Chemically Enhanced Centrifugation, CEC, otherwise known as ﬂocculation, is a method to enhance the remove of ﬁne solids in WBM through a centrifuge. Small quantities of additives are mixed with theused WBM, which coagulate and ﬂocculate ﬁne colloidal solids into larger clumps, which are then easily removed using a centrifuge.CEC reduces the volume of waste mud generated as it allows the clariﬁed ﬂuid to be reused to build new drilling ﬂuids. Overall the total volume of waste, the size of the pits, and the quantity of water required per well are all reduced.
During drilling with WBM, ﬁne colloidal solids build up, eventually leading to a requirement to dump or dilute. CEC offers an alternative a sit allow the ﬁne particles to be coagulated, ﬂocculated and removed by the use of a centrifuge. A coagulant is added to neutralise the negative charges holding the ﬁne colloidal particles apart followed a ﬂocculent (typically a polymer) to bridge together the small ﬂoccs into larger clumps, which can then be removed by gravity separation or a centrifuge.
The CEC system is a containerised compact unit designed to meter in the correct quantities of both coagulants and ﬂocculent. It has tanks to store the prepared chemical solutions and metering pumps to accurately dose them into a mud mixing line. The ﬂocculated mud should be centrifuged at low speed to ensure the clumps are not broken up by excessive shear.
Beneﬁts of chemically enhanced centrifugation :
1/ Overall reduction in water usage and increased recycling
2/ Smaller pit volumes and in closed loop system no need for a reserve pit
3/ Reduced environmental impact
4/ Real time mixing reduces overall chemical consumption
5/ Powder polymer unit reduces chemical consumption