Testing device and method for simulating flat carbonate rock reaction

Abstract

The invention relates to a testing device and method for simulating flat carbonate rock reaction. The device mainly comprises a liquid storage pot, a flow meter, an acid-resistant plunger pump, a pipeline electric heating jacket, a flat clamper, a plunger metering pump, a hydraulic oil tank, a condensation tube, an acid-resistant filter, a back-pressure valve, a liquid collection pot, a pressure gauge, a molecular vacuum pump, a data acquisition and control board, and a computer. The method comprises the following steps: (1) arranging the flat rock in the inner cavity of the flat clamper, and simulating the crack width by a shim; (2) starting the plunger metering pump, applying the sealing pressure, and taking out the shim; (3) starting the molecular vacuum pump, and zero setting the pressure gauge; (4) opening the liquid storage pot accommodating acid liquor; (5) starting the computer, inputting testing parameters, and injecting the acid liquor; and (6) calculating the reaction rate of the carbonate rock at any time. The method not only can be used for accurately calculating the reaction rate of the carbonate rock, but also can analyze and evaluate major factors affecting the reaction rate of the carbonate rock; therefore, the invention provides the specific equipment and the testing method for the research on the reaction of the flat carbonate rock.

Description

technical field [0001] The invention relates to a test device and method for simulating the reaction of flat acid rock in the development process of oil and gas fields. Background technique [0002] Fracturing and acidizing (acid fracturing) is an effective measure for the commissioning and stimulation of oil and gas wells in low-permeability carbonate reservoirs. It reacts chemically with the artificial (natural) fracture wall rock through acid liquid to form groove-like or uneven high-permeability channels, thereby improving the seepage conditions of oil and gas wells and increasing oil and gas well production. The acid rock reaction rate is one of the key factors affecting the effect of acid fracturing stimulation. Research and field practice show that temperature, acid concentration, rock type, common ion effect, acid type, surface-to-volume ratio of acid-rock system, acid flow rate, and pressure are the main factors affecting the acid-rock reaction rate. Therefore, an...

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Problems solved by technology

[0004] (1) The plate holder is sealed with rock plate resin glue, and the sealing pressure cannot be adjusted. When the pressure in the test process increases, it is easy to cause the acid liquid to leak from the side of the rock sample, and the leaked acid liquid contacts with the back of the rock sample to produce chemical reaction, a large amount of reaction products are produced, which leads to the low concentration of the acid solution tested and the high reaction rate of the calculated acid rock;

[0005] (2) The flat plate holder adopts the sealing method of tightening bolts extruding fluororubber. Due to manual tightening of the bolts, the torque of the tightening bolts will be inconsistent, resulting in uneven force on the rock plate and destroying the rock plate at the initial stage of the experiment. A large number of leaks lead to a relatively high reaction rate of the tested acid rock;

[0006] (3) The size of the rock sample is too small. In most cases, a core piece with a diameter of 2.54 cm is used for the acid-rock reaction experiment of the rotating disk, and the experimental results cannot fully represent the actual reservoir conditions;

[0007] (4) It is difficult to achieve a large displacement of acid liquid by using the intermediate container piston type to displace acid liquid, and it is impossible to simulate the flow state of acid liquid in actual fractures;

[0008] (5) A gas-liquid separator is used to collect the gaseous product of the acid-rock reaction. With the increase of the reaction product, the pressure of the gas collection port of the gas-liquid separator increases, resulting in the gaseous product CO 2 The loss along the liquid pipeline with lower pressure leads to a serious increase in the error of the experimental data;

[0009] (6) Use an infrared gas analyzer to test the CO in the mixed gas 2 The accuracy of the relative content is seriously affected by the gas flow rate, and the error of the experimental data is relatively large. At the same time, it also restricts the realization of the simulation of the acid flow state in the actual fracture with a large displacement;

[0010] (7) Using the traditional method of taking reaction acid samples to titrate the acid concentration to determine the acid rock reaction rate, the sampling process requires interruption of the experimental operation, resulting in discontinuity in the experimental process, and the accuracy of the titration operation and the determination of the titration pH value are directly affected by the The influence of the subjective judgment of the experimental operator leads to large errors in the experimental data

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