WO2013095195A1

WO2013095195A1 - Method for hydrodynamic stimulation of the bottom region of a seam

Info

Publication number: WO2013095195A1
Application number: PCT/RU2012/001045
Authority: WO
Inventors: Рустэм Наифович КАМАЛОВ; Александр Петрович ЛЫСЕНКОВ; Владимир Игоревич ЖДАНОВ; Газиз Агзамович СУЛЕЙМАНОВ; Лилия Руффетовна НИГМАТЗЯНОВА; Ольга Сергеевна БЕЛОБОКОВА
Original assignee: Kamalov Rustem Naifovich; Lysenkov Alexsandr Petrovich
Priority date: 2011-12-21
Filing date: 2012-12-11
Publication date: 2013-06-27
Also published as: US20150000905A1; RU2483200C1

Abstract

The method can be used in the oil-producing industry for intensifying the production of oil and for increasing the intake capacity during the working of the bottom region of a seam and completion of wells. In order to produce pressure draw-down and repressuring cycles at the bottom of a well, the direction of the flow of working liquid is periodically changed with the aid of the controllable movement of a jet pump. The maximum pressure draw-down value is adjusted, and periods of pressure draw-down and repressuring action are implemented with equal values of the volumes of the inflow and the liquid pumpable into the seam in one cycle. In each subsequent cycle, the volumes are increased. The cycles are continued until the increase in the values of the liquid volumes ceases. Chemical reagents are then pumped into the seam. If necessary, the cycles are repeated. The stimulation of the bottom region of the seam is completed with a pressure draw-down.

Description

METHOD FOR HYDRODYNAMIC INFLUENCE

ON THE BOTTOM ZONE OF THE LAYER

Technical field

The invention relates to the oil industry and can be used to intensify oil production and increase injectivity during treatments of the bottom-hole formation zone and development of wells by complex impact methods using special hydrodynamic equipment.

State of the art

A known method for the dynamic processing of the bottom-hole zone (RU N ° 2322578, 04/20/2008), including the descent on the tubing string of an equipment layout consisting of a pulse pressure accumulator, a packer, a circulation valve and a jet pump. The packer is pre-installed in the working position, then by lifting the pipe string the circulation valve is opened and working reagents are pumped into them. Then the pipe string is lowered and the circulation valve is closed, and the reagents are pressed with liquid from the pump unit into the bottom-hole zone during hydro-pulse treatment. Immediately after the reagent is pushed, the fluid supply is switched from the pump unit to the annulus and the fluid is pumped out from the bottomhole zone at the wellhead using a jet pump. Then the pipe string is lifted again, the circulation valve is opened and a second cycle of exposure is performed with an increase in the volume of the injected reagent. The method allows to increase the efficiency of acid SCR due to cyclic, hydro-pulse injection and extraction of reagents in a depressed mode, followed by a cyclic increase in the radius of action, without waiting for precipitation of the reaction products, in one round-trip operation. The disadvantages of the method include the need for additional manipulation of the pipe string after planting the packer for injection and forcing the reagents with the help of a circulation valve, the need for injection of pressurized liquid into the annulus to operate the jet pump, which

5 limits the application of the method according to the type of wells and the depth of the productive formations, as well as the unregulated value of the maximum depression, which can lead to narrowing of the pores, closing of cracks and violating the integrity of the casing string.

A known method of hydrodynamic effects on

South borehole formation zone (RU jY-> 2221170, 01/10/2004), according to which a liner, packer and jet pump are lowered into the well on the tubing string, a packer and jet pump are installed over the top of the reservoir and the packer is unpacked by the pump unit periodically sharply served working agent in

15 the nozzle of the jet pump and create a depression on the reservoir, maintain the effect of this depression on the reservoir by constantly supplying the working agent to the nozzle of the jet pump at a given pressure of the pump unit, then by abruptly stopping the supply of the working agent to the nozzle of the jet pump, they abruptly recover

20 hydrostatic pressure of the liquid column, accompanied by water hammer towards the reservoir, while setting the pressure of the liquid column is greater than the reservoir pressure. Repeat the above cycle of exposure to the borehole zone of the reservoir with depression and pressure of the hydrostatic column of fluid,

