Drilling Manual

Slickline Gauge Cutters and Tubing Drift Runs: Will the Next Tool Pass?

Drilling Manual — Tue, 10 Nov 2026 17:21:34 +0000

A slickline gauge cutter can provide useful evidence that a defined body has travelled through the tubing to a stated depth. That evidence matters before another intervention tool is committed to the well. It does not automatically qualify every smaller tool, certify a completely clean bore or prove access below the depth actually checked. The ...

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Tubing Punches in Workovers: Creating Communication Without Perforating the Formation

Drilling Manual — Tue, 10 Nov 2026 17:19:06 +0000

A tubing punch creates an intentional opening between the tubing bore and the space immediately outside the tubing. In a workover, that connection may be part of establishing a circulation route. It does not, on its own, show that fluid can travel through the complete intended circuit or that the well has reached the required ...

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Packer Milling During a Workover: Mill, Release or Retrieve?

Drilling Manual — Tue, 10 Nov 2026 17:16:38 +0000

Packer milling is a way of changing the metal that holds or obstructs a completion. It is not, by itself, evidence that the whole packer has been recovered or that the next assembly can pass. The useful question is more specific: which components must be removed, what will remain connected, and how will the remaining ...

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Spinner Logs in Oil Wells: From Spinner Response to a Flow Profile

Drilling Manual — Tue, 10 Nov 2026 17:13:14 +0000

A spinner log records the response of a rotating impeller to fluid moving past it. Turning that response into an interval contribution requires more than reading revolutions per second from a track. The interpretation must account for tool motion, calibration, the velocity distribution across the flow passage and, where several phases coexist, how those phases ...

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Pulsed Neutron Logging: Is There Movable Pay Behind Casing?

Drilling Manual — Tue, 10 Nov 2026 17:10:16 +0000

Pulsed neutron logging can help identify hydrocarbons remaining in a formation behind casing. It does not, by itself, establish that those hydrocarbons will move into the well at a useful rate. A saturation interpretation describes pore occupancy; producibility also depends on connected flow paths, fluid behavior and reservoir pressure. That distinction should remain visible from ...

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Multifinger Caliper Logs: What Internal Metal Loss Looks Like

Drilling Manual — Mon, 09 Nov 2026 15:17:08 +0000

A multifinger caliper records the internal shape of casing or tubing. Its mechanical measuring fingers follow the accessible inner surface, producing information about enlargement, restriction and other departures from the expected profile. That makes it useful for investigating internal damage, but an internal measurement does not reveal every condition of the steel surrounding it. [1, ...

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Step-Rate Test vs. Injectivity Test: Reading an Injection-Well Response

Drilling Manual — Mon, 09 Nov 2026 13:31:16 +0000

A step rate test and an injectivity test can both involve pumping into a well, but their names do not establish the same interpretation. An injectivity assessment asks how the exposed formation accepts fluid under stated conditions. A stepped-rate assessment examines how the pressure response changes as the injection rate changes. The latter can form ...

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Wellbore Cleanout Before Recompletion: Where Does the Debris Come From?

Drilling Manual — Mon, 09 Nov 2026 12:54:48 +0000

Wellbore cleanout before recompletion has a specific purpose: prepare the route and contact surfaces required by the new equipment, while removing debris that could interfere with installation. The material may include old mud or cement residue, deposits on the casing wall, fragments generated by milling, or debris released while upper well equipment is cleaned. Its ...

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Choosing a Workover Fluid: Brine Density, Compatibility and Formation Damage

Drilling Manual — Mon, 09 Nov 2026 11:54:48 +0000

Choosing workover fluids starts with the functions the well requires. Density must address the pressure-control objective, but the same fluid also contacts the formation, mixes with other fluids, encounters changing temperatures and may have to carry solids. A choice that satisfies only its surface density can leave important compatibility, loss and restart questions unresolved. [1, ...

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Straddle Packers for Well Repair: What Gets Isolated and What Access Remains?

Drilling Manual — Mon, 09 Nov 2026 11:48:13 +0000

A straddle packer can isolate a selected part of a completion while preserving a route through the well. Whether that is a useful repair depends on the exact connection being excluded, the places where the assembly can seal and the passage left afterward. Covering a leak is only one part of the decision. The repaired ...

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