超低渗油藏表面活性剂降压增注及提高采收率

DEPRESSURIZED-AUGMENTED INJECTION AND ENHANCED OIL RECOVERY BY THE SURFACTANT FOR THE ULTRA-LOWPERMEABILITY OIL RESERVOIR

渭北油田长3油藏为典型的超低渗油藏,在注水开发过程中,由于储层物性差,导致注水驱替困难。部分注水井表现出注入压力高,对应油井低产、含水率高,注水开发效果差。为此开展了4种表面活性剂降压增注及提高采收率实验研究。结果表明,OBS-03生化表面活性剂具有降低界面张力、降低原油黏度、降低驱替压差和提高采收率的能力,并且适合渭北长3油藏的地质条件。矿场试验表明,应用OBS-03型表面活性剂能有效降低注水压力,油井降水增油效果明显。

Chang-3 Reservoir in Weibei Oilfield is the typical ultra-low-permeability oil reservoir. In the process of the waterflooding development, due to the poor physical properties, the flooding difficulty is rather serious, some injectors show that the injection pressures are rather higher, meanwhile the corresponding oil producers are charac- terized by lower production and higher water cut, in a word, the effects of the waterflooding development are rather poorer. Aimed at the problems stated above, the studies on the injection depressurizing-augmenting and oil recovery enhancing experiments for four kinds of the surfaetant are conducted. The results demonstrate that Biochemical Sur- factant OBS-03 possesses the following abilities： reducing the interracial tension, reducing the oil viscosity and dis- placement pressure and enhancing the oil recovery, and moreover adapting the conditions of Chang-3 Reservoir. The field test shows that the applied Surfactant OBS-03 can effectivel~ decrease the water injection pressure; meanwhile the effects of reducing water cut and increasing the oil production for the corresponding oil wells are favorite and ohvious.