Wellbore cement, a procedural component of wellbore completion operations, primarily provides zonal isolation and mechanical support of the metal pipe (casing), and protects metal components from corrosive fluids. These are essential for uncompromised wellbore integrity. Cements can undergo multiple forms of failure, such as debonding at the cement/rock and cement/metal interfaces, fracturing, ...

Shaft misalignment is a common problem for many types of rotating systems. It can cause machine breakdowns due to the premature failure of bearings or other components. Common diagnostic approaches rely on detecting increasing vibration response spectra at multiples of the shaft speed. However, in many time-variant systems, such as wind turbines, the speed and load vary considerably, which can ...

A nite element based method has been developed for computing time-averaged uid-induced radial excitation forces and rotor dynamic forces on a two-dimensional centrifugal impeller rotating and whirling in a volute casing. In this method potential ow theory is used, which implies the assumption of irrotational inviscid ow. In comparison with other analyses of uid-induced impeller forces, two main...

A monitoring trial was carried out to investigate the effect of boreholes configuration on the stability and gas production rate. These boreholes were drilled from the retaining roadway at longwall mining panel 1111(1) of the Zhuji Coalmine, in China. A borehole camera exploration device and multiple gas parameter measuring device were adopted to monitor the stability and gas production rate. R...

Construction of geothermal wells that are effectively cemented and durable poses a significant operational challenge. Typically, lost circulation while drilling and cementing can make it seemingly impossible to place a complete column of cement behind casing strings. Incomplete cementation can lead to well failure caused by cyclic temperature loading on the casing that occurs throughout the lif...

This paper presents a mobile Lidar system for efficiently and accurately capturing the 3D shape of the Bas-reliefs in Angkor Wat. The sensor system consists of two main components: 1) a panoramic camera and 2) a 2D 360-degree laser line scanner, which moves slowly on the rails parallel to the reliefs. In this paper, we first propose a new but simple method to accurately calibrate the panoramic ...

Heat exchangers are widely used in power engineering and industrial applications, many techniques such as coiled tube, surface tension devices, rough surfaces, extended surfaces have been investigated to enhancethermal performance and to minimize the cost and size of the heat exchanger equipment. One of the most important techniques is tube insert. In general,tube inserts can be classified into...