The well productivity index puts a production rate beside the pressure drawdown required to obtain it. That makes it useful after a workover: a higher rate may reflect better inflow, but it may also reflect a lower flowing bottomhole pressure with no change in inflow capability. The comparison needs both rate and pressure, measured or …
A clear collar response can still leave a workover tool at the wrong depth. The response must belong to the intended collar on an accepted reference, and the tool’s working point may be several metres away from the sensor. A casing collar locator supports depth correlation; the completed calculation must carry that reference to the …
Oil well swabbing deliberately removes liquid from the production tubing to reduce the liquid column opposing formation inflow. A wireline-carried cup assembly lifts liquid toward the surface, and the resulting pressure change may help a completed well start flowing. Recovering liquid, observing formation inflow and demonstrating sustained production are three different findings. [1, p. 449] …
Water coning in oil wells occurs when production drawdown draws underlying water upward toward the producing interval. The resulting water production may justify a change in how the well is operated or completed, but it does not automatically identify a repairable defect. A workover acts on a particular completion or flow path; coning develops within …
A velocity string gives produced gas a smaller passage through which to carry liquid. That can help a loaded gas well, but the smaller passage also adds friction. The useful question is therefore whether the completed well can deliver enough gas through the proposed conduit to transport its liquids under the conditions expected after installation. …
Gas well liquid loading occurs when the produced gas cannot carry the available liquid through the well’s flow path under the prevailing conditions. Retained liquid adds a pressure burden that can restrict reservoir inflow, produce intermittent behavior or stop production. A declining gas rate may prompt the investigation, but it does not establish the diagnosis …
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 …