RU2451149C1 - Well construction method - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: well construction method includes borehole sinking, lowering and attachment of casing and production strings. During drilling of the direction, cyclic controlled-angle drilling of the direction and bore hole under grief stem is performed using screw, with periodic lifting of drilling tool and discharge of drilled out slurry. Screw and drilling tool with diameter of 500 mm or 630 mm are used for drilling. Pipes with diameter of 377 mm or 426 mm are used as conductor pipes. In its upper part casing conductor pipe is plugged and provided with connection pipe, in its lower part it is provided with circulating openings for cement solution to pass. Casing pipe is arranged in well shaft so that upper part of the pipe is above ground level.

EFFECT: reducing of construction time and cost during well construction.

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Description

The invention relates to the oil industry and may find application in well construction.

A known method of construction and operation of a well, according to which a wellbore is drilled with a given direction. Several casing strings are lowered and secured, including the last one, the “liner”. A small production casing is lowered. Pump a water lock. In this case, the first casing string is lowered, fastened with a fastening unit and insulated with a water seal close to the viscoplastic mass. The well is deepened. A water seal obtained from the drilling fluid is pumped in with the addition of binders and neutralizing agents. The next at least one casing is lowered, it is fastened from below with a fastening unit. The last casing, the lower end of which is perforated and equipped with a filter, is lowered above the oil-water circuit and fastened with a fastening unit. Last but not least, having previously pumped a water seal, a small-sized production casing equipped with a packer with an anchor and a filter. Install the packer over the reservoir and cause inflow by swabbing. The well is being exploited. Then, if necessary, canned and / or eliminated (RF Patent No. 2320849, publ. March 27, 2008).

Closest to the proposed invention in technical essence is a method of constructing a small diameter well, including drilling a wellbore, running and securing casing and production strings. The first part of the wellbore is direction, drilled with a diameter of not more than 300 mm, the second part is a conductor, drilled with a diameter of not more than 220 mm, the third part is drilled with a diameter of not more than 160 mm. As the drilling fluid, when drilling in the direction, a clay mud with a density of 1.12-1.20 kg / m ^{3 is used} , while drilling a conductor and the main trunk, industrial water with a density of 1.00-1.09 kg / m ³ . The consumption of process water is set by the absorption zones exceeding the absorption of process water. Opening of the productive interval is carried out using industrial water with the addition of a mixture of surface-active substances of the ML-81B grade in an amount of 1-3%. After drilling, the wellbore from the bottom to the mouth or, in the presence of an absorption zone, to the absorption zone is filled with a clay solution with a density of 1.12-1.20 kg / m ³ . Conduct logging studies. The layout for drilling is lowered, industrial water is pumped, and the interval of the productive formation passes at a speed of 20-30 m / h 2-4 times with a rotating bit. As production casing use a column with an outer diameter that provides a wall thickness of the cement ring of at least 16 mm (RF Patent No. 2393320, publ. 06/27/2010 - prototype).

A common disadvantage of the known methods is the length of the construction cycle and the high costs of well construction.

The proposed invention solves the problem of reducing construction time and costs during well construction.

The problem is solved in that in a method for constructing a well, including drilling a wellbore, lowering and securing casing and production casing, according to the invention, while drilling under direction, the pit is cycled at a predetermined angle by a screw with periodic raising of the drilling tool and ejection of drill cuttings, for drilling use auger and drill tool with a diameter of 500 or 630 mm, pipes with a diameter of 377 or 426 mm are used as direction pipes, the casing of the direction in the upper part is plugged and supplied they are pressed with mounting loops and a nozzle with a crane, in the lower part they are provided with circulation holes for passing the cement mortar, the casing is placed in the wellbore so that the upper part of the pipe remains above ground level.

When drilling for a direction of more than 10 m, an additional casing pipe of the required length is prepared, the bottom of the additional pipe is equipped with circulation holes for passing cement, the additional casing pipe is lowered into the well and fixed to the mouth, the main casing pipe is made without circulation holes, the main casing pipe is raised, join with an additional pipe with vertical control, pipes are connected by welding.

