Abstract: A casing landing and cementing tool has a wellbore obstruction-clearing tool at a downhole end thereof and a check valve uphole of any fluid vulnerable components to isolate the vulnerable components from the threat of cement incursion. The check valve is manufactured of drillable materials, the plunger being axially actuable but non-rotatable, the valve body being threadably secured within the tool. In one aspect the tool is a sleeve bit rotatably and reciprocally coupled about a mandrel secured to a non-rotating casing string, the check valve located in the mandrel. In another aspect, the tool is a bit coupled to a rotatable casing string, the check valve located in the bit.

Abstract: A wellbore obstruction-clearing tool connected to the bottom of a tubing string, such as casing, utilizes a sleeve which is axially and rotationally moveable in response to axial reciprocation of a tubing string to engage and clear obstructions in the wellbore. Fluid is discharged through the casing and the tool to engage the obstructions and to convey debris through the annulus to surface. Thus, the obstructions are cleared from the wellbore, permitting the casing to be advanced, without the need to rotate the casing.

Abstract: A wellbore obstruction-clearing tool connected to the bottom of a tubing string, such as casing, utilizes a sleeve which is axially and rotationally moveable in response to axial reciprocation of a tubing string to engage and clear obstructions in the wellbore. Fluid is discharged through the casing and the tool to engage the obstructions and to convey debris through the annulus to surface. Thus, the obstructions are cleared from the wellbore, permitting the casing to be advanced, without the need to rotate the casing.

Abstract: A device for stabilizing a vehicle has a container which is substantially closed and has a size adapted to a corresponding available compartment of a vehicle, the container having walls bounding an inner space, and a body of non-particulate material which fills the inner space of the container to provide a ballast for the vehicle and therefore to stabilize the vehicle.