Agitators are mainly used for the preparation of the drilling and workover fluids and chemicals on offshore oil platforms. In recent years, the methods to improve the mixing efficiency are mainly limited to the optimization of the blade shape and transmission efficiency, but with few reports about the improvement in the driving mode and the mixing principle. In view of the above problems, a mixing agitator is proposed that uses pressure gas as the power to drive the agitator for two kinds of agitation: mechanical agitation and gas agitation. The mixing flow field is numerically simulated by the computational fluid dynamics (CFD) and tested by the Laser Doppler Velocimeter (LDV). The results are compared and analyzed with those of the conventional agitator. It shows that the velocity distribution above the blades of the new agitator is relatively uniform, and there are fewer low-speed areas under the agitation of bubbles, forming a stable turbulent flow. In the region below the blades, better agitation is found on the two ribs with a wider range of action for the new agitator. The new gas-driven agitator has good research and application value.

Although the mud agitator is a small device among the offshore workover rig equipment, it plays a vital role in the configuration and mixing of the workover fluid (mud fluid). A high-efficiency mud agitator is the guaranteenecessary to ensure the smooth progress of the workover operation. The mixing of the mud fluid can be greatly affected by the selection of the mud agitator blades, the impeller diameter and the installation position of the impeller. The design of the mud agitator has been studied from the aspects of the impeller type, impeller diameter, blade layer number and power calculation according to the development of the standardization and modularization of the offshore workover rig in recent years. The mud agitators with different impeller diameters and different impeller configuration are simulated by using the CFD method. Finally, the product design is optimized through the comparative analysis of the flow field and power. It can provide reference for the design of the offshore workover rig mud agitator.

Petroleum is the irreplaceable energy source in daily life, industrial production, aerospace and military industry. As a non-renewable energy source, the development and utilization of petroleum are very important. While exploiting new oilfields, the resources of the current oilfields should be fully utilized to maintain stable production. It is therefore particularly important to use workover rigs to repair and maintain the existing wellheads. The important medium of workover is the workover fluid, which is mainly composed of mud. The success of the workover operation is related to the smooth circulation and the correct proportion (slurry preparation) of the workover fluid. The technological process and the equipment layout scheme of the workover rig projects in the recent years are researched to select the problems in the typical project for the case analysis. It is concluded that in the process of the workover fluid circulation and the slurry preparation, the different arrangement sequence of the mud tanks and the different relative positions of the mud tank and the high-pressure mud pump have the important impact on the actual construction and function realization, even resulting in the failure of the technological process due to the unreasonable arrangement of pipelines. Finally, two sets of optimization schemes are proposed based on the existing problems to provide reference in the future projects of the workover rig.