WO2011005143A1 - Well completion method - Google Patents

Abstract

The invention pertains to the oil and gas industry and can be used in the development of producing formations. A producing string (6) together with a sealing device (7) are lowered into a well (1) and the well (1) is divided into an upper cavity (8) and a lower cavity (9) with the aid of said sealing device (7) to establish a hydraulic connection between the well opening and the producing formation. The installation of equipment (10) and a check valve is carried out step by step. A washer fluid (4) is replaced by a washer fluid (15). The equipment (10) is passed through the sealing device (7) and the hydraulic connection between the well opening and the producing formation is re-established along the annular channel. The well (1) is deepened using the equipment (10) until an inflow of formation fluids occurs, the differential pressure in the well being adjusted during the process using the check valve and a blowout preventer. The equipment (10) is withdrawn from the lower cavity (9) of the well and the sealing device is closed so as to cut off the hydraulic connection between the well opening and the producing formation. The method increases the efficiency and quality with which technical operations can be carried out and prevents the undesired inflow of formation fluids.

Description

 WAY TO FINISH A WELL

The field of technology.

 The invention relates to the oil and gas industry, namely to drilling and operating oil and gas wells, and can be used for opening productive formations and completion of a well.

Prior art

There is a method of primary opening of productive formations when drilling for oil and gas, which consists in creating optimal conditions for primary drilling using various compositions of drilling fluids, RU N ° 2283418 C2, E21B21 / 00, 09/10/2006.

 The known method relates to the selection of reagents added to the drilling fluid, depending on the stage of ongoing work on the opening of reservoirs.

 A well-known method of well completion, including the primary opening of the reservoir, fixing the production casing and the secondary opening of the reservoir, RU Ne 2140521 Cl, E21BЗЗ / 13, 10.27.1999.

The known method provides a reduction in the amount of repression due to the overlap of the production string of high-pressure formations when installing it in the roof of the reservoir. Known shut-off valve related to downhole equipment and used in the operation of oil and gas wells under pressure, RU N ° 2311526 C2, E21B34 / 06, 11.27.2007; RU JVs 2250354 C2, E21B34 / 06, 04.20.2005.

 5 Controls the opening or closing of known valve shutoffs with a special tool as part of a drill or production string, depending on the work being carried out.

 The technical conditions are known for opening a productive formation in the presence of constant hydrodynamic coupling in the productive formation - wellhead system, which includes filling the well with flushing fluid and creating excess pressure (repression) on the producing reservoir with flushing fluid with a density increased relative to the equivalent gradient of the reservoir pressure, " Unified technical rules for the conduct of work during the construction of wells in oil, gas and gas condensate fields)), NPAOP 1 1.2.1.18 - 82.

 The minimum allowable amount of repression should not be less than 3% of the reservoir pressure:

where P _g . hydrostatic pressure of the column of washing fluid on the reservoir;

P _PL - reservoir pressure.

When flushing fluid is pumped, repression to the bottom (taking into account the 5 head losses in the annular space and the pressure of the flooded stream flowing from the nozzles of the bit) increases. A known method of completing a well equipped with a production string, downhole equipment (drill string), blowout preventer, which consists in lowering the production string into the roof of the reservoir, installing downhole equipment (drill string), deepening the well to the design depth with circulating flushing fluid, preventing the influx of reservoir fluids, the lifting of downhole equipment (drill string) and fixing the interval of occurrence of the reservoir, A.I. Bulatov, P.P. Makarenko, V.F. Budnikov, Yu.M. Basarygin “Teopia and practice of completing wells”. Under. ed. A.I. Bulatova. - M.: OAO Publishing House Nedra, 1998. T.4.

 This technical solution was adopted as the “closest analogue” of the present invention.

 In the “closest analogue)) when opening the reservoir, the influx of reservoir fluids is prevented by creating repression by the column of flushing fluid, which entails absorption, increasing the flow rate of flushing fluid, reducing the phase permeability of the reservoir and reducing oil recovery.

The known method of opening the reservoir confirms the presence of a constant hydraulic connection "productive reservoir - wellhead)), performed by flushing fluid, preventing unauthorized entry of formation fluids into the well. This is achieved by creating excess pressure on the reservoir with flushing fluid. The excess pressure of the flushing fluid over the reservoir pressure leads to its inevitable flow into the reservoir. The intensity and volume of absorption depend on the reservoir properties of the reservoir rocks, and range from several cubic meters to tens or even hundreds, in addition, the flushing fluid that has entered the reservoir significantly reduces the phase permeability and, accordingly, the productivity of the well, which leads to reduced oil recovery, increases the cost and time of work.

