SU1749228A1 - Method of producing borehole flushing fluid without clay - Google Patents

Abstract

Use: drilling and development of wells. SUMMARY OF THE INVENTION: A zinc chloride solution and a 40% sodium hydroxide solution are mixed. The entire volume of sodium hydroxide solution is mixed with 1-2 volumes of sodium hydroxide solution, a stabilizer based on polysaccharides in the amount of 0.4-0, J% may be added and the remaining volume of zinc chloride solution added 1 tab.

Description

The invention relates to methods for producing water based drilling fluids and can be used in the drilling and development of productive formations, preferably under conditions of abnormally high formation pressures.

A known method for producing a clay-free washing liquid consists in mixing saturated aqueous brines of calcium chloride and magnesium sulfate in a volume ratio of 1.5: 1, respectively, until a paste is formed, then the polymer is introduced into the paste, after which it is diluted with water (up to 250% water to paste volume).

There is also known a method for producing a clay-free washing liquid consisting in mixing magnesium chloride with caustic soda, adding concentrated sulfite-alcohol stillage (CSSC), carboxymethylcellulose, oil, starch, and other additives.

The closest to the invention is a method of obtaining a clay-free washing liquid, which consists in dissolving crystalline zinc chloride, caustic soda in water, mixing these components to form zinc hydroxide, which is a structure-forming solid phase. fluid. In this case, the components of the solution are taken in quantities, May. %: zinc chloride 5-55; caustic soda 2.5-15; carboxymethylcellulose 1.5-3; water - the rest.

However, the solution obtained with this method with low solids content has extremely high rheological indices with very low structural and mechanical properties. Moreover, the introduction of ut gel leads to

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greater deterioration of the structural-rheological properties, which, in turn, does not ensure the necessary stability of the fluid,

The aim of the invention is to improve the structural and rheological indicators, increase the stability of the fluid while maintaining filtration properties.

The goal is achieved by the fact that according to the method of obtaining a clay-free washing liquid, including mixing a solution of zinc chloride with a solution of caustic soda, mixing, introducing a polysaccharide-based stabilizer reagent, the whole volume of sodium hydroxide solution is mixed with a part of p-zshor zinc chloride, which take in the amount of 1-2 volumes of sodium hydroxide solution, and use a solution of sodium hydroxide with a concentration of 40 May%, introduce a stabilizer reagent based on polysaccharides and add Shuyus part of the solution of zinc chloride, while the reagent-stabilizer is introduced in the amount of 0.4-0.7 wt.%.

The method is carried out as follows.

Given the composition of the solution, calculate the amount of components required to obtain the required amount of solution.

From the calculated amounts of ZnCJ2 and NaOH, their aqueous solutions are prepared. In this case, the NaOH solution is prepared concentrated (40% NaOH, / 1400 kg / l), and ZnCIa dissolves in the remaining part of the water (its concentration may vary widely depending on the selected composition).

The entire volume of NaOH solution is mixed with an equal to or twice as large volume of ZnCIa and stirred until a homogeneous cream-like solution is obtained.

A polysaccharide (KM1D, CMEC, starch, etc.) is introduced into the resulting cream-like solution and stirred until the latter is completely dissolved.

The remaining amount of the ZnCte solution is injected into the resulting system and mixed until a white homogeneous liquid is formed, conditionally found with a stabilized hydroxide solution (SGCR). This moss solution can be used as an independent brown solution (clay-free washing liquid), and, if it is necessary to obtain a higher density, it can be supplied with standard loosening agents (barite, magnetite and

dr). for which, the required amount of the ut gel is added to the SGCD.

Changing the concentration of the NaOH solution is not possible, and the concentration of the solution

ZnCl2 is not limited as the ZnCl2 solution is prepared from the remaining water. The volume ratio of the initially mixed solutions of NaOH and ZnCl2 can be in the range from 1-1 to 1-2, respectively, only in

0 such a mixture can effectively dissolve the polysaccharide, providing - its maximum stabilizing and structuring effect.

Data on the parameters and properties of the washing liquid obtained by the proposed method are given in the table.

A liquid containing, for example, 60% ZnCl2, 4% NaOH and 0.4% CM C, can be prepared by mixing solutions of caustic soda and zinc chloride in various volume ratios.

Pr v. meper 1. 1 kg of liquid of this composition can be obtained by the following method. From the calculated amounts of zinc chloride, oral soda and water, solutions of zinc chloride (479 ml of a solution of 67% concentration) and caustic soda (71 ml of a solution of 40% concentration) are prepared. The whole solution of caustic soda is mixed with a part of a solution of zinc chloride in a volume ratio of 1: 1 (71 ml each) and, with stirring, 4 g of CMC mixing is introduced into the resulting hydrogel for 1 u oo to form a homogeneous system. After that, the resulting hydrogel stabilized CMC, injected the rest of the zinc chloride solution (408 ml) and stirred for 2 hours until a homogeneous solution is obtained.

0 The measured technological parameters of the solution obtained are: density 1800 kg / m, nominal viscosity 57 s, filtration for 30 min 4 cm static shear stress (CHCi / io) 3/5 dPa, plastic viscosity 26 mPa-s, dynamic shear stress 39 dPa, stability O kg / m3, sludge 0%, pH 4.0

To make it possible to obtain a fluid with a density of kg / m and use it to solve such technical problems as killing emergency Fountain wells, stop extrusion of plastic rocks into the well bore under the influence of geostatic pressure and others, barite concentrate is injected into the liquid in an amount 80-100 ma.ch. on 100 ma.ch. fluid.

