Method for adjusting stroke frequency of rod-pumped well

Abstract

The invention discloses a method for adjusting the stroke frequency of a rod-pumped well. The method comprises the steps that whether the rod-pumped well meets the stroke frequency up-regulation or stroke frequency down-regulation conditions or not is judged; if the condition is met, calculating to increase the parameter running frequency f and then increase or decrease the parameter running frequency f and then decrease; judging whether the parameter up-regulation operation frequency f up exceeds a motor output upper limit frequency f up, and executing the parameter up-regulation operation frequency f up when the parameter up-regulation operation frequency f up is smaller than f up; when f < upper > is greater than or equal to f < upper >, executing motor output upper limit frequency f < upper >; judging whether the down-regulation parameter operation frequency f < lower-limit > exceeds a motor output lower-limit frequency f < lower-limit >, executing the down-regulation parameter operation frequency f < lower-limit > when f < lower-limit > is greater than or equal to f < lower-limit >, and executing the motor output lower-limit frequency f < lower-limit > when f < lower-limit > is less than f < lower-limit >; if the conditions are not met, the stroke frequency up-regulation or stroke frequency down-regulation is not carried out; the problem that the workload is large due to the fact that technicians need to repeatedly try to adjust frequency conversion stroke frequency according to experience is effectively solved.

Description

Technical Field

[0001] The present invention relates to the field of pumping unit well parameter adjustment, and in particular to a method for adjusting the stroke frequency of a pumping unit. Background Art

[0002] When the well is produced at a reasonable submergence and flow pressure, a high formation fluid output and high pump efficiency and system efficiency are guaranteed. When the submergence is too low, pump evacuation and liquid hammer are likely to occur, reducing pump efficiency and system efficiency, and also causing rod and pipe vibration to reduce system service life. When the submergence is too high, the fluid output of the well cannot be fully tapped, affecting economic benefits.

[0003] With the popularity of frequency converters, frequency conversion stroke adjustment has the advantages of convenient operation and easy implementation, and has become the preferred means of parameter adjustment. However, there is currently no clear parameter adjustment guidance method on site, and technical personnel need to rely on experience to repeatedly try to adjust the operating stroke. The parameter adjustment process greatly increases the workload of personnel, and the effect of the pumping wells after adjustment is not ideal. Summary of the invention

[0004] In view of this, the present invention provides a method for adjusting the stroke frequency of an oil pump, which solves the problem that the frequency adjustment of the stroke frequency by frequency conversion requires technicians to make repeated attempts to adjust the stroke frequency based on their experience, which is a heavy workload.

[0005] In order to achieve the above-mentioned invention object, the method for adjusting the pumping frequency of a well includes adjusting the pumping frequency upward and adjusting the pumping frequency downward; wherein:

[0006] Determine whether the pumping well meets the conditions for increasing or decreasing the number of flushing;

[0007] If the pumping frequency condition is met, calculate the pumping well's operating frequency f 后上 , determine the upward adjustment parameter operating frequency f 后上 Whether it exceeds the upper limit frequency f of the motor output 上 , when f 后上 <f 上 , execute the above-mentioned adjustment of the operating frequency f 后上 When f 后上 ≥f 上 , execute the motor output upper limit frequency f 上 If the condition for increasing the number of strokes is not met, the pumping well will not be adjusted upward;

[0008] If the down-regulation condition is met, calculate the down-regulation parameter operation frequency f of the pumping well. 后下 ; Determine the lower reference operating frequency f 后下 Whether it exceeds the lower limit frequency f of the motor output 下 , when f 后下 ≥f 下, execute the lowering of the operating frequency f 后下 , when f 后下 <f 下 , execute the motor output lower limit frequency f 下 If the conditions for reducing the number of strokes are not met, the pumping well will not be adjusted downward.

[0009] In the present disclosure and possible embodiments, the sinking degree L of the pumping well before the measure is obtained f前 and operating frequency f 前 Data, use the indicator diagram to calculate the pump filling degree η before the measure 前 , according to the pump filling degree η 前 , sinking degree L f前 and operating frequency f 前 Data is used to determine whether the pumping well meets the upward adjustment condition or the downward adjustment condition.

[0010] In the present disclosure and possible embodiments, the pumping well front pump filling degree η 前 It is equal to the quotient of the effective stroke of the plunger before the measure and the total stroke of the plunger.