 Consequently, the quality and repression of the reservoir at the completion of the well primarily affects the quality of the well being constructed. Poor opening will lead to deterioration of the reservoir properties of the reservoir - its blockage. This can be caused by a large difference between the pressure of the reservoir and the hydraulic pressure of the well, the physicochemical properties of the flushing fluid, and the contact time of the “productive reservoir - wellhead”.

Disclosure of the invention.

The invention solves a problem that improves the efficiency and quality of technological operations and prevents the unauthorized influx of formation fluids. According to the invention, this problem is solved due to the fact that the method of completing a well equipped with a production string, downhole equipment (drill string), blowout equipment consists in lowering the production string into the roof of the reservoir, installing downhole equipment (drill string), and deepening the well to the design depth with circulation of the flushing fluid, preventing the influx of formation fluids, lifting the downhole equipment (drill string) and fixing the interval formation bedding.

 The sealing device is lowered on the production casing, which divides the well into upper and lower cavities in the presence of a hydraulic connection “well bore - upper cavity” and “lower cavity - productive area”, respectively, and has the ability to rotate.

 Install step-by-step downhole equipment (drill string) to the sealing device and check valve.

 The washing fluid is replaced with a washing fluid that creates a hydrostatic pressure lower than the reservoir pressure.

The downhole equipment (drill string) is passed through a sealing device that has the ability to disconnect when installing downhole equipment (drill string) and restore hydraulic connection wells - upper cavity - lower cavity - production area ”along the annular channel.

 The well is deepened until the influx of formation fluids by the downhole equipment (drill string) located in the lower cavity of the sealing device, with differential pressure regulation in the well-production-hydraulic reservoir hydraulic system using a non-return valve and blowout equipment.

 Downhole equipment (drill string) is removed at the end of the recess from the lower cavity with the closure of the sealing device when the lower cavity is separated from the upper cavity and the hydraulic connection is interrupted, the reservoir is the upper layer. "

 The applicant has not established any sources of information that would contain information about technical solutions identical to the claimed method.

 This, according to the applicant, determines the compliance of the invention with the criterion of "novelty" (N).

The immediate technical result consists in carrying out hydraulic circulation of the flushing fluid before opening the reservoir and after opening it using the non-return valve and blowout equipment, by installing a sealing device and dividing the borehole into upper and lower cavities while providing for each hydraulic connection “borehole - upper cavity ”and“ lower cavity - production area ”, due to the installation and passage of downhole equipment (drill string) through the sealing device when restoring the hydraulic connection“ well top - upper cavity - lower cavity - production area ”, deepening the reservoir to the occurrence of formation fluid influx with differential pressure control in the well-productive reservoir hydraulic system by means of a check valve and blowout preventer and during hydraulic interruption the communication channel “productive formation - upper cavity” after removing the downhole equipment (drill string) from the lower cavity with the closure of the sealing device.

 The implementation of the distinguishing features of the invention provides a number of important technical effects:

 The release of flushing fluid from the functions of creating repression on the reservoir by installing a sealing device in the roof of the reservoir to prevent unauthorized influx of reservoir fluids, reduces the flow of flushing fluid and increases well productivity.

Separation of the well with a sealing device into the upper and lower cavities ensures the creation of hydraulic connections “well top - upper cavity” and “lower cavity - productive area”, respectively, violating the direct hydraulic connection “productive reservoir - wellhead”, preventing unauthorized inflow of reservoir fluids.

 The implementation of the sealing device with the possibility of separation during the installation of downhole equipment and restoration of hydraulic communication "well bore - upper cavity - lower cavity - production reservoir" limits the duration of the direct hydraulic connection "productive reservoir - wellhead", reducing the duration of the influx of reservoir fluids .

 Deepening the well before the appearance of formation fluid flow by borehole equipment (drill string) with differential pressure regulation in the well-production-hydraulic reservoir hydraulic system using a non-return valve and blowout preventer helps to prevent formation fluid flow and increase well completion efficiency.

 This technical result is not a consequence of the known properties, and no publications are known that would contain information on the influence of the distinguishing features of the invention on the achieved technical result, which allows, in the applicant's opinion, to recognize the claimed technical solution as meeting the criterion of "inventive step" "(IS).

The implementation of the claimed technical solution is confirmed by design studies and tests of pilot batches, for the implementation of the method used ore, widely used in the oil and gas industry, which determines, in the applicant's opinion, its compliance with the criterion of “industrial applicability)) (IA). A brief description of the drawings.

