Abstract: A method and a settling tank for use in separating a solids containing fluid, such as a drilling fluid. The settling tank includes a settling compartment comprised of an inlet and an upper outlet so that the fluid passes through the settling compartment generally in a first direction from the inlet toward the upper outlet. Further, a backwash fluid source directs a backwash fluid within the settling compartment generally in a second direction which is substantially opposite to the first direction. The method includes the steps of passing the fluid through the settling compartment generally in the first direction and directing the backwash fluid within the settling compartment generally in the second direction. Finally, a method is also provided for clarfying a solids containing fluid using a settling tank, wherein the settling tank is comprised of at least three isolatable settling compartments connected in series.

Abstract: A transportable drilling fluid cleaning system for removing solids from drilling fluid at a drill site comprises a platform for transporting the system. A bin region on the platform retains solids from the drilling fluid. A settling tank on the platform separates the drilling fluid into an upper fluid fraction having a reduced concentration of solids and a lower solids fraction having a higher concentration of solids as the drilling fluid flows from an inlet chamber for receiving drilling fluid to at least one other chamber. A stand on the platform supports at least one centrifuge for separating the solids from the drilling fluid, the stand being movable between stored and operating positions. The system provides a self-contained unit that is easily transportable on a flat bed truck to provide all the ancillary equipment necessary for solids control at the drill site.