Abstract:

In the process of natural energy depletion, particularly, the foamy oil is a characteristic of “high oil viscosity, low produced gas & oil ratio, high level of oil rate, low production decline rate, and high natural depletion recovery factor”, and the foamy oil stability is a crucial factor to determine the time of “foamy oil phenomenon”. Aimed at quantifying the controlling factors affecting the foamy oil stability, the hightemperaturehighpressure (HTHP) visualized foamy oil stability test model is designed and used to test foamy oil stability under conditions of different temperature, original dissolved gas & oil ratio (GOR), pressure decline rate and pore size. Experimental results indicate that the highest temperature for stable existence of foamy oil is 60 ℃, the least original dissolved gas & oil ratio (GOR) is 5 m³/m³, the lowest pressure decline rate is 0.08 MPa/min; and it is found that the stability time of foamy oil becomes longer where porous media gets similar to the real reservoir condition, which indicates that during practical natural energy depletion phase, the “foamy oil phenomenon”  will exist for a long time. The findings above effectively guided the development of MPE3 reservoir by natural energy depletion, and played an important guidance for choosing rational operation strategy and realizing economic and efficient development for similar heavy oil reservoirs.

Key words: foamy oil, temperature, dissolved gas &, oil ratio, pressure decline rate, porous medium