[0011] In the present disclosure and possible embodiments, the condition for increasing the number of strokes is to simultaneously satisfy the pump filling degree η 前 ≥95%, sinking degree L f前 ≥200m and operating frequency f 前 ≤50Hz;

[0012] The condition for reducing the number of strokes is to simultaneously satisfy the pump filling degree η 前 <60%, sinking degree L f前 <200m and operating frequency f 前 >30Hz.

[0013] In the present disclosure and possible embodiments, the motor output upper limit frequency f 上 The range is between 61Hz and 80Hz, and the motor output lower limit frequency f 下 The range is between 10Hz and 29Hz.

[0014] In the present disclosure and possible embodiments, the upper adjustment parameter operating frequency f of the pumping well 后上 The calculation method is:

[0015] Set a reasonable sinking degree L f后 , calculate the dynamic liquid surface depth h after the measure 后 According to the oil well inflow dynamic calculation formula, the daily liquid production after the measures is predicted to be Q 液后 , pump filling degree η after setting measures 泵后 , calculate the upper parameter operation frequency f of the pumping well 后上 ;

[0016] The formula for the calculation is:

[0017]

[0018] In the formula, Q 液后 is the daily liquid output after the measures, m 3 / d;A p is the cross-sectional area of ​​the plunger, m 2 ; K is the yield coefficient; i 减 P is the ratio of the motor speed to the speed of the output shaft of the reduction gearbox; 极 is the number of motor pole pairs; pump filling degree η 泵后 ,%.

[0019] In the present disclosure and possible embodiments, the daily liquid production after the measures is Q 液后 The prediction formula is:

[0020]

[0021] In the formula, Q 液前 is the daily fluid production before the measure; P wf (h 前 ) is the bottom hole pressure of the oil well before the measure, MPa; P wf (h 后 ) is the bottom hole pressure of the oil well after the measures are taken, MPa; P R is the pressure in the middle of the oil layer, MPa.

[0022] In the present disclosure and possible embodiments, the calculation formula for the bottom hole pressure of the oil well before the measures is:

[0023] P wf (h 前 )=ρ L g(HL)+ρ′ L g(Lh 前 )+P e ;

[0024] The calculation formula of the bottom hole pressure of the oil well after the above measures is:

[0025] P wf (h 后 )=ρ L g(HL)+ρ′ L g(Lh 后 )+P e ;

[0026] Where, H is the depth of the middle part of the oil layer, m; L is the pump hanging depth, m; h 后 is the dynamic liquid level depth after the measure, h 后 =LL f后 , m; Pe is the casing pressure at the wellhead, MPa; ρL is the mixed density of the liquid in the formation, kg / m 3 ρ′ L is the density of the liquid in the well, kg / m 3 .

[0027] In the present disclosure and possible embodiments, the pump filling degree η after the measures is 泵后 The setting range is between 80% and 90%.

[0028] In the present disclosure and possible embodiments, the down-regulation parameter operating frequency f of the pumping well 后下 The calculation formula is:

[0029] f 后下 =η 泵前 ×f 前 / η 泵后 .

[0030] The present disclosure has the following beneficial effects:

[0031] The disclosed method provides a method for adjusting the stroke frequency of a pumping well, wherein the upward adjustment of the stroke frequency is based on the premise of the optimal pump fullness, with the goal of stable production under a reasonable flow pressure, to maximize the daily liquid production and optimize the system efficiency. The downward adjustment of the stroke frequency is based on the principle that the liquid production does not decrease after the measures are taken, with the goal of improving the system efficiency, so that the pumping parameters match the formation's liquid supply capacity, to achieve coordination of oil well supply and drainage, and to ensure efficient production under a reasonable submergence and reasonable flow pressure; therefore, the method of the present invention can calculate the optimal upward and downward adjustment of the oil well, provide guidance on the parameter adjustment method for on-site parameter adjustment, greatly reduce the number of manual parameter adjustments, and reduce the workload of manual parameter adjustment. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0033] Figure 1 is a flow chart of a method for adjusting the number of strokes of a pumping well according to an embodiment of the present disclosure;

[0034] Figure 2 It is a flow chart of a method for adjusting the number of strokes in a pumping well according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] The present disclosure is described below based on embodiments, but it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts that are not described in detail, those skilled in the art can also fully understand the present disclosure.

[0036] At the same time, unless the context clearly requires otherwise, the words "include", "comprises" and similar words throughout the specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, the meaning is "including but not limited to".

