Triethylene Glycol, also known as TEG, is a preferable industrial chemical for various applications which require efficient heat-transferring fluids. High-temperature applications such as geothermal plants, petrochemical reactors, hot fluid transferring pipelines, and solar systems can be named as some examples which can use TEG. TEG thermal stability is higher than many other similar glycols such as Monoethylene Glycol (MEG) or Propylene Glycol. Moreover, some scientific researchers have reported that TEG can be used up to 390 Fahrenheit degrees. In addition to the unique heat-transferring, TEG provides perfect anti-freezing properties. TEG is an ideal choice for cooling and heating transferring processes.
There are different types of heating transfer fluids, such as water, water-based fluids, natural oils, and synthetic oil-based fluids. Based on provided properties of the mentioned fluids, they are used in different industrial processes. Although, some characteristics creates some of these fluids to be superior when compared to others, such as safety in handling, low corrosivity properties, high boiling temperature, and being less hazardous to the environment.
Considering the various tasks of the drilling fluids in oil and gas well drilling, the efficiency of the drilling mud is the result of the accurate and correct selection of the mud formulation. Both water-based and oil-based muds have advantages and drawbacks with specific applications that justify their usage in drilling operations according to them. In general, water-based muds are less toxic and less expensive to produce.
Also, water-based muds are more compatible with the environment, specially about releasing drilling wastes into the sea. However, for many drilling operations with critical conditions, such as drilling deep formations with high temperature, drilling in the highly unstable shale layers, horizontal and directional drilling, drilling narrow wells that requires high torque, oil-based drilling muds are recommended to be used. On the other hand, the formulation of oil-based drilling mud is more complicated and their production cost is higher.
The advantages of oil-based drilling mud include high corrosion controlling, increasing therate of penetration (ROP), the possibility of reusing drilling mud in several wells, higher efficiency in high temperature-high pressure conditions and better lubricating the drill bit.
From technical point of view, in some cases, oil-based drilling muds are preferable to water-based drilling muds. For instance, when using water-based muds, more drilling waste is produced than oil-based muds. In addition, oil-based mud has higher resistance against different types of contaminations -such as cement, formation water, anhydrite particles, and etc.- compared to water-based muds. On the other hand, due to the high cost of preparing oil-based muds compared to water-based muds with similar density, the economic justification of choosing an oil-based muds should be done according to its performance.
Monoethylene Glycol (MEG) is mainly used as a raw material in the production of some polyesters and used in antifreeze products. MEG is used in producing many types of antifreeze agents; coolants, ani-icer and deicers. MEG is utilized in the production of vehicles’ antifreeze agents, cooling equipment and aircraft antifreeze. It is also used in cooling systems such as HVAC units in order to transfer generated heat and cool the engines in various weather situations.
MEG is a preferable antifreeze agent compared to other antifreeze chemicals due to its high efficiency. It is much more economical than Propylene Glycol in antifreeze applications, as a lower percentage of MEG compared to Propylene Glycol is required to reach the same freezing point in water. Furthermore, one of the other advantages of using MEG in antifreeze is its better heat transfer properties than other chemical compounds.
One of the most widely used materials in drilling mud is Barite. The main function of Barite in drilling mud is its weighting agent properties, which is widely used in water-based mud and oil-based muds.
Barite mines are mainly located in China, USA, India, Russia and Iran. The amount of extraction of this mineral is closely related to the process of oil & crude gas exploration. The consumption of Barite is mainly in drilling mud but a small portion of the produced barite is used in industries such as chemicals, paper, plastics, glass ceramics and pharmaceuticals.
Barium Sulfate is mineral which is used to produce Barite required in the drilling industry. Barium Sulfate ore may contain other by-products. Due to the presence of these minerals, the color of the ore may change from white and milky to yellow, gray or red.
Barite does not dissolve in water and therefore remains as suspended particles in the mud without changing its chemical properties. One of the important features of Barite is its high density, when added to drilling mud, it occupies a smaller volume of mud compared to other particles. As a result, it can increase the density and weight of drilling mud. Increasing the density of mud is suitable for immersing rock particles. Under these conditions, a larger volume of muds remains in liquid phase, as the result the flow of mud will be smoother.
Barite literally means heavy and has Greek roots. The specific gravity of this mineral is about 4.2 to 4.6. Barite hardness varies in the range of 2.5 to 3.5. This mineral is used with different density and hardness to meet requirements of various drilling formations. The amount of alkaline earth metals soluble in water should be less than 250 mg/kg. In addition, Barite used in offshore drilling rigs must meet environmental regulations in terms of the amount of mercury and cadmium content.
Calcium Chloride is used in drilling mud with powder or flakes appearance to to supply Calcium ions. Calcium Chloride is one of the drilling fluids weighting agents. It can adjust the activity of the water phase in invert-emulsion mud.
Advantages of Calcium Chloride usage in drilling mud over other weighting agents, is its low price in formulation of solid-free completion brines.
The maximum density obtainable is 11.6 Ibm/gal (SG 1.68) with the addition of Calcium Bromide. Calcium Chloride and other brine completion fluids, eliminate plugging of producing sands often encountered when perforations are made through drilling mud. These brine fluids, free of solids, eliminate the problem of cracking, solidification and settling of solid materials on packers.
Calcium Chloride is used to control the activity of oil-based mud and work over/completion fluids. It is also an effective means of providing high Chloride ion concentration levels in the aqueous phase of mud for balanced activity mud systems, for maximum shale stability.
CaCl2-containing drilling mud can be used in high pressure formations.
It is much easier to dilute this material in water and has the ability to absorb dust from drilling operations inside the well.
Various chemicals and methods are used to melt ice (deicing) roads in the cold seasons of the year. Calcium Chloride is one of the most widely used inorganics for ice melting and deicing. In addition to Calcium Chloride, other substances such as Sodium Chloride, Magnesium Chloride, Potassium Chloride and Magnesium Acetate are also used.
In cold seasons, Anti-Icing methods can be used to prevent road freezing. In case of frost, different methods and materials are used for deicing. Anti-Icing and deicing methods are described in more detail below.
Lost circulation is an occurrence in Formation when drilling fluids is lost into cracks during drilling or cementing operations. Lost circulation in drilling is always examined in two parts: prevention and remedial of loss. Prevention is to take all measures to prevent loss during drilling. This stage is usually done by technically examining the condition of the earth’s layers (geology) and recognizing the geographical area. Lost circulation treatment is also done by using additives appropriate to the structure of the earth’s layers and depending on the geological conditions, different materials and additives are used.
Preventing and controlling lost circulation reduces costs, reduces drilling time and facilitates the drilling process.
The exploration and extraction of oil industrially and economically began in the mid-nineteenth century. Hundreds of years ago, this natural source was used for lighting purposes or as a lubricant.
The invention of the first internal combustion engine and its use in all forms of life today has led to an increase in demand for the extraction and exploitation of fossil fuels. The positive and negative consequences of the expansion of these activities in the oil industry, which is done in order to meet the bulk of energy supply, is an issue that has always been faced by those in charge of this industry.