.07m^3/d$

Q＝36.14-10.07＝26.07m ³/d

Calculating daily fluid production rate under travelling valve leakage state with the present invention is 26.07m ³/ d, daily fluid production rate synchronously examined by mobile separation vessel is 25.4m ³/ d, difference is only 0.67m ³, error rate is only 2.6%.

It should be noted last that, above embodiment is only in order to illustrate technical scheme of the present invention and unrestricted, although with reference to example to invention has been detailed description, those of ordinary skill in the art is to be understood that, can modify to technical scheme of the present invention or equivalent replacement, and not departing from the spirit and scope of technical solution of the present invention, it all should be encompassed in the middle of right of the present invention.

Claims (6)

1. the computing method of daily fluid production rate under oil well pump valve leakage state, is characterized in that method is as follows:

Determine the effective stroke of down-hole ram pump under valve leakage state, namely in effective stroke, do not consider the daily fluid production rate of valve leakage impact;

By the pass close point of determined standing valve or the pass close point of travelling valve after the leakage of ram pump valve, calculate instantaneous wastage, then calculate day valve wastage according to instantaneous wastage;

With not considering in described effective stroke that the daily fluid production rate of valve leakage impact deducts described day valve wastage, namely draw the daily fluid production rate of oil well pump under valve leakage state.

2. computing method as claimed in claim 1, is characterized in that: do not consider in described effective stroke that the daily fluid production rate computing method of valve leakage impact are:

$Q_y=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440;$

In formula: Q _y: the daily fluid production rate not considering valve leakage impact in effective stroke, m ³/ d; D: pump size, m; S _i: travelling valve closes close point or standing valve closes the distance of close point to bottom dead centre, m; S _k: travelling valve opening point or standing valve opening point to the distance of bottom dead centre, m; N: jig frequency, min ^-1.

3. computing method as claimed in claim 1, is characterized in that: described day valve wastage computing method are:

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440;$

Q _l: day valve wastage, m ³/ d; D: pump size, m; ν _i: suspension point travelling speed when travelling valve or standing valve are closed, m/s; θ i: travelling valve or standing valve close the crank angle of close point, °; θ kq: the crank angle of travelling valve or standing valve opening point, °.

4. the computing system of daily fluid production rate under oil well pump valve leakage state, is characterized in that, comprising:

First computing module, for determining the effective stroke of down-hole ram pump under valve leakage state, draws in effective stroke the daily fluid production rate not considering valve leakage impact;

Second computing module, for by the pass close point of determined standing valve or the pass close point of travelling valve after the leakage of oil well pump valve, calculates instantaneous wastage, then calculates day valve wastage according to instantaneous wastage;

3rd computing module, for the daily fluid production rate and described day valve wastage of not considering leakage impact in described effective stroke being subtracted each other, draws the daily fluid production rate of oil well pump under valve leakage state.

5. computing system as claimed in claim 4, is characterized in that, the first described computing module, for passing through following formulae discovery,

$Q_y=\frac{\mathrm{\π}{D}^2}{4}\×(S_i-S_k)\×N\×1440;$

In formula: Q _y: the daily fluid production rate not considering valve leakage impact in effective stroke, m ³/ d; D: pump size, m; S _i: travelling valve closes close point or standing valve closes the distance of close point to bottom dead centre, m; S _k: travelling valve opening point or standing valve opening point to the distance of bottom dead centre, m; N: jig frequency, min ^-1.

6. computing system as claimed in claim 4, is characterized in that, the second described computing module, for passing through following formulae discovery,

$Q_L=\frac{\mathrm{\π}{D}^2}{4}\×v_i\×\frac{{\mathrm{\θ}}_i-{\mathrm{\θ}}_{\mathrm{kq}}}{6}\×1440;$

In formula: Q _l: day valve wastage, m ³/ d; D: pump size, m; ν _i: suspension point travelling speed when travelling valve or standing valve are closed, m/s; θ i: travelling valve or standing valve close the crank angle of close point, °; θ kq: the crank angle of travelling valve or standing valve opening point, °.