Online Dissolution Injection Technique Of Emulsion Polymer On Offshore Small-size Plat In Shengli Offshore Oilfield

The current main problems from the Shengli offshore oilfields are the strong unconformity of reservoirs and obvious increase of water content in produced oils, which have had a significant influence on normal exploitation for these oilfields. One of the solutions is to use profile controlling with emulsion polymers. Because of space restrictions on an offshore small-size plat, the profile controlling needs a polymer with a short dissolution time, a strong resistant cut property and a longer cross-link time. However, the domestic products could not meet these requirements. As for the difficulties in the profile controlling in the offshore oilfields, a kind of seawater radical anionic W/O emulsion polymer and relative profile controlling system were developed in this study. Laboratory experiments have shown that its dissolution time is less than 15 min, its viscosity under the conditions of 2000 mg/L, 70℃and 7S^-1 larger than 5 mPa(?) its cross-link viscosity larger than 150 mPa(?) and its stabilization duration longer than 1 year at 70℃. These parameters can meet the need for deep profile controlling. The investigation of molecular structure of the emulsion polymer by means of infrared spectrum technique has indicated that the developed cross like latex has an embeded structure, with stronger cross linkage and larger stabilization than routine polymers. The online dissolution injection procedure and equipments for the emulsion polymer were designed, and the online emulsion breaking simulation test was carried out. The results have shown that the developed emulsion polymer is suitable to be used to the online profile controlling. On the basis of this, a plot test for two wells from the Shengli Chengao Oilfield was conducted. The primary results have shown that the emulsion polymer has been effective to the profile controlling. The pressure at the month of the wells has increased by 1.48-1.79Mpa, the oil production from one correspondent well has increased from 28.67t/d to 35.8t/d, and the water content in the flow has decreased from 52.3% to 41.7%. It is believed that the developed emulsion polymer has an wide application to the Shengli offshore field exploitation.