RU2661171C1 - Method for isolating the inflow of formation water in an uncased horizontal section of the wellbore - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry, namely to isolation of water inflows in horizontal sections of wells. Method for isolating a supply of formation water in an uncased horizontal section of an oil wellbore includes the recovery of downhole equipment, carrying out geophysical studies in the open horizontal section of the wellbore, determining the interval of water inflow from the aquifer and descending onto the flexible pipe of the arrangement. Layout consists of a connector, two flap-type check valves, an emergency disconnector, a perforated branch pipe with swell packers 1 m long. At the end of the perforated pipe, a full-length tube with an inner seat is attached by means of a coupling. Initially sealing elements of the swelling packers are left for the time of swelling. Then a ball is dropped from the composite material, whose diameter is equal to the diameter of the full-pass tube. After the ball the waterproofing composition is pumped with the sale of the buffer liquid. Dropped ball enters the saddle of a full-length tube, thereby overlapping its internal space. After this waterproofing composition is pumped into the perforations of the perforated nozzle into the watered interval of the formation. Then ball is dropped into the flexible pipes to the emergency disconnector and hydraulic pressure is applied. Flexible pipe is disconnected from the perforated nozzle and lifted to the day surface. Well is then left for WOC. After that assembly with the mill is lowered into the borehole and work is carried out to drill out the perforated branch pipe, swell packers and waterproofing composition residues with washing them on the day surface. In the end, downhole equipment is lowered, the well is developed and put out on the regime.

EFFECT: proposed invention allows to increase the efficiency of repair and insulation works, to prolong the anhydrous life of the well.

1 cl, 6 dwg

Description

The invention relates to the oil industry and is intended to isolate water inflows in horizontal sections of oil wells.

A known method of isolation of produced water using a sleeveless long pipe (RF patent No. 2188929, class 7 ЕВВ 33/13, 2002).

The disadvantage of this method is the impossibility of using it in a subhorizontal and horizontal well, since the method does not allow for the injection of a water-insulating composition into a predetermined interval of the wellbore.

A known method of conducting waterproofing work in horizontal wells, which consists in pumping the tubing into the flooded interval of the horizontal barrel of the waterproofing composition, followed by the installation of a metal shutter from corrugated pipes [RF patent No. 2114990, cl. 6 ЕВВ 43/32, 33/13, 1996].

The disadvantage of this method is the difficulty of pumping a water-insulating composition strictly into the flooded interval of the horizontal wellbore, as well as the inability to implement the method in an open hole.

A known method of isolating produced water in an uncased horizontal section of a producing well, according to which, after lowering the tubing string to the bottom of the horizontal section of the wellbore, the annular space of the uncased horizontal section is filled with cement mortar, a modified polyvinyl acetate reagent, holding is carried out for 2-3 hours, followed by washing of the well ( RF patent No. 2273722, CL ЕВВ 33/13, 2004). According to the method, a thin, dense, waterproof crust is formed opposite the intervals of the water-producing strata.

The disadvantage of this method is the ability to quickly break through insulated water into a horizontal wellbore along a thin impermeable crust into the well. This is facilitated by the fact that, as a rule, horizontal trunks are drilled along the bedding, and the permeability of the rocks along the bedding is much higher than in the transverse direction. Therefore, produced water can be easily filtered by bedding along a thin impermeable crust and break into the cavity of a horizontal trunk.

A known method of isolating formation water in a horizontal oil or gas well (RF patent No. 2055156, class 6 ЕВВ 33/13, 1996).

The disadvantage of this method is the impossibility of its implementation in a horizontal well with a complex construction of the bottom, in addition, the method does not allow the injection of a water-insulating composition in a given interval of the well with an open bottom.

There is also a method of isolating water-producing strata (see RF Patent No. 2152507, 7 ЕВВ 33/13, 33/19 BI No. 19, 2000), which includes extracting pumping equipment from the well, lowering the tubing string into the well pumping through them an insulating solution with fastening properties and forcing it into an insulated formation under excessive pressure.

At the same time, as a grouting mortar, plasticized cement mortar is used with SEPACOL CE-5381 reagent or waste water treatment plants.

The disadvantages of this method include the following.

The method requires for its implementation large material and labor costs associated with the installation of a cement bridge followed by drilling it after waiting for the hardening of cement (OZZ), as well as time.

