Application of Grading Technology of Injection-Production Reallocation in Oil Sands Developed by SAGD: A Case Study in Longlake Oilfield, Canada

Abstract

In the SAGD development process of oil sands in Longlake oilfield, Canada, there exists some problems such as large injection and production difference among wells and steam ineffective circulation. Through comprehensively considering geology, production, facility and economic factors, differentiation reallocation is conducted from single well to oil drainage area, and to the whole oilfield. Firstly, according to the response between injection and production and the evaluation of residual reserve in each oil drainage area, reallocation was conducted for each drainage area Secondly, on the basis of single well dynamic analysis and effect evaluation and considering the geological and production conditions, the optimization of injection and production was carried out one well after another. Finally, based on the classification of development stage, the evaluation of facility capability as well as economic indicators, different injection and production plans were designed to screen the most reasonable one. According to the single well dynamic analysis, 6 types of reasons to adjust steam injection were summarized. Considering the remaining reserves and their quality, historical production level and current situation, reallocation of production and injection for each well was carried out. On the basis of the sequence of oil drainage area and the total volume of production and injection of the whole oilfield, systems such as oil and water treatment, liquid gathering and transportation, and steam generation were checked. Based on the capacity and potential of above systems, 4 plans of injection and production reallocation were designed. Compared to the basis plan, the final recommended plan increased by 364 m3/d, the cumulative steam-oil ratio decreased by 0.29, and the net present value increased by 96 million Canadian dollars. For actual application in Longlake, compared the production in 2017 and 2018, steam rate decreased 170 m3/d while oil rate increased 291 m3/d. This paper establishes a three-level reallocation process which comprehensively considering the demand difference of single well, oil drainage area and the whole oilfield. It provides a guiding role to reallocate injection and production in Longlake oilfield.