AMERICAN STANDARD CABLE-TOOL DRILLING RIG

The American Standard cable-tool drilling rig, utilizing a cable (hemp rope and later steel) for lifting or lowering the drilling tools and a separate "sand" line for lifting or lowering the bailer, was in use in Western Canada as late as 1947 (Alliance Trans Alberta No.2, Lsd2, Sec.18, Twp.20, Rge.1W4M). The majority of cable-tool rigs were characterized by framed wooden derricks with a long attached shed with enclosed engine. The exposed steam boiler, with its characteristically high smoke stack adjoined the other end of the linear shed. The singular identifying feature or hallmark of the cable-tool rig was its "walking beam" which by controlled rocking, served to activate the stroke of the cable and the resultant alternating percussion and churning of the chisel type bit. Between the end of the cable and the bit were the "jars" or large metal links used to facilitate the freeing of a stuck bit.

Rock samples obtained in the course of cable-tool drilling were returned to the surface with the use of a bailer. The alternate drilling and bailing every few feet was a monotonous procedure during the deepening of the open hole. These rock cuttings, unlike those circulated to the surface as a result of a rotating bit, were invariably finer as a result of the pounding and churning action of the chisel-like bit.

Before the advent of subsurface stratigraphers, the driller prepared a rudimentary lithologic log based on their examination of the bailed rock cuttings. Their uncanny descriptions of sedimentary rock types although primitive by todays standards, are nevertheless strikingly interpretive. Bentonitic shale was described as "rock putty" or "soapstone"; sideritic concretions as "ironstone"; red or ferringinous shale as "fireclay"; porous friable sand as "quicksand"; porous carbonate as "rock, white spongy"; fossiliferous limestone as "lime shelly"; siliceous carbonate as "rock, hard flinty"; and anhydrite as "rock blue, rock white or gypsum".

While drilling by cable-tool, the driller intermittently placed his hand on the drilling cable as it alternating was raised and lowered. By doing to he was able to feel the impact of the drilling bit as it repeatedly struck the bedrock. Thus through experience, albeit with a degree of intuition, he was able to "read" the nature of the bedrock as the bit passed from one rock type to another.

The driller's assistant was a tool dresser, whose responsibility was to sharpen the cutting edge of a dulled bit by firing and pounding it much like a Blacksmith's technique. The two man crew worked at a leisurely pace during the drilling phase but when a water bearing reservoir was encountered it necessitated inserting casing in the hole to curtail the flow of water to the surface. As many as seven strings of ever decreasing size was telescoped into the hole which eventually determined the limits of the bit assemblage to penetrate further strata.

The careful handling of tools around the open hole was of paramount importance. The accidental dropping of a tool into the well bore spelt the demise of the entire operation. The cry "iron in the hole" was anathema to all concerned.

J.W. Porter
From, Historic Turner Valley, Cradle of Westen Canada's Oil and Gas Industry, pg 39