The closest technical solution adopted for the prototype is a method of isolating the influx of water in an uncased horizontal section of the wellbore of a producing well, including removing pumping equipment from the well, lowering the pipe string into the well, pumping a water-proofing solution with hardening properties through them, creating an impermeable screen in the water-developing interval formation and subsequent leaching of the waterproofing solution from the well by reverse circulation after the start of setting the waterproofing composition (Patent RF №2578095, publ. March 20, 2016).

The disadvantage of this method is a significant narrowing of the horizontal section of the wellbore after waterproofing due to the leaving of an expandable sleeve with sealing (rubber) rings, as well as a check valve.

The objective of the invention is to increase the efficiency of isolation of the influx of formation water in an uncased horizontal section of the wellbore.

The technical result of the invention is to develop an effective method of isolating the influx of formation water in a horizontal uncased portion of an oil well bore, pumping a water-insulating composition into a predetermined interval of the horizontal well.

The task and technical result is achieved by the fact that the method of isolating the influx of formation water in the uncased horizontal section of the wellbore includes extracting downhole equipment, conducting geophysical surveys in the uncased horizontal section of the wellbore and determining the interval of water inflow from the aquifer. The descent on a flexible pipe of an arrangement consisting of a connector, two casement type check valves, an emergency disconnector, a perforated nozzle with swellable packers, the length of each swellable packer being 1 m. A full bore tube with an inner seat is attached to the end of the assembly using sleeve couplings. Leaving for a period of swelling the sealing elements of the swellable packers. Dumping a ball from a composite material, the diameter of which is equal to the diameter of the saddle of the full bore tube, and pumping the waterproofing composition with the sale of its buffer fluid. The discarded ball, passing through the internal space of the flexible pipes and the perforated pipe, enters the saddle of the full bore pipe, thereby blocking its internal space, and therefore the waterproofing composition begins to pump into the perforation holes of the perforated pipe in the flooded interval of the formation.

It is proposed to use a composition comprising a microdur RU, a multifunctional modifier PFM-ISO, a superplasticizer F-10 and water at a water-cement ratio of 0.5 with the following ratio of components, wt.%: Microdur RU 48.75-49.05, multifunctional PFM-ISO modifier 1.0-1.2%, F-10 superplasticizer 0.9-1.3%, water - the rest [RF Patent No. 2613067. Composition for repair and insulation works in wells / Leontiev D.S., Kustyshev A.V., Kleschenko I.I. and etc.].

The mutual influence of the components on each other, their synergistic effect in the proposed composition allows due to the reaction and curing in reservoir conditions to form a strong stone-like material.

The composition can be used for waterproofing and fastening reservoirs with low filtration and capacitive properties, since it is pumped into the reservoir in the form of a low-viscosity solution, which allows it to be pumped into the radial channel.

After pumping the required volume of the waterproofing composition into the flooded interval of the formation, the ball is discharged into flexible pipes to the emergency disconnector, hydraulic pressure is applied, the flexible pipe is disconnected from the perforated pipe and rises to the surface. After that, the well is left waiting for the cement to harden (OZZ).

After the OZZ, a layout with a cutter is lowered into the well and drilling is carried out to drill the perforated nozzle, swellable packers and the remnants of the waterproofing composition with leaching to the day surface. After the completion of the drilled work, the well is washed, the downhole equipment is lowered, the well is mastered and put into operation.

The novelty of the invention lies in the use of a full bore tube with an inner seat attached to the end of the perforated pipe with sleeve couplings and designed to block the internal space after pumping into the flexible tubes of the ball, the diameter of which is equal to the diameter of the seat of the full bore tube, by falling into the saddle of the full bore tube. Also new is the fact that a highly penetrating waterproofing composition based on R-U microdur, multifunctional PFM-ISO modifier, F-10 superplasticizer is used as a waterproofing composition.

The invention is accompanied by drawings.

FIG. 1 - the influx of produced water into the oil well with a horizontal end.

FIG. 2 - descent into the well layout with a perforated pipe and swellable packers.

FIG. 3 - dumping the ball to the saddle of the full bore tube and pumping the waterproofing composition.

FIG. 4 - discharge of the ball to the emergency disconnector and the supply of hydraulic pressure.

FIG. 5 - descent of the layout with a mill.

FIG. 6 - descent into the well of downhole equipment.

The method is implemented as follows.

The horizontal well (1), which uncovered the reservoir (2) and is flooded due to the influx of formation water (3) from the aquifer (4), is stopped. Downhole equipment is removed from the well (1) (for example, a slotted liner (5) with centralizers (6)) (Fig. 1). Geophysical studies are carried out in an uncased horizontal section of wellbore 1, for example, using an integrated geophysical instrument of the type AGAT-KG-42-6V and the interval 3 of water inflow from the aquifer 4 is determined.

