RU2473779C2 - Method of killing fluid fountain from well - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: well is filled with liquid nitrogen, tubing string is removed from the well and there performed is the control for freezing rocks and fluids adjacent to the well. After formation of shut-off plug in well and fluid fountain blocking the cement grouping is pumped into the zone above the well and pressure in well is maintained till its hardening.

EFFECT: elimination of emergency situations at fields.

3 dwg

Description

The invention relates to the oil and gas industry and can be widely used for the elimination of gas and oil occurrences (GNP) when drilling deep wells, opening productive horizons, as well as in the process of developing land and offshore fields.

There is a method of eliminating (blocking) GNP in drilling wells, as well as killing production wells, including filling wells with a high-density liquid, for example, salt solutions, creating a pressure on the bottom that exceeds the reservoir pressure (Ibragimov GZ, etc. Reference manual on the use of chemical reagents in oil production. - M.: Nedra, 1983, p. 33). However, this method is difficult to implement in cases of abnormally high formation pressures (AAP) in the wells.

A well-known technology for killing a production well, which includes reducing reservoir pressure in the area of a flowing well, for example, due to production through other wells of the field. According to this technology, the operation of the gushing well is stopped by filling it with formation water (RF patent No. 2096591). The method, partially solving the problem of reducing oil production losses by reducing well downtime, preserving the properties of the bottom-hole zone, and the hydrodynamic parameters of the productive formation, does not allow damping the fountain from a well with a high AVR.

There is a technical solution for killing drilled and exploited oil and gas, water wells, eliminating emissions of fluids into the environment (RF patent No. 2100567, published December 27, 1997). The specified technical solution is taken as a prototype. As part of numerous measures aimed at eliminating fluid emissions from the well, the method includes injecting refrigerant, for example liquid nitrogen, into its emergency zone, forming a shut-off plug in the well, and temporarily shutting off the fountain. The technology is characterized by significant costs for the use of special equipment and materials, a low level of safety of abandoned wells.

The purpose of the invention is to block or suppress fluid fountains from drilled or production wells in onshore and offshore fields.

This goal is achieved in that the method of killing a fluid fountain from a well includes adding washing liquid to the well, injecting liquid nitrogen into it, creating a shut-off plug in the well emergency zone, plugging the cement slurry and curing it in the well, and if there is liquid nitrogen in the well from the emergency zone remove the arrangement of tubing and monitor the processes of freezing the adjacent rocks, formation water, flushing fluid, increasing the viscosity of the fluid, and after cement blocking is blocked by the fountain blocking plug in the upstream zone of the well; cement is added, the flushing fluid is added, the pressure is maintained in the well until the solution has cured, and an additional shutoff plug is created in it.

The essential distinguishing features of the proposed technical solution in comparison with analogues, prototype include the following.

1. If there is liquid nitrogen in the well from its emergency zone, the arrangement of tubing is removed.

2. They monitor the processes of freezing adjacent to the borehole rocks, formation water, flushing fluid, increasing the viscosity of the fluid.

3. After blocking the fountain of the fluid by the shut-off plug, cement mortar is pumped into the upstream zone of the well and the flushing fluid is added.

4. Maintain the pressure in the well until the solution has cured.

5. Create an additional shutoff plug in the well.

Through the use of new technological prototypes in comparison with analogues, it is possible to ensure the safety of jamming of open fluid fountains in wells drilled or operated on land and at sea. Therefore, the claimed solution meets the patentability criterion of "novelty."

Signs that distinguish the claimed solution from the well-known developments were not identified in the study of this and related fields of science, technology, in other domestic, foreign sources. Therefore, the claimed method meets the criterion of patentability "inventive step".

Thus, the claimed solution having the above set of distinctive features and advantages meets the criteria of patentability: "novelty" and "inventive step".

The invention is illustrated by the drawing, where Fig. 1a shows an uncontrolled inflow of formation fluid into the well, Fig. 1b shows the injection of liquid nitrogen, the creation of a shut-off plug in the emergency zone of the well, and Fig. 1c shows the process of pumping cement, the location of the additional shut-off plug ( cement bridge) in an emergency well.

The method of silencing a fluid fountain from a well involves the following sequence: in the well equipped with a casing 1, arrangement of tubing 2, in the presence of an emergency flow of fluid 4 from the reservoir 5 into the open borehole 3 (Fig. 1a), the drilling fluid is added liquid nitrogen is pumped in and the tubing assembly 2 is removed from the reservoir 5 and above the rock horizon. As a result of freezing rocks adjacent to the well, produced water and flushing fluid, increasing the viscosity of fluid 4 in the emergency zone of well 6, a shut-off plug 7 is created and open flowing of fluid 4 from the well is blocked for a limited period (0.5 ... 5 days) (Fig.1b ) After blocking the fountain of fluid in the upstream zone of the well, equipped with a casing 1, and the open hole 3, cement slurry is pumped through the arrangement of tubing 2, cement mortar is pumped, the flushing fluid is added to the well, and then pressure is maintained in it until the solution is cured and created well additional shut-off plug 8.

The proposed method of blocking, killing fluid fountains from wells can also be successfully used to eliminate accidents at oil and gas pipelines. The method provides long-term industrial and environmental safety of mothballed facilities liquidated after accidents.

The proposed method allows in difficult mining and geological, technological conditions, and in particular in the presence of AHP, to block or suppress fluid fountains in wells.

Claims (1)

A method of silencing a fluid fountain from a well, including adding washing liquid to the well, injecting liquid nitrogen into it, creating a shut-off plug in the well's emergency zone, injecting cement into the well and curing it in the well, characterized in that if there is liquid nitrogen in the well from the emergency zone remove the arrangement of tubing and monitor the freezing of adjacent rocks, formation water, flushing fluid, increasing the viscosity of the fluid, and after blocking ayuschey stopper fountain fluid in the zone located above the well cement slurry is pumped, the pressure maintained in the wellbore before curing solution and create in it an additional tube cutoff.

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