Rocks formation

The term aquifer is used to denote an extensive region of saturated material. There are many types of aquifers. The primary distinction between types involves the boundaries that define the aquifer. An unconfined aquifer, also known as a phraetic or water table aquifer, is assumed to have an upper boundary of saturated soil at a pressure of zero gauge, or atmospheric pressure. A confined aquifer has a low permeabiUty upper boundary that maintains the interstitial water within the aquifer at pressures greater than atmospheric. For both types of aquifers, the lower boundary is frequendy a low permeabihty soil or rock formation. Further distinctions exist. An artesian aquifer is a confined aquifer for which the interstitial water pressure is sufficient to allow the aquifer water entering the monitoring well to rise above the local ground surface. Figure 1 identifies the primary types of aquifers. 

The lanthanides, distributed widely in low concentrations throughout the earth s cmst (2), are found as mixtures in many massive rock formations, eg, basalts, granites, gneisses, shales, and siUcate rocks, where they are present in quantities of 10—300 ppm. Lanthanides also occur in some 160 discrete minerals, most of them rare, but in which the rare-earth (RE) content, expressed as oxide, can be as high as 60% rare-earth oxide (REO). Lanthanides do not occur in nature in the elemental state and do not occur in minerals as individual elements, but as mixtures. 

Oil reservoirs are layers of porous sandstone or carbonate rock, usually sedimentary. Impermeable rock layers, usually shales, and faults trap the oil in the reservoir. The oil exists in microscopic pores in rock. Various gases and water also occupy rock pores and are often in contact with the oil. These pores are intercoimected with a compHcated network of microscopic flow channels. The weight of ovedaying rock layers places these duids under pressure. When a well penetrates the rock formation, this pressure drives the duids into the wellbore. The dow channel size, wettabiUty of dow channel rock surfaces, oil viscosity, and other properties of the cmde oil determine the rate of this primary oil production. 

Tungsten is usually identified by atomic spectroscopy. Using optical emission spectroscopy, tungsten in ores can be detected at concentrations of 0.05—0.1%, whereas x-ray spectroscopy detects 0.5—1.0%. ScheeHte in rock formations can be identified by its luminescence under ultraviolet excitation. In a wet-chemical identification method, the ore is fired with sodium carbonate and then treated with hydrochloric acid addition of 2inc, aluminum, or tin produces a beautiful blue color if tungsten is present. 

Deep-Well Injection Deep-well injection for the disposal of liquid wastes involves injecting the wastes deep in the ground into permeable rock formation (typically limestone or dolomite) or underground caverns. 

Fels-gestein, n. rock material rock formation> -glimmer, m. mica, felsig, a. rocky, rock-like,... 

Gebirgs-art, /. kind of stone or rock, -bildung, -fonnation, /. mountainous formation rock formation orogenesis, -kunde, -lehre, /. orology geognosy. zug, m. mountain range. 

It is estimated that the earth s age is in the neighborhood of 4 to 7 billion years. These estimates are basically derived from carbon-14, potassium-40, uranium-235, and uranium-238 dating of earth rocks and meteorites. The meteorites give important data as to the age of our solar system. Geologic time is felt to be represented by the presence of rock intervals in the geologic column (layers of rock formations in vertical depth) or by the absence of equivalent rocks in correlative columns in adjacent locations [25,26]. The two basic factors that are used to determine geologic time are ... 

Succession of flora and fauna refers to the deposition of sedimentary material, which will include the remains of plant and animal life that existed at the time of the deposition of these rock particles. The fossils of these plants and animals will be found in the rock formations that result from the deposition. The presence, absence, or change of the plant and animal life within a sequence of the geologic column provide important information that allows for the correlation of rock formations (and, thereby, relative time) from location to location. Also, the fossil records within sequences give important information regarding the evolution of life through geologic time. 

Of interest is the detailed structural configurations that can form in sedimentary rock formations, because hydrocarbons are nearly always found in sedimentary rocks. The structural features of interest are faults and folds [26]. 

Folds in layered rock formations consist of the deformation of layers without... 

Concentric (parallel) folds—rock formations parallel to each other such that their respective thicknesses remain constant (see Figure 2-43). 

Structural traps result from deformation of rock formations. Such deformations are the result of folding or faulting. 

Fault traps—involve the movement of the reservoir rock formation to a position where the formation across the fault plane provides a seal preventing further migration of hydrocarbons (see Figure 2-48). 

Sail-related (raps—formed when the plastic salt formations deform into domelike structures under the overburden forces of the beds above the salt beds. Such plastic flowing (and bulging) of the salt beds deforms the rock formations above producing anticline structures and faults in the rock formation astride the domelike structures (see Figures 2-49 and 2-50). 

The surface rock formations of the earth are continually exposed to the weathering process of the atmosphere that surrounds the earth. The weathering process through... 

Soils can consist of rock, rock particle.s, mineral materials derived from rock formations, and/or organic matter. 

Bedrock is composed of competent, hard, rock formations that underlie soils. Bedrock is the foundation engineer s description of transition from soils to rock at depth. Such rock can be igneous, sedimentary, or metamorphic. Bedrock is very desirable for foundation placement. 

Cable-tool drilling lines. Movement of wire rope against metallic parts can accelerate wear. This can also create sufficient heat to form martensite, causing embrittlement of wire and early wire rope removal. Such also can be formed by friction against the casing or hard rock formation. 

Hard to extremely hard competent rock formations can be drilled with turbine motors using diamond or the new polycrystalline diamond bits. 

Since the rock formation to be drilled is classified as extremely hard, 1.5 hydraulic horsepower per square inch of bit area will be used as bit cleaning and cooling requirement [87]. The projected bottomhole area of the bit (in. ) is... 

Soft, medium and hard rock formations can be drilled with a positive displacement motor using nearly any type of rock bit. The positive displacement motor is especially adaptable to drilling with roller rock bits. 

High-pressure squeeze cementing operations are utilized where the hydraulic pressure is used to make new channels in the rock formations (by fracturing the rock) and force the cement slurry into these channels. 

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