RU2478768C1 - Method for well drilling - Google Patents

Abstract

FIELD: mining.

SUBSTANCE: when drilling a well, a string assembly with a downhole motor is placed in the well, water is pumped through the assembly, drill-pipe connection is carried out, sludge is washed away from the downhole. Sludge washing is carried out by pumping of a drilling mude with viscosity of 30-50 according to a viscosimeter VP-5, density of 1.20-1.30 g/cm³ in the volume of 5-10 m³. In process of pumping the load is taken off the chisel, the string assembly is lifted for the length of the master drill pipe, water in drill pipes is replaced for drilling mud of higher viscosity, the drilling mud is pumped with simultaneous lowering of the string assembly until stop at the downhole, string assembly stroking is carried out with frequency of 1-2 per minute and amplitude equal to the length of the master drill pipe, with simultaneous pumping of the higher density mud, the drilling mud is replaced with water, the drill pipe is connected to the string assembly, drilling is continued. Water is used with initial density of 1.00-1.01 g/cm³. In process of drilling water density is increased due to particles of drilled rock to the density of 1.02-1.06 g/cm³. When opening the water horizon, a mixture of water is used with current density and produced water.

EFFECT: increased efficiency of drilling.

1 cl

Description

The invention relates to the construction of wells and may find application in wiring a wellbore with a large zenith angle.

A known method of drilling a well, comprising rotating and axially feeding the assembly with a bit and supplying washing liquid from the internal cavity of the assembly through the bit to the bottom, while in the absorption zone of the washing liquid, part of the flow of washing liquid from the internal cavity of the assembly is directed into the annulus above the bit (RF patent No. 2024723, CL ЕВВ 21/00, publ. 15.12.94).

Closest to the proposed invention by technical essence is a method of opening the seams, according to which, when opening the seams to the roof, the assembly is rotated and axially fed with the bit and the washing fluid is supplied through the internal cavity of the layout to the bottom. Then the casing with a wedge landing ring in the shoe part is lowered and cemented. Continue the autopsy with the supply of washing fluid through the internal cavity of the layout to the bottom to the formation with partial or complete absorption of the washing fluid. When opening a formation with partial or complete absorption of washing liquid, the annular space of the well is separated above the formation with partial or full absorption of washing liquid. The entire flow of flushing fluid is supplied through the internal cavity of the assembly into the annulus of the well above the place of separation while simultaneously creating in the annular space below the place of separation of reduced pressure and depression on the formation and ejecting liquid with slurry from the bottom through the internal cavity of the assembly into the annulus above the place of separation, mixing with flushing fluid and towards the wellhead (RF patent No. 2279535, publ. 2006.07.10 - prototype).

A disadvantage of the known methods is that when constructing a well with a remote displacement of the bottom from the wellhead, i.e. with a large zenith angle, cuttings cuttings accumulate at the bottom, leading to sticking of the drill string and impossibility of further drilling.

The proposed invention solves the problem of cleaning the bottom of the well from sludge, eliminating sticking of the drill string.

The problem is solved in that in a method of drilling a well, which includes arranging a layout with a downhole motor in a well, pumping water through a layout, building up drill pipes, flushing out cuttings from the bottom, flushing out cuttings by pumping a drilling fluid with a viscosity of 30-50 s using a VP-5 viscometer with a density of 1.20-1.30 g / cm ³ in a volume of 5-10 m ^3, for leveling the load is removed from the drill bit, the arrangement is lifted by the length of the kelly replace water in the drill pipes on the rig high viscosity solution is pumped concurrently with the drilling fluid by lowering the assembly all the way to the bottom, pacing the assembly with a frequency of 1-2 per minute and an amplitude equal to the length of the drill pipe, while pumping a solution of high viscosity, replace the drilling fluid with water, increase the layout of the drill pipe, continue drilling, while water is used with an initial density of 1.00-1.01 g / cm ³ , during the drilling process, the density of water is produced by particles of cuttings to a density of 1.02-1.06 g / cm ³ , and when opening the water-developing horizon, a mixture of water is used with current th density and formation water.

SUMMARY OF THE INVENTION

Drilling of wells with large zenith angles accompanies sticking of the drill string. If sticking occurs with loss of flushing fluid circulation, the annular space behind the drill string is rammed with rock and cuttings. There is a differential stick, in which circulation is present, and the movement of the drill string is stopped due to the force of its pressing by the weight of the column of drilling fluid when it is filtered into a permeable formation with a reservoir pressure below hydrostatic. A common cause of tacking is clogging of the wellbore, which contributes to tacking. The proposed invention solves the problem of cleaning the bottom of the well from sludge. The problem is solved as follows.

