| Oil recovery is produced as a percentage of the original underground crude oil reserves, namely the quantity produced oil and underground crude oil reserves than the original. In the economic conditions allow for higher under the oil recovery rate, that is the core of oilfield development, but also the nonrenewable resources protection, rational use and realize the sustainable development of the social needs.Nowadays to improve oil recovery method emerge in endlessly, people had a lot of to improve oil recovery indoor research, including:polymer efficiency water flooding, surface activity flooding, the alkaline water flooding, foam flooding, gas phase of mixed flooding, carbon dioxide flooding and the phase of mixed flooding and steam flooding, burning oil layers. But in practice the microscopic flooding increases for efficiency (relative to the water flooding) the only feasible solution is to use phase of mixed fluid to dramatically reduce flooding traps for liquid and oil and oil flow between IFT of (interfacial tension), the fluid or and crude oil blend phase (eliminate interfacial tension), or phase formation and oil ultra-low interfacial tension, make be trap oil happen flow, a flow production Wells to achieve maximum micro drive for efficiency. But, in the oil flow condition in other parts of the reservoir can also was again trap, row flooding efficiency can be decreased. This is because the chemical agent (such as surfactants) in the front row flooding because of the rock adsorption concentration decreased, reduce the interfacial tension ability to drop, the oil is trap down. General in EOR process, original oil reservoir is in or close to residual oil saturation, displacement must be first make oil flow to form a residual happened flowing oil belt, also is to form a continuous oil phase, and then to be effective in row for oil belt. Imagine if in to improve oil recovery process of as far as possible to avoid oil phase is water trap, maintain production Wells and water injection well between good with duct, can certainly achieve the purpose of enhancing oil recovery.Many oil workers and scholars in fact in many years ago will know that oil and water contact with the drive is for the continuity of the phase of oil recovery have influence, but people and not the factors of attention. People want water injection flooding water flooding when the front can even push, as far as possible to improve water flooding affected coefficient, but in the present development of the traditional mode, because the production Wells with well into the most short wire at maximum gradient, injection water along this line caused by the breakthrough happened refers to the phenomenon is inevitable in, because this refers to the porous media into is not caused by heterogeneity but by the current radial flow development mode of cloth decided well way, causing the crude oil is serious segmentation and traps, and the production Wells with lose connectivity, so recovery rate is very low. The follow-up to take many kinds of water, the field tests and all kinds of methods to improve oil recovery, and the result is that the division of the crude oil is more and more fragmented, and improve the recovery effect not very obvious.From the oil and gas accumulation theory, we know, the oil and gas accumulation process though is a complex process, but oil and gas into the reservoir after the process can be gathered as is flooding in wet for wet phase process, is also the oil on the water displacement process. Today’s water injection process, is water for oil displacement process. Both oil and the process of replacement is each other, but the former is tiancheng, the latter is the artificial. Comparing the two process, the process of oil and gas accumulation in the rock into the pore, most of the water from the pores in the flooding, within the scope of the rock in oil, crude oil to the YanShiTi spread coefficient is1.0when the original oil saturation is equal to accumulation process water displacement of the Chinese for efficiency that is flooding "water recovery". And reservoir original oil saturation generally high, as high as60%～80%or higher, the water injection when only one third oil recovery. The same is two-phase flow for mutual flooding process, the accumulation process is oil flooding for water, oil occupied the position of water; And the development process is water flooding for oil, water occupied the position of the oil. But why the water in the process of oil accumulation of the replacement rate is much higher than the water in the development process of the replacement rate of oil? If the oil migration and accumulation mechanism of oilfield development oil displacement mechanism of comparative study of carefully, which must include some we have not yet realize or have already known, but not the importance and application for the drive mechanism. Now finds it out, to know. As long as the natural imitation, learning the behavior pattern of aggregation process crude oil of essence, used for oil development, it is possible to greatly enhance oil recovery.For why oil and gas accumulation in the water displacement efficiency of oil, specifically, the hydrocarbon accumulation system as a complete research unit’s comprehensive analysis, the main is through to the second migration and development process of the replacement of the characteristics of the oil and water research, reverse thinking exploration of the development process of new ways to enhance oil recovery. the exhibition for fluid state keep the cloth of crude oil displacement efficiency for the higher.4、and prospects the pores of the rock was flooding in the exhibition for phase fluid displacement efficiency for state cloth the application prospect of influence, and puts forward the parallel flow line, split water oil, five points of by the method of turn for note, and, to some extent, of the EOR improvement effect has reference value. |
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