Abstract:The rotary steering and the logging while drilling systems can effectively control the well trajectory and quickly identify the formation property, which can greatly improve the operation efficiency and reduce the operation cost, especially in offshore oil and gas development; but this field has been monopolized by foreign oil companies with high rental prices for a long time. Welleader rotary steering system and Drilog logging while drilling system developed by CNOOC have been tested for times and up to application requirements. These systems were used in an adjustment well drilling on a platform in Bohai, the application results prove that the trajectory control of rotary steering system can satisfy the directional well trajectory requirements; the accuracy of the measured data and the quality of the well logging are in line with the standard requirements, by which the trajectory control and logging are realized in drilling process.