A Well Cementing/Plug Drilling Apparatus and Cementing and Drilling Process

摘要

The present invention provides a combined well pipe attachment and pump down wipe plug, in which interlocking means are provided at the interface between the plug and the attachment, which means comprise sharp protrusions operative to penetrate the surface of the plug and/or the attachment in order to inhibit or impede relative rotation between the plug and the attachment when a rotary drill bit is brought into contact with the plug, in order to drill out the plug. In one embodiment the interlocking means take the form of a flat plate (120) provided on both surfaces with teeth (117) which are strong enough and sharp enough to engage, dent and penetrate a cement surface (122) and a pump down wipe plug (121). Another embodiment comprises setting the teeth (117) in the cement surface (122), whilst a further embodiment comprises providing the teeth (117) on one, - or if the pump down wipe plug is a bottom plug as opposed to the illustrated top plug - both, ends of the pump down wipe plug (121). IMAGE