Steam Flooding Technology Research And Application Of Borehole Heat In Qi40 Area

Block Qi40, the main heavy crude oil reservoir in Liaohe oilfield, was developed by cyclic steam stimulation since 1987. In order to explore the effective production replacement types after steam soak, the feasibility of steam flooding was studied for Qi40 since 1995, through four stages of laboratory study, pilot test, expanding test, industrial promotion. This conversion not only brought increased oil recovery and higher economic benefits, but also created a good platform for steam flooding.Both steam stimulation and steam flooding belong to thermal recovery method. It is critical to reduce the heat loss of injection steam in the well bore to ensure the injection steam at the bottom has a higher dryness and make use of steam thermal viscosity breaking and driving function, during the process of exploration of heavy crude oil by injecting steam.The heat insulation technology for steam flooding is based on the technology of heat insulation for steam soak. Separate layer steam injection technology was introduced to steam flooding to enhance thermal efficiency of steam while improving column whole heat insulation effect and service life, thus steam overlap can avoided to some extent and the vertical pay-gross thickness ratio could be improved. This technology, starting from lower heat loss point in well-bore and lower column whole heat loss rate, by improving insulation pipe insulation, optimizing flexible pipe structure, installing the coupling connection sealing device, using long-term sealing devices, improved the column overall insulation effect and life to meet the steam drive long-term needs of higher dryness steam injection.Since the conversion in Qi40, the technology of heat insulation of well bore for steam flooding has been used in 138 gas injection well groups, making a good performance on-site. The bottom steam dryness has been increased from 43% to 52%, fully meet the needs of steam injection for steam flooding. So far, steam flooding has been implemented in Qi40 for 3 years, increasing production of 1600000and and phase recovery reached 4.2% higher than steam soak of several degree. The successful application of well bore heat insulation technology for steam flooding has great theoretical and practical effect on the exploration of the similar steam-flooding reservoir.