Drilling Fluid Functions

The following is the function of Drilling Fluid: 

1. Cool the drill bit and lubricates its teeth: one of the prime functions of the drilling fluid or mud is to cool the drill bit and lubricate its teeth. The drilling action requires a considerable amount of mechanical energy in the form of weight on bit, rotation, and hydraulic energy. A large proportion of this energy is dissipated as heat, which must be remove to allow the drill bit to function properly, the drilling mud also helps the removing of the rock cuttings from the space between the bit teeth, thereby preventing bit balling which is one of the common problems in drilling process. 
2. Lubricates and cool the drillstring: a rotary drillstring generates a considerable amount of heat which must be dissipated outside the hole. The drilling mud helps to cool the drillstring by absorbing the heat and releasing it, by convection and radiation, to air surrounding the surface mud tanks (pits). The mud also, provides lubrication by reducing friction between drillstring and borehole walls. Lubrication is usually achieved by the addition of bentonite, oil, graphite, etc.
3. Control formation pressure: for safe drilling, high formation pressure must be contained within the hole to prevent damage to equipment and injury to personnel. The drilling mud achieves this by providing a hydrostatic pressure just greater than the formation pressure. For effective drilling, the difference between the hydrostatic pressure and formation pressure should be zero. the hydrostatic pressure depends on the mud weight which, in turn, depends on the type of solids added to the fluid making up the mud and the density of the continuous phase. In practice, an overbalance,(Where the pressure in the wellbore in higher than the pressure in the formation), 100 to 200 psi (trip margin) is normally used to provide an adequate safe guard against well kick. The pressure overbalance sometimes referred to as chip hold down pressure (CHDP), and its value directly influences penetration rate. In general, penetration rate decreases as (CHDP) increases. When an abnormally pressured formation is encountered, the (CHDP) becomes negative and sudden increase in penetration rate is observed. This is normally taken as an indication of a well kick.
4. Carry cuttings out of the hole: for effective drilling, cuttings generated by the bit must be removed immediately. The drilling mud carries these cuttings up the hole and to the surface, to be separated from the mud. The removal of cuttings depends on the viscous properties called "Yield Point" which influences the carrying capacity of the flowing mud and "gels" which help to keep the cuttings in suspension when the mud is static to prevent them from accumulating on the bottom of the hole and causing pipe sticking. The flow rate of mud is also critical in cleaning the hole.
5. Stabilize the wellbore and prevent it from caving in: the formation of a good mud cake helps to stabilize the walls of plaster to interior walls (like plastering a room walls to keep them from flaking). The pressure differential between hydrostatic pressure of mud and that of the wellbore stable. Shale stability is largely dependent on the type of mud used To minimise the swelling stresses caused by the reaction of the mud with the shale formations. This reaction can cause hole erosion or cavings resulting in an unstable wellbore. Minimisation of wellbore instability is provided by the "inhibition" character of the drilling mud.. At last it should be noted that the best way to keep a hole stable is to reduce time during which the hole is kept open.
6. Helps in the evaluation and interpretation of well logs: wire line logs are run in mud-fills holes in order to ascertain the existence and size of hydrocarbons zones. Open hole logs are also run to determine porosity, boundaries between formations, location of geopressured (or abnormally pressured) formations and the site for the next well. Hence, the drilling mud must possess such properties that it will aid the production of good logs (Log response may be enhanced through selection of specific fluids and conversely, use of a given fluid may eliminate a log from use. Drilling fluids must be evaluated to assure compatibility with the logging program).
7. Limiting the corrosion of drilling equipment: the drilling mud in most cases will have water that contains dissolved salts as its base liquid. This serves as a medium in which corrosion takes place. If corrosion is suspected, then the cause should be determined and steps taken to prevent damage of the equipment. It has been found that in muds containing oil as the continuous phase, little or no corrosion occurs.
8. Transmit Hydraulic Horsepower to Bit: Hydraulic horsepower generated at the bit is the result of flow volume and pressure drop through the bit nozzles. This energy is converted into mechanical energy which removes cuttings from the bottom of the hole and improves the rate of penetration.

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CLASSES OF LOST CIRCULATION (Mud Losses)

Lost circulation or mud losses when oil gas drilling can be grouped into four classes:

1. Seepage losses: From 1-10 bbl/hr and lost while circulating at the normal drilling circulateng rate

2. Partial losses: From 10-50 bbl/hr and lost while circulating at the normal drilling circulating rate

3. Severe losses: Greater than 50 bbl/hr and lost while circulating at the normal drilling circulating rate. In some cases, no losses may be seen if pumping stops indicating that the ECD is the cause of lost circulation.

4. Total losses: When the mud level in the annulus can not be seen or the hole can not be filled

through the annulus. Total losses usually occur in cavernous formations.

