Reseach On The Blocking Removal Technology Of The Water And Oil Wells In Polymer Surfactant Flooding

Polymer surfactant is a new oil displacement agent, which has achieved a good oil-displacement effect in the primary field experiment of Daqing oilfield. However, the adsorption and detention of polymer surfactant in porous media during the oil displacement process, not only will reduce the concentration and viscosity of the solution, lower the controllability of mobility, but also will result in the pressure rise of injection well when large adsorbance and retention occurring and the rapid decline in the absorbing capacity of oil layer, and that affects the normal production and decreasing oil-displacement effect. It is necessary to explore the plug mechanism in reservoirs caused by polymer surfactant,as well as corresponding solutions,.In this paper, enhanced oil recovery technologies in china and abroad were extensively surveyed and the chemical flooding mechanisms were explained as well as blocking mechanism of polymer surfactant was analysed through LAB experiments. The results show that the factors make polymer surfactant blocked in the layer could be of many different aspects, including calcium, magnesium, natrium, ammonium, etc. Formaldehyde can make viscosity of polymer surfactant rise or make it granule. Coloured floccule is generated during reaction process among ions with high valence, sulfur ion, and polymer surfactant. The polymer surfactant is attracted powerfully by trivalent ion that turns it to coagulate eventually blocked in the reservior. A new blocking remover was developed to remove polymer surfactant blocking. Through the LAB core simulation experiments, the effect of blockage relieving was evaluated and found very effective. The research contents in this thesis have significant values for field widespread use of the polymer surfactant flooding.