SU1093793A1 - Powder composition for preparing buffer fluid - Google Patents

Abstract

POWDER MIXTURE FOR PREPARING BUFFER LIQUID, containing alkali, carboxymethylcellulose and lignin, characterized in that, in order to increase its salt resistance, heat resistance and liquefaction, it additionally contains nitrost — a product of difficult hydrolizable polysaccharides; ; ° C: Nitrost is the oxidation product of hardly hydrolyzable polysaccharides and lignin 0.10-89.7 Alkali 0.1-8.0 Carboxymethylcellulose 0.1-2.0 Lignin Ostalnoe (L

Description

with so

with CO

The invention relates to the field of drilling and attaching oil and gas wells.

When cementing wells drilled on high-density drilling muds, it is necessary to use buffer fluids that can hold the reservoir and prevent it from falling out in areas of displacement with drilling and cementing fluids.

The formulation of a buffer fluid capable of retaining the desired material is known. Its composition includes 3-b / o-aqueous aqueous solution of modified starch, 0.15-0.2 / o okzil or 0.5% of reagent L-6 and the filler is cement or cement mixture 1

The disadvantages of this. Buffer fluid is the complexity of the composition and technology of preparation, the time of its preparation in the drilling environment is 6-8 hours, while it is necessary to use hot water.

Closest to the invention is a powder mixture of BP-100 for preparing a buffer liquid, containing 82.50 / 0 agentus or lignin, Soda ash and 1.5% carboxymethylcellulose (CMC - 600). A buffer liquid based on such material is prepared by mixing it with water in a ratio of 1: 3. After one hour of stirring the mixture in a cementing unit, a structured system is obtained that is capable of holding ut 2.

The disadvantage of the buffer fluid from the known powder mixture is that it can be used to displace drilling fluids with low salinity (up to 1%) from wells with temperatures up to 100 ° C, as with more mineralization and temperatures above 100 ° C, the contacting liquids form viscous, difficult to pump mixtures.

The aim of the invention is to increase the salt resistance, heat resistance and liquefaction ability of the powder mixture. This goal is achieved by the fact that the powder mixture for preparing a buffer liquid containing alkali, carboxymethylcellulose and lignin, additionally contains nitrost, the oxidation product of hardly hydrolyzed polysaccharides and lignin, in the following ratio of components, May. %: Nitrost oxidation product

hardly hydrolyzable polysaccharides and lignin 0.1-89.7 Alkalis0.1-8

CMC 0,1-2,0

Lignin the rest

Dry nitrost is a dark brown powder and is the remainder of the complexone production, consisting mainly of hard hydrolysable polysaccharides in the form of microcrystalline cellulose.

Specific examples of the preparation of the powdered material and the characteristics of the buffer liquid based on this material.

An example. For the preparation of the powder mixture, take, kg: nitrost 1; CMC 1; lignin 90. The resulting mixture is thoroughly mixed, and then dissolved in water at a ratio of 1: 3, and after 30 minutes of stirring, the rheological parameters of the buffer fluid are determined: h (effective viscosity, mPa-s) 18; (dynamic shear stress, / Pa) 0.86; HC (conventional viscosity, p.) 28; B (water loss, cm / ZOmin) G2. When such a buffer liquid is mixed with the cement-based cement of the UTG-200 in a ratio of 1: 9, a mixture is formed, which thickens in 200 minutes at 170 ° C,

0 and the mixture of cement slurry with a buffer liquid based on a known substance thickens under the same conditions in 135 minutes. The cement slurry without a buffer liquid at a given temperature thickens in 180 minutes. Consequently, the buffer liquid based on the proposed mixture does not shorten the thickening time of cement slurries.

Example 2. Take, kg: nitrost 45.5; , four; CMC 0,5; lignin 50. These components are thoroughly mixed and shut off with water in a 1: 4 ratio. After 30 minutes of stirring, a buffer fluid is obtained having the following rheological parameters: 1–12 mPa-s; t 0.72 Pa; HC 32 s. The resulting buffer liquid does not shorten the time of thickening of cement slurries at 170 ° C. So, the mixture of the buffer liquid on the basis of the proposed powder mixture with the cement backing of USHC-200, was taken in ratios 1: 3 and 1: 9,

0 thickens respectively for 250 and 220 minutes, and the mixture with the specified cement slurry is thickened in 105 and 90 minutes, respectively, while clean cement slurry for 150 minutes.

Example 3. Take, kg: nitrost 87,89; NaOH 0.1; CMC 2; lignin 10.01. The mixture was thoroughly mixed and shut off with water in a ratio of 1: 4. After 30 minutes of mixing, a buffer fluid is obtained with rheological parameters. 1

0 16 mPa.s; HC27s; C, 0.86 Pa; At 5cm3 / Z.min. The buffer fluid of the specified composition does not cause coagulation of the drilling fluid and does not shorten the thickening time of the cement slurry. So, if a clean grouting cement SHPSS-200 gas at 5 ° C at 170 ° C for 90 minutes, then a mixture of cement slurry with a known substance in a ratio of 9: 1 thickens in 80 minutes, and a mixture of cement slurry

3, 10937934

 With the proposed buffer liquid in y-wah, using an oil thermostat to

this ratio thickens to 120 min. different temperatures, measured using

The salt resistance of the buffer fluid, the on-vibration viscometer BBH-3 in the prepared drilling fluid from the proposed powder capacity, and their different mixtures are shifted, and its effect on the drilling plant-s in different ratios from the buffer fluid is evaluated by the viscosity change. The viscosity of the resulting mixtures also of the buffer fluids and the drilling fluid themselves are determined at different temperatures from the turn, as well; and mixtures thereof, taken in different vibration viscometer capacities, and compare ratios. For this purpose, high viscosity of mixtures with the viscosity of clean, muddled drilling mud, heaters are taken. The results are shown in the table.

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From the table it follows that the buffer is the buffer liquid from the proposed

the liquid prepared from the predra-powder mixture has a high

powder mixture not only doesn’t mobility, does not reduce the time it takes. Highly viscous mixtures from mineral-thickening cement slurries, degraded drilling muds, but also liquefies drilling muds of various minerals 5-5 times, and water drainage is in the temperature range from 0 before

at the same time, the drilling mud cottages do not rise to -170 ° C, it has low water loss

is coming. Water loss drilling mud and high sedimentation stability,

Buffer fluid is evaluated using what allows you to adjust its density

VM-6. The data show, ranging from 1.06 to 2.1 g / cm.

Claims (1)

A POWDER-MIXED MIXTURE FOR PREPARATION OF A BUFFER LIQUID, containing alkali, carboxymethyl cellulose and lignin, characterized in that, in order to increase its salt resistance, heat resistance and thinning ability, it additionally contains nitrost - an oxidation product of difficult hydrolyzable polysaccharides with the following lignin ratio and polysaccharides. ₀ : Nitrost is an oxidation product of hard-hydrolyzable polysaccharides and lignin. Alkali Carboxymethyl Cellulose Lignin 0.10–89.7 0.1-8.0 0.1-2.0 Else SU .... 1093793