[0037] Figure 1 is a flow chart of a method for adjusting the number of strokes of a pumping well according to an embodiment of the present disclosure; Figure 1 As shown: the method for adjusting the pumping frequency of a well comprises the following steps:

[0038] Step 1: Obtain basic data before well measures, including operating frequency f 前 , dynamometer diagram, daily liquid output Q 液前 , dynamic liquid level h 前 , sinking degree L f前 , Volumetric water content of surface produced fluid f w前 and input power P 前 , using the dynamometer diagram to calculate the pump filling degree η before the oil well measures 泵前 and improve system efficiency η′ 系前 ;

[0039] η 泵前 =S 有效前 / S 总 ;

[0040]

[0041] Among them, Q 前油 , Daily oil production on the ground before measures, m 3 / d;ρ o , ground crude oil density, kg / m 3 ; g, acceleration due to gravity, m / s 2 ;f w前 , volumetric water content of surface produced fluid before measures; P′ 油 , crude oil power, kW; P 前 , system input power before measures, kW; S 有效前 S is the effective stroke of the plunger before the measure; 总 is the total plunger stroke.

[0042] Step 2: According to the pump filling degree η before the measure 前 , sinking degree L f前 and operating frequency f 前 Data, to determine whether the oil well meets the conditions for increasing the number of flushing; the preferred conditions for increasing the number of flushing in the present disclosure need to simultaneously meet the pump fullness η 前 ≥95%, sinking degree L f前 ≥200m, frequency f 前 ≤50Hz.

[0043] Step 3: If the conditions for increasing the number of strokes are met, the pump filling degree η after the measures are taken is guaranteed. 泵后 The best principle is to produce under reasonable flow pressure; set a reasonable submergence L f后 According to the oil well inflow dynamic calculation formula, the daily liquid production after the measures is predicted to be Q 液后 , pump filling degree η after setting measures 泵后 , the pump filling degree η after the measures preferably set by the present disclosure 泵后 The optimal range is between 80% and 90%; calculate the upper adjustment parameter operating frequency f 后上 ; The specific calculation process is as follows:

[0044] h 后 =LL f后 ;

[0045] P wf (h 前 )=ρ L g(HL)+ρ′ L g(Lh 前 )+P e ;

[0046] P wf (h 后 )=ρ L g(HL)+ρ′ L g(Lh 后 )+P e ;

[0047]

[0048]

[0049]

[0050]

[0051] Where P wf (h 前 ) is the bottom hole pressure of the oil well before the measure, MPa; P wf (h 后 ) is the bottom hole pressure of the oil well after the measures are taken, MPa; J o is the oil recovery index; P R is the pressure in the middle of the oil layer, MPa; H is the depth in the middle of the oil layer, m; L is the pump hanging depth, m; h 后 is the dynamic liquid surface depth after the measure, m; P e is the wellhead casing pressure, MPa; ρ L is the mixed density of liquid in the formation, kg / m 3 ρ′ Lis the density of the liquid in the well, kg / m 3 ;Q 液后 is the daily liquid output after the measures, m 3 / d;A p is the cross-sectional area of ​​the plunger, m 2 ; K is the yield coefficient; i 减 P is the ratio of the motor speed to the speed of the output shaft of the reduction gearbox; 极 is the number of motor pole pairs.

[0052] Among them, the reasonable sinking degree L f后 According to the conventional technology in this field, it is formulated based on comprehensive research and development according to different oil fields, different blocks, different fluid properties, reservoir properties, different pump diameters and depths, oil layer supply capacity, etc. Usually, the technical personnel of the geological institute of each oil production plant formulate a reasonable submergence L suitable for their own oil production plant according to their own actual situation. f后 .

[0053] Step 301: Determine the operating frequency f 后上 Whether it exceeds the upper limit frequency f of the motor output 上 ; The preferred motor output upper limit frequency f in the disclosed embodiment 上 The range is between 61Hz and 80Hz.

[0054] Step 302: When f 后上 <f 上 , then according to the operating frequency f 后上 implement;

[0055] Step 303: When f 后上 ≥f 上 , then according to the operating frequency f 后上 =f 上 implement;

[0056] Step 4: If the conditions for increasing the number of flushing are not met, the oil well does not meet the adjustment conditions;

[0057] According to the operating frequency f 后上 After stable operation, re-measure the daily liquid production, dynamic liquid level, power diagram, and input power of the oil well, calculate the improved system efficiency after the oil well measures, and evaluate the application effect. The calculation formula is as follows:

[0058] Application effect = η′ 系后 -η′ 系前 .

