Bore-hole hydraulics simulator

A dynamic fluid loss testing system comprising:

• means for flowing the drilling fluid axially through a permeable partition in the form of an open-ended sleeve, which divides a first volume surrounded by the sleeve and containing the drilling fluid from a second volume surrounding the sleeve and adapted to collect filtrate passing through the permeable partition,
• means for placing a pressure differential across the partition so as to promote the passage of filtrate into said second volume,
• means for collecting the filtrate passing into the second volume, and
• means for continuously adding fluid to said first volume to compensate for the decrease resulting from the loss of filtrate passing into the second volume.

A bore hole hydraulics simulator system, comprising:

• a closed loop circuit around which drilling fluid can pass, and means for forcing the drilling fluid to circulate in said circuit,
• a permeable partition in the shape of an open-ended sleeve defining part of the circuit through which the drilling fluid circulates, the permeable partition dividing a volume within the sleeve containing the circulating drilling fluid from a further volume external to the sleeve adapted to collect filtrate passing through the permeable partition,
• means for placing a pressure differential across the partition so as to promote the passage of filtrate therethrough,
• means for collecting the filtrate passing through the porous partition, and
• a fluid compression vessel filled with drilling fluid under pressure and communicating with the circuit around which the drilling fluid circulates, so that as filtrate is lost through said permeable partition, fluid can be added to the circuit around which the drilling fluid circulates, said closed loop circuit having a constant volume.