CS199001B1 - Polymeric drilling fluid - Google Patents

Description

The object of the invention is a polymer drilling fluid based on glucan or mannoglucan polymer or glucan and cellulose polymer, suitable for a fast and enhanced drilling mode of underground deep wells.

Drilling polymer washings containing glucan or mannoglucan polymers, and possibly glucan cellulosic polymers, reduce their viscosity by 30 to 0 S as their flow rate increases, e.g. However, as soon as the flow rate drops. when the casing returns to the surface, the viscosity again increases by 40 to 70%. This feature of the polymer drilling fluid is advantageous as it is readily pumped through the drill string to the borehole face at reduced viscosity, and well drills the drill to the surface at increased viscosity.

Therefore, polymer drilling fluid is used in reinforced and fast drilling. However, both glucan and glucomannon-type polymers, in particular biopolymers, are very economically unfavorable. In the pursuit of economy, the polymers are therefore strengthened by the addition of chromium trichloride or chromium sulphate or chromlignosulfonates in an amount of 10 to 30% by weight, based on the polymer dry weight. The chromite salts react with carboxy, hydroxyl, or keto groups to form lead, hydroxyl, or oxidized ketone bonds, which result in the formation of a giant molecule having a high viscosity and a three-dimensional gel structure. The thixotropic properties of the irrigation and the adsorption of the polymer onto the clay particles are thereby increased, so that the irrigation suppresses the dispersion of clay rocks and thus reduces the risk of cavities.

A disadvantage of the well-known polymer drilling fluid is that, due to the low pH value of the polymers, the crosslinking does not occur at a sufficiently high degree and the indicated effects do not exhibit the desired quality and quantity.

This disadvantage is overcome by the polymer drilling fluid according to the invention, which comprises 5 to 30% by weight of basic chromium sulphate based on the dry weight of the polymer.

The advantage of the polymer drilling fluid according to the invention is the increased efficiency resulting from the higher degree of crosslinking of the polymers. In fact, basic chromium sulphate acts on glucan and mannoglucan-type polymers as well as on glucan cellulose polymers even at a low pH of 7 to 9. In doing so, it strengthens their structural mechanical properties.

Example I

1000 ml of a 1% aqueous glucan type polymer solution was affected with 2 g of basic chromium sulfate at room temperature and perfectly homogenized with an AM-3 mixer for 20 minutes. The original plastic viscosity of the polymer solution increased from 7.0 mPa · s to 50 mPa · s.

-2 * 2

The Bingham flow limit increased from 0.95 Nm to 67.03 Nm. Original apparent viscosity

199,001 increased from 7.66 mPa · s to 95.76 mPa · s, forming a gel-like polymer structure.

Example II

1000 ml of a 1% aqueous solution of a carboxymethyl cellulose polymer would be affected by 2 g of basic chromium sulfate at room temperature and perfectly homogenized with a mixer for 20 minutes. The original plastic viscosity of the polymer solution increased from 6.0 to 24.0 mPa · s, the apparent viscosity from 7.5 mPa · s to 25.5 mPa · s and the Bingham-2 -2 flow limit from 1.4 Nm to 7.6 Nm to form a gel-like polymer structure which improves the structural mechanical properties of the polymer solution as a flushing medium.

Claims (1)

SUBJECT OF THE INVENTION A polymeric drilling fluid based on a glucan or mannoglucan polymer or a glucan oellulose polymer, characterized in that it contains 5 to 30% by weight of basic chromium (III) sulphate, based on the dry weight of the polymer. Printed by Moravian Printing Works, plant 12, Leninova 15, Olomouc