Electric Submersible Pump in Oil Wells: How an ESP Works

An electric submersible pump (ESP) is an artificial-lift system that adds energy to the produced fluid downhole. You may also see the name written as electrical submersible pump. A power cable feeds an electric motor, the motor turns a shaft, and a series of centrifugal stages raises the fluid pressure between the pump intake and …

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Gas Lift in Oil Wells: Continuous vs. Intermittent Lift

Gas lift in oil wells uses compressed gas to help reservoir fluids reach the surface. In a conventional tubing-flow completion, gas travels down the space between casing and tubing, crosses into the tubing through a valve, and returns with the produced fluids. The entry point is therefore in the wellbore. Reservoir pressure maintenance, in contrast, …

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Nitrogen Lifting With Coiled Tubing: How Well Kickoff Works

Nitrogen lifting with coiled tubing can restart a well when a column of liquid holds enough pressure against the producing interval to prevent inflow. The coiled tubing (CT) carries nitrogen down to a selected depth. The returning column then weighs less. As bottomhole pressure falls, reservoir fluid may begin to enter the well. [1], [2] …

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Drill Collar vs Drill Pipe: Key Differences

Drill collar vs drill pipe: the key differences are construction and function. Drill pipe forms the long connection between the surface equipment and the bottom hole assembly (BHA). Drill collars concentrate weight and stiffness within the BHA. However, both components transmit torque, carry axial loads and provide an internal passage for drilling fluid. [1],[2] This …

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Matrix Acidizing: Sandstone & Carbonate Guide

Matrix acidizing is a stimulation treatment that places a reactive acid system into reservoir pore space while keeping injection conditions below the relevant formation-fracturing limit. Its purpose depends on the rock and the restriction. In sandstone, the target is commonly susceptible material impairing near-wellbore flow. In contrast, dissolution in carbonate rock can create channels that …

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Formation Damage: Causes, Diagnosis & Prevention

Formation damage is a reduction in the ability of reservoir rock near a well to transmit the fluid being produced or injected. It can result from blocked pore throats, changes in sensitive minerals, or changes in fluid saturation and relative permeability. Consequently, a damaged interval may need more pressure difference to deliver the same flow …

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Pipe Handling Equipment: Types, Uses & Selection

What Is Pipe Handling Equipment? Pipe handling equipment is the group of tools and machines used to transfer, lift, support, guide, connect and rack jointed tubulars on a drilling rig. The group includes transfer equipment between the pipe racks and drill floor. Other tools handle tubulars at well center and in the setback area. The …

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Well Integrity: Barriers, Testing and Monitoring

What Is Well Integrity? Well integrity is the condition in which a well contains its fluids and prevents unintended movement into other formations or the surface environment. Managing it means designing, verifying, monitoring and maintaining the barriers, equipment and working practices needed to preserve that containment throughout the well’s life. [1] A well integrity assessment …

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Coiled Tubing Fatigue: Calculations & Life Tracking

Coiled tubing fatigue is the progressive damage caused by repeated loading of the tubing. During normal deployment, the reel and guide arch repeatedly bend and straighten the tube beyond its elastic range. Internal pressure, tubing geometry and the history of each section influence how quickly that damage develops [1, 2]. Consequently, two strings with the …

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Coiled Tubing Sand Cleanout: Fluids & Calculations

Coiled tubing sand cleanout removes accumulated fill by loosening it, entraining it in a circulating fluid and carrying it through the return path to surface. In addition, a successful treatment needs enough transport capacity throughout the well, a fluid compatible with the completion and formation, and operating pressures that preserve the planned circulation system. However, …

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