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Laboratory experiments for determination of the rock carbonate
content as a rule are conducted with limestone СаСО because it is
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the most widespread in rocks and forms the main part of the

carbonates listed above. By the volume of СО released during
2
reaction is determined the mass percentage content of carbonates in
the rock in scaling to СаСО .
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The rocks of productive formations which contain considerable

quantities of carbonates can be subjected successfully to treatment by
hydrochloric acid with the aim of formation permeability increase and
intensification of oil (gas) recovery.

5.3 Equipment, materials and reagents. The structure of
the device and the principle of its operation

The following equipment, devices, materials and reagents should
be used for the experiment: the device (apparatus) for determining the
carbonate content of rocks (АC-4 (АК-4) apparatus), analytical

balance, porcelain or metallic mortar, the rock grinded to powder,
barometer, thermometer and hydrochloric acid (1:1) half diluted by
water.

The structure of АC-4 (АК-4) apparatus and the principle of
its operation. Chart of the device (apparatus) for determining the
rock carbonate content (АC-4 (АК-4)) is given in figure 5.1.

The АC-4 (АК-4) apparatus consists of thermostat 1; reaction bottle 2;
test tube 3; coil 4; burette with graduated marks 5; cylinder
6; equalizing bottle 7; valve 8, thermometer 9 and plug 10.

The principle of device operation consists in measuring
the volume of gas (carbon dioxide СО ) which is released in
2
the process of reaction of acid with rock and in determining
the amount of solved rock (carbonates) according to stoichiometric

equation (5.1).

5.4 Procedure and calculations

5.4.1 Before the beginning of this experiment the extracted dry
rock has to be grinded to powder in a porcelain or metallic mortar.

Take 0.5 – 5 g of the grinded rock (the weight depends on

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