To do this, lower the geophysical instrument into the uncased horizontal section of the wellbore on a flexible pipe with stored cable, determine the change in phase composition by the profile of the horizontal trunk with the multiphase composition of the produced products and determine the length L of the interval 3 of the aquifer 4 of the uncased horizontal section of the wellbore 1 to be waterproofed .

On the flexible pipe (7), the assembly consisting of a connector, two casement type check valves, an emergency disconnector, a perforated pipe (8) with swellable packers (9) 1 m long each so that the interval between swellable packers is 1-2 m longer than the flooded interval L in the horizontal section of the well (1).

The connector, check valves and emergency disconnector can be used in any known design. Water swellable packers (9) are made in the form of elastic sleeves 1 m long. Swellable packers of any known design can be used as water swellable packers. As a pipe (8), a segment of a tubing with channels in the form of holes is used.

A full bore tube with an inner seat (10) is attached to the end of the perforated nozzle (8) by means of sleeve connections (Fig. 2).

After descent into the horizontal section of the well (1), the arrangement with swellable packers (9) is left for the period of swelling of the sealing elements (for example, from 48 to 96 hours). After that, a ball (11) of composite material, the diameter of which is equal to the diameter of the saddle of the full bore tube, is dropped into flexible pipes (7), and a water-proofing composition (12) is pumped with a buffer fluid (13). The discarded ball (pos. 11 of Fig. 3) enters the saddle of the full bore tube (10), thereby blocking its internal space. The waterproofing composition (12) is pumped into the perforations of the perforated pipe (8) and pumped into the flooded interval of the reservoir (2). The injection volume of the waterproofing composition (12) to create a waterproofing screen in the interval 3 is determined by the technological service of the repair enterprise, for example 3 m ³ (Fig. 3).

After that, the ball (14) is discharged into the flexible pipes (7) to the emergency disconnector, hydraulic pressure (for example, water) is supplied, the flexible pipe (7) is disconnected from the perforated pipe (8) and rises to the surface (Fig. 4). After that, the well (1) is left waiting for the cement to harden.

After the OZZ, an assembly with a milling cutter (15) is lowered into the well (1) and drilling of the perforated nozzle (8), swellable packers (9) and the remains of the waterproofing composition (12) with washing to the day surface is carried out (Fig. 5).

After the completion of the drilled work, the well (1) is washed, the downhole equipment is lowered (5, 6) (Fig. 6), the well is mastered and put into operation.

The proposed method of isolating the influx of formation water in an uncased horizontal section of the wellbore of an oil producing well improves the efficiency of repair and insulation works, and extends the anhydrous period of operation of the well.

Description:

1 - well with a horizontal end;

2 - reservoir;

3 - interval inflow of formation water;

4 - aquifer;

5 - slotted shank;

6 - centralizer;

7 - flexible pipes;

8 - perforated pipe;

9 - swellable packer;

10 - full bore tube with grooves;

11 - a ball of composite material of a certain diameter in a full bore tube;

12 - waterproofing composition;

13 - buffer fluid;

14 - ball for emergency disconnector;

15 - mill.

Claims (1)

A method of isolating formation water inflow in an uncased horizontal section of an oil well bore, including extraction of downhole equipment, conducting geophysical surveys in an uncased horizontal section of an oil well bore and determining an interval of water inflow from an aquifer, lowering on a flexible pipe assembly consisting of a connector, two casement check valves type, emergency disconnector, perforated nozzle with swellable packers 1 m long, characterized in that to at the perforated nozzle, with the help of coupling connections, a full bore tube with an internal seat is attached, leaving the swellable packers sealing elements for swelling, dumping a ball of composite material, the diameter of which is equal to the diameter of the seat of a full bore tube, and pumping the waterproofing composition with the buffer fluid in it, getting the discarded ball into the seat of the full bore tube, thereby blocking its internal space, pumping the waterproofing composition into the perforation holes the perforated nozzle into the flooded interval of the reservoir, dumping the ball into the flexible pipes to the emergency disconnector, applying hydraulic pressure, disconnecting the flexible pipe from the perforated nozzle and raising it to the surface, leaving the well on the WZ, lowering the assembly with the cutter into the well and drilling perforated nozzle, swellable packers and residues of the water-proofing composition with a washout on the day surface, descent of downhole equipment, well development and output m.

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