Hydraulic Fracturing

Hydraulic Fracturing

Simply, What is Hydraulic Fracturing & What is the Fluid used for this purpose ??!! Hydraulic fracturing is consider to be a well stimulation technique used especially in low permeable reservoirs. To overcome formation damage and increase the production rate. It is considered the 1st step in the water injection process by opening fractures in the reservoir formation to inject water through. During fracturing, a special kind of fluid is needed to fracture the formation. It should have the flowing characteristic & must be compatible with the formation. This fluid has high viscosity to carry the Proppant. The Proppant is the main special additive in the fracturing fluid. It helps to keep the fractures open. It mainly consists of linear gel, cross linker and breaker. Linear gel is responsible for…
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Offshore rigs

Offshore rigs

The offshore rigs generally carry out the same operations as the onshore ones. They just differ in the place of drilling depending on the water depth, and the desired mission. The Drill ship is one of the offshore rigs. It is mainly used in the exploration phase, but it can be also used in the drilling process. Recently, the companies equipped them enough to be able to carry out dual missions such as drilling and casing handling. On each Drillship, there is an opening located on the base of the hull. This opening is simply called "Moon Pool"as shown in the below figure. The drilling equipment can pass through it. The below figure shows the main components of the Drillship. The drillships should be maintained fixed on the desired location…
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Journal Angle

Journal Angle

Journal Angle: It is one of the design factors for the Tri-cone Roller Cutting Bits. It is defined as the angle of the pin formed by a line perpendicular to the axis of the journal and the axis of the bit. Journal angle takes different values based on the type of formation. Examples:  Soft Formations: journal angle (33).  Medium Formations: journal angle (34 – 36).  Hard Formations: journal angle (39).
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Gas Solubility “Rs”

Gas Solubility “Rs”

Gas Solubility "Rs": The gas solubility "Rs" is defined as the number of standard cubic feet "scf" of gas dissolving in one stock-tank barrel "STB" of crude oil at a certain pressure and temperature. The solubility of natural gas in crude oil is a strong function of the pressure, temperature, API gravity, and gas gravity. For a particular gas and crude oil existing at a constant temperature, the solubility increases with pressure until the saturation pressure is reached. At the saturation pressure (bubble-point pressure), all the available gas is dissolved in the oil and the gas solubility reaches its maximum value.
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Pumps

Marketing -3 R&D SPE -3 In Oil Fields, Pumps are used to pump the Drilling Fluids "OBM or WBM" into the well-bore through the Drill String. The number of used pumps is based on the required flow or pumping rate of drilling fluid. At least, there must be one Primary pump and one Back-up pump to be used in case of breaking down. There are mainly two types of these pumps: a) Duplex Pumps consisting of Two Pistons "Cylinders" ----> (Double Acting "Two Inlets-Two Outlets") b) Triplex Pumps consisting of Three Pistons ----> (Single Acting"One Inlet-One Outlet) This Gif shows the difference in acting between One way piston "Single acting" used in Triplex Pumps and Two Way Piston "Double Acting" used in Duplex Pumps. The left one is the single…
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Duplex pump

Duplex pump

Duplex pump is a pump used in oil fields to pump the mud from the surface to the well-bore through the Drill String. It consists of two pistons. It has higher flow rate than the single pump because of not having a dead spot in the pump stroke. However, it is considered to be less efficient than the triplex pump. As one piston is finishing its stroke cycle, the other one would start its stroke. Working by this mechanism, it can keep large flow rate of pumping without a break. The below figure shows the formula used to calculate the flow rate for this pump.
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Drilling rig

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 .
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Determining the Casing Setting Depth

Determining the Casing Setting Depth

What are the primary considerations in determining the Casing Setting Depth? 1-Lost circulation zones (should be planned to be done from bottom to top of the well) 2- Differential sticking (should be planned to be done from top to bottom) 3- Abnormal formation pressure (especially in the deep wells) What are the required pressures to determine the Casing Setting Depth? 1) Formation pressure 2) Fracture pressure 3) Hydro static pressure including a- pressure to overcome the formation pressure b- A trip margin in mud to control swab pressures c- An equivalent increase in the mud weight to determine the surge pressure d-safety factor  
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Cement additives

Cement additives

Cement additives are added to the cement to improve the properties of cementing slurry. They are mainly divided into many kinds according to the associated effect. The following are the main four additives. A) Accelerators are used to increase the early strengthen time. They are useful at shallow depths with temperatures less than 100F to decrease the time into 4 hours. ( e.g. sodium metasilicate & sodium chloride) B) Retards are used to increase the pumping time of slurry. They are mainly affect the viscosity. (e.g. lignosulfonates) C) Extenders are used to decrease the induced hydrostatic pressures on the weak formations by allowing the addition of more water to the slurry to lighten the mixture and keep the solids from separating. (e.g. bentonite) D) Pozzolans are added to portland cement…
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Directional drilling

Directional drilling

Directional drilling is a vital technique in petroleum industry. It has mainly three different profiles. The first configuration is "Build and Hold" where the well is drilled vertically until it reaches the "kick off point (KOP)". Then, the angle is built up to reach the required inclination. In the tangential section, this inclination is maintained reaching the target zone. This technique is mainly used to reach a target zone with low depth and a huge horizontal displacement. The second configuration is "Build Hold and Drop" which is similar to the first type, except in the tangential section, where the inclination angel is reduced until it reaches the target zone. This technique is used when the target zone has a huge depth with low horizontal displacement. The third configuration is "Deep…
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