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DRILLMEC PRESENTS HOD, NEW SYSTEM FOR CONTINUOUS FLUID CIRCULATION

Continuous flow of drilling fluids offers many advantages, including well-bottom well pressure control combined with improved blade cleanliness and stability. In the current scenario of the oil market, these features become key requirements for personnel safety, operational efficiency and cost reduction, particularly in drilling environments with very narrow margins with ever-increasing water depths , and well situations characterized by high pressure and high temperature.

HoD (Heart of Drilling) technology is an advanced system for continuous circulation, developed and patented by Drillmec, where an automated control system provides for switching of sludge circulation between the drive head (top drive ) and a lateral opening integrated into each valve (sub) mounted at the top of the drilling lengths before starting the drilling step. A completely self- locking, remote-controlled key locks the opening and closing of the integrated side door with an operation that does not involve any manual action.

When a new length is added to the drill string, a sub mounted on the perforated length, and in the well, is positioned at the rotary table and the automatic key, which links a lateral flow line, is engagement with the sub. Once the key lock hydraulic clamps are securely connected to the sub, the probe staff can move away from the most vulnerable area, delimited by a red perimeter, and handle the rest of the operating sequence by a control panel remote. Acting on the key controls from the control panel, the operator opens the outer cover of the sub side opening, which remains inside the key throughout the operating sequence. When the control system confirms the opening state of the outer cap, the drilling mud stream can be directed by the top drive to the side opening in the sub before unscrewing the top drive from the drill string; after adding a new drilling length, the mudflow can be redirected to the top drive. The flow rate of drilling sludge to the shaft remains constant throughout the entire connection sequence, thus maintaining a dynamic shaft condition characterized by a constant bottom well pressure and continuous drilling of the BHA (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. the drilling mud stream can be directed by the top drive to the side opening in the sub before unscrewing the top drive from the drill string; after adding a new drilling length, the mudflow can be redirected to the top drive. The flow rate of drilling sludge to the shaft remains constant throughout the entire connection sequence, thus maintaining a dynamic shaft condition characterized by a constant bottom well pressure and continuous drilling of the BHA (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. the drilling mud stream can be directed by the top drive to the side opening in the sub before unscrewing the top drive from the drill string; after adding a new drilling length, the mudflow can be redirected to the top drive. The flow rate of drilling sludge to the shaft remains constant throughout the entire connection sequence, thus maintaining a dynamic shaft condition characterized by a constant bottom well pressure and continuous drilling of the BHA (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. after adding a new drilling length, the mudflow can be redirected to the top drive. The flow rate of drilling sludge to the shaft remains constant throughout the entire connection sequence, thus maintaining a dynamic shaft condition characterized by a constant bottom well pressure and continuous drilling of the BHA (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. after adding a new drilling length, the mudflow can be redirected to the top drive. The flow rate of drilling sludge to the shaft remains constant throughout the entire connection sequence, thus maintaining a dynamic shaft condition characterized by a constant bottom well pressure and continuous drilling of the BHA (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. thus maintaining a dynamic shaft condition characterized by a constant bottom drain pressure and continuous BHA drilling (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases. thus maintaining a dynamic shaft condition characterized by a constant bottom drain pressure and continuous BHA drilling (Bottom Hole Assembly). The continuous circulation system HoD can be used both during the drilling phases and in the maneuvering phases.

Some important considerations during the design process have given rise to high safety standards for staff and equipment, ease of integration into the drilling rigs in operation, and the ability to minimize downtime by integrating a maintenance management system in control systems.

All components of the HoD system are designed according to applicable APIs for a working pressure of 7500 psi and a maximum flow rate of 1000 gpm during connection. The side side opening design guarantees a double safety barrier between the pressure inside the drill and the outside during connection to the probe and in the well. Both barriers are independent and have been tested at one and a half times the exercise pressure.

The system is designed to be integrated into ground and sea systems, with the manifold running the sludge flow, the hydraulic unit and the control system integrated in the same frame with a small footprint. This feature provides complete flexibility during installation, safe and fast assembly operations without the need for expensive modifications to the sludge circuit of the drilling rig. The typical installation layout isolates the manifold from the pumping system during the drilling phases. Consequently, the load losses added to the mud circuit are minimized and the duration of the valves in the sludge manifold can be drastically increased. In addition, with the non-pressurized sludge manifold during drilling,

Operations during connection are completely controlled through a secure area on the probe plane or directly from the perforator cabin. Human intervention is only required to engage and remove the automatic key, but the key itself and the associated hinge are not pressurized during such operations. For newly conceived Drillmec systems, where the HoD Continuous Circulating System can be integrated directly into the mud system, a fully automated keypad handling system has also been developed.

