GAS WELL DRILLING

Field of the Invention

[0001] The present invention relates to the field of managing solids and liquids in oil and gas well drilling.

Background of the Invention

[0002] In the process of drilling wells, well bore drilling fluids are pumped downhole from the well drilling platform. These drilling fluids lubricate the drill bit and carry away cuttings generated as the drill bit digs. Exemplary drilling fluids are oil base fluids, brine base fluids, or water-based fluids. Drill cuttings (typically small pieces of shale or rock and other solids) are carried by the drilling fluid from the well bore in a retur flow stream to a primary separator. The primary separator performs an initial separation of the fluids from the solids. Once separated from the solids, the drilling fluids may be reused.

[0003] It is not usually possible to separate all the solids from the drilling fluids with a primary separator. There are several types of primary separators, but “shale shakers” are commonly used.

Generally, the primary separators are only able to separate 60-70% of contaminant solids from drilling fluids.

[0004] Often, the solids are simply too small to be separated. Additionally, drilling fluids are frequently formulated to contain finely ground solid additives that a primary separator cannot distinguish from fine drill cuttings, known as low gravity solids. Barite, a well know weighting agent, is one example of such solid additives.

[0005] From the primary separator, the separated moisture carrying drill cuttings are fed by an auger conveyor or by a front loader to the hopper of a vertical drier. The vertical drier uses centrifugal force to further separate solid drill cuttings from residual liquids and fine solid additives. The dried drill cuttings are sent to waste, and the separated liquids and fine solids are then typically saved for reuse in the drilling fluid.

Summary of the Invention

[0006] A vertical drier system and method for managing oil well solids and liquids includes a vertical drier; a hopper for well drilling cuttings mixed with residual liquids; and an enclosed drag chain conveyor having an opening in said hopper for picking up drill cuttings and associated liquids. The enclosed drag chain conveyor extends from the hopper to a vertical drier, there being an opening in said enclosed drag chain located at said vertical drier, whereby drilling cuttings and associated fluids being conveyed by said drag chain are delivered to said vertical drier for drying.

The enclosed drag chain conveyor returns again to said hopper in a continuous enclosed loop except for said opening in said hopper and said opening to said vertical drier.

[0007] These and other objects, features and advantages of the invention will be more fully understood and appreciated by reference to the Description of the Preferred Embodiments and the supporting drawings.

Brief Description of the Drawings

[0008] FIG. 1 is an elevated perspective view of the preferred embodiment apparatus;

[0009] FIG. 2 is a plan view of the apparatus;

[0010] FIG. 3 is an enlarged view of the indicated portion of FIG. 2;

[0011] FIG. 4 is side elevational view of the apparatus;

[0012] FIG. 5 is a cross sectional view taken on plane FV-IV of FIG. 5;

[0013] FIG. 6 is an enlarged elevation of the vertical drier portion of the apparatus;

[0014] FIG. 7 is a plan view of the vertical drier portion of the apparatus; and [0015] FIGS. 8 A and 8B are perspective views of the cuttings hopper with its cover opened and closed, respectively.

Description of the Preferred Embodiment

[0016] In the preferred embodiment, vertical drier system includes vertical drier 10 and a hopper

20 for well cuttings with residual liquids, an enclosed drag chain conveyor 30 for conveying cuttings via a feeder leg 3 Of from hopper 10 to the top of said vertical drier 10, where it dumps the cuttings into drier 10 via an enclosed chute 11 (FIGS. 1, 2, 4, 6 and 7), A return leg 3 Or facilitates return of the drag chain conveyor to the end of hopper 20 and back through it in a continuous loop.

Drag chain conveyor is enclosed, except for openings 31 located in said hopper 20 so the drag chain picks up cuttings as it passes through hopper 20, and an opening above said vertical drier for delivering drill cuttings into chute 11 and on into said vertical drier 10 (FIG. 4). An overflow container 40 is provided, in case said vertical drier 10 or said enclosed drag conveyor 20 is out of order, or in the event the vertical drier is not needed (FIGS. 1 and 2). The following parts list identifies the various components and parts discussed herein:

Parts List

10 vertical drier

11 enclosed chute into vertical drier

12 enclosed efflux tube from drier 10 to fluid receiving tank

13 enclosed fluid receiving tank

14 conveyor for dried cuttings

20 cuttings hopper

21 hinged cover

30 enclosed drag chain conveyor

3 Of feeder leg of conveyor 20 3 Or return leg of conveyor 30 30a enclosing tube

31 openings in cuttings hopper

32 chain

33 pick-up discs

34 feeder gear box and drive motor unit

35 return gear box

40 overflow container 41 cutaway

[0017] Vertical driers separate liquids and fines from drill cuttings by centrifugal force. They include a top opening through which cuttings can be fed into the drier. The centrifuge forces liquids and fines to the outside wall of the centrifuge while the dried cuttings drop down along the vertical axis of the drier. Any of the commercial vertical driers can be used in the present invention. They can be used for water-based drill cuttings (shale or clay), oil-based cuttings, mineral slurry dewatering and the like.

