Research on Refracturing Technology of Ultra-low Permeability Fractured Oilfield

Abstract

The development of ultra-low permeability reservoir in Daqingzi area, Qian an. With a long period of mining, the number of refractured wells is increasing year by year, but there is no benefit after fracturing. There is an urgent need for low-cost fracturing techniques to make refracturing more cost-effective. In this paper, on the basis of fully understanding reservoir physical properties, in-depth analysis of the major problems facing the refracturing of Daqingzi oilfield, and analysis of refracturing potential. Through field experiment, post-frac analysis and effect evaluation, the refracturing technology route suitable for this area is gradually explored. In this field experiment, the problem of underinjection was solved through the analysis and targeted transformation of injection wells. The average daily injection capacity of a single well was increased, injection pressure was reduced, the formation pressure of surrounding producing wells was restored to the original formation pressure, and the refracturing time of producing wells was reached, and the individual refracturing design of producing wells was carried out. In addition, post-frac analysis and effect evaluation were carried out. The results show that the injection-production relationship of the well group is improved obviously after the measures, the effect of increasing fluid and oil is remarkable, and the average fracturing cost per well is reduced. The new technology of holistic fracturing of injection and producing wells centered on injection well is defined. It provides technical support for increasing production and controlling cost of ultra-low permeability reservoir.