Run: Wireline Logging Descent and Retrieval, Toolstring Passes, and WCSB Open-Hole Programs

In well logging a run is a single operation in which a logging tool, or toolstring, is lowered into a borehole on wireline and then retrieved while it records measurements of the formation and the wellbore. The term names one complete trip of the instrument from surface to the target depth and back, and a typical well requires several runs because no single toolstring carries every sensor. Logs are usually recorded as the tool is pulled up the hole at a controlled speed, since logging upward gives steadier tension and more uniform cable behaviour than logging down, though some measurements are taken on the way in. Each run is identified in the log header by a run number, the depth interval logged, the date, the toolstring composition, and the hole and fluid conditions at the time, so that data from different runs can be depth-matched and spliced into a continuous record. The number and design of runs reflects which properties the operator needs and how compatible the sensors are. A common open-hole program might combine a triple-combo on the first run, gathering gamma ray, resistivity, and porosity from density and neutron tools together, then a second run for sonic and image logging, and a third for sidewall coring or formation pressure and fluid sampling. Cased-hole evaluation has its own runs, such as a cement bond log run, a production logging run, or a perforating run on wireline. The concept extends beyond wireline electric logs: operators speak of a logging-while-drilling run when sensors are conveyed on the drillstring, a coiled tubing run, or a pipe-conveyed logging run in highly deviated or horizontal wells where gravity cannot pull a tool down a lateral. In the Western Canadian Sedimentary Basin, where Montney and Duvernay development relies heavily on horizontal drilling, many evaluation runs are pumped down or pipe-conveyed rather than dropped on bare wireline, because the tool cannot fall through a horizontal section under its own weight. Every run carries cost and risk: rig or unit time accrues during the descent, logging, and retrieval, and a tool can become stuck, requiring fishing operations that add days and significant CAD expense. Operators therefore plan runs to minimize trips while capturing all required data, and they pressure test the surface equipment and verify tool function before each run begins. AER requirements under Directive 059 and related logging and well-evaluation expectations frame what data must be acquired, and the quality of each run is judged by its depth control, repeat sections, and the absence of cable or tool problems. A successful run delivers a clean, depth-correct log that feeds petrophysical analysis, completion design, and reserves evaluation.

Sequencing an Open-Hole Logging Program

A WCSB open-hole program is sequenced to balance data needs against trips in the hole. The first run is usually the triple-combo, recording gamma ray, resistivity, and density-neutron porosity in one descent because these sensors stack compatibly. A second run carries sonic and borehole image tools for mechanical properties and fracture characterization. A third run, if budgeted, takes formation pressures and fluid samples or cuts sidewall cores. Each successive run risks borehole deterioration, so operators front-load the most critical measurements. Logging the open hole promptly after reaching total depth reduces the chance that swelling shale or a washout will compromise a later run.

Conveyance Choices in Horizontal Wells

Montney and Duvernay laterals defeat gravity-driven wireline because a tool simply will not slide down a horizontal section. Operators respond with pump-down logging, where fluid circulation carries a tool on wireline through the lateral, or pipe-conveyed logging, where the toolstring is strapped below drillpipe or coiled tubing and pushed to depth. Logging-while-drilling captures data on the same run as drilling, avoiding a separate trip entirely. Each method changes the run plan, the surface spread, and the cost; a pipe-conveyed run ties up the drilling rig, while a pump-down run needs a pumping unit but frees the rig sooner.

Related Terms

A run cannot begin until the logging unit completes its rig up, since the tool only enters the hole after the surface spread is assembled and tested. The data a run records depends on the sensors in the wireline toolstring, and the most common first descent is the combined triple combo that captures the core petrophysical curves. When a tool becomes stuck during a run, the operator turns to fishing operations to recover it, a costly contingency every run plan tries to avoid.

Real-World WCSB Scenario: Open-Hole Program on a Duvernay Vertical Pilot

An operator drilling a Duvernay vertical pilot near Fox Creek planned three logging runs to characterize the reservoir before committing to horizontal development. The first run, a triple-combo, logged gamma ray, resistivity, and porosity over the full 3,500-metre section in about six hours of unit time. The second run added sonic and image data for geomechanics, and the third recovered formation pressures and fluid samples to confirm reservoir charge.

The three runs together cost roughly CAD 250,000 in wireline services. When the second toolstring briefly hung up on a ledge, the crew worked it free without resorting to fishing, avoiding a potential CAD 150,000 or more in lost time and recovery operations. The clean log suite anchored the petrophysical model used to design the subsequent multi-well horizontal program.