25 the number of cycles "depression + restoration of hydrostatic pressure" is determined by the degree of restoration of permeability of the borehole zone of the reservoir by periodically conducting control measurements of the flow rate of the well before and during cyclic exposure to the borehole zone of the reservoir, but if the productivity is over the last two control measurements wells did not increase, then the work is stopped. A cyclic change in pressure on the borehole zone of the reservoir allows for alternating effects on the formation with the formation of water hammer, which leads to an increase in the radius and quality of processing of the borehole zone. The impact is accompanied by periodic measurements of the flow rate to monitor the effectiveness of the processing. The disadvantages of the method include the force effect of pressure on the casing above the packer, which limits the amplitude of the alternating action on the formation. Action depression is only possible at a constant supplying working fluid to the jet pump nozzle and a pulse energy of water hammer is not concentrated in the range of a producing formation, and is distributed throughout ^'packer space.

A known method of hydrodynamic effects on the reservoir (RU Ns> 2360103, 06/27/2009), which consists in installing tubing on the column above the perforation interval of the jet pump and packer, unpacking the latter and the pulsating flow of the working fluid into the nozzle of the jet pump to create depression in the productive layer. Then create repression on the reservoir by supplying the working fluid to the annulus, through the jet pump into the under-packer space and the reservoir in a magnitude greater than the reservoir pressure. Repeat the above cycle of exposure to the borehole zone of the reservoir with depression and repression. The flow rate and pressure in the sub-packer zone are measured and the degree of recovery of the permeability of the near-wellbore zone of the productive formation is determined by the value of the increase in the production rate of the well, and the effect on the formation is stopped when the production rate of the well becomes unchanged. The method allows the use of a cyclic change in pressure in the interval of the reservoir, which increases the intensity of the hydrodynamic effects, especially in the periodic pulsation mode. Disadvantages The method includes restrictions on the magnitude of the created repression exceeding the value of the reservoir pressure, since the pressure of the liquid during the repression is created in the casing string having a small pressure pressure. Therefore, the requirement to achieve the amount of repression exceeding the value of reservoir pressure leads to a narrowing of the applicability of the method according to the type and depth of the wells. According to this method, a pulsator is installed in front of the jet pump, on which the main pressure loss of the injected working fluid occurs, therefore, the rate of increase in flow rate is limited, due to the dependence of the flow rate on the pressure at the nozzle of the jet pump.

The closest to the invention in technical essence and the achieved result is a method of hydrodynamic impact on the borehole zone of the reservoir (RU N ° 2222716, 01/27/2004), which consists in the fact that the packer and the jet pump installed on the tubing string are lowered into the well, set jet pump and packer over the top of the reservoir and unpack the latter. The pumping unit, at a given pressure, periodically sharply delivers the working fluid to the nozzle of the jet pump, creates and maintains a depression on the reservoir by constantly supplying the working fluid, due to the abrupt switching of the supply of the working fluid from the pipe string into the under-packer space, creates repression on the reservoir pressure pulse from water hammer. At the same time, the pressure value in the pulse is set higher than the reservoir pressure value. The cycles of exposure to depression and repression are repeated with periodic control measurements of the flow rate of the well. Work is terminated if during the last two measurements the well productivity has not increased. The implementation of the method is intended to increase reliability and productivity when performing treatments to restore the permeability of the borehole formation zone in order to increase debits production and injection wells. The advantages of this method include the regulation of flows during operation, which increases the efficiency of alternating hydrodynamic effects, in combination with hydraulic shock, on

5 near-wellbore zone of the formation, the permeability of which is periodically controlled by the rate of production in the mode of depression. The need to use an additional drive, for example, a wireline cable, to control the flow of the working fluid and the formation of periodic depressions and repressions reduces the reliability of switching control and limits the applicability of the method by type, for example, in horizontal and well depths. The disadvantage is the low value of the repression, due to hydraulic connection with the annulus above the packer, which limits the applicability of the method in terms of the amplitude of the alternating

15 impact and the magnitude of the pressure when injecting chemicals into the formation. The formation of pressure pulses is possible only in a short time interval when switching the flow direction, the pulse energy is not concentrated in the interval of the reservoir, but spreads throughout the entire sub-packer space, reducing

20 impact effectiveness.