SUMMARY OF THE INVENTION

Well construction is accompanied by a long construction time and high cost of work. This proposal is aimed at reducing construction time and costs during well construction. The problem is solved in that when drilling directions instead of drilling equipment use equipment for earthworks such as augers.

As you know, the direction is the very first casing string or one casing in the construction of wells, designed to secure the estuary part of the wells from erosion by drilling drilling fluid and collapse. The direction, as a rule, is one. However, there may be cases of fixing wells in two directions. Typically, the direction is lowered into a well-prepared pit or well and cemented to its full length.

Fastening - the descent of the casing string or one casing pipe during the construction of a well into a well-prepared pit or well in advance and cementing the entire length. Pit cementing is not performed for the drill pipe.

A direction and a pit are drilled at the well under the lead drill pipe.

The depth of drilling and direction fixation is selected depending on the depth of the loose unstable rocks of the Quaternary sediments and take 10-20 m.

The depth of drilling and mounting the pit under the lead drill pipe is selected depending on the type of drilling rig, the length of the lead drill pipe and the height of the rotary base.

The diameter of the drilling and mounting direction are selected depending on the standard design of the well. A spare diameter is provided to allow expansion and fastening of the wellbore in the second direction in case of complications of a mining and geological nature that do not allow further drilling under the conductor. These conditions are met by the fact that a screw and a drilling tool with a diameter of 500 or 630 mm are used for drilling, and pipes with a diameter of 377 or 426 mm are used as direction pipes.

The diameter of the drilling and mounting the pit under the lead drill pipe is selected depending on the diameter of the lead drill pipe.

The angle of inclination of the drilling and the fastening of the pit under the lead drill pipe is selected depending on the type of drilling rig.

After arriving at the site for the placement of the drilling crew during the construction of the well, a self-propelled drilling machine is installed, for example, M-150 at the pit drilling point under the lead drill pipe, the alignment is checked, the required mast angle is set.

Cyclic drilling of the pit is carried out at an angle with a boring tool-screw, with a diameter that allows the prepared casing to be lowered to a given depth, with a periodic lifting of the boring tool and the discharge of drill cuttings. In the process of drilling periodically, every 2 m, check the angle of the mast. After drilling the pit to the design depth, the self-propelled drilling machine is dismantled and moved to the drilling point under the direction. The casing is lowered into the pit and left there without cementing the annulus.

At the drilling point under the direction, a self-propelled drilling machine is installed, the alignment is checked, the mast tilt angle is set to zero.

Cyclic directional drilling is carried out with a drilling tool with a screw, a diameter that allows the prepared casing to be lowered to a depth that overlaps the occurrence of loose unstable rocks of the Quaternary sediments (10-20 m) with periodic lifting of the drilling tool and the discharge of drill cuttings. In the process of drilling periodically, every 2 m, check the zero angle of the mast.

The main casing pipe when drilling up to 10 m and its use without an additional casing pipe is prepared as follows. The bottom of the casing under the direction is equipped with a cutting tool or welding with circulation holes for cementing work. The top of the casing 1 (see Fig. 1) is provided with a plug 2 with a pipe 3, to which a cement mortar supply from the cementing unit is connected. The supply is provided with a crane (not shown).

Using lifting equipment, the casing pipe is lowered into the well under direction with the weight of the pipe unloaded to the bottom of the well. The casing pipe is placed in the wellbore so that the upper part of the pipe remains above ground level.

When drilling for a direction of more than 10 m, an additional casing of the required length is prepared from the reserve brought to the well. In this case, the circulation holes in the main casing are not performed, and they are transferred to the lower end of the additional casing.

An additional casing with the help of lifting equipment is lowered into the well and fixed at the mouth. The main casing pipe is lifted using lifting equipment, joined with an additional casing pipe with vertical level control by level gauge, and welding is connected to an additional casing pipe. The casing pipe is placed in the wellbore so that the upper part of the pipe remains above ground level.

At the wellhead, with the help of centering elements, the casing is centered under the direction with vertical control over the level gauge.

At the site, the placement and tying of cementing equipment is performed. After the preparatory work is carried out, the cement is grilled, pumped and pushed through the pipe casing 3 with the outlet of the cement into the annulus. After stopping the selling process, the valve is closed, the well is left to wait for the cement to harden. Disassemble the cementing equipment. After 1-2 days, the cement mortar is added to the annular space from the surface.

