SU1035229A1 - Rock cementing method - Google Patents

Abstract

A METHOD FOR CEMENTATION OF MOUNTAIN BREEDS, including alternate injection, of a cement and ionic solution into wells under pressure, assigned depending on the properties of the solution, the nature of fracturing and the physicomechanical properties of the rocks in the roof of the cemented zone, characterized in that , fractured deformable rocks, after the cementation of each previous well, the next time the Young's modulus and Poisson’s ratio are measured, which determine the coefficient of The enlarging agent for opening uncemented cracks f) according to the formula b {.CM. REW where she t | - measured Young's modulus (MPa) and Poisson’s ratio of partially cemented rocks; VL is the initial (before injection of the solution) value of the coefficient of fracturing of partially cemented rocks, injection of the solution is stopped at a pressure P determined from the formula P (Kp Po4-1) (PO where P is the final distant injection not taking into account the rock deformations in the cementation zone , MPa; P - final injection pressure, determined for initial crack fissure and physicomechanical properties of rocks in the roof of the cemented zone, MPa; оо, 5 - coefficient depending on SP of cement-to-water ratio of the solution; l - coefficient increase in dissolution of uncemented cracks during injection of the solution, 1 / MPa.

Description

The invention relates to the holding and fastening of mine workings with the use of cementation of rocks.

The known method of cementation of rocks by injecting cementation solutions under pressure, assigned depending on the properties of the solution and the nature of Ll treshinatost.

The disadvantage of this method lies in ignoring the physicomechanical properties of rocks, which can lead to hydraulic fracturing of the rock mass and waste cement.

 The closest in technical essence and the achieved result to the invention is a method of cementation of rocks, including alternate injection of a cement mortar into wells under pressure, assigned depending on the properties of the solution, the nature of fracturing and the physico-mechanical properties of rocks in the roof of the cemented zone 2,

HejjocTaTOK of a known method consists in ignoring the physicomechanical properties of rocks in the directly cemented zone. This method excludes only hydrodisintegration, but does not allow for the increase of cracks due to deformation of the massif in the cementation zone. This leads to an increase in the radius of the spread of the solution and the waste of cement.

The purpose of the invention is to reduce the consumption of the cementation solution during the cementation of fractured deformable rocks.

This goal is achieved by the fact that according to the method of cementation of rocks, including alternate injection of cement mortar into wells under pressure, assigned depending on the properties of the solution, the nature of fracturing and the physico-mechanical properties of rocks in the roof of the cemented zone during cementation of fractured deformed rocks the previous well, in the following, the Young's modulus and the Poisson’s ratio are additionally measured, which determine the expansion ratio mental type fracture by the formula.

--- ((

Hz E and Lj - measured Young Moaul., (MPa) and Poisson's ratio of partially cemented rocks;

 - the initial (before the solution is injected) the value of the fracture coefficient of partially cemented highland rocks,

the injection of the solution is stopped at a pressure P determined from the formula

R (

Ro rro

where P is the final pressure of the injection, taking into account the deformation of rocks in the cementation zone, MPa;

P is the final injection pressure, determined for the initial fracturing and physicomechanical properties of rocks in the roof of the cemented zone, MPa;

, 5 - coefficient depending on the cement-water ratio of the solution;

- the ratio of the magnification of the opening (b and uncemented without 1 cracks during injection of the solution, 1 / MPa.

FIG. Figure 1 shows the graphs of the limits for decreasing the final pressures; pumping; in fig. 2 - graphs of limits for exclusion of cementation radius increase.

FIG. 1 and 2, curves 1 and 2 correspond to the values of the coefficient K included in formula (2), equal to 2 and 2.5; Rj and R are, respectively, the distribution radii of the solution without taking into account and taking into account the deformation of the ropiaix rocks.

The method is implemented as follows.

The cement hole is drilled. During the drilling process, periodically for each lithological difference of rocks, which are opened by the well, core sampling is made for the core sampler. The volume of the core for the cemented rock strata is used to determine the initial value of the fracture coefficient m (for example, П1р 0, ОО; 5). On core samples, using well-known methods, measure the Young's modulus E and Poisson's ratio, I (for example, O, 25); E-O, 2, 10 MPa). According to formula (1), the value of the coefficient for increasing the crack opening is calculated for the rocks penetrated by the well, b (in this example, L 0.15 f).

L) | Pa

Hydraulic testing of the well was performed. According to a known method, depending on the hydrostatic pressure of the near-earth waters, the hydraulic resistances of the initial fractures, the initial fracturing and the physicomechanical properties of the rocks in the roof of the cemented zone, the concentration of the grouting solution (for example C: B 1: 0.5) and final injection pressure P without taking into account the deformability of rocks (for example, PJ 5MPa). Pump the solution in the squas; gin The injection is stopped at the pressure of the scientific research institute P, assigned according to the formula (2) (in the considered example P 3.8 MPa).

The application of the proposed method of cementation allows to reduce the consumption of cement while ensuring the quality of cementation and to obtain a significant economic effect by eliminating the increased distribution radius | 1.

pPo

 S

Pui.2

Claims (1)

ROCK CEMENTING METHOD, including alternating injection of a cement slurry into wells under pressure, assigned depending on the properties of the mortar, the nature of the fracture and physico-mechanical properties of the rocks in the roof of the cemented zone, characterized in that, in order to reduce the consumption of cement mortar during cementation, . fractured deformable rocks, pos. For the cementation of each previous well in the subsequent, the Young's modulus and Poisson's ratio are additionally measured, 'by which the coefficient of increase in the opening of uncemented cracks is determined by the formula rocks; - the initial (before the injection of the solution) value of the fracture coefficient of partially cemented rocks, the injection of the solution is stopped at the Pressure P determined from the formula P _ (1fR _about m) ^1, * _d. ~ „V ® where P is the final injection division taking into account rock deformations in the cementation zone, MPa; P — final discharge pressure, o determined for the initial fracture and physicomechanical properties of the rocks in the roof of the cemented zone, MPa; K = 2-2.5 - coefficient depending on the cement-water ratio ^{to the} solution; - the coefficient of increase in the opening of cementless cracks during injection of the solution, 1 / MPa. > f 1035229