Disclosure of invention

The present invention is based on the task of increasing the efficiency and operational reliability of the method of exposure, expanding technological capabilities and conditions of applicability to 25 different types of wells with increasing intensity of hydrodynamic effects.

The technical result is achieved by the fact that in the known method of hydrodynamic impact on the bottomhole formation zone, which includes the descent of the body with a jet pump into the well, isolation of the annulus from the internal volume of the pump string compressor pipes above the top of the reservoir, periodically changing the direction of flow of the working fluid in the well to create depression cycles with repression, determining the volumes of pumped fluid during depression and creating a hydraulic pulse to the reservoir during repression, according to the invention, the direction of flow of the working fluid in the well is changed when controlled the movement of the jet pump in the housing, the magnitude of the maximum depression is regulated, the amount of fluid injected into the reservoir is determined the period of repression, and the periods of depression and repression are carried out at equal volumes of inflow and fluid injected into the reservoir in one cycle, while these volumes are increased in each subsequent cycle, the cycles continue until the growth of fluid volumes ceases, then the chemical reagents are injected into the reservoir , if necessary, the cycles are repeated, and the impact on the bottomhole formation zone is completed during depression.

In order to increase the intensity of the impact on the bottom-hole zone of the formation, in order to soften the mud and align the filtration profile, it is advisable to create additional hydraulic impulses with depression of energy on the casing wall in the interval of the productive formation in depression cycles with repression.

The movement of the jet pump to change the direction of flow in the well can be controlled both remotely and automatically, which greatly expands the possibilities of applying the method in vertical and horizontal wells. Remote control of movement occurs using cable technology. Automatic control occurs by supplying the working fluid to the nozzle of the jet pump and the spring force of the spring, which returns the jet pump to its original position when the feed is stopped. To effectively use the method when creating depression cycles with repression in various well designs and using it in combination with other technologies for treating the bottom-hole formation zone, the working fluid can be pumped into the well through the annulus or through the tubing string.

When conducting hydrodynamic effects in wells with a multilayer development system, it is advisable to use selective, interval processing using additional isolation of the annulus below the bottom of the reservoir.

It is advisable simultaneously with the pulse action during repression to exceed the rock pressure at the depth of the selected interval of the productive formation to create an additional network of microcracks in the bottomhole formation zone and increase the filtration area, as well as to regenerate previously existing cracks. Moreover, for a more effective excess of rock pressure, it is possible to use fracturing fluids, for example, oil-acid emulsions, and it is advisable to install a recording device to record the current hydrodynamic parameters in the processing interval.

It is possible to pump chemical reagents into the tubing string in the depressed mode, during the operation of the jet pump and circulate the fluid with the spout from the well at the wellhead, and to pump chemical reagents into the reservoir - in the repression mode with closed annulus at the wellhead. It is advisable at the end of the impact to clean the bottom-hole zone of the reaction products of chemical reagents with their removal to the wellhead in a controlled depression mode. To increase exposure, it is advisable to pump chemicals into the reservoir as part of gas-liquid mixtures. It is possible to end the hydrodynamic effect on the bottomhole formation zone in the regime of controlled depression by lowering the liquid level in the well, for example, using a compressor.

To assess the effectiveness of work to increase well productivity before and after exposure, it is advisable to record downhole pressure recovery using a pre-installed downhole tool.

The essence of the proposed method of hydrodynamic effects on the bottomhole formation zone is that to change the direction of flow of the working fluid in the well, controlled movement of the jet pump is used, while the direction changes the entire flow, and not part of it, as in the prototype, which increases the efficiency of using hydraulic power flow to create depression or the formation of a hydraulic impulse in the interval of the reservoir. Using a remotely or automatically controlled movement of the jet pump allows you to set the frequency of the change in flow direction to create depression cycles with repression and carry out alternating pressure effects on the porous structure of the rock. Such modes allow the radius-controlled penetration of the impact into the pore space of the bottom-hole zone. The cyclic exposure to variable pressures at the bottom of the well with equal volumes of inflow and fluid injected into the reservoir provides a phased and effective cleaning of the pore space of the bottomhole zone with the replacement of the volume of contaminated reservoir fluid with the same volume of clean injected fluid. Subsequent injection of chemicals with alternating exposure to the formation increases the efficiency of their penetration and significantly reduces the time of work. The maximum value of depression is regulated not only by the pressure generated by the pumping unit, but also with the help of an additional device pre-configured to operate when the minimum permissible pressure on the bottom is reached, which prevents significant narrowing of the pores and closure of cracks, as well as from a violation of the integrity of the casing with significant crushing loads. Such a device may be a pressure regulator, the principle of which is based on maintaining the calculated pressure drop.

