Mechanism analysis of the hottest low frequency el

Mechanism analysis of low frequency electric pulse vibration wave technology

1 From the point of view of wave dynamics and rock mechanics, the low-frequency pulse vibration wave has a small attenuation in the formation, the propagation distance can reach more than 200m away from the well zone, and the proportion is quite high and can maintain a certain strength, so as to give a strong impact vibration force to the oil and water in the formation and pore media, and make the affected formation rocks and fluids vibrate violently with a great acceleration. Due to the long-term effect of geological forces, oil reservoir rocks have faults, fractures, bedding and other factors. At this time, under the action of strong low-frequency pulse waves, non-uniform rocks produce relatively tearing shear stress. When this shear stress exceeds the fatigue strength of rocks, macro cracks, micro cracks and micro cracks will appear. These fractures can be clearly seen from the comparison of CT scanning images of cores before and after the test. They are similar to the impact of fracturing on the formation, so as to dredge and increase the formation pores, improve the formation permeability, and achieve a series of purposes of plug removal, permeability enhancement, enhanced oil production and injection

2. The shear action on the rock, oil, gas and water interface

low frequency pulse wave can change the solid state in the reservoir porous medium, the state of the oil-water interface and the binding effect of the capillary force specimen are cylinders, improve the distribution and migration of oil and water in the porous medium, and promote the accumulation and seepage of remaining oil. Oil bearing sandstone is a complex medium, which is composed of rock particles, filled clay minerals, saturated oil, gas and water and other complex components. The physical properties of each component are very different. Due to their different acoustic impedance when low-frequency pulse waves

vibrate, their vibration speed greatly reduces the loss degree and acceleration are different, resulting in shear force at the solid solid (clay cement), solid liquid, oil gas water interfaces, The greater the difference of acoustic impedance, the greater the shear stress on the contact surface, and the following effects appear: (1) the clay cement on the surface of rock particles is shaken off, so as to remove the pore blockage, expand the pore radius, and improve the pore connectivity; (2) Change the state of solid-liquid interface, overcome the adsorption affinity of crude oil on the surface of rock particles, and make the oil film fall off the surface of rock particles; (3) Improve the state of oil, gas and water interface in porous media, overcome the binding stagnation effect of capillary force, reduce the interfacial tension between oil and water, and redistribute and gather the remaining oil in the form of oil beads and oil columns, so as to facilitate drainage and displacement

3. Effect on fluid

low frequency pulse wave will produce cavitation when it propagates in the fluid. When the pulse wave propagates in the liquid, due to its high power and relatively high frequency, the density of the liquid changes quickly and the difference is large. This change makes the liquid sometimes under pressure and sometimes under tension. But the liquid itself can withstand compression, and the ability to withstand tension is very poor. Therefore, when the liquid cannot support this force, it will break and produce some sub holes that are almost vacuum, generating positive and negative charges in the formation of sub holes. Then the liquid is compressed. At this time, the hole is compressed until it collapses. During the collapse process, local high temperatures of thousands of degrees will be generated in the hole, as well as the discharge phenomenon with the disappearance of sub holes. The crude oil is cavitating under the action of this pulse wave. The intensity of this cavitation is proportional to the frequency of the pulse wave. The molecular structure of crude oil is destroyed by cavitation and shear stress, which reduces the viscosity of crude oil. The test results show that the viscosity of crude oil decreases by about 6% after the action of pulse wave

4. Water control and oil increase

low frequency pulse can produce alternating electromagnetic field in the process of discharging 5 and starting the experimental power. There are great differences in the electrical properties of oil and water. In the case of oil-water seepage, when crude oil and water containing electrolytes are excited by the electric field, the cations move to the cathode and also take away the water molecules. According to the potential gradient and pressure gradient, the current and fluid flow direction are different, which can reduce the permeability of water and objectively achieve the purpose of controlling water and increasing oil