RU2410514C1 - Method for well construction - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: invention relates to oil industry and may find application in well construction. In process of well construction, well direction, conductor and main shaft are drilled, casing and flow strings are lowered and fixed. Direction is drilled with bit of diameter of 490 mm with application of clay drilling agent with density of 1.12-1.20 kg/m³. Conductor drilling is carried out in two stages. At first intermediate conductor is drilled with bit of diameter of 393.7 mm with application of mineralised water as drilling agent with density of 1.16-1.20 kg/m³. When drilling intermediate conductor, every 12 m drifting is carried out, which consists in lifting and lowering of bit with rotation and flushing, and when sticking effect appears, sticking interval is worked on, by pumping of mineralised water, and rotary bit is used to work interval of sticking zone to eliminate sticking effect. At the second stage after drilling of intermediate conductor, a conductor is drilled with bit of diameter of 295.3 mm, and after casing and fixation of conductor, the main shaft of well is drilled with bit of diameter of 215.9 mm.

EFFECT: invention solves problem of well construction under conditions complicated with zones of drilling tool sticking.

Description

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

A known method of operating a well, comprising drilling a well along a predetermined profile and lowering casing of various types, including countersunk perforated outside the well. They are fastened with removable anchors. They are isolated in the well by preliminary injection of heat-resistant, sedimentation-resistant, highly structured, anticorrosive, viscoplastic fluid-sealant in conjunction with a sealed medium separator. The production column is not perforated; it is attached to the mouth of the previous column with additional force from squeezing out of the well by the weight of a column of hydraulic seal acting on a sealed medium separator from the wellhead. A sealed medium separator is placed in a secret perforated column above the roof of the reservoir. At its end, a centralizer is placed on rollers with a hydromonitor nozzle for erosion of sediments and compensation of hydro-gas impacts from the reservoir side. The control and management of the annular, annular and tube spaces is carried out by the circulation of the hydraulic fluid through hydraulic valves, environmental sensors installed above the sealed separators among all the columns. Removable anchors with sealed dividers are brought into transport position. After preliminary circulation of the hydraulic fluid lock, the pipe structures of the columns with their rigging are completely removed and completely replaced (RF Patent No. 2139413, publ. 1999.10.10).

The known method is complicated, requires large expenses for drilling, the design of the well is metal-intensive. Drilling a well according to this method with passing through the zones of sticking of the drilling tool and absorption of the drilling fluid causes considerable difficulties or even becomes impossible.

Closest to the invention in technical essence is a method of construction, operation, preservation and liquidation of a well, including drilling a wellbore in a given direction, lowering and securing several casing strings, including the latter - a “liner”, a small production casing and pumping an active insulating material - a water seal . The first casing string is lowered, fastened with a fastening unit and isolated with a hydraulic seal close to the viscous-plastic mass, the well is deepened, the hydraulic seal obtained from the drilling fluid is added by adding binders and neutralizing agents using a small-sized device - the unit for preparing and pumping cement to the required parameters, depending from the stability and permeability of the rocks passed, the next next at least one casing string is lowered, it is fastened from below with a fastening unit, and the last the casing, the lower end of which is perforated outside the well and equipped with a coarse filter, is lowered above the oil-water circuit and fastened with a fastening unit above the roof of the reservoir, last but not least, pre-pumped by a water seal, a small production string equipped with a packer with an anchor and a secondary filter, set the packer over the reservoir and cause swab inflow, operate the well, and then, if necessary, preserve and / or liquidate (RF Patent No. 232 0849, publ. 03/27/2008 - prototype).

The known method is complicated, the use of a water trap does not allow to create a reliable well design due to the susceptibility of the water trap to erosion from the inflow zones and squeezing into the fluid exit zones. The method does not solve the issue of sticking of the drilling tool in the sticking zones, and preventing the absorption of drilling fluid in the absorption zones is temporary.

The proposed invention solves the problem of constructing a well in conditions complicated by the areas of sticking of the drilling tool.

The problem is solved in that in a method for constructing a well, including drilling a direction, a conductor and a main wellbore, lowering and securing casing and production strings, according to the invention, the direction is drilled with a drill bit with a diameter of 490 mm using clay mud with a density of 1.12-1.20 kg / m ³ , the conductor is drilled in two stages, first the industrial conductor is drilled with a bit with a diameter of 393.7 mm using mineralized water with a density of 1.16-1.20 g / cm ³ as a drilling fluid, every 12 m you are drilling under the industrial conductor complete the patterning, which consists in raising and lowering the bit with rotation and washing, and when the sticking effect is manifested, the sticking interval is worked out, for which mineralized water is pumped and the sticking zone passes 2-4 times, at the second stage after drilling the industrial conductor, the conductor is drilled with a bit with a diameter of 295.3 mm, and after casing and fixing the conductor, the main wellbore is drilled with a chisel with a diameter of 215.9 mm.

