Drive Pipe Other names for this casing are Drive pipe or Stove pipe. Surface formations are lose and consolidated, They consist mainly of sand and stones. Due to this the surface hole will need to be cased off before any drilling can take place. Large heavy walled pipe is often driven to a point of refusal or a safe depth. I say often this may not always be the case The conductor pipe is the first casing to be put in place, and is generally installed before the rig arrives on location. I say generally as now days it has become  more common for the rig to  install the pipe. On land, the hole for this shallow casing is often dug with an auger drill mounted on a truck, or driven using a diesel or steam hammer. Such casing can be driven to 250 feet. Conductor casing measuring between 16 to 24" outside diameter is used onshore, and between 24 to 48" for offshore. However the size of this casing will depend on the depth of the hole, the deeper the hole the larger the casing. On land a cellar is dug. This will house the well if completed. The Cellar will normally house only one well. however I have worked over cellars that have as many a six wells.   There are three ways of putting this casing into the ground Driven ( driving with a diesel hammer ) Drilled ( The hole drilled beforehand the casing is then run and cemented in to place )  Drill and drive ( The pipe will be driven to refusal. A bit will be run  and a short section of hole drilled. The pipe will then he hammer in until refusal, the same processes repeated until the pipe is at the required depth  ). Such a string of pipe could be driven as deep as 450' until the fresh water zones are covered  There are many reasons for such pipe: To return drilling fluid and cutting back to surface and clean the hole. Protect fresh water sands. Stop washouts under the drilling rig. To give a base and support for the next string of casing  Protect the following casing string. As the hole is drilled, cuttings must be removed. To remove the cuttings a drilling fluid is pumped and circulated around the hole. This fluid, often referred to as spud mud, is pumped down the drill string, out from the bit and back up between the drill string and drive pipe and returned it a cleaning system. For this to be affective a riser is attached to the drive pipe.