Key technologies for efficient and stable production through intelligent zonal fine water injection in Qinghai Oilfield, NW China

Abstract

In response to the unsatisfactory water injection performance in Qinghai Oilfield caused by complex reservoir geological conditions, the fourth-generation cable-controlled zonal water injection technology was innovatively upgraded. An integrated fine water injection technology system was established, integrating fine reservoir characterization, intelligent zonal water injection with precise monitoring, and remote dynamic regulation. Through the design of high-temperature-resistant measurement and control circuits and the development of low-flow downhole flow measurement technology, a small-diameter cable-controlled water distributor suitable for complex conditions characterized by high temperature, high pressure, and high salinity was developed. In addition, a remote monitoring and management system for zonal water injection was established, enabling real-time monitoring of production parameters and dynamic regulation of injection rates throughout the entire layered water injection process. The technology system has been applied in the Huatugou and Yingdong demonstration areas. The intelligent zonal water injection can effectively improve the injection profile, enhance waterflood sweep efficiency, control the natural production decline rate of well groups, increase the qualification rate of zonal water injection, and slow down the rise of water cut. Economic evaluation results show that, compared with conventional zonal water injection technology, the proposed intelligent zonal fine water injection method demonstrates significant advantages in reducing operational costs and improving development efficiency. The results indicate that the upgraded fourth-generation cable-controlled zonal water injection technology can significantly improve waterflood performance and provides a replicable and scalable engineering solution for fine water injection and efficient, stable production in complex fault-block reservoirs.