The best embodiment of the invention

Pre-choose the method of supplying the working fluid into the well, for example, through a string of tubing and, for example, an automatic variant of moving the jet pump to control the flow in the well. The corresponding equipment layout is assembled at the mouth and lowered into the well on the tubing string, a housing is sequentially fixed to each other, in which a jet pump with a flow direction switch, a pressure regulator, a packer with an anchor and a liner with a flow regulator are installed. A packer with an anchor is installed above the roof of the reservoir and put into working position so that the liner is located in the perforation interval. The discharge line from the pumping and acid units is connected to the tubing string, and the receiving line is connected to a measuring tank filled with working fluid. The exit line from the annular space of the well is connected to the measured capacity. Then, the pumping unit under pressure delivers the working fluid into the tubing string to the nozzle of the jet pump and creates a depression that is adjustable in magnitude in the interval of the formation, accompanied by the inflow of formation fluid and its delivery together with the working fluid circulating through the annulus to the wellhead in a measured tank . Determine the size of the inflow from the reservoir. Then stop the flow of working fluid, while under the action of the spring's elastic force, the jet pump moves, which, upon further supply of the working fluid, switches the flow direction past the jet pump nozzle under the packer into the liner and further into the formation. In the repression mode,

5 bottom-hole zone is the volume of the working fluid equal to the extracted volume during depression. The flow of the working fluid is stopped again; automatically, under the action of the spring force, the jet pump is displaced. With further supply of fluid, the flow direction is switched to the nozzle of the jet pump and the flow of fluid from the reservoir is called up by the volume larger than the initial one. Periodic switching on and off of the supply of working fluid to the well are accompanied by the formation of hydraulic pulses directed through the liner in the interval of exposure, and continue until the moment when the value

15 the productivity of the inflow from the reservoir and, accordingly, the magnitude of its injectivity will cease to grow. Then, when the fluid flow is supplied to the nozzle, chemical reagents are pumped into the tubing string, and when the flow is switched past the jet pump under the packer, reagents are forced into the reservoir. Final

20, the pore space is cleaned from reaction products in a controlled depression mode with fluid inflow from the formation at the wellhead.

Upon reaching the desired injectivity or flow rate of the well, the treatment is stopped. They tear off the packer and lift the layout of equipment 25 to the surface. Thus, the processing is performed in one round-trip operation with one strapping of ground equipment.

Industrial applicability of the method.

The effectiveness of the proposed method is confirmed by experimental studies at well N21184 of the Vatinskoye field. Well the UV1 oil-bearing stratum with a bottom temperature of 95 ° C was discovered, represented in the perforation interval of 2515–2529 m by clay sand and siltstones with an average permeability of 0.0044 μm ² . Before the treatment of the bottom-hole zone (BHP), the well was operated with a flow rate of 6.0 m / day and a water cut of 4%; the productivity coefficient was 0.044m / day-atm. The reservoir pressure is 18.4 MPa.

For SCF, the equipment layout consisting of: was lowered into the well on tubing (tubing)

- housing (in which a jet pump with a nozzle, a mixing chamber and a diffuser, and a flow switch are installed);

- pressure regulator;

- packer with an anchor;

- a shank with a flow regulator and an additional pressure pulse generator with a concentrator.

Commodity oil with a density of 0.86x10 kg / m was used as the working fluid. The pressure regulator was configured to maintain the pressure in the range of exposure not lower than 4.0 MPa. A packer with an anchor was installed at a depth of 2450m, and a liner at a depth of 2521m.

The first cycle: using the working fluid from the measured capacity, the pump unit caused the circulation of the flow through the tubing, the nozzle of the jet pump, the annulus, and the measured capacity in the well. When depression on the reservoir caused an influx from the reservoir with a capacity of 6.0 m ³ / day and pumped out 0.5 m ³ fluid. Then, the flow of working fluid was stopped, while the jet pump automatically switched the direction of flow under the packer into the liner and further into the reservoir. They were pumped into the reservoir in the repression mode of 0.5 m ^{3 of} pure liquid.

