Study On Reasonable Technology Policy Of Cyclic Steam Stimulation In Natural Fractured Heavy Oil Reservoir

Since the 21 st century, along with the reduction of conventional petroleum exploration, more and more people have paid attention to heavy oil. Fractured heavy oil reservoir have both the character of fractured reservoir and heavy oil reservoir. This kind of reservoir has a wide range of distribution. When using method of steam stimulation, it is necessary to consider both the characteristics of conventional heavy oil reservoir and the influence of natural fractures. Study on reasonable technology policy of natural fractured heavy oil reservoir steam stimulation has important significance for the scientific development of natural fractured heavy oil reservoir.In this paper, through extensive research, using reservoir engineering and numerical simulation methods, combined with the actual reservoir parameters, the fractured heavy oil reservoir steam stimulation technology and reasonable policies are studied, the main research achievements are as follows:(1) Through extensive research, summarizes the typical geological and fluid characteristics of natural fractured heavy oil reservoir and the problems in the development process, including: the development of the natural energy production decline rapidly, a low primary recovery rate, channeling of steam injection is serious, water cut increased rapidly;(2) Through the theoretical derivation method, matrix oil production prediction model of during steam injection volume prediction model is established. After the calculation, the process of steam injection imbibition and thermal expansion of the oil was analyzed. From analysis, the imbibition is the main mechanism of steam flooding from the matrix, followed by thermal expansion, and the influence of different parameters on matrix oil sensitivity analysis was carried out;(3) Both vertical wells and horizontal wells of the 25 parameter combination scheme is simulated, the cumulative oil production and oil steam ratio under different schemes are calculated by means of setting up the orthogonal test table. Through the establishment of evaluation index, application range analysis methods of different steam injection parameters of vertical well and horizontal well steam stimulation effect size sorted, and combined with the calculation results and the actual production of different steam injection parameters are optimized;(4) Through the fracture modeling, parameters of fractured reservoir are described, such as: fracture density, fracture azimuth, fracture dip, fracture opening, and set a fracture system attribute model.;(5) Combined with the fracture modeling, establish the model of mechanism of fractured heavy oil reservoir. By the method of numerical simulation, the different types of fracture sensitivity analysis of steam stimulation are carried out. Of vertical well and horizontal well steam stimulation, well spacing along or perpendicular fracture azimuth are calculated. The angle between horizontal well and fracture azimuth, vertical position of horizontal well and well pattern are optimized. That horizontal well stimulation effect is better than the straight well.