西加拿大盆地M区块层序地层与油砂资源评价

Sequence Stratigraphy and Evaluation of Oil Sands Resources in Block M,Western Canada Basin

正确认识油层平面分布是油砂资源评价的基础,无井区油层厚度的预测需要以地质认识为指导。以钻井资料为基础,对M区块的层序地层与沉积特征进行了研究,分析层序格架和储层展布;并在此基础上开展油层分布预测与油砂资源评价,取得了以下新认识:(1)首次对区块进行了层序地层划分。区块可划分为2个长期旋回和6个中期旋回和10个短期旋回。(2)首次系统厘定了区块的沉积相类型及发育特征。区块发育河流、三角洲、滨岸、河口湾和浅海5类沉积相,11类沉积亚相和15类沉积微相。(3)评价结果改变了前人认识,大幅度增加了区块的资源潜力。评价认为区块油砂资源量为2.2×10~8t,比前人评价结果增加22.5%;钻探结果证实了评价结果的正确性,发现区块东部为资源最富集区,改变了前人认为区块西部为主力区的认识。

Reasonable understanding of reservoir plane distribution is the basis of the oil sands resource evalua-tion. The reservoir thickness prediction of no well area needs the guide of geological understanding. Based on well data, the sequence stratigraphy and sedimentary characteristics block M were studied, and sequence stratigraphic framework and reservoir distribution were analyzed. Then the oil reservoir distribution prediction and evaluation of oil sands resources were made on this basis. The following new understandings are achieved. （1）The sequence stra-tigraphy study was made in this block for the first time. The main strata of the Block can be divided into two long-term cycles and six mid-term cycles and 10 short-term cycles. （2）The sedimentary facies types and characteristics of the Block were determined systematically for the first time. Five facies, 11 subfacies and 15 microfacies were iden-tified in the block, namely fluvial, delta, shore, estuarine and neritic. （3）The evaluation results show that the re-source potential of the block increased significantly, and the understanding of the predecessors are changed. The oil sands resources are 2.2×10^8 tons according to the evaluation results, with an increase of 22. 5% over the previous evaluation results. The drilling results confirmed the validity of the study results, found the eastern part of the block for the most resource-rich region and changed the previous understanding that the western block was the main oil sands accumulation area.