Abstract: Bohai Bay Oilfield has explored and practiced well completion technologies and their sand control modes for over 10 years according to its geological characteristics, reserve scale and geographical location, and it has successively developed and implemented several completion technologies and their sand control modes, including appropriate sand control, ECP+high-quality screen, expandable screen and fracture packing. However, these well completion technologies and their sand control modes can hardly satisfy Bohai Bay Oilfield's requirements of high production and stable production. It is shown from the pre-stage test that the appropriate sand control technology of running the high-quality screen into the open hole was once the main sand control mode in Bohai Bay Oilfield due to its low well completion cost and low skin factor. And by May 2011, it had been applied in 171 production wells. As the production goes, however, most production wells are suffered from fast production decline, serious sand production and short service life. In this situation, the frac-packing sand control technology solves the difficulty of sand production in oil wells effectively, while keeping the long-term stable production of oil wells. By July 2015, the frac-packing sand control technology had been applied in Bohai Bay Oilfield by more than 150 well times in 507 sand control horizons. And this technology is now the main sand control mode used in late production wells in Bohai Bay Oilfield. In this paper, the main reasons for the change of well completion technologies and their sand control modes in Bohai Bay Oilfield were analyzed, and the corresponding optimization and improvement suggestions were proposed. The research results provide the guidance for the selection of sand control modes in heavy oil fields in the future.