[0059] Figure 2 is a flow chart of a method for adjusting the number of strokes in a pumping well according to an embodiment of the present disclosure; Figure 2 As shown: the method for adjusting the number of strokes in a pumping well comprises the following steps:

[0060] Taking oil well Y1 as an example, the method for adjusting the pumping frequency of a well disclosed by the present invention is used to adjust the pumping frequency. The specific steps are as follows:

[0061] Step 1: Obtain basic data before well measures, including operating frequency f 前 =45Hz, dynamometer, daily liquid output Q 液前 =32.52t / d, dynamic liquid level h 前 =745m, sinking depth L f前 =255m, surface produced fluid volume water content f w前 =30% and input power P 前 =7.59kW, calculate the pump fullness η before the oil well measures according to the dynamometer diagram 泵前 =97%, improved system efficiency η′ 系前 =25.35%.

[0062] Step 2: According to the pump filling degree before the measure η pump before = 97%, the sinking degree L f前 =255m, operating frequency f 前 =45Hz while satisfying the pump fullness η 前 ≥100%, sinking degree L f前 ≥200m, frequency f 前 ≤50Hz; meets the conditions for increasing impulse frequency.

[0063] Step 3: When the conditions for increasing the number of strokes are met, the pump filling degree η 泵后 Assuming no drop, set the pump filling degree η 泵后 = 85%; with production at a reasonable flow pressure as the goal, set a reasonable submergence L according to the conventional technology in this field f后 =100m, according to the oil well inflow dynamic calculation formula, predict the daily liquid production after the measures, and calculate the frequency f of the upward adjustment parameter operation 后上 =59Hz; the specific calculation formula is as follows:

[0064] P wf (h 前 )=ρ L g(HL)+ρ′ L g(Lh 前 )+P e ;

[0065] P wf (h 后 )=ρ L g(HL)+ρ′ L g(Lh 后 )+P e ;

[0066] L f后 =Lh 后 ;

[0067]

[0068]

[0069]

[0070]

[0071] Where P wf (h 前 ) is the bottom hole pressure of the oil well before the measure, MPa; P wf (h 后 ) is the bottom hole pressure of the oil well after the measures are taken, MPa; the pressure in the middle of the oil layer P R =11.65Mpa; depth of middle oil layer H = 1450m; pump hanging depth L = 1000m; dynamic liquid level depth after measures h 后 =900m; wellhead casing pressure P e =0.4MPa; Liquid mixed density in the formation ρ L =0.85×10 3 kg / m 3 ; Liquid density in the well ρ′ L =0.89×10 3 kg / m 3 ; Plunger cross-sectional area A p =0.246×10 -2 m 2 ;Production coefficient K = 1.08; i 减 The ratio of the motor speed to the speed of the output shaft of the gearbox = 69; the number of motor pole pairs P 极 =8.

[0072] Step 301: Determine the operating frequency f 后上 =59Hz does not exceed the upper limit frequency f of the motor output 上 ; Set the upper limit frequency f of the motor output 上 =65Hz;

[0073] Step 302: f 后上 <f 上 , then according to the operating frequency f 后 =59Hz execution;

[0074] Oil well Y1 operates at frequency f 后上 =59Hz After stable operation, the daily liquid production of the oil well was re-measured to be 35.00t / d, the dynamic liquid level was 904m, the power diagram, the input power was 8.26kw, and the water content was 31%. The improved system efficiency after the oil well measures was calculated to be 34.08%, and the improved system efficiency after the measures was increased by 8.73 percentage points; the calculation formula is as follows:

[0075] Application effect = η′ 系后 -η′ 系前 =8.73%.

[0076] Embodiment 2

[0077] Taking oil well Y2 as an example, the method for adjusting the number of strokes of a pumping well according to an embodiment of the present disclosure is used to adjust the number of strokes. The specific steps are as follows:

[0078] Step 1: Obtain the basic data of oil well Y2 before the measure, including the operating frequency f 前 =50Hz, dynamometer diagram, daily liquid output Q 液前 =24.26m 3 , dynamic liquid level h 前 =904m, sinking depth L f前 =91.4m, surface produced fluid volume water content f w前 =25% and input power P 前 =12.38kW, calculate the pump filling degree η before the oil well measures according to the dynamometer diagram 泵前 =11%, improved system efficiency η′ 系前 =14.78%.

