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Design of Pump and Meat Systems
Published in Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen, Design of Remediation Systems, 2020
Jimmy H.C. Wong, Chin Hong Lim, Greg L. Nolen
This method is relatively expensive, thus it may not be economical for small jobs. In addition, casings are required to keep the borehole open when drilling in soft, caving formations, such as below the water table.
Construction and testing of deep foundations
Published in An-Bin Huang, Hai-Sui Yu, Foundation Engineering Analysis and Design, 2017
The casing method is used when drilling of the borehole must go through water or permeable or caving soil before reaching competent and non-caving bearing stratum. The casing method can be conducted in two alternative procedures. The first is to drill the borehole before inserting the casing. This procedure is described in Figure 8.24. Initial drilling can be in dry or under-slurry, as shown in Figure 8.24a, until the slightly oversized borehole is extended beyond the caving soil layer. A casing is inserted and sealed into the stable soil and the interior slurry is removed using a slurry bailer (Figure 8.24b). The drilling then continues in dry condition to the bearing stratum (Figure 8.24c). The reinforcement cage and concrete are placed under dry conditions similar to those in dry method (Figure 8.19b and c).
Groundwater Hydraulics
Published in Frank R. Spellman, Land Subsidence Mitigation, 2017
A well is a hole in the ground called the borehole. To prevent collapse, a casing is placed inside the borehole. The well casing prevents the walls of the hole from col- lapsing and prevents contaminants (either surface or subsurface) from entering the water source. The casing also provides a column of stored water and housing for the pump mechanisms and pipes. Well casings constructed of steel or plastic material are acceptable. The well casing must extend a minimum of 12 inches above grade.
Prediction for Big Data Through Kriging: Small Sequential and One-Shot Designs
Published in American Journal of Mathematical and Management Sciences, 2020
Jack P. C. Kleijnen, Wim C. M. van Beers
A borehole is a narrow shaft in the ground that is meant for the extraction of liquids (e.g., water, oil) or gases (e.g., natural gas). An analytical model of such a borehole is used in many publications on simulation methodology; examples of such publications are Erickson et al. (2018), Gramacy (2016), Gramacy and Apley (2015), Santner, Williams, and Notz (2018. p. 222), and Sun et al. (2018). This borehole model has as output the water flow rate w measured in m3/yr. Its k = 8 original inputs zj and their ranges are listed in Table 1. To obtain the standardized inputs 0 1, we use this Table and the linear transformation xj = Its black-box function is
Effect of curing conditions on the mechanical properties of cement class G with the application to wellbore integrity
Published in Australian Journal of Civil Engineering, 2018
Elaheh Arjomand, Terry Bennett
Wellbores provide access to natural resources such as oil and gas and are encased in concentric layers of steel casing and cement sheaths. After drilling the borehole, steel casing is inserted and is held in place and protected by a sheath of cement which is pumped into the annular gaps. Although wellbores are sealed and block any interaction which may occur between formation fluid and geologic strata, the integrity of wellbores might still be compromised (Davies et al. 2014; King and King 2013). At this stage, wellbores may turn into the high-permeability conduits for the formation fluids (Watson and Bachu 2007) which could pose a potential risk to the environment by contaminating groundwater and/or the atmosphere. The cement sheath is responsible for providing zonal isolation and preventing the leakage of formation fluids during the lifetime of a wellbore (Ravi, Bosma, and Gastebled 2002) and therefore the cement sheath should be designed and placed so that it withstands the external conditions imposed upon it, including, in-situ stresses, high internal pressures and high temperature.
Offshore drilling blowout risk model – an integration of basic causes, safety barriers, risk influencing factors and operational performance indicators
Published in Safety and Reliability, 2018
Pedro Perez, Guido Dalu, Natalia Gomez, Henry Tan
The mud is critical for maintaining well integrity through hydrostatic pressure (ph). The casing and cementing phase starts with the installation of a large diameter steel pipe known as a conductor. Typically, a 30–36-inch diameter pipe (conductor) is installed, with the aim of preventing hole collapse and providing a conduit for circulation (fluid return) for the subsequent hole section, avoiding severe wash outs (mud circulation causing unwanted hole enlargement due to excessive flow rate and/or unconsolidated formation) or losses. Oil and gas wells are drilled in different sections, with decreasing diameters as depth increases. As detailed by Thomas (2001), the number of phases depends on the geological characteristics of the formation and the total depth of the well. After having been drilled, each phase is completed with the installation and cementation of a casing string. Casing strings have different functions according to the section they cover, including: preventing borehole collapse, avoiding contamination of underground fresh water layers close to the surface, avoiding migration of fluids from the formation, and sustaining the well head and well control equipment.