Investigation Of Foam To Improve The Effect Of Steam Soak For Jinglou Oilfield

The gravitational overlap and viscous fingering could be controlled if foam is addedduring the steam soak, so the static foam property and the interfacial tension of7kinds ofsurfactants was evaluated. The experiment results show that during the concentration range of0.1%to0.5%, the foam properties of three surfactants including sodium dodecyl benzenesulfonate (SDBS), alpha-olefin sulfonates (AOS) and Henan Oilfield surfactant (TFP-2) aregood, the foam volume, liquid separation and foam stable half-life period are larger than700mL,5min and2h, respectively, however, the lowest interfacial tension (IFT) is larger than10-1mN/m. In order to construct a low IFT foam system, assistant surfactant sulphobetaine(SBET-17) is added, and two low interfacial tension systems-SDBS/SBET-17andTFP-2/SBET-17compound systems are constructed. The optimized host agent concentrationis0.1%and the assistant agent concentration is0.03%-0.08%. Through the heat resistanceand alkaline resistance evaluation, it is found that after40days heat treatment at150℃, theeffective concentration of the two surfactants is about85%, indicating that both of them havegood heat resistance.The injection and production parameters of N2(or N2foam) assisted steam soak for2113well group from Jinglou One-zone were optimized using numerical simulation software. Thesingle well simulation result shows that when the oil saturation is high, pure steam should beinjected during the initial stage since the formation temperature is low and its capacity toabsorb steam is poor; while when the oil saturation is low, N2(or N2foam) should be injectedin the beginning of the development. According to the orthogonal experiment result of thewell group, the injection rate and the steam quality are the most important parameter thatinfluences both the cyclic oil production and the oil/steam ratio, that is to say, the cyclic oilproduction increases with the increase of injection rate while the oil/steam ratio decreases,and both of them increase if the steam quality is high. The value of cyclic oil production is affected by the injection mode, the foam concentration and shut-in well time in order; and theoil/steam ratio is influenced by the shut-in well time, the foam concentration and the injectionmode in order.