[0079] Step 2: According to the pump filling degree η before the measure 前 =11%, sinking degree L f前 =91.4m and operating frequency f 前 =50Hz data, when the fullness is satisfied 泵前 <60% and sinking degree L f前 <200m, operating frequency f 前 >30Hz pulse rate reduction condition; meets the pulse rate reduction condition.

[0080] Step 3: When the conditions for reducing the number of flushing times are met before the measures are taken, the daily liquid production Q before and after the measures is taken 液后 The premise is not to reduce the system efficiency, and the goal is to improve the system efficiency; according to the parameter adjustment formula, the pump η after the measures are taken 泵后 = 85%, calculate the oil well down-hole parameter adjustment operation frequency f 后下 =6.5Hz; the specific calculation formula and process are as follows:

[0081] Q 液前 =Q 液后 ;

[0082]

[0083] η 泵前 ×f 前 =η 泵后 ×f 后下 ;

[0084] f 后下 =η 泵前 ×f 前 / η 泵后 . 10 3 kg / m 3 ; Plunger cross-sectional area A p =0.246×10 -2 m 2 ;Production coefficient K = 1.08; i 减 The ratio of the motor speed to the speed of the output shaft of the gearbox = 69; the number of motor pole pairs P 极 =8.

[0085] Step 301: Determine the operating frequency f 后上 =59Hz does not exceed the upper limit frequency f of the motor output 上 ; Set the upper limit frequency f of the motor output 上 =65Hz;

[0086] Step 302: f 后上 <f 上 , then according to the operating frequency f 后 =59Hz execution;

[0087] Oil well Y1 operates at frequency f 后上 =59Hz After stable operation, the daily liquid production of the oil well was re-measured to be 35.00t / d, the dynamic liquid level was 904m, the power diagram, the input power was 8.26kw, and the water content was 31%. The improved system efficiency after the oil well measures was calculated to be 34.08%, and the improved system efficiency after the measures was increased by 8.73 percentage points; the calculation formula is as follows:

[0088] Application effect = η′ 系后 -η′ 系前 =8.73%.

[0089] Embodiment 2

[0090] Taking oil well Y2 as an example, the method for adjusting the number of strokes of a pumping well according to an embodiment of the present disclosure is used to adjust the number of strokes. The specific steps are as follows:

[0091] Step 1: Obtain the basic data of oil well Y2 before the measure, including the operating frequency f 前 =50Hz, dynamometer diagram, daily liquid output Q 液前 =24.26m 3 , dynamic liquid level h 前 =904m, sinking depth L f前 =91.4m, surface produced fluid volume water content f w前 =25% and input power P 前 =12.38kW, calculate the pump filling degree η before the oil well measures according to the dynamometer diagram 泵前=11%, improved system efficiency η′ 系前 =14.78%.

[0092] Step 2: According to the pump filling degree η before the measure 前 =11%, sinking degree L f前 =91.4m and operating frequency f 前 =50Hz data, when the fullness is satisfied 泵前 <60% and sinking degree L f前 <200m, operating frequency f 前 >30Hz down regulation condition; meets the down regulation condition.

[0093] Step 3: When the conditions for reducing the number of flushing times are met before the measures are taken, the daily liquid production Q before and after the measures is taken 液后 The premise is not to reduce the system efficiency, and the goal is to improve the system efficiency; according to the parameter adjustment formula, the pump η after the measures are taken 泵后 = 85%, calculate the oil well down-hole parameter adjustment operation frequency f 后下 =6.5Hz; the specific calculation formula and process are as follows:

[0094] Q 液前 =Q 液后 ;

[0095]

[0096] η 泵前 ×f 前 =η 泵后 ×f 后下 ;

[0097] f 后下 =η 泵前 ×f 前 / η 泵后 .

Claims

1. A method for adjusting the stroke frequency of a pumping well, comprising adjusting the stroke frequency upward and adjusting the stroke frequency downward; characterized in that: Determine whether the pumping well meets the conditions for increasing or decreasing the number of flushing; If the pumping frequency adjustment condition is met, calculate the pumping well's adjustment parameter operation frequency f 后上 , determine the upward adjustment parameter operating frequency f 后上 Whether it exceeds the upper limit frequency f of the motor output 上 , when f 后上 <f 上 , execute the above-mentioned adjustment of the operating frequency f 后上 When f 后上 ≥f 上 , execute the motor output upper limit frequency f 上 If the condition for increasing the number of strokes is not met, the pumping well will not be adjusted upward; If the down-regulation condition is met, calculate the down-regulation parameter operation frequency f of the pumping well. 后下 ; Determine the lower reference operating frequency f 后下 Whether it exceeds the lower limit frequency f of the motor output 下 , when f 后下 ≥f 下 , execute the lowering of the operating frequency f 后下 , when f 后下 <f 下 , execute the motor output lower limit frequency f 下 If the conditions for reducing the number of strokes are not met, the pumping well will not be adjusted downward.

