| The"loft oil"at the top of fault block reservoir occupies a large proportion in China's oil and gas energy structure,but it is not easy to exploit.Gas injection is an effective way to improve the final oil recovery of this kind of"loft oil".However,in view of the problems of gas accumulation in conventional gas injection,as well as water and gas alternately injecting water shielding,artificial air top drive is a new direction to solve such problems.The advantage is that even if the gas does not mix with the crude oil,it will improve the final recovery rate,and the development effect is better than other types of immiscible flooding.Therefore,it is of great significance to carry out the research on the technical policy of the artificial gas cap drive in the fault block reservoir,which is of great significance to the effective use of the partial accumulation area of the remaining oil in the fault block reservoir and the further improvement of the final oil recovery of the reservoir.By means of reservoir numerical simulation,the percolation mechanism and seepage characteristics of artificial gas cap drive in fault block reservoir are studied first,the stability of gas gravity drive is analyzed,and the seepage law and dynamic characteristics of artificial gas top drive are summarized.The main control factors and sensitivity evaluation of artificial gas top drive in fault block reservoir are carried out.Reservoir static parameters and reservoir dynamic parameters are taken into consideration.The influence of different factors on the development effect of artificial gas top drive is studied,and the sensitivity evaluation standard is established.At last,the technical policy limit of artificial gas cap drive in fault block reservoir is studied.The distribution law of residual oil in the actual complex fault block reservoir is analyzed,and the mining effect under different development modes is compared,and the technical policy limits for the development of water drive auxiliary artificial gas cap drive are given.The main understandings of the research are as follows:(1)Gravity differentiation plays a key role in the migration process of injected gas to the top of structure.(2)The factors,such as the dip angle,the width of the oil strip and the vertical heterogeneity,are the most sensitive factors,and the factors such as the viscosity ratio and the injection production ratio of underground oil and water mainly affect the stability of the gas top drive,which are sensitive factors.(3)The remaining oil in Y47-X28 well area is mainly controlled by structural factors and development factors.Water drive assisted artificial gas cap drive is the most suitable development mode in this block.(4)the optimization suggestion for the technical policy of Y47-X28 well area is given,which is as follows:the optimal injection production ratio 1:1,the gas water injection ratio 1:1,the water injection speed 8.5m~3/d,the recovery speed of 17m~3/d,and the gas injection speed of 1.12t/d. |
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