Laboratory experiment and field application of high pressure and high quality steam flooding

Steam flooding is an effective way to improve oil recovery after steam huff and puff for heavy oil reservoirs. The typical screening criteria for steam flooding requires reservoir pressure to be less than 5 MPa, the steam quality of conventional steam flooding in bottom hole is about 30%, heavy oil reservoir in Shengli Oilfield with character of deep burial depth, active edge and bottom water and high formation pressure (7-8 MPa), the increase of oil recovery using conventional steam flooding is not obvious, Therefore, the formation and development of steam chamber during steam flooding are studied by indoor physical simulation experiments, the feasibility of high-quality steam flooding under high pressure is analyzed. The experimental results show that the quality of steam injection has obvious influence on the expansion of steam chamber. As the steam quality increases under high pressure, the specific volume of underground steam increases, the formation time of steam chamber is shortened, the expansion distance of steam chamber increases, the effective steam flooding time is prolonged, and recovery rate improves obviously. Field tests of high-quality steam flooding under high pressure were carried out in Gudao Zhongerbei heavy oil reservoir of Shengli Oilfield, the result shows that the bottom-hole steam quality of steam injection wells is 50% and above (20% higher than conventional steam flooding), the steam chamber was effectively expanded and the performance of producing rate for production wells improves obviously. The recovery rate of the test area reached 52.1%, which was 16.8% higher than that of steam huff and puff. High-quality steam flooding technology was an effective way to improve the recovery rate of high-pressure heavy oil reservoirs.