What is Geothermal Drilling :
A process that cuts or enlarge the holes of circular cross section for hard materials is known as Drilling.The process of creating bore holes in the earth to extract earth’s heat is known as Geothermal Drilling.Generally a drill bit is used in drilling as rotary cutting tool. From hundreds to thousands of rpm the drill bit is rotated and pressed against the work piece. This makes the cutting edge to remove chips from hole. In drilling the resource is stored in the form of volcanic or hard sediment rocks.
We may often come up with the names Drill bit and Drill Rig. Lets have a brief discussion on it.
Drill Bit: These are used as cutting tools which create circular holes. These are of many sizes and comprises of many uses. These are fixed in a tool called drill which rotates them and provide force to create holes. Some bits are available which are used for non cylindrical shaped holes.
The important part of drill bit is shank. It is present at the other end of the drill bit.
There are many types and kinds of drill bits. Each drill bit has its own specification.
Drill Rig :
A massive structure or a machine which create holes and also used to drill water,oil wells or natural gas extraction wells.These wells can also be small and can be moved manually by one person.
Drill Rig Selection :
Drill rig selection will be based on well parameters like diameter,depth and casing design.With the parameters criteria we will determine what kind of drill rig should be used.
Factors determining the hole diameter :
• Logging tools - logging tools will fit into almost any reasonable hole size, but if more complex tools, especially imaging tools such as a formation micro-scanner they defines minimum hole size.
• ...
... middle of paper ...
... in the difficulty of casings landing
Hole Enlargement :
Here the hole size is very large than expected and needed and the problems related to these are
Hydraulic erosion
Mechanical abrasion caused by drillstring
Inherently sloughing shale
Fracture
It happens when the wellbore drilling-fluid pressure crosses the formation-fracture pressure. The associated problems are lost circulation and kick occurrence.
Collapse
Borehole collapse occurs when the drilling-fluid pressure is very less to maintain the structural integrity of the drilled hole. The associated problems are pipe sticking .
Ref : http://petrowiki.spe.org/Borehole_instability#Types_and_associated_problems
Lost Circluation :
It is the partial or complete loss of drilling fluid. When hydrostatic pressure is greater than breaking strength, create cracks and fluid gets leaked and flows.
Yan, F., Feng, X., Chen, R., Xia K., Jin, C., Dynamic Tensile Failure of the Rock Interface
...a producing well is significantly lower than at other areas where no well is drilled. The driving force could be either natural or created by engineering design involving fluid injection through certain wells placed optimally to achieve the best results. Experimental data suggests that reservoir rocks are abundantly permeable in both vertical and horizontal directions. Among a myriad of factors related to geological and geochemical processes, the permeability of a rock is influenced by the slit, shape, configuration, and connectivity or a porous network.
The brittle failure is due to high contact stresses at the cutting edge due to a combination of critical cutting parameters. The weak cutting edge du to the crate also contributes to the brittle failure.
A reservoir is considered as a compaction drive is when the pore volume contraction takes prominently to overall expansion while the reservoir is saturated. This drive is supplemented by solution gas drive and may or may not by water/gas cap drive. This reservoir acts like their non-compaction counterparts except that they exhibit enhanced recoveries. For example, the oil recovery will be greater for a solution gas drive by which the compaction drive will act like a normal solution gas drive reservoir. This is because of the direct consequence of the extra rock expansion that compaction drive reservoirs actually have. Due to the extra compaction, some production occurs. For instance, the permeability may decline, fracture may happen and subsidence but all there problems are manageable and the result of compaction is very favorable.
