Abstract:

It is recognized that the normal chemical plugging agent cannot plug water and control profile effectively in formations with permeability ratio data more than three. Stable oil-in-water micro suspension emulsion （grain size 1～5 μm） was prepared from main material oil-soluble resin, emulsifier and stabilizer through disperse mill. The optimal formula was determined as follows: 50%～60% resin +0.35%～0.40% octadecyl trimethyl ammonium chloride or 0.35%～ 0.40% sodium benzenesulfonat +0.1% CMC +0.10%～0.15% calcium chloride +1%～5% SL+ water. Demulsifier formulation were also determined, 2%～3% aqueous solution of sodium hydroxide and 3%～5% calcium chloride solution were used for cationic emulsion and anionic emulsion corresponding. Viscosity, electron microscopy analysis of grain size, acid solubility, oil solubility tests were also carried out. Performance test shows that it has high temperature range and good injection and selectivity performance. Core flooding test shows that the breakthrough pressure gradient was 26 MPa/m, the plugging rate is greater than 97%, it kept high plugging rate after large amount of water flooding and it had good profile control performance for heterogeneous reservoir with the permeability ratio data being of seven.

Key words: shallow water delta, sequence-based lithofacies paleogeography, sandbody distribution, reservoir prediction, Chang 8 oil reservoir set, Zhenyuan area, Ordos Basin