Research On The Practice Of Polymer Flooding Development Super-high Permeability Formation Abstract

This article focused on the effect of the super-high permeability formation of Gudao Oil field to polymer flooding development, analyzed the reason of the super-high permeability formation forming, indoors researched and experimented the profile control, channeling prevention and shutoff techniques in oil fields. The infilling, moving and shutting off laws of inorganic solid grain in porous media are researched by microscopic simulation techniques. Based on the research results, the profile controlling technology developed through three stages: at early stage, the profile controlling experiments was done by two kinds of seepage control material of grain morphology and gelatinous/ frozen glue; at middle period, the two kinds of seepage control material of grain morphology and frozen glue were used multiply; at later stage, the PI decision technique, the integrally profile controlling technique of polymer flooding bulk and the optimization technique of array of seepage control material plug were applying to gain better shutoff result. The advance and channeling of injected polymer on the way of super-high permeability formation would decrease the incremental production of some oil wells by polymer flooding. The oil well shutoff techniques of polymer and field experiments were done. The techniques included lignin-sulphonate compound shutoff agent and hydrotropic cationic heavy polymer. The former used PFC- slow cross-linking polymeric compound anti channeling system to eliminate channeling of polymer. Its principal was shutoff the high capacity channel of immediate vicinity of well bore by high viscosity indissolubility gel formed in the high permeability formation which was the functional group resulted from the reaction of injected polymer with molecular structure in anti-channeling agent. The latter depended on floccules which were the results of hydrotropic cationic heavy polymer with anionic polymer from formation to shutoff the high permeability formation, control the production profile and change the sweep area of sequent water flooding.Along with the applying of polymer flooding, the productive well testing techniques to polymer flooding are developing. At the beginning, the permeability decreased and inject-pressure increased quickly. After the equilibrium time of formation capturing and adsorbing polymer was attained, the inject-pressure leveled off or increased slowly. While the water flooding stage began, the inject-pressure decreased again. The top-hole-pressure (TOP) and influx kept changing at three stages. On the oil fields, the TOP data were used to research absorbing capacity of formations. The Hall plots were used to research the change of injective characteristics of injective wells in a long term. The data would be treated by integration and the inclination of every linear portions of Hall plot could be calculated by piecewise regression. The inclinations display the change of filtrational resistance of every inject terms and the amplitudes of plot display the effectiveness of polymer flooding. Running electronic pressure gauge, opening and closing the inject wells in a same formation alternatively, recording the pressure responses of oil wells, in another word, multiple well test, could used to display the connectivity between oil wells and inject wells and the change of formation parameters.