Roundtable Discussion; The Future of Mineral Sands. Watch the video here.
Dai2belts- wells do not always go to plan - so there is no way that they will go from running 13-3/8 casing and miss out the 12-1/4 section. What is they miss it out and there is an issue in the 8-1/2 section and they have to run casing and then drill say a 6 inch section with smaller BHA etc that they probably do not have. Also better to run logs in a bigger wellbore
Wasendo - the spirals do indeed help clean the wellbore with their configuration, but crucially they reduce the surface area that is in contact with the wellbore to reduce the potential of differential sticking of the tubular to a lower pressure permeable and porous zone - differential sticking can often occur in lower pressure sandstones
Daibelts - the size of the hole is dictated by the size of the bit - not the tubulars. If the bit size if 8.5 inches, then the BHA - Bottom hole assembly will be configured of : bit, drill collars (maybe 6-7 inch OD), Heavy weight drill pipe - maybe 4-5 inch OD and then normal drill pipe to surface
They will take samples from the wireline logging for analysis. The mud loggers use a device called a degasser located in the header box of the shale shakers that will monitor the gas in mud. The air from the degasser is pushed to the logging unit where it is analysed
Well design is often around the fracture gradient / formation pressure window. The mud density needs to be between the 2 at all times. As you go deeper both these increase - so you have to case off the hole. There are other factors also
Main rig carrier is a strange term - could be the drawworks, top drive or pipe handling equipment.
I have worked in Africa for the last 8 years - so it’s: source part, (suggest they get 2 of the same part in), ship it, chase customs clearance, transport it to rig site and install.
They will drill the 17.5 inch hole with a 17.5 inch bit size
This will be less that the Inside diameter of the conductor casing - if the outside diameter is 20 inch then depending on the grade of conductor casing the ID will be in the region of 18.5 inches
They will run 13-3/8 casing in the 17.5 inch hole ( assuming they run casing)