The second cycle: in the depression mode, an inflow from the reservoir with a productivity of 7.2 m / day was caused and 1.0 m of fluid was pumped out. In the repression mode, 1.0 m ^{3 of} pure liquid was pumped into the reservoir. Third cycle: in the depressed mode, inflow from the reservoir with a productivity of 9.6 m 3 / day was caused and 1.5 m 3 of fluid was pumped out. In the repression mode, 1.5 m ^{3 of} clean liquid was pumped into the reservoir.

Fourth cycle: in the depression mode, an inflow from the reservoir with a productivity of 9.6 m / day was caused and 1.5 m of fluid was pumped out. In the repression mode, 1.5 m ^{3 of} clean liquid was pumped into the reservoir.

In the depression mode, 4 m ^{3 of} hydrochloric acid + 3.6 m ^{3 of} clay acid were pumped into the tubing, the jet pump was moved to the repression position, 2.4 m of clay acid were continued to be pumped, and 8 m working fluid was pumped into the reservoir. After the reaction of the acid, a depressive effect was carried out for 2 hours to purify the reaction products. The inflow productivity was 14-15 m / day.

After the SCR, the well was put into operation with a stable flow rate of 16 m ³ / day and a water cut of 11%; the productivity coefficient was 0.14 m / day. atm.

Claims

CLAIM

1. The method of hydrodynamic effects on the bottom of the formation, including the descent into the well of the housing with a jet pump, isolation of the annular space from the internal volume of the tubing string above the roof of the reservoir, periodic change in the direction of flow of the working fluid in the well to create depression cycles with repression, determination of the volumes of pumped liquid during depression and the creation of a hydraulic impulse to the reservoir during repression, characterized in that the flow direction and the working fluid in the well is changed during the controlled movement of the jet pump in the casing, the maximum depression is regulated, the period of repression is determined by the volume of fluid injected into the reservoir, and the periods of depression and repression are carried out at equal volumes of inflow and injected fluid in one the cycle, while the indicated volumes in each subsequent cycle increase, the cycles continue until the growth of the liquid volumes ceases, then the chemicals are pumped into the plastic , Cycles are repeated, if necessary, and finish effects on the bottomhole formation zone with depression.

2. The method according to claim 1, characterized in that in the cycles of depression with repression create additional hydraulic impulses, the energy of which is concentrated on the casing wall in the interval of the reservoir.

3. The method according to claim 1, characterized in that to change the direction of flow of the working fluid in the well, the jet pump in the housing is moved remotely using cable technology.

4. The method according to p. 1, characterized in that for changing the direction of flow of the working fluid in the well, the jet pump in the housing is moved automatically - by supplying the working fluid to the nozzle of the jet pump in one direction and the spring force of the spring returning the jet pump in the opposite direction when the supply is stopped.

5. The method according to claim 1, characterized in that to create depression cycles with repression, the working fluid is fed into the well through the annulus.

6. The method according to claim 1, characterized in that for the creation of depression cycles with repression, the working fluid is fed into the well through a tubing string.

7. The method according to claim 1, characterized in that the annular space is additionally isolated below the bottom of the reservoir.

8. The method according to claim 1, characterized in that the amount of repression is set above the value of rock pressure at the depth of the selected interval of the reservoir

9. The method according to claim 6, characterized in that in order to exceed the rock pressure, fracturing fluids are pumped into the reservoir.

10. The method according to claim 1, characterized in that in the process of exposure in a selected interval of the reservoir, hydrodynamic parameters are recorded.

11. The method according to claim 1, characterized in that the chemical reagents are pre-pumped into the tubing string during depression, and pumped into the reservoir during repression.

12. The method according to claim 1, characterized in that the chemical reagents are injected into the reservoir as a part of gas-liquid mixtures.

13. The method according to claim 1, characterized in that they complete the impact on the bottomhole formation zone in a controlled depression mode with pumping out the formation fluid.

14. The method according to claim 1, characterized in that they complete the impact on the bottomhole formation zone in a controlled depression mode by lowering the liquid level in the well.

15. The method according to claim 1, characterized in that before and after the hydrodynamic effects, the bottomhole pressure recovery is recorded in the interval of the reservoir.