B239 6 Ultra-low Permeability Reservoirs With Long Lead Waterflooding Technology Research

With the development of exploration technique, In our country, the number、reserve、 scale of the low and extremely low permeable reservoir discovered are expanding. The reserve volume in low and extremely low permeable reservoir is abundant, which has become a stable development important potential of petroleum industry in our country. Low-permeability reservoirs have the characteristics of the wide distribution, the great reserves, the low abundance, the bad properties, how effective development is essential. The research on the development plan in the exploration of low permeable reservoir has an important significance.Advanced water injection is one of the stimulation treatments to improve the exploitation effects of the extreme-low-permeability reservoir, the method of advanced water injection start pouring water into the reservoir several months before the production well opened up, Comparing with the synchronous water injection and the delayed water injection, the advanced water injection method could not only build up an effective system of displacement pressure, increase the producing pressure drop, but could also preserve the reservoir energy effectively, so that the reservoir permeability could avoid the nonelasticity damage caused by the decline of the reservoir pressure, which as a result could protect the seepage channel from being hurt, and raise the recovery ratio of the extreme-low-permeability reservoir, so as to improve the exploitation effects.Chang6oil reservoir is the main force layer of B239Well-block reservoir, which is0.41mD of permeability and belongs to ultra-low permeability oil field. Through the analysis of the main geological features s fluid property、flow characteristic of B239Well-block reservoir, the research on evaluating the development effect of advanced water injection as well as in the process of developing the existing problems, we have carried out the following research and obtain the corresponding results:1、Analysis on the geologic characteristic and development situation of B239Well-block as well as research production rate snet injection percent、water drive index、effective system of displacement pressure. The reservoir is bad properties and low permeability. At present, it has not formed effective system of displacement pressure between oil wells and water wells. Producer-injector spacing is too large. Water drive advancing is more slowly.2n B239Well-block reservoir needs to implement the advanced water injection and time of advanced water injection is85-90days. Pore pressure should keep at around110%of the initial reservoir pressure at around110%which is18.4MPa.3、Using reservoir engineering analysis method, carried out the development technical policy of advanced water injection in B239Well-block. Establish the reasonable formation Pressure level、reasonable flow pressure、water injection pressure、water injection timing、 reasonable quantity of injected water and other indicators,which guides the rational development of the oil field.4、Using reservoir engineering and numerical simulation methods, it has proved pattern well spacing. It is the best solution plan that adopts the square inverted nine-spot pattern of B239Well-block reservoir. Ratio of volume injection to production is the best selection of about1.33after infill adjustment.5、Implementing the advanced water injection method and infill adjustment could build up an effective system of displacement pressure. But it doesn’t form effective system of displacement pressure if oil water well is too large.