2. The method for adjusting the pumping frequency of a well according to claim 1, characterized in that: Obtain the submergence degree L of the pumping well before the measure f前 and operating frequency f 前 Data, use the indicator diagram to calculate the pump filling degree η before the measure 前 , according to the pump filling degree η 前 , sinking degree L f前 and operating frequency f 前 Data is used to determine whether the pumping well meets the upward adjustment condition or the downward adjustment condition.

3. The method for adjusting the pumping frequency of a well according to claim 2, characterized in that: The pump filling degree η before the pumping well measure 前 It is equal to the quotient of the effective stroke of the plunger before the measure and the total stroke of the plunger.

4. The method for adjusting the pumping frequency of a well according to any one of claims 1 to 3, characterized in that: The condition for increasing the number of strokes is to simultaneously satisfy the pump filling degree η 前 ≥95%, sinking degree L f前 ≥200m and operating frequency f 前 ≤50Hz; The condition for reducing the number of strokes is to simultaneously satisfy the pump filling degree η 前 <60%, sinking degree L f前 <200m and operating frequency f 前 >30Hz.

5. The method for adjusting the pumping frequency of a well according to claim 4, characterized in that: The motor output upper limit frequency f 上 The range is between 61Hz and 80Hz, and the motor output lower limit frequency f 下 The range is between 10Hz and 29Hz.

6. The method for adjusting the pumping frequency of a well according to any one of claims 1 to 3 or 5, characterized in that: The upper adjustment parameter operating frequency f of the pumping well 后上 The calculation method is: Set a reasonable sinking degree L f后 , calculate the dynamic liquid surface depth h after the measure 后 According to the oil well inflow dynamic calculation formula, the daily liquid production after the measures is predicted to be Q 液后 , pump filling degree η after setting measures 泵后 , calculate the upper parameter operation frequency f of the pumping well 后上 ; The formula for the calculation is: In the formula, Q 液后 is the daily liquid output after the measures, m 3 / d;A p is the cross-sectional area of ​​the plunger, m 2 ; K is the yield coefficient; i 减 P is the ratio of the motor speed to the speed of the output shaft of the reduction gearbox; 极 is the number of motor pole pairs; pump filling degree η 泵后 ,%.

7. The method for adjusting the pumping frequency of a well according to claim 6, characterized in that: After the above measures, the daily liquid production volume Q 液后 The prediction formula is: In the formula, Q 液前 is the daily fluid production before the measure; P wf (h 前 ) is the bottom hole pressure of the oil well before the measure, MPa; P wf (h 后 ) is the bottom hole pressure of the oil well after the measures are taken, MPa; P R is the pressure in the middle of the oil layer, MPa.

8. The method for adjusting the pumping frequency of a well according to claim 7, characterized in that: The calculation formula of the bottom hole pressure of the oil well before the above measures is: P wf (h 前 )=ρ L g(H-L)+ρ′ L g(L-h 前 )+P e ; The calculation formula of the bottom hole pressure of the oil well after the above measures is: P wf (h 后 )=ρ L g(H-L)+ρ′ L g(L-h 后 )+P e ; Where, H is the depth of the middle part of the oil layer, m; L is the pump hanging depth, m; h 后 is the dynamic liquid level depth after the measure, h 后 =LL f后 , m; P e is the wellhead casing pressure, MPa; ρ L is the mixed density of liquid in the formation, kg / m 3 ρ′ L is the density of the liquid in the well, kg / m 3 .

9. The method for adjusting the pumping frequency of a well according to claim 7 or 8, characterized in that: Pump filling degree η after the measures described 泵后 The setting range is between 80% and 90%.

10. The method for adjusting the pumping frequency of a well according to claim 9, characterized in that: The down-regulation parameter operating frequency f of the pumping well 后下 The calculation formula is: f 后下 =the 泵前 ×f 前 / or 泵后 。

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