SU968330A1 - Method of producing temporary plug in a well - Google Patents

Description

(54) METHOD FOR ESTABLISHMENT-TIME PLUG IN THE WELL

The invention relates to the oil and gas industry in the field of well workover, in particular to methods for creating a temporary plug in a well.

There is a known method of creating a plug by injecting a suspension of sand in a carrier fluid into the well, followed by filling the pipe string with liquid 1.

The disadvantage of this method is that its implementation requires the descent and ascent of the pipe string, the pumping and sanding unit.

Closest to the invention is a method for creating plugs, comprising forming briquettes from a mixture of clay and sand and dropping them into the well 2.

The disadvantage of this method is that part of the clay comes out of the plug composition and contaminates the bottomhole formation zone, thereby deteriorating its reservoir properties.

The aim of the invention is to eliminate contamination of the near-wellbore formation zone.

This goal is achieved by the fact that according to the method, which includes forming briquettes from a mixture of bulk and binder materials and dropping them into the well, aqueous solutions of inorganic salts, such as chloride or sodium chloride, are used as a binder.

The use of aqueous salt solutions as a binder helps to prevent deterioration of reservoir properties of the reservoir, to regulate the rate of formation of the plug, while no plugging of the plug is required.

The method is carried out as follows.

15

Bulk material, such as sand, is poured into cylindrical forms made of polyethylene, impregnated with a saturated hot solution of any salt and kept at

20 room or elevated temperature. In winter, briquettes can be molded from sand moistened with fresh water by freezing.

Briquettes so obtained

Claims (3)

25 dumped in a Squa-hinu. The number of briquettes to create a plug in the well in each case is determined by calculation, based on the volume of the stem to be disconnected. Having settled down to the bottom, they form a plug, salt or ice, from which after a certain time they dissolve in the well of fluid. The proposed sample creation method was tested under laboratory conditions. With this, fractions of 0.2 mm from sand were formed into cylindrical briquettes with a diameter of 50 and a length of 100 mm, which were placed in a liquid similar in composition to the well, and were visually determined by the formation of traffic jams — sandy sediments from them. Example. The sand was loaded into cylindrical forms made of polyethylene, an aqueous solution of calcium chloride of 60% concentration heated to boiling was poured in, and the forms were kept at room temperature for 7 hours (until complete crystallization of calcium chloride), after which the briquettes were removed. Then, the time of formation of plugs from two briquettes after immersion of one of them into a glass beaker with formation water (water density 1.18 g / cm) at room temperature, and the other with the same water at Pb was determined. The time of formation of plugs in solution was determined calcium chloride with a density of 1.3 g / cm at 20 and 3b ° С, which was 2, 1.5, respectively; 3 and 2 hours. EXAMPLE 2. Briquettes were molded as in Example 1, but a saturated solution of sodium chloride was used as a binder, and the forms were kept at ilOO ° C for 1 hour in an oven. As in Example 1, the time for formation of the plugs in the formation water and in the calcium chloride solution was determined. The timing of the formation of the plugs was the same as in the case of using calcium chloride. Example 3: Briquettes were obtained by freezing sand wetted with ordinary process water, and then determined the time of formation of traffic jams, as in Examples 1 and 2. The time of formation of traffic jams in formation water and the calcium chloride solution was at room temperature 2 , 6 h, and at | - 2 hours. Comparisons were prepared briquettes containing clay as a binder (the ratio of sand and clay is 1: 2). Cooked briquettes were immersed one by one in glasses with formation water. After 4 hours, the balls broke up, while a loose mass of sand, clay and water was formed at the bottom of the glasses. The BNBM advantage of the proposed method of creating a plug in a well is that it allows to obtain a tight plug by completely washing out the binder from its composition with the well fluid. In addition, when the binder is dissolved in the well fluid, the possibility of contaminating the near-wellbore formation zone is excluded. The expected economic effect from the use of the invention per one well is an average of 1 thousand rubles. in comparison with the well-known method, it eliminates the cost of the expensive equipment: pumping units, mixers and the need to manufacture and lower the filling pipes. The invention method of creating a temporary block in the well, including the formation of briquettes from a mixture of bulk and binder materials and dropping them into the well, characterized in that, in order to avoid contamination of the reservoir zone, aqueous solutions of inorganic minerals are used as a binder. salts. Sources of information taken into account in the examination 1.US. Patent No. 4,102,398, cl. 166-276, publ. 1978 2. Kharkov 3.Acapital repair of oil and gas wells. M., Nedra, 1969, p. 65-66 (prototype).