Well recompletion can bring a different reservoir interval into production through an existing well. For this change of producing zone, the design must solve two connected problems: exclude the old interval as intended and provide a usable production path from the new one. Whether the tubing can remain installed depends on the actual completion, its …
Water shutoff in oil wells aims to reduce unwanted water production by interrupting the responsible flow path or changing how water moves through the treated interval. Choosing a plug, cement treatment or chemical system comes after identifying that path. The decision must also account for oil that may be lost when an interval is isolated …
Deciding whether a producing well has a tubing leak or packer leak requires more than a rise in tubing–casing annulus pressure. Both can provide communication with the same annulus, while other completion paths, deliberately applied pressure and temperature effects can produce similar surface observations. Diagnosis requires the actual completion layout, a pressure and operating history, …
Pulling production tubing means recovering the production string from an existing well. The packer may come out with it, remain set while the tubing seals are withdrawn, or require a separate retrieval operation. The result depends on the installed tubing-to-packer connection, the packer’s recovery design and the condition of the equipment. [1, 2] Start with …
The key difference in a workover rig vs drilling rig comparison is the job the equipment package must perform. Drilling requires a system for making new hole. By comparison, workovers require access to an existing completion, with enough lifting, rotation and pumping capability for the planned operation. However, the categories overlap. A drilling rig can …
Plunger lift removes accumulated liquid by sending a free-travelling plunger up the production tubing with a liquid slug above it. During this lift, gas below the plunger supplies the energy. After the liquid reaches surface, the well produces gas before the next cycle. The plunger helps separate the lifting gas from the liquid and reduces …
Two wells need repairs. In the first, a failed gas-lift valve sits in a side-pocket mandrel designed for wireline retrieval. In the second, by contrast, the job is to recover and replace a damaged joint of production tubing. Although both are completed wells, only the second job requires equipment that can pull and handle the …
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 …
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, …
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] …