Management software provides complete remote control of operating sequences, as well as providing real-time status of each component of the system on the remote control panel. The connection sequence can be performed with a fully automated or semi-automatic routine. In both cases, the control system acquires and processes signals from integrated sensors into the main components of the system, reducing human errors with text messages and alarms. The software also includes a Computerized Maintenance Management System (CMMS) that helps maintain a historical database of operating parameters for each component of the system, plan and monitor maintenance activities, and manage transaction reports.

After successfully completing rigorous hydrostatic and functional testing programs, the HoD Continuous Circuit System has recently completed field application in a deep pit for the confinement of a ground field in Europe. In particular, the HoD® Continuous Circulating System has been used to perform 12-inch and 1/4 phase drilling with the objective of maintaining constant ECD ("equivalent circulation density") density during connections, improve drill and hole battery cleaning and stability during drilling and drum extraction from the well. For this application, "ad hoc" designed and built for acid environments containing H2S,

The entire HoD package showed excellent results in terms of functionality and reliability of components in extreme working conditions and characterized by high specific weight sludges and high hydraulic parameters. Continuous circular connections were carried out in complete safety with a maximum pressure of the plant probe manifold of 4,200 psi and a maximum flow rate of 750 gpm.

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Mud Pump for Oil Gas Drilling

A mud pump is a large pump used to move heavy drilling fluid, known as mud, into a hole when drilling or oil extraction. The pump circulates the mud pushing it down into the hole and then move on again. Sludge pumps are pumps, which means they use oscillating pistons or pistons to move the fluid.

A mud pump is just one effect pump, so fluid moves in one direction. A hole, or well, was exerted in the soil, and the mud was pushed from the mud pump-down pipes to the bottom of the hole. The pressure then pushes the mud to the annulus, or the space surrounding the pipes.

The "mud" used is oil extraction consisting of emulsified water or oil, clay and chemicals. For safety reasons, it is tailor-made for the special chemical conditions of the drilling. Its purpose is to float rock cuttings from the hole, clean the bottom of the hole and cool the drilling equipment. It also acts as an initial barrier in the event of an outbreak by resisting pressure from any fluid within the rock that could enter the good.

Most modern mud pumps are triplex style pumps, which have three cylinders. Older, or developing, oil platforms may still use duplex pumps with only two cylinders. Some recent pumps have up to six cylinders.

A mud pump is a key piece of machinery in the oil extraction process. In a drilling rig, the drilling process starts with a hole drilling drill hole in the ground. After a hole has been perforated, a tube is inserted into the well to ensure it maintains its shape and structure. Within this casing, a smaller tip is used to drill deeper, and another tube, said casing, is inserted into the hole. It is common for up to five holes, each slightly smaller than the next, to be bored during oil extraction.

Like the rock drill, the mud pump moves such cuts the good. The rock cuttings are subjected to a "shaker" that removes them from the mud. The mud is then reused by the mud pump. This process continues until the well is perforated in its depth.

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Drill String

A drilling battery is a tool that is used to drill deep hole holes in the ground in order to locate and extract oil or other resources. The construction of this device allows for rapid drilling and at the same time to extract large amounts of rock and mineral from a digging site. Mud is also injected down through the drilling battery to cool the tip while it is moving and to soften the surface that is boring through, reducing the likelihood of an improper cutting and increasing the overall bit time. A medium drilling string extends 15,000 feet (4,572 m) into the ground once mounted on the ground and up to 30,000 feet (9,144 m) or more when built offshore,

Within the drill battery assembly, there are four main components: lower hole mounting (BHA), transition tube, drilling rods and drill bit subs. The BHA is the stabilizing system that consists of the same tip and massive heavy rods that apply enormous amount of force down to facilitate drilling. A passage pipe connects the heavy rods to the actual drill pipe, and together these two components provide the necessary stability to ensure that the tip remains solid at such drastic depths. Drilling rods are also the majority of the length inside a drilling column, so they must be constructed using specific chemical compositions and forged at extreme temperatures.

Most components within a drill column are constructed at 31 or 46 feet (9.4 or 14 m) intervals, and two to four of them are combined to do what is termed a stand. Each substrate is then lowered into the ground before drilling initiated, in order to ensure that the drill always stays within perfect alignment. Similarly, they are removed from the ground before the drill is extracted.

Sometimes, the stands can get stuck and become difficult to remove, and specialized recovery tools called drill string jars and resonant vibrators are used to remedy this otherwise difficult situation. These methods are normally implemented by experienced oil companies. Technological advances discovered during the mid-20th century have made drilling strings much easier to handle.

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Mud Gun

A mud gun is a device used to shake the mud on a drilling rig. More than a nozzle of a gun, a mud gun is connected to a pump to circulate the drilling mud and prevent solids from settling into the mud tank. The mud mixture is sucked into a tube by a powerful pump and ejected into the sludge tank to be pushed through the mud gun nozzle. The process is similar to how a jet of water works on a power washer.

