Evaluation Of Plugging Effect Of Gel Particles Based On Low Field Nuclear Magnetic Resonance Technology

In order to quantitatively characterize the change of pore space in the reservoir before and after gel particle displacement from a microscopic perspective,the influence degree of permeability,temperature,injection pressure,injection volume and formation water salinity on the plugging effect is revealed from the plugging mechanism.On the basis of characterizing the physical and chemical properties of PEG-1 single-phase polymer gel particle system flooding agent by using laser particle size analyzer and other experimental techniques,the author takes artificial core and natural core as the research objects,uses low-field nuclear magnetic resonance technology,and combines dynamic physical simulation experiments to comparatively analyze the changes of physical parameters and T₂ curve differences of nuclear magnetic resonance before and after core flooding and at different times,quantitatively characterizes the fluid distribution and pore volume changes under different conditions,and quantitatively evaluates the plugging efficiency of gel particles on pores of different scales under different conditions.The results show that PEG-1 gel particle system has weak acid as a whole and good solid content,all of which are more than 8%.It has excellent dispersion performance and can be uniformly dispersed in deionized water without precipitation.The gel particle system has excellent swelling performance,and the particle size expands from 0.77?m to 144.00?m in the initial stage to 1.13?m to 666.00?m;for artificial cores,the plugging pore throat dimension of gel particle system flooding agent is between 0.10 ms and 60.95 ms;for natural cores,the plugging pore throat dimension is between 0.10 ms and 1147.53 ms;the plugging efficiency of gel particles is positively correlated with injection pressure,injection volume and temperature,and negatively correlated with permeability and formation water salinity.The plugging effect of gel particle system flooding agent on larger pore throat space?> 10ms?is always better than that of smaller pore throat space?0.1ms¹0ms?.