The issues of leakage with respect to the clearance between the pump plunger outer diameter and the pump barrel inner diameter and other operation conditions have been revisited in this paper. Both Poiseuille flow rate due to the pressure difference and Couette flow rate due to the plunger motion have been considered. The purpose of this study is to better understand the nature of the leakage with respect to pressure difference, eccentricity, and motion related to the plunger of typical sucker rod pump systems. More specifically, based on the newly derived relaxation time scales for transient solutions of the governing Navier–Stokes equations, the quasi-static nature of relevant measurement techniques is confirmed for the current production systems. This key observation is also demonstrated with a computational model using the experimentally measured pressure difference and the plunger movement.

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Casing drilling is used as an alternative to conventional drilling with drillpipe in order to reduce non-productive time. The smaller annular space in casing drilling elevates the annular pressure loss considerably at similar flow rates in conventional drilling. Consequently, the Equivalent Circulating Density (ECD) is more affected by annular drilling fluid dynamics in casing drilling than the conventional drilling. The higher ECD experienced in casing drilling brings concerns about exceeding fracture gradient which can lead to induced lost circulation. However, several field observations demonstrate successful application of casing drilling in combating lost circulation and strengthening the wellbore.Smearing effect theory backed by smaller cuttings at the shale shaker, eccentric casing wear, and discrepancy between analytical and field measurements are three main evidences for potential significant eccentricity in casing drilling operations. This paper demonstrates the inherent eccentricity of casing drilling as one of the parameters that controls the annular pressure losses. Eccentricity reduces the velocity in the narrow section of annulus. Similarly, it reduces the annular pressure losses considerably. In addition, controlling the fluid rheological properties as well as the flow rate are recommended to manage the casing drilling hydraulics. This comprehensive study of pressure loss and velocity profile at various annular sizes can help analyzing several field observations and designing the hydraulics of drilling operations.

The modern hydraulic fracturing technique was implemented in the oil and gas industry in the 1940s. Since then, it has been used extensively as a method of stimulation in unconventional reservoirs in order to enhance hydrocarbon recovery. Advances in directional drilling technology in shale reservoirs allowed hydraulic fracturing to become an extensively common practice worldwide. Fracturing technology can be classified according to the type of the fracturing fluid with respect to the well orientation into vertical, inclined, or horizontal well fracturing. Depth, natural fractures, well completion technology, capacity, and formation sensitivity of a shale reservoir all play a role in the selection of fracturing fluid and fracturing orientation. At present, the most commonly used technologies are multi-section fracturing, hydra-jet fracturing, fracture network fracturing, re-fracturing, simultaneous fracturing, and CO 2 and N 2 fracturing. This chapter briefly reviews the technologies used in shale reservoir fracturing.

Long-term zonal isolation provided by cement is a crucial task in the life of oil and gas wells. However, significant number of primary cementing jobs experience problems; particularly in highly deviated wells, extended reach wells, and wells prone to severe washouts. Primary cementing efficiency has attracted more attention since the development of shale gas industry and the Macondo Blowout in the Gulf of Mexico. Sustained casing pressure reported in some of the wells in Marcellus shale play and the root of several blowouts is attributed to cementing job performance. Therefore, studies on the performance of cementing operations are essential in restoring the public opinion on petroleum industry by addressing problems that have major social, environmental and economical consequences besides the technical interest.Casing is prone to deviate toward the bottom of the well especially in horizontal wells. This eccentric annular space leads to annular velocity disturbance in favor of wider region of the annulus. Finally, part of the narrow section of annulus would be left un-cemented. The bypassed mud is potential path for the formation fluid communication with other formations or to the surface. Poor cementing can affect the hydraulic fracturing job as well.This paper is part of a comprehensive three-dimensional time-dependent computational fluid dynamics (CFD) model developed to account for dominant parameters affecting the mud displacement process in horizontal wells. Parameters such as casing eccentricity, cement yield strength, cement plastic viscosity, the density difference between mud and cement, pumping rate and washout are studied. The effects of the first three parameters are addressed in this paper.Current best cementing practices have deficiencies in providing excellent cementing efficiency. Therefore, a novel technique, using Magneto-Rheological fluid, is also proposed to improve the displacement efficiency. Magneto-Rheological fluid can act as a plug in the wider region of annulus under magnetic field applied through the casing. Consequently, flow will be directed to the narrower annular region that could not be cemented or cleaned otherwise. The results are appealing and further study on application of Magneto-Rheological fluid in petroleum industry is suggested.