Perforating mud is a damp substance that resembles a thick clay and is used to cool the drilling head and to carry the surface drilling remains in drilling well and oil or gas drilling operations. The mud is recycled by passing through a series of filters or screens as it is circulated in the hole and back into the mud tanks on the drilling. To keep the mud as fluid as possible, a mud gun is used to keep the tank agitated and mixed. Mud is made by mixing water or oil with a clay substance that also contains many other chemicals in a large reservoir called the mud tank on a drilling rig.

The type of mud used during drilling depends on the type of drilling that is performed. The mud gun is the same for any kind of mud used. Often made by adding a nozzle type on a piece of pipe, mud gun works like positioning an inch above the end of a water pipe. This is pressurized mud in the tank, making it a mixing action. Exhausting the mixture also helps in removing debris from the mixture as it is filtered through the various screens in the tank.

The viscosity of the mud is very critical, with a thin blend being able to keep the cuttings from the suspended drilling head until it reaches the surface and can be shielded from the blend. A blend that is too thick can waste profits and can also slow down drilling productivity. Another function of the mud gun is to keep the suspension of the puncture cuttings so that they can be removed at the first pass through the screens. Talees that are not removed at first pass through the screens can break into smaller pieces that are more difficult to remove from the mix.

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Mud Tank

A mud tank is a large container used to contain drilling fluid reserves, also known as drilling mud, for a drilling rig. Drilling fluid is used to reduce the friction on the drilling components to allow them to work faster and faster with less risk of breaking. Many companies produce and restructure mud tanks of various shapes and sizes for industrial use, and entrepreneurs specializing in cleaning tanks and other drilling equipment are also available. The cost for tanks and associated services varies greatly, especially when personal designs are involved.

Historically, wells in the soil near a well have been used to contain sludge, and mud tanks are sometimes referred to as mud wells in a reference to this. A modern mud tank is a large container, usually open over and divided into different compartments. In some situations, a plan can be used to reduce the risk of worker accidents, with a parapet and a gangway, allowing people to look into the tank to control the level and consistency of the drilling fluid.

New fluid can be periodically added, and components can be mixed in to modify the formulation if it is deemed necessary. Perforation mud acts as a lubricant and coolant and the demands placed on it are very high. It is essential to maintain a constant flow in a puncture site to prevent stoppages. If a plant runs out of fluid, closing it temporarily can be extremely expensive.

Several drilling fluid blends are used, depending on the type of drilling, the geology, and the equipment in use. The fluid tank to pump mud on and through the drill. Mud baths can be set to receive recycled drilling fluid, a common practice in many sites. In these situations, the fluid is pumped from the puncture site, passed through a series of tanks to separate the fluid from rocks and other debris, and then routed back into a mud tank.

These tanks can eventually become in-crusted with drilling mud and can be corroded by fluid components. For this reason, waste companies and periodically clean their tanks with high pressure cleaners and other equipment. A large company run their own mud tank cleaning and maintenance, while smaller companies can call a company to clean their mud tanks and prepare them for continuous service in the field.

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Mud Weight in Drilling Operation

Mud weight is a term used to express the amount of drilling fluids used in sinking wells, especially in the exploration and extraction of crude oil industry. The weight of the mud of a drilling fluid is generally expressed in pounds per gallon (ppg), even if more than one unit of measurement is used, including kilograms per cubic meter (kg / m 3). The drilling fluids are used to cool the tips, to remove drilling debris from the shaft, and to avoid collision wrap. A mud scale, consisting of a level sliding scale, is generally used to determine the weight of the mud.

Considering the rugged environment that generally surrounds pit drilling, the process is even more complex and delicate. Tips work at great depths and are subject to extreme conditions, like the other components involved in the process. One of the elements used to reduce the voltage on these components is the drilling fluid within which the tip operates. These sludges, as are commonly known, cool the tip, and help in the removal of drilling debris. They also suspend cuts during breaks in the drilling process and hydrostatic pressure control inside the well.

Several means are used as drilling sludges, including water, oil, and gas-based fluids. The type of drilling mud used in a particular drilling site is carefully formulated to meet specific environmental conditions with different wells, rarely using the same mixture of mud. One of the most important variables in formulating drilling fluids is mud or fluid density. Wrong mud weight values ​​can cause several serious problems, such as circulation leakage. The density of these fluids is controlled by the addition of barites or, less frequently, halite and calcium carbonate.

A specially designed sliding scale known as a mud equilibrium is used to calculate the weight of mud drilling fluids. This instrument consists of a cursor equilibrium beam equipped with a type bubble leveling system. A sealed container is attached to one end of the beam where the sample of the drilling fluid is placed. The slider is moved along the bar to determine the density of the fluid.

Mud weight values ​​are generally expressed in pounds per gallon or ppg. Other units are used if, including kg per cubic meter (kg / m 3) and grams per cubic centimeter (g / cm 3). The weighing and test procedures used to measure sludge weight values ​​are set out in a set of globally recognized standards published by the American Petroleum Institute.

