RU2806905C1 - Well construction method - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: invention relates to a method for constructing a well, and in particular, to a method for drilling and securing a direction. The well construction method includes drilling a wellbore to a direction, lifting a drilling tool and lowering a directional pipe string. The column of direction pipes protrudes above ground level by no more than 0.3 m. Before lowering the directional pipe string to the ground, a fixed support with a central hole is installed coaxially with the well. The upper part of the directional pipe column is equipped with a clamp. After lowering the direction pipe string, it is mounted with a clamp on a fixed support, after which the upper part of the direction pipe column is centred relative to the central hole of the fixed support. Before pumping the cement slurry, a flushing fluid with a volume of 2-3 m³ is supplied into the well.

EFFECT: reduction in the likelihood of destruction of the well walls and disruption of the alignment of the pipe string relative to the well.

1 cl, 1 dwg

Description

The invention relates to the oil industry, namely to a method for constructing a well, and in particular to a method for drilling and securing a direction. There is a known method for constructing and operating a well, according to which a wellbore is drilled in a given direction. Several casing strings are lowered and secured, including the last one - the “liner”. A small-sized production string is lowered. Pump up the water seal. In this case, the first casing is lowered, secured with a fastening unit and isolated with a water seal close to the viscoplastic mass. The well is being deepened. A hydraulic seal obtained from the drilling fluid by adding binders and neutralizing reagents is pumped. The next, at least one, casing string is lowered and secured 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 secured with a fastening unit. Lastly, a small-sized production string equipped with a packer with an anchor and a filter is lowered, having previously pumped the hydraulic seal. A packer is installed above the productive formation and inflow is caused by swabbing. The well is being exploited. Then, if necessary, they are preserved and/or liquidated (see RF patent No. 2320849, IPC E21B 33/14, publ. 03.27.2008, bulletin No. 9). The closest to the proposed invention in technical essence is a method for constructing a small-diameter well, including drilling a wellbore, running and fastening casing and production strings. The first part of the wellbore - the direction - is drilled with a diameter of no more than 300 mm, the second part - the conductor - is drilled with a diameter of no more than 220 mm, the third part is drilled with a diameter of no more than 160 mm.

When drilling a direction, a clay solution with a density of 1.12-1.20 kg/m ³ is used as a drilling fluid; when drilling a conductor and the main shaft, industrial water with a density of 1.00-1.09 kg/m ³ is used. The consumption of process water is set to exceed the absorption of process water by absorption zones. The productive interval is opened using process water with the addition of a mixture of surfactants of the ML-81B grade in an amount of 1-3%. After drilling, the wellbore from the bottom to the mouth or, if there is a loss zone, to the loss zone is filled with a clay solution with a density of 1.12-1.20 kg/m ³ . Conduct logging studies. The drilling assembly is lowered, process water is pumped, and a rotating bit passes through the productive formation interval 2-4 times at a speed of 20-30 m/hour. As a production column, a column with an outer diameter is used that provides a wall thickness of the cement ring of at least 16 mm (see RF patent No. 2393320, IPC E21B 7/20, E21B 43/00, publ. 06.27.2010, bulletin No. 18), which is accepted as a prototype.

A common disadvantage of the known methods is the duration of the construction cycle, high costs during the construction of the well direction, possible destruction of the well walls, and disruption of the alignment of the direction column relative to the well.

The technical objective of the proposed invention is to develop a method for constructing a well that will reduce the likelihood of destruction of the well walls, misalignment of the pipe string relative to the well, and overall reduce the cost and duration of construction of the well direction.

The solution to the technical problem is achieved by the fact that in a method of well construction, including drilling a wellbore to the direction, lifting the drilling tool, lowering a pipe string from at least one pipe, to the direction, with the exception of the bottom of the pipe touching the bottom of the well, centering the upper part of the column directional pipes, injection of cement slurry until it exits the annulus, according to the technical solution, before lowering the directional pipe string into the well, the wellhead is equipped with a fixed support with a central hole, the central hole of the fixed support is coaxially located with the well, and the upper part of the directional pipe string is equipped with a clamp, after lowering the directional pipe string, it is placed with a clamp on a fixed support, after which the upper part of the directional pipe string is centered relative to the central hole of the fixed support, and before pumping the cement mortar into the well, a flushing liquid with a volume of 2-3 m ³ is supplied.

