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].
Most all cements used in the oil field are Portland cements. This dry cement is created by mixing raw materials that contain high amounts of calcium, silicon, aluminum, and iron. These materials are ground up and heated in a kiln
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During hydration the cement reacts with the water to form three main components; calcium hydroxide (Ca(OH)2), Calcium Silicate hydrate (C-S-H), and aluminum trisulfate also known as ettringite [4]. The C-S-H forms a gel that accounts for around 50% of the paste and is where most of the strength of the cement comes from by becoming a binding phase for all of the crystal structures formed in the cement paste. Calcium hydroxide then accounts for around 15 % of the cement paste and forms uneven hexagonal crystals that are grown around the C-S-H. Ettringite along with other products of the C₃A and C₄AF reactions account for 15- 25% of the paste form more crystalline parts of the paste the do not provide much to the strength of the cement …show more content…
This porous region is important because of the fluids contained inside them. These fluids will have free particles on cement that have not been reacted as well as unreacted ions. This liquid phase creates a link between the hydrated cement and outside environment as fluids can slowly travel through these pores. During the hydration process as all the reactions take place the porosity and permeability decrease as the strength increases in a process known as hardening [5]. This is due to the growth of C-S-H and can take varying amounts of time to become fully hydrated depending on environmental conditions. Figure 1.1 shows these mechanical changes happening over time in relation to the different products being reacted. The American Petroleum Institute (API) recognizes nine different Portland cement types. These different types of cements are distinguished by their different compositions allowing them to be used in different conditions. These different types of cement are presented in Table 1.2 along with their applications. In the united states the most common class used is class H because of its ability to be mixed with a variety of different additives to achieve a range of different requirements [7].
Table 1.2 API cement classes and application [6]
API class
The purpose of this short memo is to discuss aspects of use, applicability, and environmental impacts of porous pavements as gleaned from practical findings and pertinent examples. A porous pavement is one with high enough porosity and permeability to allow rain and snowmelt to pass through it, thereby reducing the runoff from a site and surrounding areas. In intensely built up areas, pavements account for more than half of all the land, and for about two-thirds of total built cover (Ferguson, 2005, 2-3). Parking lots, in particular, account for the majority of paved areas. Pervious paving materials have the capability of providing a dual purpose in parking and other areas with low to moderate traffic; they serve both as a parking/traffic area and to manage stormwater.
In this experiment, solid calcium nitrate, solid diammonium hydrogen phosphate, and aqueous ammonia are used to form calcium hydroxyapatite.
...the action of drilling is going on because so that if the same incident ever happen again, their will be more men to take the first aid action in trying to stop the leak. Also maybe the company should change the type of pipe they are using to engage in transferring the drilled oil because it might be the material used to make the pipe that is weaken and ended up causing the oil company billions of dollars.
There are many potential adverse health impacts caused by the chemicals used at the drilling site, which are later often unintentional released into the environment. These chemicals are hazardous and as Witter et. al. (2008) state “some of the chemicals used in this process are brought to the surface, potentially contaminating soil, air, and water, while some of the chemicals are left underground, potentially subsurface aquifers” (4). This makes it difficult to track which chemicals are causing effects and where they are coming from. Another piece to the puzzle is that the drilling companies do not disclose the full-list of chemicals so there is a great mystery in what chemicals and what concentrations are used in the process (Lauver 2012:383). However, recently there researchers have begun to breakdown the chemical identities and concentrations.
This is related to the blending of the fluids and rocks of the reservoir. Skeletal properties of interest to reservoir engineers include porosity, pore size distribution, compressibility, and absolute permeability of the rod. Interaction or dynamic properties of reservoir rocks are affected by the nature and by its interaction with present fluids, as...
First, a production well is drilled down into the ground for thousands of feet and then gradually leveled so that the tip of the drill travels horizontally through the ground. The second part of the process is where it gets the name of “fracking” because the second step in the process is where a mixture of sand, water, and chemicals, many of which are known to be harmful, are forced under extremely high pressure down into the shale through the horizontal part of the drill.... ... middle of paper ... ... Retrieved from the Gale Science in Context database. (A264004904) -.
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
This process takes place on wells that are already drilled. The land must be cleared around where the well is located. Water is then pumped into the well at extremely high pressure. When water is sent this deep at high pressure, it causes the rocks in the shale formation layer, found in Figure 1, to crack. This layer is where oil and natural gas is found. When the rocks crack they release the oil and natural gas inside them. The water now has some natural gas and oil in it and can come back to the surface where it is to be separated. This can only be done because of the ability to drill horizontally. These wells go down very far into this layer and then the drill is able to make a turn so that it is drilling parallel with the ground. This increases the surface area of the contact that the water at high pressure has with the sh...
The main aim of reservoir characterization is to build an all-round understanding of petrophysical properties. The goal of this essay is to understand the laboratory measurements and basic definitions of the petrophysical properties porosity, permeability, relative permeability, capillarity, and saturation. Pore-size distribution is presented as the common link between these properties.
The most economical method for ground improvement is aggregate piers. Before aggregate piers were used, engineers had to replace the weak soil with an engineering fill in order to use shallow foundations, but in some cases (load is very high) they had to use deep foundations, which is much more expensive. By using aggregate piers, we can now use shallow foundations in marginal soil without having to replace it. By using compacted aggregate to create stiff pier element, aggregate piers help to increase the bearing capacity, liquefaction resistance, shear strength, rate of consolidation and it reduces settlement.
Concrete and masonry products contain silica sand and rock containing silica. Since these products are primary materials for construction, construction workers may be easily exposed to respirable crystalline silica during activities such as the following:
Concrete is a composite material used widely in the construction industry. Concrete is basically a mixture of cement, water, aggregates and admixture (sometimes). Cement is a fine gray powder that consists of oxidizes calcium, silicon and aluminum. The aggregate used is normally gravel, crushed stone or sand. Admixture is a solid or liquid substance that gives a certain characteristics of the concrete. The cement reacts with water chemically and binds the aggregates together through a process called hydration during hardening or curing of concrete. It means that water helps in the hardening of the concrete while the cement bind the aggregate and also react with water to form a solid mass.
This equation assumes that the secondary consolidation settlement occurs after the dissipation of excess pore water pressure.
,n.d. web. 21 May 2014 Petroleum engineering. Encyclopedia Britannica. N.P., n.d. Web.