Abstract: An offshore deck or platform unit is provided with depending legs having shock absorbing stabbing tip assemblies for engagement with the upstanding columns of a marine substructure to transfer the weight of the deck to the substructure by positioning the deck relative to the substructure with a barge and ballasting down the barge to move the deck into engagement with the substructure. The barge also carries a deck support structure comprising plural sand jack assemblies which provide for disengagement of the barge from the deck. The stabbing tip assemblies include coaxially arranged primary locating pins which are dropped into position to hold the location of the deck relative to the columns and annular resilient collars for transferring vertical and lateral shock loads between the columns and the deck during the transfer process.

Abstract: Offshore wells are drilled with an improved drivepipe/casing assembly made up of plural sections of casing connected end to end, which are driven to a predetermined depth followed by drilling out a wellbore portion below the lower distal end of the casing assembly and then followed by redriving the drivepipe/casing assembly to refusal to eliminate the need for a conventional casing string and associated cementing operations. Certain ones of the casing sections are provided with earth impinging and displacing rings of slightly larger diameter than the outside diameter of the casing to reduce earth to casing friction during driving and to minimize the redriving effort required.