[0018] In the preferred embodiment, the vertical drier is equipped with a chute 11 which conducts the cuttings from an emptying opening in enclosed conveyor 30 at the top of conveyor leg 30f, down through the chute and into the interior of vertical drier 10 (FIGS. 1 and 6). An enclosed efflux tube 12 extends from drier 10 to an enclosed fluid receiving tank 13 (FIG. 7) for conveying separated fluids and additive fines. From enclosed tank 13, these fluids and fines can then be pumped into cutting fluid mixers where they are re-introduced into the cutting fluid. The dried cuttings drop down from the center of drier 10 onto an auger or other type of conveyor 14 where they are conveyed to dried waste cuttings storage for disposal (FIG. 6).

[0019] Cuttings hopper 20 is secured to one side of overflow container 40 (FIGS. 1 and 2). It is generally of an inverted “L” shape in cross section, such that the leg 20a of the hopper extends outwardly from its connection to container 40, and then downwardly as leg 20b (FIG. 5). At its bottom, hopper 20 is secured to and opens into openings in leg 3 Of of drag chain conveyor 30.

Return leg 30r passes through the space between leg 20b of hopper 20 and the side wall of container

40. Hopper 20 is segmented into three sections 20a, 20b and 20c in order to provide spacing for flanges connecting segments of drag chain conveyor 30 where it extends between said sections

(FIG. 4).

[0020] Hopper 20 includes a hinged cover 21, which when opened allows fluid carrying drill cuttings to flow into hopper 20 (FIG. 8A). When closed, the cuttings being fed slide over the top of hopper 20 and into overflow container 40 (FIG. 8B). Cover 21 is inclined to the horizontal when closed, to facilitate cuttings sliding over it and into container 40.

[0021] Enclosed drag chain conveyor 30 comprises an enclosing tube 30a within which travels a chain 32, having pickup discs 33 secured at spaced points along said chain, usually spaced about a foot apart (FIG. 3). Pickup discs 33 have a diameter which matches the inside diameter of enclosing tube 30a such that material which is picked up through the openings 31 in enclosing tube

30a is conveyed by discs 33 as they travel through enclosing tube 30a. Drag conveyor discs 33 are 3-12 inches in diameter. The preferred embodiment chain uses 8-inch diameter discs 33 and a corresponding inside diameter in tube 30a.

[0022] Drag chain conveyor 30 uses a continuous chain 32 which passes around a feeder gear box

34 at the end of hopper 20 and begins its return to upper gear box 35 located at the top of chute 11

(FIG. 4). Gear box 35 is connected to chute 11 in such a way that the entire assembly is enclosed.

Gear box 34 includes a drive motor which drives conveyor chain 32. [0023] Overflow container 40 is a three-sided metal container with a heavy-duty metal floor (FIG.

1). The side wall 41 to which hopper 20 is secured has a cutaway 42 at the top for the distance of hopper 20, through which cuttings can flow over covered hopper 20 and into overflow tank 40.

[0024] When the system is in use, fluid laden drill cuttings flow into open hopper 20, where they are picked up through enclosed drag chain openings 31 by the passing enclosed drag chain 32 through hopper 20. They are conveyed upwardly through enclosed drag chain conveyor leg 30f to the opening into chute 11, which feeds the drill cuttings into the top of vertical drier 10. Vertical drier centrifugally separates the fluids and fines from the cuttings and feeds the fluids and fines through pipe 12 into enclosed container 13. The cuttings drop down onto disposal conveyor 14 which conveys the cuttings to a disposal container or site. Drag chain conveyor 30 continues to travel through the enclosed conveyor return leg 30f back to the gear box 34 which turns the return loop around into a feeder loop.

[0025] Because drag chain conveyor 30 is enclosed, and its connection to vertical drier 10 through chute 11 is enclosed, volatile contaminants (VOCs) can be prevented from escaping to the atmosphere. In a preferred embodiment, a vacuum is placed on the system to vacuum VOCs away to a scrubber for treating and eliminating them. A preferred location for the vacuum system would be at the top of vertical drier 10, and of course connected both to vertical drier 10 and to feeder chain 30.

[0026] The fact that feeder chain 30 is enclosed and its connection to chute 11 and vertical drier

10 is enclosed also makes the operation of the preferred system much cleaner. Messy spills are minimized. [0027] Of course, it is understood that the above are preferred embodiments of the invention and that various changes and alterations can be made without departing from the spirit and scope of the invention as set forth in the appended claims.