Bore holes

Until downhole motors became available a whipstock (Fig. 3.15) which is a slightly asymmetric steel joint, was inserted in the drill string. The assembly is oriented downhole and a rathole is drilled which is then enlarged to full bore hole size. The technique is still used in wells where hole conditions e.g. high temperatures, are unsuitable for downhole motors (see below). 

Residual stresses in the formation, resulting from regional tectonic forces may cause the borehole to collapse or deform resulting in stuck pipe. Prevention sometimes high mud weights may help delay deformation of the bore hole. 

Long Spacer Detector Short Spacer Detector Radioactive Source Bore Hole... 

With the reference block method the distance law of a model reflector is established experimentally prior to each ultrasonic test. The reference reflectors, mostly bore holes, are drilled into the reference block at different distances, e.g. ASME block. Prior to the test, the reference reflectors are scanned, and their maximised echo amplitudes are marked on the screen of the flaw detector. Finally all amplitude points are connected by a curve. This Distance Amplitude Curve (DAC) serves as the registration level and exactly shows the amplitude-over-distance behaviour" of the reference reflector for the probe in use. Also the individual characteristics of the material are automatically considered. However, this curve may only be applied for defect evaluation, in case the reference block and the test object are made of the same material and have undergone the same heat treatment. As with the DGS-Method, the value of any defect evaluation does not consider the shape and orientation of the defect. The reference block method is safe and easy to apply, and the operator need not to have a deep understanding about the theory of distance laws. 

There are, however, a variety of other sources of methane that have been considered for fuel supply. Eor example, methane present in coal (qv) deposits and formed during mining operations can form explosive mixtures known as fire damp. In Western Europe, some methane has been recovered by suction from bore holes drilled in coal beds and the U.S. Bureau of Mines has tested the economic practicaUty of such a system. Removal of methane prior to mining the coal would reduce explosion ha2ards associated with coal removal. As much as 11.3 x 10 (400 trillion (10 ) cubic feet or 400 TCE) of... 

Oil well cements (78) are usually made from Pordand cement clinker and may also be blended cements. The American Petroleum Institute Specification for Materials and Testing for Well Cements API Specification 10) (78) includes requirements for nine classes of oil well cements. They are specially produced for cementing the steel casing of gas and oil wells to the walls of the bore-hole and to seal porous formations (79). Under these high temperature and pressure conditions ordinary Pordand cements would not dow propedy and would set prematurely. Oil well cements are more coarsely ground than normal, and contain special retarding admixtures. 

These motors are comparatively long and slender requiring a smaller bore diameter to slide easily into the bore hole/ bore well with the pump. 

Water extraction from bore holes and river beds for water supply and irrigation... 

Since the Wenner rod is mechanically somewhat delicate, it is only used in loose soils or in bore holes. For all measuring rods, the specific soil resistivity is equal to the product of the measured ac resistance and the shape factor Fq, which is determined empirically. 

Bohrung, /. boring, bore, bore hole drilling (drilled) well caliber. 

Basically all formations penetrated during drilling are porous and permeable to some degree. Fluids contained in pore spaces are under pressure that is overbalanced by the drilling fluid pressure in the well bore. The bore-hole pressure is equal to the hydrostatic pressure plus the friction pressure loss in the annulus. If for some reason the borehole pressure falls below the formation fluid pressure, the formation fluids can enter the well. Such an event is known as a kick. This name is associated with a rather sudden flowrate increase observed at the surface. 

Water from towns main supplies is usually suitable for the preparation of water-based cutting fluids. That from factory bore holes is also generally suitable, although occasionally it contains excessive amounts of corrosive salts. Water from rivers, canals and ponds usually contains undesirable contaminants, and should be tested before use. A good first test is to mix a small quantity of emulsion and allow it to stand for 24 hours in this time, no more than a trace of the oil should separate. If serious separation occurs, the water should be analyzed to indicate the sort of remedial treatment required. 

Concave surfaces are of industrial importance, in relation to the internal surface of bores, holes and pipes, but are not found on typical solid testpieces and have received much less discussion. The stress patterns will tend to be the opposite of those found on convex surfaces for example, an oxide growing by cation diffusion should be in tension at the metal interface. Bruce and Hancock have discussed the oxidation of curved surfaces and show how the time to adhesive failure of the oxide can be predicted if its mechanical properties are known. 

In the order Muricidae these carnivorous snails attack molluscs or sessile crustaceans by boring holes in their shells using softening secretions. Hypobranchial and other glands contain small molecular weight substances with pharmacological activity (e.g., murexine, 5HT, etc.). 

In nondispersed systems no special agents are added to deflocculate the solids in the fluid. The main advantages of these systems are the higher viscosities and the higher yield point-to-plastics viscosity ratio. These alterated flow properties provide a better cleaning of the bore hole, allow a lower annular circulating rate, and minimize wash out of the bore hole. 

Fig. 3.15 Left External view of the MIMOS II sensor head (SH) with pyramid structure and contact ring assembly In front of the Instrument detector system. The diameter of the one Euro coin is 23 mm the outer diameter of the contact-ring is 30 mm, the inner diameter is 16 mm defining the field of view of the Instrument. Right. Mimos II SH (without contact plate assembly) with dust cover taken off to show the SH Interior. At the front, the end of the cylindrical collimator (with 4.5 mm diameter bore hole) Is surrounded by the four SI-PIN detectors that detect the radiation re-emltted by the sample. The metal case of the upper detector is opened to show its associated electronics. The electronics for all four detectors Is the same. The Mossbauer drive is inside (in the center) of this arrangement (see also Fig. 3.16), and the reference channel is located on the back side In the metal box shown In the photograph...

Heikkila K. (2008). Environmental evaluation of an air-conditioning system supplied by cooling energy from a bore-hole based heat pump system. Building and Environment, 43(1) 51-61. 

To prepare the explosive, simply mix about one gallon of fuel oil or motor oil to one bag (80-100 pounds) of fertilizer. The mixing can be done in the bag or in the bore hole prepared to receive the charge. Use about the same amount of the mixture in weight as would be required of dynamite. 

Iron mixed-valence materials such as green rust and fougerite are sensitive to air exposure and soil pollution by nitrates. A MIMOS instrument autonomously lowered or raised within a plexiglas tube, which was put down a bore hole, allowed... 

The Weyburn site was selected because, during 44 years of oil exploration, Saskatchewan required oil companies to keep extensive geological records. Core samples from 1,200 bore holes allowed an extensive look at subsurface conditions and a way to track the movement of oil and gases. 

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