Further, the claimed technical solution is illustrated by a description of an example of its implementation with reference to the accompanying drawings, where in FIG. 1 - Well, schematically;

 in FIG. 2 - Well with a sealing device, schematically;

 in FIG. 3 - Well in working position, schematically; in FIG. 4 - Sealing device, cut.

The best embodiment of the invention.

In FIG. 1 to 4 are presented:

 Well - 1.

 Mouth - 2

 Blowout control equipment - 3.

 Flushing fluid - 4.

 Productive layer - 5.

 Production tower - 6.

Sealing device - 7. The upper cavity (wells 1) - 8.

 Lower cavity (wells 1) - 9.

 Downhole equipment (drill string) with check valve - 10.

 Case (devices 7) - 11,

 thread (on the housing 11) - 12.

 Bearing -13.

 Seal in the form of a grip -14.

 Flushing fluid - 15.

 Well 1 with wellhead 2 is equipped for primary opening of the reservoir 5. Well 1 is filled with flushing fluid 4.

 Blow-out equipment 3 is installed at the mouth 2 in the form of universal and ram preventers (Fig. 1) to prevent the release of formation fluids and a manifold with a fitting (Fig. 1) to control the intensity of the flow of flushing fluid from the well 1 during the technological operation to deepen the well 1.

 At the wellhead 2, a rotating preventer (FIG. 3) is installed for sealing the downhole equipment (drill string) 10 and the wall of the well 1 at the wellhead 2 during a technological operation to deepen the well 1.

Downhole equipment (drill string) 10 includes a check valve (not shown). The check valve is installed on the production casing 6 in the process of lowering the downhole equipment (drill string) 10 upon reaching its lower part of the sealing device 7 (until the downhole equipment (drill string) 10 passes through the sealing device 7).

 An operational string 6 with a sealing device 7 is installed in the roof of the producing formation 5.

 The sealing device 7 divides the well 1 into the upper 8 and lower 9 cavities (figure 2).

 The sealing device 7 is made, for example, in the form of a collet having the ability to disconnect when installing downhole equipment (drill string) 10.

 The sealing device 7 comprises a housing 11, a bearing 13, and a seal 14. The housing 11 is threaded 12 for connection with a production casing 6. A seal in the form of a collet 14 is placed in the housing 11 fixed in the bearing 13 (Fig. 4).

 The sealing device 7 has the ability to rotate, to provide “closed” or “open”, skip downhole equipment (drill string) 10 and overlap the cross section of the production string 6.

 Consider the sealing device 7 cannot limit the claimed invention and is an example of confirmation of the implementation of the proposed method.

The sealing device can be made in the form of any known device that meets the requirements of reliable sealing with the possibility of separation in the inter action with downhole equipment (drill string) for its passage and installation in the working position.

 The method is as follows.

 Well 1 is filled with flushing fluid 4.

A sealing device 7 is lowered into the roof of the producing formation 5 on production casing 6.

 The lowering of the sealing device 7 is carried out in the open position, and after the cement slurry is displaced and the separation plug is moved down, the sealing device 7 takes the closed position.

 The well 1 is divided by a sealing device 7 into the upper 8 and lower 9 cavities.

 The upper cavity 8 provides the creation of a hydraulic connection "well top - upper casing."

 The lower cavity 9 provides the creation of a hydraulic connection "lower cavity - productive area".

 There is no direct hydraulic connection “productive reservoir - wellhead”.

 Downhole equipment (drill string) 10 equipped with a check valve is installed up to the sealing device 7.

The installation of downhole equipment (drill string) 10 is carried out after cementing the casing and performing preparatory work. Phased downhole equipment (drill string) 10 is installed to the sealing device 7 and the check valve.

 Wash liquid 4 is replaced with wash liquid 15, which creates a hydrostatic pressure less than reservoir pressure.

Replace the wash fluid 4 with the wash fluid 15, the hydrostatic pressure of which, in total with the pressure loss in the annular space, will meet the requirement: where P _g . hydrostatic pressure;

P _n pressure loss in the annular space;

P _pl . reservoir pressure.

 The condition that ensures that the washing fluid 15 has a hydrostatic pressure less than the reservoir pressure allows further technological operations to be carried out without repression.

 The use of oil or oil products as the washing liquid 15 is most preferable; in this case, the collectors are not wetted by aqueous filtrates and, accordingly, the phase permeability is not reduced.

The downhole equipment (drill string) 10 is passed through a sealing device 7.

