RU1782271C - Method to remedy breakdown - Google Patents

Abstract

The invention relates to oil and gas production, in particular to the elimination of accidents arising from the breakdown of pipes and tools and significant amounts of metal falling into the bottom. The method involves the installation of an acid bath containing ka. As an active medium, aqua regia a mixture of nitric and hydrochloric acids in a ratio of 1: 3 with the addition of sodium nitrite and monoethanolamine (0.05 - 13 to 100 parts by weight). These additives significantly increase the activity of the acid mixture and shorten the time for the liquidation of the accident and the restoration of the well. 1 silt. 2 tab.

Description

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The invention relates to the field of drilling and can be used in the destruction of various objects in a well.

A known method of eliminating accidents and sticking pipes by mechanical destruction of the metal, which requires the use of special tools, for example, pin bits, downhole or shoe milling machines.

There is also known a method for eliminating accidents with a drill string made of aluminum alloys in the well, including drilling the upper part of the emergency string and capturing it with a fishing tool, followed by lifting, and before drilling, isolating part of the pipe string located below the accident zone, and an acid bath is installed in the accident zone.

A disadvantage of the known method is its high complexity. It is related

with the fact that the acid bath to be installed, in its volume, containing hydrochloric or grime acid (a mixture of hydrochloric and hydrofluoric acids) only reduces the strength of the pipe; but it does not completely dissolve, does not destroy. Therefore, the completion of emergency operations requires the use of highly labor-intensive drilling and lifting operations for the emergency part of the pipe.

The purpose of the invention is to reduce the complexity of work due to the acceleration and complete destruction of the metal.

A method for liquidating an accident involves installing an acid bath in the accident zone, into which a mixture of sodium nitrite and mono-TeMelami is added in a ratio of 1.1: 1, in an amount of from 0.65 to 13 parts by weight. to 100 parts by weight acid, while aqua regia is used as the acid — a mixture of nitric and hydrochloric acids in a ratio of 1: 3, respectively.

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Reagents that met the requirements of the standards were used: sodium nitrides TU 38-10274-79, solution, basic substance content 280 g / l; monoethanolamine TU 6-02-915-79, grade I, the content of the basic substance is not less than 9 8%. These two components in the presence of acids react with the release of gas, nitrogen, which significantly accelerates the dissolution of the metal in acids.

The proposed method was used where it was not possible to eliminate the accident caused by the breakage of the bit mechanically using a cutter and fishing tool. The well was eliminated. On the face were pieces of metal that could not be caught or smashed. By lowering the container from the turbodrill body, bottom-hole filling of nitric acid, hydrochloric acid, sodium nitrite solution and monoethanolamine was performed. The resulting gas-saturated aqua regia was kept at the bottom of the well with full sealing and no circulation.

Then, the well was depressurized, the resulting reaction mixture was neutralized by adding caustic soda to pH 8 - 9. After that, a polymer solution was applied to the circulation pump, the circulation was resumed, the drilling tool was put into the hole and re-drilling was started. By supplying a polymer solution, the density of the drilling fluid was adjusted to 1.03 - 1.25 g / cm3, viscosity from 7 to 50 MPa s, water loss not more than 7 cm3 / 30 min.

The required amount of acids (depending on the content of the main substance in the commercial product) was 1.25 parts by weight for nitrogen and 6.75 parts by weight. for hydrochloric acid with respect to 1 part by weight of steel. Table 1 shows the calculation of the required amount of breaking length of 50 kg of steel, which makes it possible to determine the need for acids to destroy any amount of metal.

PRI me R 1. The well was eliminated due to the inability to eliminate the accident caused by the breakage of a bit with a diameter of 215.9 mm At the bottom of 3000 m were pieces of metal with a total mass of 37 - 50 kg. To dissolve such an amount of metal, 42.5 L of nitric acid and 1005 L of hydrochloric acid were required, the dissolution lasted 6.6 days (156 hours). In a neighboring well of the same area with the same initial conditions, 0.293 m3 of sodium nitrite solution (6.9 h) and 0.0722 m3 (72.2 l, 6.1 h) of MEA were added to the acid mixture. The well was sealed tightly and kept without circulation for 2.5 days. When the well was opened, it turned out that the metal at the bottom was completely dissolved. Thus, an addition of 13% of a mixture of sodium nitrite and monoethanolamine was saved in 3.5 days. Then, the mixture at the bottom was neutralized with caustic soda to pH 8–9, a polymer solution was added, and circulation was resumed. A drilling tool was lowered to the face, and drilling continued.

PRI me R 2. To eliminate the accident caused by a broken bit, as a result of which about 50 kg were stopped at the bottom

5 metal and the well was liquidated; by lowering the container from the turbodrill body, 42.5 l of nitric acid, 1005 l of hydrochloric acid, 145.5 l of sodium nitrite (3.5 h) and 36.1 l (3.0 h) were bottom-hole poured ) mono ethanolamine, the well was sealed and kept for 4.5 days. Then they opened, neutralized, added a polymer solution, resumed circulation, lowered the bit to the bottom, continued drilling.

5 EXAMPLE 3. To dissolve 50 kg of metal at the bottom of the well (2870 m) within 6.5 days, 42.5 L of nitric and 10005 L of hydrochloric acid were required. With the addition of 0.35 h (29.3 L) of sodium nitrite and 0.30 h (7.2 L)

0 monoethanolamine, the dissolution rate increased and the dissolution time was reduced to 6.0 days. Next, the well was depressurized, the mixture at the bottom was neutralized with caustic soda, circulation was added,

5 lowered the bit to the bottom, continued drilling.

The dissolution rates of steel were investigated without additives and with the addition of various amounts of sodium nitrite and monoethanol. The research results are shown in table 2 and in the drawing. The data presented indicate that:

steel dissolves in acids: slower in nitric, slightly faster in hydrochloric

5 (curves 1 and 2). In their mixture, aqua regia, complete dissolution of the metal occurs within 6.5 days (curve 3);

when a mixture of sodium nitrite and monoethanolamine is added to aqua regia, the dissolution of steel is accelerated. The minimum dissolution accelerating amount is 0.65 parts per 100 parts of acid mixture. The maximum amount is 13 hours per 100 parts of an acid mixture, while the time for a solution of 5 metal is reduced to 2.5 days: this period of time is very convenient for preparing the well for the resumption of drilling operations and in all production instructions for preparatory and final 2-3 hours of work are allotted. So

Thus, the concentration range of the additive of sodium nitrite and monoethanolamine 0.65 - 13 parts by weight per 100 parts acid mixture is necessary and sufficient to reduce the complexity of emergency operations to restore wells;

the drilling fluid obtained after alkalizing the reaction mixture and introducing a polymer solution into it has good viscosity properties ((Table 2, column 10), as well as low corrosion activity (column 11).

Compositions and properties of tested Pesnes

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Claims (1)

SUMMARY OF THE INVENTION A method for liquidating an accident, comprising installing an acid bath in an accident zone, characterized in that, in order to reduce the complexity of the work by accelerating and completely destroying the metal, sodium nitrate and monoethanolamine are additionally introduced into the mixture in a ratio of 1.1: 1.0 in the amount of 0.05-13 wt.h. to YuOmaach. acid; in this case, royal acid vodka is used as the acid — a mixture of nitric and hydrochloric acids in a ratio of 1: 3, respectively. Table 1 table 2 V1 I 8 S 9 eneeciyC Hnhadoaj, csd qo-oodoHQ Compiled by Tehred M. Morgenthal 8 Proofreader M. Sharoshi