After moving the drilling crew during the preparatory work using the welding unit, cut off 0.5 m of the upper part of the direction casing. The cut-off part is used in the construction of the following wells.

Then, through the direction, the conductor is drilled, the casing string is assembled and lowered and secured with cement mortar, the main well is drilled through the conductor through the conductor, the production string is assembled and lowered and cement cement is secured. Perforate the production casing in the interval of the reservoir, cause the influx of oil, lower the pumping equipment and launch the well into operation.

At the end of the construction of the well during the dismantling process, the casing is removed from the pit under the lead drill pipe. The extracted casing is used in the construction of the following wells.

Concrete example

An oil producing well is being built at a depth of 1200 m. A direction and a pit are drilled at the well for a leading drill pipe.

Drilling and fastening of the direction are carried out with a depth of 20 m for the sinking of loose unstable rocks of the Quaternary sediments. Drilling and fastening a pit under the lead drill pipe is carried out at a depth of 14 m.

For direction drilling, a screw and a drilling tool with a diameter of 630 mm are used; pipes of a diameter of 426 mm are used as direction pipes.

When drilling under the direction, an additional casing 10 m long is prepared from the reserve brought to the well. The bottom of the casing under the direction is equipped with a cutting tool with four circular holes with a diameter of 70 mm for cementing.

An additional casing with the help of lifting equipment is lowered into the well and fixed at the mouth.

The main casing pipe with a length of 10 m in the upper part is plugged and equipped with mounting loops and a nozzle with a crane, lifted using lifting equipment and joined by welding with an additional casing with vertical control over the level gauge.

Using lifting equipment, the casing pipe is lowered into the well under direction with the weight of the pipe unloaded to the bottom of the well.

At the wellhead, with the help of centering elements, the casing is centered under the direction with vertical control over the level gauge.

At the site, the placement and tying of cementing equipment is performed. After the preparatory work, the cement is mixed, pumped and forced through the nozzle with a tap into the main casing and then through the additional casing and circulation openings in the annular space. After stopping the selling process, the valve is closed, the well is left to wait for the cement to harden. Disassemble the cementing equipment.

With the help of lifting equipment, the casing is lowered into the pit under the lead drill pipe.

After moving the drilling crew during the preparatory work using the welding unit, the upper part is cut to a height of 0.5 m from the main casing pipe. The cut-off part is used in the construction of the following wells.

Then, through the direction, the conductor is drilled, the casing string is assembled and lowered and secured with cement mortar, the main well is drilled through the conductor through the conductor, the production string is assembled and lowered and cement cement is secured. Perforate the production casing in the interval of the reservoir, cause the influx of oil, lower the pumping equipment and launch the well into operation.

At the end of the construction of the well in the process of dismantling, the casing is removed from the pit under the lead drill pipe, the pit is filled up. The extracted casing is used in the construction of the following wells.

The cost of building a direction and a pit by the proposed method is about 130 thousand rubles per well, the cost of building a direction and a pit in the traditional way by a drilling crew and a drilling rig is about 700 thousand rubles per well, that is, using the proposed method reduces the cost of work by 570 thousand rubles per well. The duration of the construction of the direction and the pit by the proposed method is about 220 hours per well, the cost of constructing the direction and the pit in the traditional way by the drilling crew and the drilling rig is about 390 hours per well, i.e., the application of the proposed method reduces the duration of work by 170 hours per well.

Application of the proposed method will solve the problem of reducing construction time and costs during well construction.

Claims (1)

A method of constructing a well, including drilling a wellbore, lowering and securing casing and production strings, characterized in that while drilling the direction, the direction and pit are drilled cyclically under the lead drill pipe at a predetermined angle by an auger with periodic lifting of the drilling tool and the discharge of drill cuttings for drilling they use a screw and a boring tool with a diameter of 500 or 630 mm, pipes with a diameter of 377 or 426 mm are used as direction pipes, a direction casing in the upper part of the head shayut and supply pipe in the lower part is provided with circulation openings for the passage of the cement slurry, the casing disposed in the wellbore so that the upper part of the pipe is above ground level.

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