System and method for treating drilling mud in oil and gas well drilling applications

A mud treatment system for offshore drilling operations, said system comprising;

• (a) a first combination fluid comprising a first fluid having a first density, a second fluid having a second density and a solid particulate material suspended therein;
• (b) a shaker device with a first inlet into which said first combination fluid is introduced, wherein said first combination fluid is disposed in said shaker, said shaker further comprising a first outlet and a second outlet;
• (c) a second combination fluid comprising the first fluid and the second fluid, wherein said first outlet of said shaker is disposed to receive said second combination fluid and said second outlet of said shaker is disposed to receive said solid particulate matter;
• (d) a first tank comprising a storage area, a portion of said second combination fluid disposed therein, a first inlet in fluid communication with the first outlet of said shaker and a first outlet;
• and
• (e) a centrifuge device having a first inlet in fluid communication with the first outlet of said first tank, a first outlet disposed to receive said first fluid and a second outlet disposed to receive said second fluid.

A method employed in offshore well drilling operations at the surface for use in treating a first combination fluid rising to the surface from a wellbore in a seabed via a tubular member, said first combination fluid comprising a first fluid having a predetermined first density, a second fluid having a predetermined second density, and drill cuttings, said method comprising the steps of:

• (a) introducing the first combination fluid at the surface;
• (b) removing the drill cuttings from the first combination fluid to produce a second combination fluid comprising the first fluid and the second fluid;
• (c) processing the second combination fluid to separate the first fluid and the second fluid from one another;
• and
• (d) storing the first fluid and the second fluid in separate storage units at the surface.

A system for treating return mud rising from a wellbore to a surface rig via a tubular member in well drilling operations, said return mud comprising a drilling fluid having a first selected density, a base fluid having a second selected density which is less than the first density of the drilling fluid, and drill cuttings, said surface rig having an operating deck, said system comprising:

• (a) a shaker device for receiving the return mud from the tubular member and removing the cuttings from the return mud to produce a clean return mud;
• (b) a first set of tanks for receiving the clean return mud from the shaker device and for storing the clean return mud;
• (c) a separation unit located above the operating deck of the surface rig for receiving the clean return mud from the first set of tanks and separating the return mud into said drilling fluid and said base fluid, said separation unit comprising:
• (i) a centrifuge device, (ii) a first set of pumps for pumping the clean return mud from the first set of tanks to the centrifuge device, (iii) a drilling fluid collection tank for receiving the drilling fluid, (iv) and a base fluid collection tank for receiving the base fluid;
• (d) a second set of tanks for receiving the drilling fluid from the drilling fluid collection tank and for adding at least one conditioning agent to the drilling fluid;
• (e) a third set of tanks for receiving the drilling fluid from the second set of tanks and for storing the drilling fluid;
• (f) a fourth set of tanks for receiving the base fluid from the base fluid collection tank and for storing the base fluid;
• (g) control means for manipulating system variables and for displaying drilling and drilling fluid data;
• (h) a second set of pumps for returning the drilling fluid from the third set of tanks to the wellbore via a drill tube;
• and
• (i) a third set of pumps for re-injecting the base fluid from the fourth set of tanks into the tubular member via a charging line.