RU2261984C1 - Well operation method - Google Patents

Abstract

FIELD: oil industry, particularly to produce oil with sucker-rod pump.

SUBSTANCE: method involves installing flow string with sucker-rod pump on rock in dib-hole through stepped pipe liner; arranging sucker-rod pump in well at maximal possible depth, wherein distance between sucker-rod pump and well head is equal to multiple pipe liner length. Sucker-rod pump is arranged so that the pump is in well oscillation antinode zone tuned for one of higher modes of natural system vibrations. Piston stroke is increased and decreased to maintain well output. Then sucker-rod pump is operated along with simultaneous applying dilatation and wave action on productive formations by sucker-rod pump movement.

EFFECT: increased well output and reduced water content in produced oil due to increased intensity of dilatation and wave action.

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Description

The present invention relates to the oil industry and may find application in oil production by a sucker rod pump.

A known method of oil production by a rod pump suspended on a string of tubing (Reference book for the operation of oil fields. M: "Nedra", 1964, volume 1, S. 214-295).

The disadvantages of the method are large losses of the stroke of the plunger and pump performance due to the deformation of the pipes and rods, as well as due to the lack of dynamic effects on the formation, stimulating filtration and oil flow to the wells.

Closest to the proposed method in technical essence is a method of operating a well in which a tubing string with a sucker rod pump is installed on a rock in a sump under its own weight through a stepped shank and oil is taken from the well (RF Patent No. 2136851, class E 21 In 43/00, publ. 1999/09/10 - prototype).

In this arrangement of equipment, compressive static (created by the weight of the pipe string) and dynamic (created by the dynamics of the pump) load acts on the rocks in the sump, which reduce the stroke losses of the plunger, create a field of dilatation (softening of the rocks) around the well and subject to the conditions of vibration resonance and matching wells with the environment develop wave processes in productive formations, providing a stimulating effect on the flow of oil to the surrounding wells.

The disadvantage of this method is the weak manifestation of the effect of the dilatation wave effect and, as a result, a low increase in flow rate and a small decrease in water cut of the produced oil.

The invention solves the problem of increasing the flow rate and reducing the water content of the produced oil by increasing the intensity of the dilatation wave effect.

The problem is solved in that in the method of operating the well, which includes installing a string of tubing with a sucker rod pump on the rock in the sump through a stepped shank, operating the sucker rod pump and extracting oil from the well with simultaneous wave-dilating action on the productive formations with the dynamics of the sucker rod pump, according to the invention, the sucker rod pump is placed in the well at the maximum possible depth at a distance that is a multiple of an integer number of liner lengths, increase the number and reduce the stroke length unzhera from the conservation of the well production rate.

The features of the invention are:

1) installation of a tubing string with a sucker rod pump on the rock in the sump through a stepped shank;

2) operation of a sucker rod pump;

3) the selection of oil from the well with simultaneous dilatation-wave action on the productive formations by the dynamics of the operation of the sucker rod pump;

4) placement of the sucker rod pump in the well at the maximum possible depth;

5) the same, at a distance from the mouth, a multiple of an integer number of shank lengths;

6) an increase in the number and decrease in the length of the plunger strokes while maintaining the flow rate of the well.

Signs 1 to 3 are common with the prototype, signs 4-6 are the salient features of the invention.

SUMMARY OF THE INVENTION

The dilatation field is created when the tubing string is supported by rocks in the sump of the well. Under the influence of the weight of the tubing string in the rocks, a seal zone is formed under the support plane of the liner, and a decompression (dilatation) zone is formed above the support plane, including in the reservoir. In the dilatation zone of the reservoir, the permeability of the reservoir increases and the flow of oil to the well improves.

The most intense dilatation field is formed in the perforation interval of the bottomhole zone, near the wellbore, where the string and rock are weakened by perforation channels and have minimal rigidity. With distance from the wellbore, the field decays quickly. Therefore, the dilatation field has a positive effect mainly on the operation of the exciting well itself; it affects the surrounding wells weakly. Creating an intense wave field around the well allows you to cover the impact of a larger volume of the reservoir and increase the efficiency of the production well.

The use of a new arrangement of equipment in the well allows increasing the intensity of the wave field by increasing the frequency.

An increase in the field frequency is achieved by tuning the wells to higher modes of natural frequencies of the oscillatory system.

The proposed method uses a layout of equipment installed on the bottom and tuned into resonance string tubing, as well as in the use for wave action on the reservoir field of high frequency.