When the borehole equipment (drill string) 10 passes through the sealing device 7, it opens when the flushing fluid 15 is injected into the borehole ore (drill string) 10 along the annular channel, the hydraulic connection "well top - upper cavity - lower cavity - production area" is restored.

 Well 1 is deepened until there are signs of an influx with circulation of flushing fluid 15.

Before opening the reservoir 5, the rotating preventer (FIG. 3) is turned on and the flushing fluid 15, rising to the mouth 2, is sent to the manifold and through an adjustable fitting (FIG. 1) into the circulation system,

 Produce a further deepening of the well 1.

 Evidence of the beginning of the opening of the reservoir 5 is the increasing intensity of the flow to the well 2. The intensity of the flow coming out of the well is regulated using the manifold fitting (Fig. 1).

 The deepening of the well 1 is carried out with the regulation of the intensity of the outflow of the washing fluid.

 The intensity of the outflow of washing liquid is regulated by the manifold fitting (Fig. 1) of blowout preventer 3.

 End the deepening of the well 1 and stop the circulation of the flushing fluid 15.

After the full opening of the reservoir 5, the pumping of the washing liquid 15 is stopped, and the check valve is automatically closed and the hydraulic connection is interrupted along the internal channel of the pipes. Downhole equipment 10 is lifted, interrupting the hydraulic connection “productive layer - upper layer”.

After removing the downhole equipment (drill string) 10 from the lower cavity 9 of the well 1, the sealing device 7 closes and the hydraulic connection “productive formation - upper cavity” stops, while the lower cavity 9 is sealed from the upper one, being constantly under reservoir pressure (P _pl ) _> at the same time, the influx of reservoir fluids from the lower cavity to the upper becomes impossible, and further actions are determined by the ratio:

* Submarine "A ₁ - <G ru _>

where P _PL - reservoir pressure;

P _g hydrostatic pressure;

P _py . operating pressure of the sealing device.

15 Subject to the requirements of this ratio, further lifting of downhole equipment (drill string) is possible 10.

If the difference between the reservoir (P _pl ) and hydrostatic (P _g ) pressure of the flushing fluid 15 in the upper cavity 8 0 is greater than the working pressure (P _py ) of the sealing device 7, then the flushing fluid 15 will be replaced with another fluid, the density of which will comply with the requirement described ratio, then carry out further lifting of the downhole equipment (drill string) 10.

5 Fix the interval of the reservoir 5. To fix the occurrence interval of the reservoir 5, a liner (not shown) is lowered similarly to the descent of downhole equipment (drill string) 10, while the liner can only cover the lower cavity 9, and the sealing device 7, in this case, will act as a valve -cutter.

 The proposed method can be opened any reservoir fluids, including: oil, gas, water, or combinations thereof.

 The proposed method can be implemented in wells with any angle of inclination.

 The proposed method allows you to:

 -increase the efficiency and quality of technological operations when completing the well;

-to prevent unauthorized influx of formation fluids without creating repression by the flushing fluid on the reservoir;

-increase well productivity;

 -to reduce the duration of the direct hydraulic connection “productive formation - well mouth”.

Industrial applicability.

The proposed method used equipment that is widely used in the oil and gas industry, this determines, according to the applicant, his compliance with the criterion of "industrial applicability)) (IA).

Claims

 Claim. A method of completing a well equipped with a production string, downhole equipment (drill string), blowout equipment, which consists in lowering the production string into the roof of the reservoir, installing the downhole equipment (drill string), deepening the well to the design depth with flushing fluid circulation, and preventing inflow formation fluids, lifting of downhole equipment (drill string) and fixing the interval of occurrence of the reservoir, characterized in that accelerate the sealing device on the production casing, which divides the well into upper and lower cavities in the presence of a hydraulic connection “well bore - upper cavity” and “lower cavity - productive area”, respectively, and has the ability to rotate, stage-by-stage borehole equipment (drill string) is installed to the sealing device and the non-return valve, the wash fluid is replaced with a wash fluid that creates a hydrostatic pressure less than the reservoir pressure, the downhole equipment is passed drilling (drill string) through a sealing device, which has the ability to disconnect when installing downhole equipment (drill string) and restore the hydraulic connection "well top - upper cavity - lower cavity - productive layer" through the annular channel, deepen the well until the inflow of formation fluids with downhole equipment (drill string), located in the lower cavity of the sealing device, with differential pressure control in the hydraulic system “well bore - productive bed” by means of a check valve and anti-blowout equipment, remove downhole equipment (drill string) at the end of the recess from the lower cavity with the closure of the sealing device when separating the lower cavity from the upper cavity and interrupting the hydraulic connection active layer - upper layer. "