New Technique Invention And Application Of Characterizing Microscopic Remnant Oil In Reservoirs

In order to study the mode of occurrence and law of Remaining oil of water flooding and polymer flooding different physical properties reservoir of Daqing oil field, and the view of quantitative and high-resolution visualization of remaining oil from the microscopic point, identify the micro control factors of remaining oil, the article based on the independent research and development of confocal laser, fluorescence microscope, cast body image analysis technology as the core. Combined with scanning electron microscopy, petrophysical property analysis and mip analysis in daqing oil field experimental method pizza north-north two regions with high permeability reservoirs, elm forest areas low-super low permeable reservoirs, a detailed study of the different permeability core pore structure characteristics and washing of remaining oil in the process of change, micro types and mode of occurrence, water flooding and crude oil weight ratio relations and the different pore structure and the permeability of the fluid velocity field pore distribution characters, and oil emulsiflcation phenomenon after asp flooding produced to the influence of remaining oil distribution and recovery obtains the following results:Developed the full spectrum fluorescence microscopy technique of frozen core grinding slice oil-water rock, laser scanning confocal microscope detection of remaining oil, microscopic three-dimensional reconstruction of the remaining oil, and formed a mature detection supporting means of microscopic distribution of remaining oil. Declared three state invention patent that include the analysis method of emulsifying crude oil emulsion confocal laser, the flooding model of the real core observation in constantly and a kind of method that oil multi-gas process of observe the real core. Wrote four enterprise standards that the digital image analysis for the hole of core and crack analysis, the method of confocal laser for crude oil emulsion analysis and microscopic residual oil distribution.Developed a set of software that for fluorescence image analysis of micro residual oil to reach the technical target of microscopic high resolution clear distinction and quantitative identification remaining oil-water rock, visual observation of three-dimensional distribution, quantitative proportion of crude oil light and heavy components.By core test of Sabei and Yushulin peripherals low permeability reservoir, the micro-remaining oil in the Daqing oil field is divided into 3 categories of 10 subclasses occurrence, bound state, semi-bound state, free state. Bound state 3 categories:pore surface sheet film, adsorption-like particles, slit-like; half-bound states of three types:corner-shaped, throat-shaped, pore center of precipitation; free state in 4 categories:cluster, state within the grain, adsorption-like between the grain, light mist. Established mature corporate standards remaining oil experiments of Daqing oil field.Simulated real core with different pore structure by Multi-physics modeling software, Simulated velocity variation of different coordination number core samples with different pore structure of the image method. Found that the high velocity concentrated in a narrow throat, when the relatively low coordination number (equal to 3) and better connectivity,the velocity differentiation low, may drive more the remaining oil; when coordination number increased (> 4-5) and better connectivity, the high-velocity concentrated in a relatively wide throat, the velocity differentiation high, may remain more remaining oil. Reservoir heterogeneity is stronger, finer grain size, the higher the coordination number, the more reservoir oil.Found that the certain relationship between clay mineral type and displacement efficiency of water flooding, not only the total amount of clay in oil reservoir after water flooding has a certain downward trend, and a certain regularity of different clay changes, illite and illite/ smectite mixed layer content down the fastest, then for chlorite, kaolinite again, displacement order of clay minerals, illite and illite/smectite mixed-layer, chlorite, kaolinite. With illite and illite/smectite mixed-layer more conducive to higher oil water flooding.Core test results of site inspection wells show that the extent of crude oil displacement controlled by rock physical properties, and good physical area, a high degree of displacement, throat width of the distribution is concentrated in the 15-25 micron oil, oil displacement efficiency.Flooding conditions and displacement efficiency studies have shown that proportion of Crude oil light and heavy components in high permeability reservoirs had no obvious relation with the flooding conditions, with the degree of flooding and displacement increases, reducing the proportion of light component is not obvious; but proportion of crude oil light and heavy components in low-super low permeability reservoir had a certain relationship with the degree of flooding conditions, with the degree of flooding and displacement increases, the proportion of light components were less obvious, heavy component was significantly increased.Oil emulsion after the asp flooding produced,there are correspondence in emulsion type and emulsion liquid viscosity, the average grain and diameter emulsion liquid viscosity among them, the more smaller with emulsion average particle size distribution, the more concentrated it will and the viscosity will more higher,and to these pore play a quite sealing role,thus to spread influence about oil flow of adjacent pore, for homogeneous reservoir, as the increaseof emulsion liquid viscosity, the recovery have reduce, for Heterogeneity of reservoir, as the increaseof emulsion liquid viscosity, the recovery have increase.The experiment of remaining oil shows that:still have considerable remaining oil has not been taken out after the water flooding and the tertiary recovery,the moving of each layer of remaining oil and the rate of recoverable remaining oil can also have a large improvement by the development of new technology, it is great significance to the continued development of oil fields and China's energy strategy.