The wireless intelligent water distributor is an emerging technology increasingly applied in oilfields to enhance oil recovery. Although the system has many advantages, the high energy consumption of its integrated control valve hinders its adoption in long-term applications. However, existing studies have not sufficiently captured the mechanical characteristics of forces acting on the spool, particularly under the influence of multiple coupled factors, such as fit clearance, deflection, and fluid-structure interaction, which limit the ability to accurately assess energy consumption. To address this gap, this study develops a comprehensive energy consumption model of the control valve, specifically addressing the design of fit clearance, a critical factor influencing energy efficiency. Utilizing a loosely coupled fluid–structure interaction algorithm, we established a mechanical model of the spool to investigate the fluid-solid interaction mechanisms within the fit clearance. For the first time, the effects of contact friction on energy consumption are incorporated. An optimization algorithm was then applied to determine the optimal fit clearance by balancing low friction and minimal leakage. The validity of our numerical model was confirmed through comparison with both theoretical and experimental results. Our results demonstrate that the fit clearance has a pronounced impact on the valve's energy usage: the total maximum energy consumption for one full stroke with a 0.05 mm clearance is 3.33% higher than with a 0.25 mm clearance. When the spool is independently driven, this value is 7.21%. The optimal fit clearance is determined to be 0.127 mm. These results can improve the overall performance and extend the service life of intelligent water distributors. The findings and models developed in this study provide essential theoretical support and practical strategies for optimizing control valve energy consumption.

Pipeline Inspection Gauge (pig) is an important equipment for oil and gas pipelines during different stages of their operations to perform functions such as dewatering, cleaning, and inspection. Owing to the hyperelasticity, time and temperature-dependent material behaviour of the sealing disc attached on the pig, the contact between the pig and the pipeline expresses complex behaviour, leading to an uncertainty in the prediction of the pig's frictional force. Knowing the deformation of the sealing discs well is essential and can be highly meaningful for predicting the pig motion, as well as reducing the pigging risks. In this study, the geometrical deformation of the sealing discs with different sizes are investigated through experiments and numerical simulations. The effects of the four nondimensionalized parameters (interference, thickness per pipeline inner diameter, and clamping ratio) of the sealing discs on the deformation behaviour were observed and discussed, and an improved mathematical model for predicting the geometrical deformation of the sealing discs was proposed and verified. With the auxiliary angle α added in the improved mathematical model, the relative error declines to 1.87% and 3.18% respectively for predicting deformation of the sealing discs in size of 2-inch and 40-inch pig. The results of this study can help better understand the frictional force of a pig with sealing discs, as well as its motion.

The migration process of the pig in oil and gas pipeline is a complex dynamic problem. During the pigging operation, the variation of friction force caused by the nonlinear contact between the sealing disc and the pipe wall is the key factor affecting the dynamic characteristics of the pig motion. At present, the existed pigging models for predicting pigging behavior regard friction as an invariant constant. Experimental research indicates that the friction force of the pig varies with the contact force and the lubrication conditions. Therefore, the assumption that the friction force is constant cannot reflect the friction dynamic characteristics of the pig during pigging, and will also affect the accuracy of the pigging model. Exploring the variation of friction force of pig under different conditions is the basis of establishing the transient dynamic model of a pig. As a result, in this paper, a method of direct measurement of contact force between the pig and the pipeline is presented, the contact force, the friction force, as well as the friction coefficient of the pig are obtained from the experiment. Research results in this paper can help to establish a more accurate dynamic model of pig.