Research On The Determination Methods Of Blocking Agent Injection Depth Or Position

The technology of profile control and water shut-off has been common used in most of oil fields, however, with the increase of formation heterogeneity contradictions, conventional technology of profile control and water shut-off cannot satisfy the need of oil field production and the determination of blocking agent position has limited the development of it. In order to improve the technology of profile control and water shut-off, this article determined the mathematical and physical method of targeting the blocking agent position from the point of mechanics of flow through porous media and resistivity measurement. The method of targeting blocking agent position by resistivity measurement evaluated the electrical property of fluid in porous media. It was found through experiments that NaCl or KCl should be chosen to control the salinity of water injected with the optimum salinity of 15000mg/L~30000mg/L. Meanwhile, the resistivity of physical model decreased with the increase of flow velocity and generally increased with the increase of blocking agent volume. According to the experimental process above, the mathematical model of blocking agent injection depth and apparent resistance, was determined. The calculation method of blocking agent position determined the injection depth equation of blocking agent in different layer. The accuracy of this method was evaluated through sand pack flooding experiments with calculation error under within 10% when permeability is more than 1μm2. At last, this article analyzed the application conditions and field application procedure of the determination methods of blocking agent stated above.At last, this article analyzes the application suitability of blocking agent position targeted methods and summarizes the general application process respectively. In order to target the accurate position of blocking agent, firstly, the glass fiber reinforced plastics casing log can be used to determine the vertical position and length of blocking agent where it comes into the reservoir; then, generally the horizontal injection depth of blocking agent can be determined by calculation method of blocking agent position which decreases the determination range of blocking agent; finally, ground potential detection can be applied to determine the exact position of blocking agent horizontally.