When drilling in a well, a layout with a downhole motor is placed, pumping through the layout of water, extension of drill pipes, leaching of cuttings from the bottom are carried out. Sludge washing is carried out by pumping a drilling fluid with a viscosity of 30-50 s using a VP-5 viscometer with a density of 1.20-1.30 g / cm ³ in a volume of 5-10 m ³ . A viscous and dense solution of selected density and viscosity is most suitable for removing sludge from the bottom of a drilled well. As a viscous drilling fluid, clay mud, polymer-bentonite mud, polymer mud, and the like can be used. When pumping, the load is removed from the bit by raising the layout, raising the layout to the length of the leading drill pipe, replacing the water in the drill pipes with drilling fluid of increased viscosity, pumping the drilling fluid while lowering the assembly to the bottom in the bottom and raising the layout, i.e. spacing layout with a frequency of 1-2 per minute and an amplitude equal to the length of the lead drill pipe, while pumping a solution of high viscosity. Wash sludge from the bottom of the well. Pacing and emphasizing the layout on the face as a mechanical effect contributes to the breakdown of sludge conglomerates, the grinding of sludge particles and facilitates the washing out of sludge. After washing the sludge, the drilling fluid is replaced with water, the layout of the drill pipe is increased, and drilling is continued. Before the next build-up of the drill pipe assembly, measures are again taken to remove sludge by pacing and flushing with viscous drilling fluid. The proposed measures contribute to loosening and suspension of the sludge, and a viscous solution helps to retain the particles of sludge in the solution and their removal from the well.

When drilling, water with an initial density of 1.00-1.01 g / cm ³ is used as a washing liquid. During the drilling process, particles of drill cuttings are not completely removed from the water and thus the density of water is produced by particles of drill cuttings to a density of 1.02-1.06 g / cm ³ . More dense water contributes to better retention and removal of rock particles from the bottom of the well. At the opening of the water-developing horizon, washing water is mixed with produced water. After sinking the water-developing horizon, a mixture of water with current density and produced water is used as a washing liquid.

As a result, when drilling a well, it is possible to clean the bottom of the well from sludge and to eliminate sticking of the drill string and other drilling complications.

Case Studies

Example 1. When drilling in a well, an arrangement of drill pipes with a downhole motor and a bit with a diameter of 215.9 mm is placed. Spend pumping through the layout of water with an initial density of 1.005 g / cm ³ , building drill pipes, leaching of cuttings from the bottom. Starting from a depth of 600 m, sludge are washed out by pumping a drilling fluid with a viscosity of 40 s using a VP-5 viscometer with a density of 1.25 g / cm ³ in a volume of 8 m ³ . The drilling fluid has the following composition: clay mud (clay powder 130 kg / m ³ , weighting agent - dolomite 358 kg / m ³ , soda ash 5 kg / m ³ , carboxymethyl cellulose 3 kg / m ³ , product KMK-BUR2 20 kg / m ³ , AB Catamine 0.45 kg / m ³ , oil 5 kg / m ³ When pumping, the load is removed from the bit, the layout is lifted to the length of the lead drill pipe 12 m, the water in the drill pipes is replaced with a drilling fluid with increased viscosity, the drilling fluid is pumped with simultaneous lowering the layout all the way to the bottom, pacing the layout with a frequency of 1 run -podem per minute and an amplitude equal to the length of the kelly, with simultaneous pumping higher viscosity solution. Replace the drilling fluid is water with a current density of 1.03 g / cm ^3, the arrangement of the drill pipe are increasing and continue drilling. In the range 810-909 m a water-developing horizon is drilled, while washing water with a current density is mixed with produced water. After drilling a water-developing horizon, a mixture of water with a current density and produced water is used as a washing liquid. Drill a well to the design level without sticking the drill string.

Example 2. Perform as example 1.

A polymer-bentonite drilling fluid with a viscosity of 30 s is used with a VP-5 viscometer with a density of 1.20 g / cm ³ in a volume of 5 m ³ , a layout pacing with a frequency of 2 per minute is used, water with an initial density of 1.00 g / cm ^{3 is used} , the time in the process of drilling the density of water is carried out to a density of 1.02 g / cm ³ .

Drill a well to the design level without sticking the drill string.

Example 3. Perform as example 1.

A polymer drilling fluid with a viscosity of 50 s is applied using a VP-5 viscometer with a density of 1.30 g / cm ³ in a volume of 10 m ³ , pacing the layout with a frequency of 1.5 per minute is used, water with an initial density of 1.01 g / cm ^{3 is used} , the time in the process of drilling the density of water is carried out to a density of 1.06 g / cm ³ .

Drill a well to the design level without sticking the drill string.

The application of the proposed method will solve the problem of cleaning the bottom of the well from sludge.

Claims (1)

A method of drilling a well, including placing a layout with a downhole motor in a well, pumping water through a layout, building up drill pipes, flushing mud from the bottom, characterized in that mud flushing is carried out by pumping a drilling fluid with a viscosity of 30-50 s using a VP-5 viscometer with a density of 1, 20-1.30 g / cm ³ in a volume of 5-10 m ³ , when pumping, the load is removed from the bit, the layout is increased to the length of the lead drill pipe, the water in the drill pipes is replaced with a drilling fluid of increased viscosity, the drilling fluid is pumped with simultaneous lowering the assembly all the way to the bottom, pacing the assembly with a frequency of 1-2 per minute and an amplitude equal to the length of the lead drill pipe, while pumping a solution of increased viscosity, replace the drilling fluid with water, increase the layout of the drill pipe, continue drilling, while water used with an initial density of 1.00-1.01 g / cm ³ , during the drilling process, the water density is produced due to particles of cuttings to a density of 1.02-1.06 g / cm ³ , and when opening the water-developing horizon, a mixture of water with current area tnosti and formation water.