Directional drilling types

Of course, it is lrequently desirable to utilize a controlled directional drilling technique. There are several reasons, as indicated by Fig. 15. The three most commonly patterned directional holes are shown in Fig. 16. The planned course of direction depends upon several factors, including rig capacity, hole size, mud program, types of formation, and the casing program. Meticulous surveying is required to achieve the desired results. Several types of drilling tools may be required. 

Tests using a constant stress (constant load) normally by direct tension have been described in ISO 6252 (262). This test takes the specimen to failure, or a minimum time without failure, and frequently has a flaw (drilled hole or notch) to act as a stress concentrator to target the area of failure. This type of testing, as well as the constant strain techniques, requires careful control of specimen preparation and test conditions to achieve consistent results (263,264). 

Drilco Rubber Type. See Figure 4-169 and Table 4-102 [56]. Shock is absorbed by an elastometer situated between the inner and outer barrels. This shock absorbing element is vulcanized to the barrels. The torque has to be transmitted from the outer into the inner barrel. This tool is able to absorb shocks in axial or in radial directions. There is no need to absorb shocks in the torque because the drill string itself acts like a very good shock absorber so the critical shocks are in axial directions. These tools cannot be used at temperatures above 200°F. Though they produce a small stroke the dampening effect is good [56]. 

The gamma rays are detected today with sodium iodide crystals scintillation counters. The counters, 6 to 12 in. long (15 to 30 cm) are shock mounted and housed in the drill collars. Several types of measurements can be made total gamma rays, direction-focused gamma rays, spectral gamma rays. 

Application of Corrosion Inhibitors. There are basically two main techniques used to apply corrosion inhibitors in drilling operations. In the first method inhibitors are added to the drilling fluid system either by mixing the additives through the rig s chemical hopper or through additions into the mud pit. The treatment can be achieved in two ways, batch treatment or continuous treatment. In some cases it may be necessary to use both types of treatment simultaneously. The second technique of applying is directly coating the corrosion inhibitors on the drillpipe. 

Direct Treatment. Although batch and continuous treatment are both quite effective, there is a problem with inhibitor waste. When corrosion inhibitors contact the circulating drilling fluid, they are likely to coat the solids in the fluid system (cuttings or other solids). By applying the corrosion inhibitor directly to drillstem components before they are run in the hole, the corrosion inhibitor is the first thing that contacts the exposed metal surface. There are two methods for this type of corrosion inhibitor treatment. 

Unconfined or water table aquifers maintain a saturated surface that is exposed directly to the atmosphere. These are often similar to a bathtub full of sand or gravel to which water has been added. A well drilled through the water table would fill with water to the common water elevation in the tub. Thus, the potentiometric head in the aquifer is at the elevation of the water table. Unconfined aquifers are also characterized by a fluctuating water table, which responds seasonally. With unconfined aquifers, the water table is at atmospheric pressure, and only the lower portion of the aquifer is saturated. Recharge to a water table aquifer comes from rainfall that seeps downward to the water table. The water table level in this type of aquifer rises in direct proportion to the effective porosity. If the equivalent of 2 in. of rainfall seeps into the water table (actually reaches the water table) in an aquifer with an effective porosity of 0.3, the water table would rise 6.7 in. Alternatively, if the same water is pumped and removed from a well, the water table aquifer is then derived from the storage in the formation in the immediate vicinity of the well. Natural... 

Although faulting and thrusting has complicated the distribution of rocks types one key aspect within 5 of 8 drill holes remains consistent. All HW volcaniclastic samples in direct contact with the ore horizon belong to HW4 and all FW volcaniclastic samples in direct contact with the ore horizon belong to FW1. 

With the Laskin-type nozzle shown in Figure 9, a high velocity air jet issues directly into a liquid and entrains a filament of the liquid into droplets, which are carried to the surface and out. The nozzle is constructed of Teflon. A small orifice is drilled at right angles to the axis of the air feed line. A liquid feed hole is centered above the air orifice and longitudinal to the nozzle. 

To be referred to next is the most modem diamond anvU type, generating pressures of order of 10 -100 GPa. The cell illustrated in Figure 6(e) consists of two gem diamonds with optically flat surfaces, between which a sample confined in a drilled hole of a thin metal gasket is sandwiched. To attain isostatic compression an inert gas or an organic liquid, like a 4 1 volume mixture of methanol and ethanol, is contained with the sample. The generated pressure is measured directly from the pressure shift of the fluorescence line of mby powder mixed with the sample. Temperatures to 5000 K can be obtained by laser heating. The quantity of sample confined in a typically 0.1-mm-wide hole is extremely small, just a few microcrystals. At present, research has focused on in situ observations using X-ray and other optical methods, rather... 

Direct sampling of free soil gas requires that a sampling probe be inserted into the ground to collect a soil gas sample. The deeper the penetration, the more difficult and expensive the procedure becomes, eventually requiring that analysis be conducted on drilling fluids or rock samples recovered from a hole. Deeper holes almost always encounter water, which also influences the collection of free gases, forcing one to analyse the gas content of some type of recycled water or mud system which is used to drill the hole. 

Some of the procedures of value for processing of mixed plastic wastes may also be useful for the recovery of value from the laminates used for efficient packaging of food and beverages (e.g., milk cartons, Tetrapaks). A combination of heat and pressure may be employed on a recycle stream of this type of material to fuse the mixed fibrous and resin components into a dense board-like product [31, 32]. This highly weather and insect resistant product, Eco Superwood Plastic Lumber, may be sawn, nailed, drilled, etc., like wood, and it resists rotting in direct contact with the soil without the need for preservatives. 

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