Laboratory Research On Enhanced Oil Recovery By Chemical Flooding Through Horizontal Wells

Based on the matured technologies in horizontal well and chemical flooding, the feasibility of chemical flooding with horizontal wells to enhance oil recovery after polymer flooding has been studied in lab in this paper. The best chemical program of horizontal wells was optimized and guiding suggestions on oil field application has been put forward.Three-dimensional physical model of positive rhythm has been developed on the basis of Sazhong oil reservoir. Adding a certain amount of clays into sand can effectively improve the pore structure of artificial core. Experiment of capillary force showed that the size and distribution of pore structure of artificial physical model were all similar to that of artificial core.Based on the experiments on the chemical flooding performance evaluation and formulation selection, the author has determined the injection parameters of each chemical flooding programs through horizontal wells. The preferential sequence of the schemes are as follows: ASP system> binary composite system> high score high concentration of polymer systems> polymer-surfactant-agent system.The paper has analyzed the difference between chemical flooding in horizontal wells and chemical flooding in vertical wells, based on percolation theory and adsorptive retention capacity. In horizontal wells, combination flooding systems has a heavier chromato separation and adsorbance contrasting to vertical wells. Horizontal well pattern swept area is much larger than that of vertical wells.