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CONVENTIONAL OIL

Definition Oil is a hydrocarbon formed over thousands of years from the decomposition of dead plants and organisms. Intense heat and pressure on this material triggers a reaction, which leads to the creation of oil

Conventional oil is a term used to describe oil that can be produced (extracted from the ground) using traditional drilling methods.  It is liquid at atmospheric temperature and pressure conditions, and therefore flows without additional stimulation.  This is opposed to unconventional oil, which requires advanced production methods due to its geologic formations and/or is heavy and does not flow on its own. 

You may have heard of these terms used to distinguish different types of oil:

​Light vs. Heavy - this refers to the density of oil and its ability to flow.  Lighter oil can be refined with minimal processing due to higher fractions of light hydrocarbons.

Sweet vs. Sour - this refers to the sulphur content of the oil, sulphur must be removed prior to refining.  When oil has sulphur greater than 0.5% it is referred to as "sour."

Because of these variations, oil quality is a spectrum and the distinction between conventional and unconventional is not always black and white. Generally, however, if traditional drilling techniques are used in the oil production it is considered conventional regardless of its physical properties.

Conventional oil is produced using drilling technologies that utilize the natural pressure of an underground reservoir.  Production of a conventional oil well has four main phases[2]:

Exploration: Geological exploration is a series of technologies that are used by geologists and geophysicists to predict the location and extent of underground oil reservoirs.

Drilling: Once a reservoir has been located with sufficient certainty, a drilling rig is used to bore a hole from the surface to the oil reservoir.  Piping is then inserted, allowing the oil to be brought to the surface.  Some of the oil in the reservoir will be produced using the natural pressure of the reservoir.  

Pumping: Gradually the pressure of the well will decrease as oil is produced. At this point a pump will be connected to allow the remaining oil to be extracted.

Abandoning: After all the economically viable oil has been extracted from the well, the well is filled with cement to prevent any hydrocarbons from escaping and a special cap is placed over it to protect the area[3].

Context

Conventional oil tends to be less expensive and complex to extract than unconventional oil due to the routine nature of the production techniques.  This oil is also the most valuable in global markets because it requires the smallest amount of processing prior to refining to create value-added products. Consequently, many of our global conventional oil supplies have already been extracted, limiting the availability of these source for future extraction[2].

Generally, drilling and well abandonment are well-understood and regulated processes but there are always risks with such industrial operations. In drilling, pressure must be regulated carefully to avoid accidents and immediate environmental impacts like land disturbance must be carefully monitored.  After abandonment, well leaks can occur if improper procedures were taken.  

As with all fossil fuel production, there are also concerns with greenhouse gas emissions from their combustion 

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9 Distinct Mud Systems

For mud to manage its many tasks, a broad range of different fluid systems have been developed. 9 distinct mud systems are defined here. 

The first seven are water-based, while the eighth is oil-based. The ninth category is a specialized one in which air or gas is the continuous fluid. 

The 9 categories are:

1. Non dispersed. These may consist of spud muds, natural muds and other lightly treated systemsgenerally used for shallow wells or top-hole drilling.

2. Dispersed. At greater depths or where hole-conditions may be problematic, muds are often dispersed, typically by means of lignosulphonates or other deflocculants. These and similar products are also effective filtrate reducers.

3. Calcium treated. Divalent cations such as calcium and magnesium, when added to a mud, inhibit the swelling of formation clays and shale, and are therefore added to control sloughing shale, hole enlargement and to prevent formation damage. Hydrated lime, gypsum (calcium sulphate) and calcium chloride are principal ingredients of calcium systems. Gyp systems (note: Gyp = gypsum) usually have a pH of 9.5 to 10.5 and an excess gyp concentration of 2 to 4 lb/ bbl; Lime systems have an excess lime concentration of 1 to 15 lb/bbl and a pH of 11.5 to 12.0.

4. Polymer. Muds incorporating long-chain, high-molecular-weight chemicals are effective in increasing viscosity, flocculating muds, reducing filtrate loss and stabilizing the formation. Various types of polymers are available for this purpose, including Bentonite extenders. Bio polymers and cross-linked polymers are also used and have good shear-thinning properties at low concentrations.

5. Low solids. This includes systems in which the amount and type of solids are controlled. Total solids should not range higher than about 6% to 10% by volume (and clay < 3% by volume). One primary advantage of low-solids systems is that they significantly improve the rate of penetration.

6. Saturated salt. Include several groups: Saturated salt systems have a chloride ion concentration of 189 000 ppm. Saltwater systems have a chloride content from 6 000 to 189 000 ppm, and at its lower level are usually referred to as brackish or seawater systems.

