Drilling system

A drilling system comprising topside equipment, a drilling unit and a drill string extending between said topside equipment and said drilling unit, wherein said drill string comprises:

• a drill pipe,
• a mud pipe concentrically received within said drill pipe and defining a mud passage for supply of drilling mud from said topside equipment to said drilling unit,
• electrical conductor means providing electrical communication between said topside equipment and said drilling unit and comprising three concentric angularly spaced arcuate conductors of equal radii received within said mud pipe,
• an inner pipe received concentrically in said mud pipe and said arcuate conductors,
• three spacer portions on said inner pipe extending radially outwardly between said arcuate conductors to engage said mud pipe, and
• wherein a first and a second fluid passage extending between said topside equipment and said drilling unit are provided between said conductors and said mud pipe and within said inner pipe respectively.

In a drilling system comprising a drill pipe extending between topside equipment and a drilling unit, electrical conductor means extending within said drill pipe comprising:

• three arcuate electrical conductors of equal radii,
• an outer pipe concentrically received within said drill pipe,
• an inner pipe received within said outer pipe for conveyance of drilling mud to said drilling unit, said inner and outer pipes being spaced to provide therebetween a further passage for fluid communication between said topside equipment and said drilling unit,
• three angularly spaced spacer means extending between said outer pipe and said drill pipe, a respective one of said arcuate conductors being received between each adjacent pair of said spacer means with spacing to define fluid passage means for fluid communication between said topside equipment and said drilling unit.

A drill pipe assembly for use in a drilling system, the assembly comprising:

• a drill pipe,
• an intermediate pipe concentrically received within said drill pipe with spacing to define a first conduit of annular cross-section therebetween,
• an inner pipe concentrically received within said intermediate pipe with spacing to define a second conduit of annular cross-section therebetween,
• a plurality of spacers extending radially between said intermediate pipe and one of said drill pipe and said inner pipe to divide one of said first and second conduits into a plurality of arcuate conduit portions of generally arcuate cross-section, and
• a plurality of electrical conductor means of generally arcuate cross-section, each of said electrical conductor means being located within a respective one of said arcuate conduit portions.

A drilling system comprising topside equipment, a drill unit, and a drill string extending from said topside equipment to said drill unit, wherein:

• said drill string comprising:
• a drill pipe,
• a mud pipe,
• a tubular conductor assembly, said conductor assembly comprising a plurality of conductor elements each having the form of at least part of a tube;
• and each of said drill pipe, said mud pipe and said plurality of conductor elements extending from said topside equipment to said drill unit,
• means mounting said mud pipe and said conductor assembly substantially concentrically within and spaced from said drill pipe, and spaced apart from each other, thereby to provide within said drill pipe a mud passage for supply of drilling mud from said topside equipment to said drill unit, and a first and a second fluid passage each providing fluid communication between said topside equipment and said drill unit, said first and said second fluid passages being at least in part defined by said conductor assembly,
• said drill unit comprising:
• a drill bit,
• an electric motor for driving said drill bit, said electric conductor elements being connected to said electric motor for supplying power thereto from said topside equipment, and
• fluid passage means extending through said electric motor and communicating with said first and said second fluid passages,
• said topside equipment comprising:
• means for supplying drilling mud through said mud passage to said drill unit, and
• means for circulating fluid downwardly through one of said first and second fluid passages to said drill unit, through said fluid passage means, and upwardly from said drill unit to said topside equipment through the other of said firs and second passages.