关键词: 清水洼陷, 深层勘探, 沉积体系, 有效储层, 源内成藏模式

Abstract: The middle and shallow layers of Liaohe Depression in the Bohai Bay Basin are now under the mature exploration and development stage. It is necessary to make detailed evaluation of the deep layers in order to identity the amount of the reserve and improve development performance. Block S229 is located in the northern part of Qingshui Sag. With a buried depth of 3750 to 4650 meters, it is the second member of Shahejie Formation. Exploration came to a standstill owing to the difficulty to predict the deep layers of the reservoir and understand the accumulation conditions. Based on the analysis of single-well data, this paper focuses on three areas of “establishing the intra-source depositional system, understanding the intra-source reservoir characteristics, and characterizing the sealing performance of the trap” and establishes the intra-source accumulating model of “hydrocarbon controlling by means of sourcing, reservoir controlling in formation of the depression, and compound transportation”. It is considered that the underwater branch channel was the favorable facies in formation of the reservoir with development of original pores. Erosion and low-degree secondary silicon increase created the favorable conditions for reservation of original pores, formation of secondary pores and improvement of permeability. As a result, favorable traps were found. Based on “integration of evaluation and development”, the 1-million-ton high-yield oil flow was acquired from three wells, providing the experiences for exploration and development of the in-source deep-layer sandstone oil reservoir.