7. Workover. Completion and workover fluids are specialized systems designed to minimize formation damage, and be compatible with acidizing and fracturing operations (acid soluble) and capable of inhibiting swelling clays that reduce formation permeability. Density is obtained  through dissolved salt to avoid long term settling.

8. Oil/synthetic. Oil-based fluids are used for high temperature wells, deviated holes and wells where pipe sticking and hole stabilization is a problem.

 They consist of two types of systems:

1) Invert emulsion muds are water-in-oil fluids and have water as the dispersed phase and oil as the continuous phase. They may contain up to 50% water in the liquid phase. Emulsifier (commonly fatty acids amine derivatives, high-molecular-weight soaps), and water concentrations are varied to control rheological and electrical stability;

2) Synthetic fluids are designed to duplicate the performance of oil-based muds, without the environmental hazards. Primary types of synthetic fluids are esters, poly alpha olefins and food grade paraffin. They are environmentally friendly, can be discharged offshore and are non-sheening and biodegradable.

9. Air, mist, foam and gas. Four basic operations are included in this specialized category according

to the IADC. These include:

1) Dry air drilling, which involves injecting dry air or gas into the wellbore at rates capable of achieving annular velocities that will remove cuttings;

2) Mist drilling involves injecting a foaming agent into the air stream, which mixes with produced water and lifts drill cuttings;

3) Stable foam uses chemical detergents and polymers and a foam generator to carry cuttings in fast-moving air stream;

4) Aerated fluids rely on mud with injected air (which reduces the hydrostatic head) to remove drilled solids from the wellbore.

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Horizontal Well

What is 'Horizontal Well'

A well that is transformed into horizontal in depth, providing access to the oil and gas reserves in a wide range of angles. horizontal wells has grown in popularity during the 1980s, such as natural gas and oil exploration turned away from less productive than vertical wells. This type of well is used to gain access to conventional sources of reserves.

horizontal wells became economically viable in 1980, such as computerized mapping and directional localization and holes made access difficult to reach deposits of oil and natural gas, easier and more convenient. Of the three categories of drilling horizontal rays - short, medium and long - average drilling is more prevalent

horizontal wells tend to be much more productive than vertical wells. This is because they allow a single well to reach more points, without the need for further vertical wells. This makes each far more productive individual, since most tanks are more productive throughout their horizontal axis that their vertical access. horizontal wells also reduce the risk of introducing water or gas intrusions in the case of oil exploration.

While more productive than vertical wells, horizontal wells tend to be more expensive. Although this cost has decreased over the years tends to be a learning curve associated with exploring new types of fields, especially for developers and inexperienced.

horizontal wells usually starting with the drilling of a vertical well. Drilling vertically allows engineers to examine rock fragments at different levels, in order to determine where the reserves are located. horizontal wells are then "kicked off" from the auction primary vertical, and enter the tank to an "entry point" after the drilling of an arched hole.

The extraction of oil and gas from conventional sources, such as shale rock formations, often requires the use of horizontal drilling technologies.

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Vertical Well

A well that is not converted into horizontally in depth, allowing access to the oil and gas reserves are located directly below the point of surface access. Historically, natural gas and oil exploration has involved the use of vertical wells because the directional drilling technology was expensive and complicated. Drilling of vertical wells is considered a conventional method.

Vertical shafts differ directional wells, such as horizontal wells, deep because they require the use of directional drilling. This makes them less expensive to develop, although less productive because of their limited range.

While vertical wells may be less complicated to bring in line of directional wells, their limited angles make them less able to reach a wider part of the underground area. Because a vertical shaft can access only the reserves of petroleum and natural gas directly under, making a large manufacturing industry requires the drilling of many vertical wells. They are especially handy in case of reserve thin layers located over a wide area. Since a vertical well can be drilled in a single direction, the exploration company must estimate the most productive portion of the reserve from the beginning; a vertical drilled well can go right through the reserve, drawing only a portion of the available energy.

horizontal wells usually starting with the drilling of a vertical well. Drilling vertically allows engineers to examine rock fragments at different levels, in order to determine where the reserves are located. horizontal wells are then "kicked off" from the primary vertical shaft.

The extraction of oil and gas from unconventional sources such as shale rock, often requires the use of horizontal drilling technologies because the source can be executed in the horizontal direction. If the reserves are located in a residential area, well vertical drilling would require both the displacement of residents or require them to live next to a tower.

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Directional Drilling

A drilling technique in which a well is bored to multiple angles. Directional drilling refers more often for the non-vertical angle drilling, including horizontally. It is used both to recover oil and natural gas underground, and is useful in situations where the shape of the tank is abnormal. It is also used to adjust pressure created by the gas in mines (degassing).

As a technique, directional drilling allows oil and gas operators to approach a potentially productive zone, without the need of a well to be drilled directly above that area. A central site can serve holes that reach more and more to non-vertical angles positions. This reduces the number of facilities and which must be constructed and maintained. With no need to build new wells may also lead to the exploration of smaller fields that would otherwise be uneconomical.

