In my last column, I wrote about the need to pull casing from the ground. Maybe you drilled a dry hole, or need to remove bent pipe or set a well screen by the telescoping method. I previously talked about two methods for casing not too tight in the ground: the slotted pulling head and pipe pulling jars. For casing driven down deep and really tight in the ground, we may want to use one of two other methods.
Here, I focus on the first: a very popular tool called a casing spear (or, sometimes, trip spear). You can lower this tool to any position inside the casing and teeth expand to grip that inside. You need to use long-stroke jars just above the trip spear with a drill stem and rope socket above the jars. The stroke of these jars needs to be longer than the stroke on the machine, and the operator would generally set the stroke at its shortest length. Small water well rigs have a short stroke of about 18 inches, so we would need to select jars made for a stroke of at least 24 inches or, preferably, 30 inches. The reason for this is that the casing spear is adjusted at the surface to slide down inside the pipe.