Field Trial of Intelligent Completion Technology for Horizontal Wells in Bottom - Water Reservoirs: A Comprehensive Evaluation of Productivity Improvement Strategies

Abstract Reservoirs with edge and bottom water are a crucial reservoir type in oilfield development. Influenced by factors including the structural height of the developed oil layers, the location of edge and bottom water layers, and oil - well production systems, during the production process, edge and bottom water rise and bottom - water coning frequently occurs. These phenomena cause premature water breakthrough and even water flooding in oil wells, significantly impeding the exertion of well productivity, reducing reservoir recovery efficiency and development benefits. Therefore, it is of great urgency to develop and apply suitable technical solutions for intervention and management, which will contribute to optimizing the development performance of such reservoirs. This paper draws on the concept of proactive prevention and control in intelligent completion. Leveraging the advancements and development of current distributed fiber optic monitoring technology, a novel intelligent completion technology is proposed. This technology features real-time full-wellbore monitoring through distributed fiber optic cables deployed outside the casing, and production control of pay zones via switchable casing sliding sleeves. Compared with existing mainstream intelligent completion technologies, it has technical advantages such as fewer wellbore-matched tools, no impact on the inner diameter of the wellbore, and no interference with subsequent operations, thereby enhancing the technical adaptability. A field trial was carried out, and dynamic monitoring during the stage fracturing and reconstruction process was completed. Based on the continuous real-time dynamic monitoring of the temperature by the distributed optical fiber outside the casing and the acoustic vibration, it can reflect in real time the situation of the fracturing fluid and proppant in the formation of each layer section. After the well was put into production, the daily liquid production was 10.76 m3, with a water cut of 83.5%, and the daily oil production was 1.78 tons. However, after a period of production, the bottom water coned in and broke through, causing the water cut of the well to rise to 100%. According to the distributed optical fiber monitoring, the bottom water of the reservoir was mainly observed in the third- and fourth-layer sections. The casing sliding sleeves of the third and fourth production layer sections were closed. After this measure, both the daily liquid production and the water cut of the well significantly decreased. The daily oil production increased from 0.56 tons to 2.87 tons, achieving the technological goal of quickly restoring the productivity of the water-flooded horizontal well in the development of the reservoir with bottom water. In response to the production contradictions in bottom water reservoirs, drawing on the ideas of existing intelligent completion technology, a novel intelligent completion string, with distributed optical fibers outside the casing and switchable casing sliding sleeves as its core, has been innovatively designed, expanding the connotation of intelligent completion technology. The field trial of intelligent completion in Well Chi* has been successful, indicating that the intelligent completion technology can achieve the monitoring and interpretation of the whole process from fracturing and reconstruction to later production of oil wells. It provides an important basis for the optimization and adjustment of later production as well as the control of production intervals. By means of comprehensive monitoring and regulation, it has effectively restored the productivity of water-flooded wells in bottom water reservoirs, which is of great significance for the efficient development and production practice of oilfields.