Early involved directional drilling tip of the tip with a different vertical angle, resulting in a straight line away from the well. The modern drilling techniques allow the use of tips that can bend; allow engineers to adjust the direction of the well is drilled to a certain extent. This can be accomplished through the use of hydraulic jets

Directional drilling is used in the development of mines, in order to reduce the risk of potentially dangerous gas breakages. In-mine drilling techniques allow companies to create holes in advance of my face.

While the basic concepts of directional drilling date back to the 19th century, has become a popular technique such as computer technology has become more common. The toe angle used for bored shaft can be regulated by a computer using GPS signals to pinpoint the location of an oil and gas field. Engineers create the 3D field models to determine the best location for good, and the best approach to the hole to follow.

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What is Drilling Mud

Fluid used in the drilling of wells. Drilling mud, also referred to as drilling fluid is one of drillingknowledge, is used to clear the hole of debris created during the drilling process, to cool the tip, and maintain the pressurized hole. The composition of the drilling mud used in the drilling process depends on the type of hole being drilled and the material to be bore. 

Drilling muds have been used to improve drilling operations for most of modern history. The water was used to smooth the surface material and remove scraps when they were drilled groundwater wells. contemporary drilling activities are much more sophisticated, and wells can reach miles below the surface in order to reach oil and natural gas.

The type of drilling mud used depends on the material drilled through, the technical requirements of the mud performance (viscosity and speed), cost and regulations. One of the primary functions of the drilling mud is to remove the shavings created by the drill hole. Because the wells are so deep it is impossible to remove the debris on the bottom without the use of some form of liquid. specialized Liquids are often used because they have high speed and viscosity, which allows them to move more easily when a drill both materials is in operation and to keep cutting suspended in the liquid when the drill is stopped.

The use of drilling mud, particularly specialized sludge using potentially hazardous chemicals is regulated. Regulations are used to ensure that the waste material is kept away from ground water, rivers and lakes, where pollution could cause the water to be safe and unusable for the public. Used drilling mud and sediment created during the drilling process can be used as pool treatments pumping in large pools.

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What Mud Fluid in drilling for ?

The drilling mud are primarily for:

1. to lubricate and cool the drill drilling that would otherwise warming, for the friction with the rock , quickly arrive at break.
2. Pipe on the surface of earth and rock fragments (commonly known by the English technical term for cutting ) produced by the action of the chisel.
3. Exercise a counter pressure hydrostatic hole at the bottom and along its walls discoveries (ie not tubate) to contain the leakage of the fluid layer and to avoid the risk of kick or in more severe cases the real eruption of the well.
4. Supporting walls of the hole (thanks to the pressure exerted by the hydrostatic load), in order to prevent landslides and loss of the punched hole. This feature is said that the mud must do "panel" that must practically "plaster" the walls of the well.
5. The most important properties of the drilling mud must be the "thixotropy", namely the characteristic that, at the time that the circulation in the pit stops, the sludge to be gelled fluid holding imprisoned in suspension the cutting resulting from the drilling. Otherwise these debris, stopping the circulation of the fluid, would fall to the bottom hole imprisoning the chisel and the "battery terminal part" drilling.

In the oil exploration monitoring geological of drilling muds, by analyzing the microscope of fragments of rock it allows to recognize the stratigraphy of the perforated rocky succession and provides the first indications of the characteristics petrophysical properties of the reservoir . 

Furthermore, the analysis by means of gas chromatographs , of the fluids contained in the outgoing mud from the well, provides important clues for the detection and recognition of mineralized levels to hydrocarbons.

In some cases similar muds are used temporarily to support the walls of trenches or over works of excavation of civil engineering within loose soil, prior to the implementation of their final completion.

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Drilling Rig

A drilling rig is a machine that creates holes in the earth sub-surface. Drilling rigs can be massive structures housing equipment used to drill water wells, oil wells, or natural gas extraction wells, or they can be small enough to be moved manually by one person and are called augers. Drilling rigs can sample sub-surface mineral deposits, test rock, soil and groundwater physical properties, and also can be used to install sub-surface fabrications, such as underground utilities, instrumentation, tunnels or wells. Drilling rigs can be mobile equipment mounted on trucks, tracks or trailers, or more permanent land or marine-based structures (such as oil platforms, commonly called 'offshore oil rigs' even if they don't contain a drilling rig). The term "rig" therefore generally refers to the complex of equipment that is used to penetrate the surface of the Earth's crust.

