Shale bin/settling tank/centrifuge combination skid

US Patènt # 6863809


Invèntors: Smith; Donald Roy (Calgary, CA); Kapicki; Melvin Douglas (Leduc, CA)
Assignee: BOS Rentals Ltd. (Calgary, CA)
Appl. No.: 366050
Filed: February 13, 2003

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.




This application claims priority to Canadian Patènt Application No. 2,414,321, entitled "Shale Bin/Settling Tank/Centrifuge Combination Skid," filed on Dec. 13, 2002, which is hereby incorporated by reference.

FIELD OF THE INVÈNTION

This invèntion relates to apparatus for separating solids from fluids. In particular, the apparatus is useful for removing solids from drilling fluids used in well drilling operations.

BACKGROUND OF THE INVÈNTION

Wells for recovering oil, gas and the like are typically created by drilling into an underground source using a hollow drill string supported in a drilling rig. The drill string includes a drill bit at the lower end that is rotated into the ground to create a well bore. As the drill bit is rotated, drilling fluid is pumped down through the interior of the drill string to pass through the bit and return to the surface in the well bore external to the drill string. The drilling fluid acts to lubricate the drill bit and carries the loose solids created by the drill bit to the surface. At the surface, the used drilling fluid is collected and recycled by removing some or all of the solids. The viscosity or solids content of the drilling fluid can be varied depending on the stage of the drilling process and the location of the drill bit below the surface.

Equipment and methods for handling the drilling fluid to remove solids in order to recycle the fluid are well known. Settling tanks, shale shakers, flocculating tanks and centrifuge or cyclone separators can be interconnected to handle the drilling fluids from a drill site and separate the used drilling fluid and undesirable solids for subsequent recycling of the drilling fluid. Canadian Patènt No. 2,219,053 issued May 25, 1999 to Grand Tank (International) Inc. discloses an arrangement of settling tanks and centrifuges to achieve this result.

Presently, a mud storage tank to hold drilling fluid and a shale shaker to perform screening of larger solids tend to be standard equipment for a drilling rig. In normal well site operation, drilling fluid is circulated out of the a borehole and passed over a shale shaker which is a screen to separate large solid particles from the drilling fluid. The shale shaker is generally positioned directly above the mud storage tank. The rest of the equipment for solids handling including a settling tank, a shale bin for collecting solids for disposal, centrifuges and a flocculent tank tends to be available as individual pieces of equipment that must be delivered to the well site in separate loads. It is important to choose compatible equipment that is interconnectable and that is properly sized to be of appropriate capacity to work with other selected equipment. Once delivered to the site, the various pieces of equipment must be assembled together. Generally, a picker truck is needed to lift the centrifuge equipment onto a conventional raised centrifuge stand. It requires superior organization and scheduling skills to ensure the components of a solids handling system are delivered in a timely manner to the work site and assembled into an efficient and reliable solids handling system.