SU1709064A1 - Method of releasing stuck drill pipes - Google Patents

Abstract

The invention relates to the drilling of offshore oil and gas wells. The purpose of the invention is to increase the efficiency of the method in its implementation at a well with a subsea mouth connected to the surface by a riser with a fitting line (LH) running along it. To do this, an overpressure is created in the well 1 by pumping a gaseous agent through LS 8 under a pressure equal to the hydrostatic pressure of the drilling fluid in the riser 7. Then drill string 4 is pulled so that the drill string 4 closes when the preventer is closed dice last. After sealing the wellhead with a preventer 6, the pressure is also released through LS 8. This will lead to a decrease in the force pressing the string 4 of pipes to the wall of well 1 and to its release. 1 il.-g ^

Description

The invention relates to the drilling of offshore oil 1; (s and gas wells with an underwater estuary from floating semi-submersible drilling rigs (PBU) and drilling ships.

Lime methods for eliminating sticking of a boring vessel with liquid baths.

The disadvantage of the analogue method is low efficiency, due in particular to the large gap in time from sticking to the installation of the bath.

Methods are known for eliminating sticking of a drill string using the method of communicating vessels.

The disadvantage of analog-bureaus is the possibility of clogging of the drilling outlets of the bit and loss of circulation.

The closest technical solution, the prototype of the invention, is a method of eliminating the sticking of the boring pipe; Tons, including sealing the annular space of the well and a sharp decrease in its hydrostatic pressure. Eliminate the sticking of the drill string by a sharp decrease in the hydrostatic pressure in the well.

The method also includes disconnecting from the stuck portion of the column, lowering the packer device and connecting to the emergency end.

The disadvantage of the prototype is low efficiency due to the large gap in time from sticking to the use of the device.

The aim of the invention is to increase the efficiency by accelerating the implementation of the method in a well with an underwater mouth connected to the surface of the river by a riser (marine) with a fitting line (LS) running along it. ,

The goal is achieved by terminating the air through a puddle with a pressure equal to the hydrostatic pressure of the drilling fluid in the riser, sealing the wellhead and relieving the pressure on the LS.

The following differences in the claimed method can be seen from the picture:

air injection in LS;

sealing the well at the mouth with a preventer;

this eliminates the need for a packer device in the annulus of the well;

pressure relief at LS through the nozzle;

the possibility of carrying out the method immediately after sticking a stuck (without losing time on the cuffs, lifting the pipe string, lowering the device and connecting to the emergency end), which dramatically increases the effectiveness of the anti-sticking action.

The drawing shows the implementation of the proposed method.

When drilling well 1 with an underwater well 2 with an FPGP 3, the drill string 4 was sticking under the action of a pressure drop in the well-reservoir system. A permeable stratum 5 is shown. The mouth 2 is equipped with a preventer 6 and connected to the surface of the day (SSF) by raiser 7 with LS 8 running along it.

Immediately, as a result of the sticking, open (remote control) LS at the lower end and slowly pump into it with an air-filled high-pressure compressor, displacing the liquid in the LS into the riser. The pressure in the LS is brought almost to the hydrostatic pressure of the drilling fluid (level 9) in riser 7, but does not exceed it — otherwise air will flow into the riser. The fitting 10 is closed all this time.

Stop the injection, pull the drill string in such a way that the lock of the drill pipe at the closure of the preventer would be above the dies of the latter. Close the preventer seal the annular space of the well. Open the nozzle, relieve pressure in the LS, thereby instantly

reduce the hydrostatic pressure in the well by the amount of hydrostatic pressure of the drilling fluid in the riser. Reducing the system pressure drop

the well-reservoir leads to a decrease in the force pressing the string of pipes to the well wall and the release of the string.

An example of the claimed method.

During the drilling of the well with the FPPD, the drill string was stuck in the well at a depth of 2200 m, opposite the formation 4 with a pressure of 33 MPa. Riser length 250 m. Density

drilling mud 1650 kg / m.

In this case, the drop in the well-reservoir system is 10-5 1650 2200-33 3.3 MPa. It was decided to sharply reduce the hydrostatic pressure in the well by 4 MPa.

To open the bottle, it enters the air to a pressure of 4. MPa. The length of the riser and the density of the drilling fluid allow this operation to be performed, because the hydrostatic pressure

The drilling fluid in the riser is equal to 10 250x х1бВО 4г1 MPa. Pull the drill string down and close the spot preventer so that the drill lock is above the pretenter plate. The nozzle is opened to release pressure and sharply reduce the pressure in the annular space of the well. The weight indicator and column movement determine the release of the pipe string from sticking.

Compared to the prototype, the technical and economic efficiency of the inventive method can be estimated by the specific losses of time and money spent on tackling one well.

Claims (1)

Invention Formula The method of eliminating sticking of the drill string, including the creation of an overpressure in the well by pumping a gaseous agent into it, sealing the wellhead and the release of pressure, so that. in order to increase its efficiency when carried out on a well with an underwater mouth connected to the day surface by a riser with a fitting line running along it; drilling mud in the riser.