The essence of the well construction method is illustrated by the drawing.

In fig. Figure 1 shows the layout of a pipe string for direction.

Drilling a well according to the direction is carried out, for example, with a mobile drilling rig of the URB type instead of drilling rigs of the URALMASH type, with a lifting capacity of 75 tons or more.

The depth of drilling and fastening direction is selected depending on the depth of loose unstable rocks. The depth can be up to 50 m or more.

The diameter of the well for the direction is selected depending on the standard design and depth of the well. For directional drilling, a bit, for example, with a diameter of 500 or 630 mm is used, and pipes, for example, with a diameter from 245 mm to 426 mm are used as directional pipes.

At the drilling point, for example, a mobile drilling rig is placed under the direction, the alignment is checked, and the mast inclination angle is set to zero.

A well is drilled in the direction of a drilling tool, for example, a bit, which ensures the descent of a prepared pipe string (casing) to a depth, covering the occurrence of loose unstable rocks.

During the drilling process, the zero angle of the mast is periodically checked. After reaching the required drilling depth, the tool is raised up.

Next, a pipe or pipe string of 2 directions is lowered into well 1 (Fig. 1), ensuring that the distance between the bottom of the pipe string 2 and the bottom of well 1 is at least 1 m. The upper part of the pipe string of 2 directions should protrude above ground level by no more than 0. 3 m. The upper part of the 2nd direction pipe string is equipped, for example, with a clamp 3 for landing on a fixed support 4 with a central hole (not indicated in the figure) to support the 2nd direction pipe string in weight. The fixed support 4 is installed on the ground or compacted base, ensuring the alignment of the central hole with the well 1 before lowering the 2nd direction pipe string into the well 1.

The central hole of the fixed support 4 can be made cylindrical, and the support 4 can be made of metal, for example, in the form of a ring. The immobility of the support 4 is ensured, for example, by making in its peripheral part at least two through holes (not shown in the figure) with an equal angular distance, through which counter-made pins (not shown in the figure) are driven into the ground. At least 3 pins can be driven into the edges of support 4.

The central hole of the fixed support 4 can be made square or cylindrical, and in this case the diameter of the hole of the fixed support 4 or the length of the side of the square can be made no more than the diameter of the well 1.

The upper part of the 2nd direction pipe string is also equipped with a plug 5 with a pipe 6 for supplying flushing liquid and cement mortar.

Upon completion of the lowering of the 2nd direction pipe string, a coaxial arrangement of the top of the 2nd direction pipe string and the central hole of the fixed support 4 is ensured using centering elements (not shown in the figure) installed between the upper part of the 2nd direction pipe string and the hole of the fixed support 4. Since the central hole Since the fixed support 4 is installed coaxially with well 1, the top of the pipe string in direction 2 is also ensured to be coaxially positioned relative to well 1.

At the site, the cementing equipment is arranged and tied up. After the preparatory work, a flushing fluid (process water or clay solution depending on absorption) with a volume of 2-3 m ³ is poured or pumped into the well. Next, the cement slurry is pumped through the plug pipe with the cement slurry exiting the annulus. Flushing the well with a small volume of technical water or clay solution reduces the likelihood of destruction of the walls of the well, and also ensures the lifting of the collapsed part of the soil to the surface. This eliminates the misalignment of the pipe string 2 and the well 1, and also increases the strength of the cement due to the prevention of mixing of the cement mortar with the soil.

After stopping the cement slurry injection process, the well is left to wait for the cement to harden. The cementing equipment is being dismantled.

Claims (1)

A method of well construction, including drilling a wellbore to a direction, lifting a drilling tool, lowering a pipe string from at least one pipe to a direction, with the exception of the bottom of the pipe touching the bottom of the well, centering the upper part of a directional pipe string, pumping cement mortar to its exit from the annulus, characterized in that before lowering the directional pipe string into the well, the wellhead is provided with a fixed support with a central hole, the central hole of the fixed support is ensured to be coaxially located with the well, and the upper part of the directional pipe string is equipped with a clamp, after lowering the directional pipe string is placed with a clamp on a fixed support, after which the upper part of the directional pipe column is centered relative to the central hole of the fixed support, and before pumping the cement mortar into the well, a flushing liquid with a volume of 2-3 m ³ is supplied.