They wanted to try to develop a water-based mud that would not have a strong effect on the Pierre shale and would be environmental friendly to dispose of the cuttings. They studied the PDC bits in order to help the drilling rates while drilling through this troublesome shale. They performed the project with two 8 1/2 –in PDC drill bits and nine different types of drilling fluids. Two of the drilling fluids were oil based while seven of the drilling fluids were water based. The different types of drilling fluids can be seen in figure two. The cores used for the experiment came from outcrops of the Pierre shale in Colorado and they were preserved in diesel oil in order to make the shale fully saturated during the experiment and this would model a soft formation where bit balling would be prevalent [5]. The two experimenters also used two types of PDC bits for the experiment; a steel-body ribbed PDC and a matrix-body bladed PDC bit. Hemphill and Clark ran many different tests changing the flow rate, weight on bit, drilling fluids, and the two different drill bits. They first concluded that the two different bits had different penetration rates for the Pierre shale. The matrix bodied bladed bit drilled faster than the steel body bladed bit in all of the mud samples
Although some hydraulic fractures form naturally, most wells are manmade. A high-pressure fluid of toxic chemicals and sand suspended in water is injected into pipes from the well to create cracks in the rock. Natural gas, petroleum,
Rock thickness will have enough permeability to transcend fluids towards a bore well. This characteristic is usually called as “Net reservoir rock.” In the oil and gas industry, another quantity “Net Pay” is computed which is the rock thickness which can transcend hydrocarbons to the bore well at an optimum rate. Reservoir models are built upon their measured and derived properties to estimate the amount of hydrocarbon present in the reservoir, the rate at which that hydrocarbon can be produced to the Earth’s surface through wellbores and the fluid flow in rocks. As far as Industry of Water Resources is concerned, likewise models are utilized to analyse amount of water that can be produced to the surface over long periods of time, without depleting the aquifer.
Power tools are very important in house building because carpenters can work a lot faster and get the house done so the family can move in as soon as possible. There are a few main power tools that every carpen...
Many parts, for example, screws, nuts, bolts, and fittings, are produced by automatic turning operations [10]. Some alloying elements sometimes added to impart special characteristics to brass. Lead, which is insoluble in copper alloys, is used to improve machinability of leaded brass. However, Pb and Bi or other elements that are used to improve the machinability often deteriorate the low and high temperature ductility of brass [11]. The content of Pb element is varies between 2.5 and 3.5 %, which make the machining processes at high speed and good surface [12]. The solubility of lead in copper alloys is very low therefore, it is found in microstructure as dispersed globules all over the material. These globules lead act as a lubricant decreasing the friction coefficient between the tool and the material by creating discontinuities of chip fragmentation. Therefore, it makes reducing in cutting force and then, the tool wear rate is minimized [13]. Different alloying elements help to improving the machinability are usually added to brass. The most common element using in this situation is lead, which improving the machinability with regard to excellent chip breakage, low tool wear and high applicable cutting parameters. These aspects can be explained by two basic phenomena; first of all, the solubility of lead in brass is extremely low and lead segregates in the entire microstructure, particularly at the grain boundaries. Hence, shear strength is reduced, resulting in very good chip breakage. Secondly, lead exhibits a low melting temperature and during cutting process, a thin, semi-fluid lead film reduces friction with cutting forces
This defect occurs in all castings but more frequently in heavy sections in all alloys with along solidification range. This is different from hot tears and creaks.
Geothermal energy is one of the oldest sources of energy. It is simply using and reusing (reusable energy) heat from the inside of the earth. Most of the geothermal energy comes from magma, molten or partially molten rock. Which is why most geothermal resources come from regions where there are active volcanoes. Hot springs, geysers, pools of boiling mud, and fumaroles are the most easily exploited sources. The ancient Romans used hot springs to heat baths and homes, and similar uses are still found in Iceland, Turkey, and Japan. The true source of geothermal energy is believed to come from radioactive decay occurring deep within the earth.
Wellbore cementing is a critical part of oilfield drilling operations normally conducted a number of times during the drilling of a well. Cementing is completed by pumping cement down through the casing then back up the annulus between the casing and formation creating a hydraulic barrier between the casing and the formation in addition to protecting and supporting the casing. During latter times in a wells life cementing can also be conducted order to plug zones or entire wells that are no longer producing [1].
For several tasks, it is available with drill bits which are quite helpful in screw driving and space mission applications. It is fitted with electrical motor that can drill a hole in the object by moving the bit in a rotating mode. It can work in a variable speed and easy to adjust in accordance to the requirements of the task and comfort of the skill worker. These days cordless drill accessories are used frequently than common drill accessories. The reason of using cordless drill accessories is that they contain battery fitted in the hand...
The screw fasteners are the most prominent part of the hardware family. These are employed in a wide array of applications in order to fix things. These are employed for the purpose of holding items so that these should properly get fixed. These are used in various industries for varied industrial purposes. Some of the industries in which these are used tremendously are construction, machinery, production, automobile, aircraft, furniture & many more.