Numerous studies of the influence of the wave field on the filtration processes indicate a direct dependence of the rate of fluid filtration in reservoirs on the intensity (frequency) of the wave field. Such dependences are confirmed by wide experience in the application of wave (acoustic, seismic, ultrasonic, seismoacoustic, etc.) methods of stimulating the formation and bottom-hole zone.

A similar positive effect due to the use of higher frequencies of the wave field is achieved in the proposed method of oil production.

During well operation, a tubing string with a sucker rod pump is installed on the rock in the sump through a stepped shank. The sucker rod pump is placed in the well at the maximum possible depth. In addition, the sucker rod pump is placed in the well at a distance from the mouth N _n equal to an integer number of liner lengths n multiplied by the liner length L _x so that it is in the antinode zone of the well’s vibrations tuned to one of the highest modes of the system’s natural vibrations. Shank length L _x must be minimum L _x . _min . From the condition of maintaining the flow rate of the well, the number of plunger strokes is increased while the plunger stroke length is reduced. In this mode, the operation of the sucker rod pump and the selection of oil from the well. In this case, a dilatational wave effect on productive strata is realized by the dynamics of the pump operation. As a result, the flow rate of the well increases, and the water cut of the produced oil decreases.

Concrete example

Oil is produced from an oil well with the following parameters: bottomhole depth N ₃ is 1650 m, perforation interval at depths 1595 - 1580 m, dynamic fluid level in the well 700 m, reservoir pressure in the well zone 14.5 MPa, bottomhole pressure 9.5 MPa , the diameter of the plunger of the deep-well pump 32 mm, the area of the plunger without the area of the rods S _PL 7.03 mm ² , the number of strokes of the plunger N is 3, the stroke length of the plunger ΔL is 3 m, the depth of the pump N _n = 1280 m. To use the pump drive a two-stage column of rods with a diameter of 16 and 19 mm, allowing laden pump according to the reference data to a depth of not more than 1460 m. The current production rate of oil 2.5 t / d., water cut 50% oil.

Calculate the minimum length of the shank L _x.min , at which the pump is immersed to the maximum depth

L _x . _min = H ₃ -H _n = 1650-1460 = 190 m

The condition L _{x is} imposed. _min = H ₃ / n, whence n = H _s / L _x . _min = 1650/190 = 8.68.

Since n must be an integer (multiple) number, round 8.68 to 9. Then L _x . _min = H ₃ / n = 1650/9 = 183.33 m. Take the length of the shank L _x . _min equal to 183.33 m. Determine the depth of the suspension of the pump, N _n = N ₃ -L _x . _min = 1650-183.33 = 1466.67 m, which exceeds the permissible value according to the reference data.

Take n = 8 and finally get L _x . _min = H ₃ / n = 1650/8 = 206.25 m. Determine the depth of the pump, N _n = H ₃ -L _x . _min = 1650-206.25 = 1443.75 m, which is within the acceptable range. The length of the rod string is increased to a depth of 1443.75 m, including 100 m due to the diameter of 16 mm and 63.75 m due to the diameter of 19 mm.

Determine the theoretical flow rate of the well

Q _theory = S _PL · N · ΔL · 1440 = 703 · 10 ^-6 · 3 · 3 = 9.1 m ³ / day.

The operating mode of the rocking machine is changed in the direction of increasing the number of plunger strokes N to the maximum N _max by reducing the plunger stroke ΔL to the minimum value ΔL _min , which for this rocking machine is 0.9 m, while

N _max = N · ΔL / ΔL _min = 3 · 3 / 0.9 = 10.

Allowable swing frequency is 6.5 swings per 1 min. Take N _max = 6.5. and get

ΔL _min = N · ΔL / N _max = 3 · 3 / 6.5 = 1.38 m.

With these parameters, the well is launched into operation. In this mode, pump filling is improved by reducing plunger stroke losses due to pipe deformation and by improving oil flow due to increased dilatation-wave action on productive formations by the dynamics of the rod pump. The actual flow rate increases by 10-15% in relation to the wells operating on the prototype. In this case, the oil flow rate increased to 3.5 tons / day with a decrease in water cut to 43.5%.

The application of the proposed method will increase the flow rate and reduce the water content of the extracted oil.

Claims (1)

A method of operating a well, including installing a string of tubing with a sucker rod pump on a rock in a sump through a stepped shank, operating a sucker pump and extracting oil from the well with simultaneous wave-dilatation action on productive formations by the dynamics of the sucker pump operation, characterized in that the sucker rod pump placed in the well at the maximum possible depth at a distance from the wellhead, a multiple of an integer number of liner lengths, and so that it is in the zone of antinode of vibrations with Vazhiny tuned to one of the higher mode oscillations of the system, thus increasing the number and decrease the length of the plunger moves while maintaining well production.