Device and method for large-size visual physical simulation of fingering of acid liquid in acid fracturing crack

Abstract

The invention relates to a device and a method for large-size visual physical simulation of fingering of an acid liquid in an acid fracturing crack in an oilfield chemistry and acid fracturing laboratory and a research laboratory. The device and the method can simulate flowing and reaction conditions of an acid liquid in an acid fracturing crack, can be used for observation of fingering of an acid liquid, and can determine associated parameters. The device is characterized in that a high-pressure constant-flow pump of a liquid pumping unit is connected to a liquid storage tank; a liquid outlet of the high-pressure constant-flow pump is connected to middle containers; the middle containers are connected to a six-way valve; the six-way valve is connected to a liquid inlet of a crack simulation unit; a stainless steel front frame is connected to a rear cover by fastening bolts; exhaust holes and drainage holes are arranged respectively at an upper part and a low part of the stainless steel front frame; liquid inlet holes and liquid outlet holes are arranged respectively at a left end and a right end of the stainless steel front frame; an observation window is arranged in the center of the stainless steel front frame; a rock plate is arranged between the stainless steel front frame and the rear cover; an electric heating panel and a heating probe are embedded in an outer side of the rear cover; a temperature sensor is arranged in the center of the rear cover; the liquid inlet holes and the liquid outlet holes of the stainless steel front frame are provided with a differential pressure transducer; and an image gatherer is installed right in front of the crack simulation unit. The device and the method improve a degree of mechanization and automation. A simulation experiment carried out by the device satisfies storage layer real-environment requirements, and is safe and fast.

Description

technical field [0001] The invention relates to a large-scale visualized physical simulation device and method for acid liquid fingering in acid fracturing fractures used in oil field chemistry and acid fracturing laboratories and research laboratories. technical background [0002] Fracturing and acidizing is one of the important stimulation techniques for carbonate reservoirs. The production stimulation effect of acid fracturing is closely related to the flow reaction process of acid fluid in artificial fractures. During acid fracturing, acid flow in fractures is accompanied by acid fingering. It is extremely important to understand the evolution characteristics and changing rules of acid fingering in fractures to accurately characterize the flow reaction process of acid in fractures. At present, indoor research mostly uses a physical simulation device with parallel plate slits to simulate the acid flow reaction process. Most existing physical simulation models of acid f...

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Problems solved by technology

Most existing physical simulation models of acid flow are based on the Hele-Shaw physical model, and such devices include the following categories: 1. "Transparent glass parallel plate + transparent glass parallel plate" or "transparent resin parallel plate + transparent resin "parallel plate" simulation device, although this type of device can realize the visualization of the acid flow process well, but it cannot simulate the acid-rock reaction, and the similarity with the actual acid flow reaction process is weak; 2. "Transparent glass plate + reaction "Reactive rock slab" simulation device, which can realize the visualization of the acid flow reaction process under acid-rock reaction conditions, but its temperature and pressure difference adjustment accuracy is low, which reduces the reliability of the conclusions; 3. "Reactive rock slab +Reactive rock slab” simulation device, this type of device can simulate the flow reaction process of acid liquid under high temperature and high pressure, but the flow reaction process cannot be visualized, which has caused problems for the analysis of important phenomena such as acid liquid fingering in the flow reaction process. Difficulty; 4. "Three plates and double slits composed of glass plates of different sizes + marble plates + steel plates" simulation device, this type of device can simulate normal temperature, medium and low pressure (maximum temperature up to 50°C, pressure 0.8MPa), different crack inclination angles and consideration of acid Visual simulation of acid rock reaction under the influence of liquid filtration, but the heating method is that the hot fluid passes through the slit to heat the rock plate, the heating speed is slow, and the reliability and stability of the temperature cannot be guaranteed. At the same time, the degree of automation of the experimental equipment is low , the labor intensity of the experimenters is high, and the operation is inconvenient

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