In the process of oilfield development, the common method is to inject water into the underground reservoirs, that result in the problems of high water content and low oil production capacity during the oil extraction, thereby affecting the oil field development work. This paper studies the characteristics of the distribution and tapping technology of the remaining oil in the thick oil reservoir in the process of oilfield development and explores the innovative elements that it implemented.

Energy economy is an important component of socio-economic development. Efficient oil extraction can alleviate the shortage of China's energy supply and  promote rapid economic construction and development of China. Thus in the research on the distribution and tapping technology of remaining oil in thick reservoir, we should make a good use of the relevant technologies to achieve efficient development of the remaining oil of thick oil layer.

In the process of oil exploration, through the study on the distribution of the remaining oil, the appropriate mining method according to the distribution characteristics can effectively improve the extraction rate of the oil inside. The main distribution features of the remaining oil in thick reservoir are: the distribution regions are mainly near the large faults, lithology zone, fault zones corners; the plane distribution patterns are mainly narrow ribbon and isolated island; vertical distribution are mainly in low permeability with poor physical properties. Researches on the distribution characteristics of microscopic high water-cut remaining oil include more pores sheet-like residual oil and less pore dispersed residual oil.

1.1 Sheet-like remaining oil

Sheet-like remaining oil includes the sheet-like remaining oil of the water spread outside and the clustered remaining oil of water ripple domain. The sheet-like remaining oil of the water spread outside refers to remaining oil in the model corners after the injection of water. The clustered remaining oil of water ripple domain is formed when the injected water flow around the pores and produced through small throats pores surrounded by large pores.

1.2 Dispersed remaining oil

Dispersed remaining oil includes two maim forms, that is the isolated island-like and columnar shape

2.1 Steering fracturing technology

As it is more and more difficult to do oil exploration, the stimulation effect of the conventional repeated fracturing techniques is getting worse. The use of steering fracturing technology can solve this problem. There are two main ways of design and application of steering fracturing.1. For multiple reservoir after the transformation, and the slit that does not comply well network requirements, we can use part of frac sand to clear the old joints, and during that time, use temporarily blocking agent to block the old joints. Mechanical fracturing sand to construct a new seam to expand the oil flow area and improve the oil yield results; 2.For the reservoir with a high water-cut but large quantity of residual oil, we can add temporary blocking agents first, then fracturing sand to achieve the closure of old sewing, construction of new joints, and improvement of the oil yield. Steering principle of this technique is its original maximum and minimum horizontal principal stress induced stress sum> original minimum induced stress and the sum of the maximum horizontal stress

2.2 Profile plugging technology

The main purpose of this technique is to adjust the flat contradiction between the layers to reach the purpose of changing the direction of water flooding and improving water areal sweep efficiency.

The research on distribution and tapping technology of the remaining oil in thick oil reservoir in the process of oil field development can effectively solve the related problem with excavation of the resident oil, enhanced oil recovery, improved thick oil reservoir exploitation, and increase economic benefits of the oil fields.

The innovation points are as follows.

3.1 Establishment of the unit division method of the internal structure of thick oil reservoir.

Based on analytic hierarchy principle, the establishment of fluvial sand grading system make the study moved from the previous level of five units of the structural units to 4 units of the structural unit.

3.2 Establishment of a method of thick oil layer internal structural units of the geological model.

With RMS modeling techniques, the statement sand Anatomy digital results, it established a three-dimensional properties of the structural unit model, which makes the network output reached 0.1m and lay a solid foundation for detailed simulation of thick oil.

3.3 Establishment of a variety of technology on complicated tapping.

According to the ideas of reducing distance among wells and the distribution characteristics of the resident oil, we take the advantage of the current mature tapping technology to block the thick reservoir layer to improve its productivity. By long plastic tube closure of complex rhythmic layers within the high permeability layer closure to improve recovery rates in the thick layer of low permeability reservoirs. At the same time, it provides technical support to the tapping of the thick oil layer of more than 3m.

3.4 Comprehensive analysis about the causes of remaining oil.

It provides a comprehensive analysis about the influence of sand body, inner layer sandwich, fault, permeability, injection affect relations on the thick oil layer remaining oil. It also provides quantitative analysis on these factors. It clarifies the macro and micro distribution of the remaining oil distribution by core observation, flooded layer interpretation, indoor core experiments and numerical simulation combined data.

Epilogue

In short, oil energy is the important energy source not only for our country, but also for the whole world. It plays an important role in promoting economic developments and meeting the human needs of life. Regarding the current situation of shortage of Chinese petroleum resources, we have to strengthen the research on the remaining oil distribution to solve the remaining problems in oil exploration. (Source: Chemical Management)

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