If the liquid containing 60% ZnCI2, 4% NaOH and 0.4% CMC is added by introducing 85% barite, the parameters of the solution are as follows: density 2500 kg / m, viscosity 70 sec, filtration 2.5 cm; CHCi / s: 5/9 dPa, plastic viscosity 54 mPa-s, dynamic shear stress 121 dPa, pH 4.0; stability 0 kg / m, sludge 0%.

PRI mme R 2. 1 kg of a liquid of the same composition is prepared as follows: from calculated amounts of zinc chloride, caustic soda and water, solutions of zinc chloride (479 ml of a solution of 67% concentration) and caustic soda (71 ml of solution 40 % concentration). The whole solution of caustic soda (71 ml) is mixed with part of the zinc chloride solution in a volume ratio of 1: 2 (i.e., 142 ml) and 4 g of CMC was added to the resulting hydrogel with stirring, stirring continued for 1 until a homogeneous system is formed. After that, the remaining part of the zinc chloride solution (337 ml) was introduced into the stabilized CMC hydrogel and stirring was continued for 2 hours until a homogeneous liquid was obtained.

The technological parameters of the liquid obtained are: a density of 1,800 kg / m; conditional viscosity 57 s, filtration 4 cm, CHCi / o 3/5 dPa, plastic viscosity 26 mPa s, dynamic shear stress 39 dPa, stability 0 kg / m3, sludge 0% -, pH 4.0.

Example 1 kg of liquid of the same composition is obtained as follows; From the calculated amounts of zinc chloride, caustic soda and water, solutions of zinc chloride (479 ml of a solution of 67% concentration) and caustic soda (71 ml of a solution of 40% concentration) were prepared. The entire solution of caustic soda is mixed with a three-fold solution of zinc chloride (213 ml) and 4 g of CMC is added with stirring, stirring is continued for 1 hour until a homogeneous system is formed. Thereafter, while stirring, the remaining part of the solution of zinc chloride (266 ml) is introduced into the resulting system and stirred for 2 hours until a homogeneous solution is obtained. The technological parameters of the solution obtained are as follows: density 1800 kg / m, nominal viscosity 54 s, filtration 15 cm, CHCi / y O / O dPa, plastic viscosity 17 mPa-s, dynamic shear stress 13 dPa, stability 30 kg / m3 , sediment 6%, pH 3.

When 80% barite iron is introduced into this solution, its parameters are: density 2500 kg / m3, viscosity 82 s, filtration 12 cm. CHCi / io 0/2 dPa, plastic viscosity 21 mPa-s, dynamic shear stress 23 dPa, stability 20 kg / m3, sludge 10%; pH 4

EXAMPLE 4. To obtain 1 kg of a clay-free washing liquid of the composition,%. ZnCl2 60%; NaOH 4; CMC 0.4; water 35.6, when using a solution of NaOH of 35% concentration, it is necessary to use a solution of ZnCl2 of 88% concentration while the solubility of zinc chloride in water provides the possibility of obtaining a solution with a maximum concentration of 75%. Thus, in this case (using a 35% NaOH solution), it is impossible to obtain a washing liquid of this composition.

Example 5: To obtain 1 kg of liquid composition,%: ZnCte 50; NaOH 4; CMC 0.4; water 45.6, when using a solution of NaOH of 35% concentration (82.2 ml), it is necessary to prepare 561 ml of 61.1% solution of ZnCte. Mix 82.2 ml of zinc chloride and sodium hydroxide solutions. With stirring, 4 g of CMC is introduced into the resulting gel and stirred for 1 hour until a homogeneous system is formed. Thereafter, the remaining portion (478.8 ml) of the zinc chloride solution is introduced into the resulting CMC-stabilized hydrogel system and stirred for 2 hours until a homogeneous solution is obtained. The technological parameters of the solution are as follows: density 1550 kg / m; conditional viscosity 39 s; filtration 6 cm; CHCi / y o / o dpa; plastic viscosity 13 mPa-s; dynamic shear stress of 6 dPa; stability 0.0 kg / m; sucks 1%.

The use of the proposed method allows, at a lower cost, to achieve a higher density and stability of the solutions than the known technical solutions.

The low concentration of hydroxy zinc solids allows large amounts of standard weighting components to be injected into the liquid, which, in turn, creates real objective prerequisites for obtaining superheavy solutions (with a density of 2500 kg / m3 and higher) with a minimum amount of solids compared with the known systems of heavy solutions.

Claims (1)

Invention Formula The method of preparation without a clay washing liquid, including mixing a solution of zinc chloride with sodium hydroxide solution, mixing the mixture, introducing a polysaccharide-based stabilizer reagent, characterized in that, in order to improve the structural and rheological parameters by reducing viscosity while maintaining thixotropy, stability while maintaining filtration properties; sodium hydroxide solution is pre-mixed with a part of zinc chloride solution equal to 1-2 volumes of solution roksida solution, wherein sodium hydroxide is used at a concentration of 40 mass% and the remainder of zinc chloride solution administered after administration stabilizer reagent, wherein the reagent stabilizer is used in an amount of from 0.4 to 0.7% by weight of the drilling fluid