Plastic Casing Puller Drive Shoe
Plastic casing has become very popular in many areas of Canada and the U.S.A. It is light and easier to handle than steel casing and it is not prone to corrosion.
Although most plastic water well casing is strong, it is susceptible to cracking or shattering by heavy drill tools and pressure exerted on the casing.
Where a seal is required at the bottom of surface casing to prevent sand, silt, mud or unwanted water to get past, a pressure seal is the best seal to have. It is not sensible for the driller to “drive” plastic casing by beating or pushing it into a hard impermeable formation wherein a seal can be achieved.
As a result, drillers are obliged to use a non-pressure seal using a variety of product such as bentonite, rubber and other non-pressurizing methods in an attempt to effect a seal. However, none of these seals have been shown to be as effective as the “pressure seal”.
The Plastic Casing Puller Drive Shoe which is patented in the U.S.A. and Canada very effectively solves this problem. Firstly, a special high quality steel seal or “shoe” is attached to the bottom of the plastic surface casing.
Secondly, a corresponding “pushing tool” is connected to the rotary rig’s drill stem and is sent down the hole inside the plastic casing. The “pushing tool” very effectively connects with the “shoe” and the substantial weight of the drilling rig is transferred to the “shoe”, effecting a high pressure seal without putting any pressure on the plastic casing whatsoever.
After the seal is effected, then the driller can sensibly use air to drill the bottom hole. Air drilling is far more effective than water or “mud” drilling, as air will not shut water off; the driller knows exactly where and when he encounters water; the driller knows how much water the aquifer is producing; and “over drilling” the well deeper is unnecessary.
Without a pressure seal, air drilling can weaken or blow the seal away.
Big Iron Drilling does not claim to do what is not possible. But, with proper well design and sensible drilling methods, chances of success are far greater.