Enhancing Oil Recovery Through Integrated Seismic Geology and Engineering: A Case Study in the Sai 6 Reservoir of Changqing Oilfield
Authors: Ren Jiawei , Bai Xiaohu , Du Xianfei , Lu Hongjun , Chen Junbin , Yu Wei , Miao Jijun 
Published: January 2025

In recent years, fiber-optic distributed acoustic detection technology (uDAS) has emerged as a rapidly advancing tool in the field of well-site joint exploration. Characterized by its compact size, flexible observation capabilities, high imaging accuracy, and continuous monitoring capabilities, uDAS technology holds significant promise for enhancing oil recovery efforts. However, its integration and application in the secondary fine interpretation and development of old oil fields have yet to be fully explored. This article aims to address this gap by introducing the application progress and research outcomes of combining VSP well-site joint production with DAS optical fiber sensing monitoring technology. Specifically, the study focuses on improving oil recovery in the old area of the Sai 6 reservoir in Changqing Oilfield. The research presents a comprehensive methodology that integrates high-precision seismic interpretation data, joint well-seismic reservoir modeling, and advanced geological and engineering simulation techniques. By leveraging these methodologies, the study seeks to establish a precise three-dimensional seismic-geological model of the target area and optimize the refracturing process to maximize production efficiency. The research outcomes represent China's first attempt to integrate seismic geology and engineering technology in old oil fields, offering valuable insights and guidance for enhancing oil recovery in mature reservoirs. The methodology employed in this study entails a systematic approach to integrating various data sources and simulation techniques aimed at enhancing oil recovery in the old area of the Sai 6 reservoir. Initially, high-precision seismic interpretation data is acquired to establish a foundational understanding of the subsurface structure and properties. Subsequently, a joint well-seismic reservoir modeling process integrates well data with seismic interpretation to develop a precise three-dimensional seismic-geological model of the target area. This model serves as the basis for subsequent analysis and simulation efforts. Advanced geological and engineering simulation techniques are then applied to optimize the refracturing process, encompassing comprehensive analyses of reservoir dynamics, geomechanics, and fracturing simulation. Predictions of production capacity for the entire life cycle development process of a typical well group are made, facilitating long-term planning and optimization strategies. Spatial distribution analysis of remaining oil post-long-term production provides insights into reservoir behavior and recovery opportunities. Complex fracture simulation methods are employed to optimize stimulation parameters for repeated stimulation, maximizing production efficiency. The integration of optical fiber sensing technology into three-dimensional well and ground joint production signifies a significant advancement in the oil and gas industry, enabling the acquisition of seismic signals with higher density and enhancing reservoir characterization capabilities. This innovation has been particularly impactful in revitalizing mature oil fields by facilitating precise potential tapping and efficient extraction of remaining reserves. Through the deployment of this technology, accurate mapping of subsurface conditions via three-dimensional seismic reservoir modeling has been achieved, significantly improving the accuracy of geological models, especially in delineating lateral sand bodies between wells. Additionally, the establishment of an integrated workflow combining seismic geology and engineering has played a pivotal role in assessing re-fracturing potential and optimizing production strategies. Through comprehensive analysis and simulation, this approach ensures efficient resource utilization and enhances production yields. Overall, the application of optical fiber sensing technology, coupled with advanced reservoir modeling techniques, represents a transformative shift in oil field management, promising improved operational efficiency, extended field lifespan, and maximized recovery.