Cable tool - drilling, bailing, driving pipe - v1.1

Описание: This is the reworked version of my first prototype light cable tool rig, designed for installing shallow wells in mostly-unconsolidated formations that are too challenging for light-rotary rigs. In this region the overburden consists mostly of altered (weathered) granite containing some depth of laterite and often intrusive seams of quartz. In some locations this material forms a productive aquifer above bedrock. Currently this water is accessed extensively from hand-dug wells, but these traditional wells are dangerous to dig and cannot get very far below the static water level so they go dry with seasonal fluctuations. Drilling with light cable tools in these conditions is slow but sure, and with a low equipment cost the economics are very promising and we will be able to offer low-cost boreholes.

0:00 starting the hole with a guide pipe
0:16 spudding mechanism
0:39 drilling just below ground level (laterite)
0:50 bailing the hole
3:19 driving pipe


SOIL PROFILE (feet)

0-1 soil
1-8 laterite, solid
8-13 laterite, less cemented, more like stiff red clay
13-26 clay, color transition from "peanut sauce" to "latte" to "cement"
** static water level 20 feet
26-33 find sand, cement gray, pink granites dominate in washed sample
33-46 coarse sand, cement gray, pea-sized crystals of decomposed granite
46-48 increasingly coarse sand with larger granite fragments

This well was terminated at 48 feet and a single 3m screen (125mm diameter, 0.75mm slot). Gravel placed as the 200mm temp casing was pulled back (although with the coarseness of the formation it may have been fine with natural development). The temp casing will be completely removed and the well conditioned with a surge block (still in work).