SUMMARY OF THE INVENTION

During the construction of wells, there are areas in which the walls of the drilled well capture elements of the underground layout (bit), which makes further drilling impossible, and extracting the layout from the well presents significant difficulties. Existing technical solutions do not solve this problem, and if they do, then only partially. The proposed method solves the problem of constructing a well in conditions complicated by the areas of sticking of the drilling tool. The problem is solved as follows.

During the construction of a well, a direction is drilled to a depth of 40-50 m with a bit with a diameter of 490 mm using clay mud with a density of 1.12-1.20 kg / m ³ . A bit of such a large diameter is used to provide the possibility of placing a conductor in the well. Run down and cementing (fixing) the casing string in the direction.

A conductor consisting of two parts is drilled through the direction: the industrial conductor and the actual conductor.

First, the industrial conductor is drilled to a depth of about 250 m with a bit with a diameter of 393.7 mm using mineralized water with a density of 1.16-1.20 g / cm ³ as a drilling mud. The industrial conductor is designed to overlap the sticking zone, mainly located at depths from 75 to 120 m. When drilling under the industrial conductor, every 12 m, a template is made that consists in raising and lowering the bit with rotation and washing with mineralized water, and when the sticking effect is manifested, the interval is worked out sticking, for which they pump mineralized water and a rotating bit pass the interval of the sticking zone to eliminate the effect of sticking. The use of mineralized water helps to reduce or completely eliminate the effect of sticking. Mineralized water appears to prevent buckling of the rock in the sticking zone or minimizes buckling. After drilling the industrial conductor, the casing string is lowered and the annulus is cemented (fixed).

A conductor is drilled through the industrial conductor to a depth of about 500 m with a bit with a diameter of 295.3 mm, a casing string is lowered and the annulus is cemented (fixed).

The main borehole is drilled through the conductor with a chisel with a diameter of 215.9 mm to the design level, the casing of production pipes is lowered and cemented (fixed).

As a result, it is possible to go through the sticking zone and ensure further drilling of the well without complications by sticking.

Concrete example

Perform the construction of an oil well.

Drill direction to a depth of 45 m with a bit with a diameter of 490 mm using clay drilling mud with a density of 1.18 kg / m ³ . Run down and cement the pipe casing in the direction.

The industrial conductor is drilled through the direction with a bit with a diameter of 393.7 mm using mineralized water with a density of 1.18 g / cm ³ as a drilling mud. When drilling under the industrial conductor, patterning is performed every 12 m. Starting from a depth of 75 m, a sticking effect is manifested. Every 12 m, they work out the sticking interval, for which mineralized water is pumped and a 12-meter interval passes through a rotating bit until the sticking effect is eliminated. After a depth of 120 m, the sticking effect does not appear. Drill the industrial conductor to a depth of 250 m without patterning and study. After drilling the industrial conductor, the casing string is lowered and the annulus is cemented.

A conductor is drilled through the industrial conductor to a depth of 500 m with a bit with a diameter of 295.3 mm, a casing string is lowered and the annulus is cemented (fixed).

The main borehole is drilled through the conductor with a chisel with a diameter of 215.9 mm to the design level of 1700 m, the string of production pipes is lowered and cemented.

Drilling a well is not accompanied by tacking the layout for drilling. The use of the drilling method according to the prototype or other technical solutions using clay drilling mud or other solutions instead of mineralized water, as well as drilling without patterning and development leads to sticking of the drilling layout, loss of tools, and sometimes to elimination of the wellbore and drilling of the understudy .

The application of the proposed method will allow to solve the problem of well construction in conditions complicated by the zones of sticking of the drilling tool.

Claims (1)

A method of constructing a well, including drilling a direction, a conductor and a main wellbore, running and securing casing and production strings, characterized in that the direction is drilled with a drill bit with a diameter of 490 mm using clay mud with a density of 1.12-1.20 kg / m ³ , drilling jig is carried out in two stages, initially drilled promkonduktor chisel diameter 393.7 mm using as mud brine density 1,16-1,20 g / cm ^3, when drilling under promkonduktor every 12 m operate shablonirovku, zakl which occurs in the ascent and descent of the bit with rotation and washing, and when the sticking effect is manifested, the sticking interval is worked out, for which mineralized water is pumped and the sticking zone passes the interval of the sticking zone until the sticking effect is eliminated, at the second stage after drilling the industrial conductor, the conductor is drilled with a bit with a diameter of 295, 3 mm, and after casing and mounting the conductor, the main wellbore is drilled with a bit with a diameter of 215.9 mm.