Small to medium-sized drilling rigs are mobile, such as those used in mineral exploration drilling, blast-hole, water wells and environmental investigations. Larger rigs are capable of drilling through thousands of metres of the Earth's crust, using large "mud pumps" to circulate drilling mud (slurry) through the drill bit and up the casing annulus, for cooling and removing the "cuttings" while a well is drilled. Hoists in the rig can lift hundreds of tons of pipe. Other equipment can force acid or sand into reservoirs to facilitate extraction of the oil or natural gas; and in remote locations there can be permanent living accommodation and catering for crews (which may be more than a hundred). Marine rigs may operate thousands of miles distant from the supply base with infrequent crew rotation or cycle.

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DRILLING OR DRILLING TOWER

The derrick or drilling tower is a steel tower used in rigs underground.

Its purpose is structural, because it serves to store the drilling rods during the same, but also withstand the stresses of the injection system of the drilling mud , the voltages of the ' winch and the weight of the top drive . 

The main and almost exclusive use, it has the oil rigs, but also can be wrought in plants (increasingly large caliber) that deal with the drilling for geothermal purposes or for the construction of water wells.

The construction of drilling rigs is regulated by the rules API (American Petroleum Institute), and applies worldwide.

The rules stipulate the API building materials that must be used depending on the application, the construction and design criteria, but also the application of each tower of a type plate, that brings its serial number, the year of construction , the manufacturer's name, the availability of methods of the manufacturer, the place of construction, the steel used to achieve tensile properties and the number of the rule that respects.

The drilling towers are of different types, in function of the system in which they must work. They can also be simple telescopic tubes, in the case of plants fast moving , ie drilling rigs that are easily and quickly be moved from one site to another. As a rule, the fast moving , are constituted by commercial means ie trucks with flatbed modified to accommodate the drilling tower, which as stated is of the telescopic type. In this case the tower is not mounted, but only controlled with a system of hydraulic jacks that allow it to be extended to its maximum length. Before performing this operation, however, the truck must have been well fixed to the ground, and the tower must be in a perfectly vertical position, as well as constrained.

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Drilling for oil

After the drilling of one exploration well, designed to confirm the presence of oil and other wells are drilled to delineate the deposit. Most wells are drilled using a drill bit, a cutting tool on the end of a set of drill pipe supported by a metal tower called derrick. The drill bit is rotated. The drilling speed varies greatly depending on the nature of the rocks traversed. Of the "drilling mud" (a mixture of clay with water and chemicals) is continuously injected inside the stems. It goes back into the space between the rods and the walls of the well. The mud serves to cool the drill bit and remove the cuttings. Back on the surface, the slurry is filtered and reinjected into the well. Analysis of the debris can qualify the rocks traversed. 

Advances in drilling techniques now allow the completion of drilling small diameter boreholes deviated (obliques), horizontal multidrains, etc ... This progress has allowed the exploitation of deposits that were previously unprofitable, for technical reasons and / or economic. 

For offshore deposits (offshore), is generally used for pumping platform independent. Special ships can be used to exploit deposits of lower capacity.

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Ratio of water to oil (OWR)

Oil / water ratio Is A number Representing The fraction of liquid oil basis and Water in the mud. In general, It Is a Relationship Between The percent oil in The Liquid Phase And The percent water in liquid phase.

 

 

The Number Can Be Determined by autoclaving samples of mud.

 

We Can OWR calculate this equation as per below :

 

Percent oil in liquid phase = 100x % by vol ÷ of oil (% by vol of oil +% by vol of water )

 

Percent water in liquid phase = 100x % by vol of water ÷ (% by vol of oil +% by vol of water )

 

Can you learn more about oil water ratio (LWR) calculation from drillingformulas.com > Calculate Water Oil Ratio

 

This figure is very vital Because it tells us How Much Water in the mud . If You Have Deviated from excessive water mud WAS specification , You Will Have Problems SEVERAL face with high PV , YP high , high pressure pumping , fluid bad property loss ,etc. . Because Water in the oil base mud Will act like solids . What's more, as you know water and oil are not compatible with each other so when water is added into the system ,you must add emulsifiers to maintain a solid emulsion in the mud .

 

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Advantages of oil-based mud

mud is oil based drilling mud which has oil as the external phase. mud is oil based invert emulsion because the external phase is oil and the internal phase is water. Water oil ratio range of 50% oil: water 50% oil 95% to 5% water. Currently, many operators prefer to use oil-based mud instead of water based mud .

 

 

You may wonder why the oil companies nowadays many use this type of mud.Regardless, I summarize it for you.

• The oil-based mud is good for the environment at high temperature, because the base fluid is oil.

• It is good for drilling in the shale formation, because it does not react with clay formation leading to an unstable shale.

• It usually creates sludge cake cutting. It's really good because you can reduce the risk for pipe stalemate.

• It can be treated and reused. Through the mud for long term may reduce the overall cost of drilling muds.

• Base oil as the external phase is so good lubricant significantly reduce drilling torque.

• It is good to use in some areas where you're faced with the problem hydrate such as drilling in deep water.

• Generally, when drilling mud base oil dipstick hole can be easily achieved.

 

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