Centrifugal pump systems

1. Field of the Invention

The present invention is directed to centrifugal pumps; to systems using them; and, in certain particular aspects, to such systems for pumping solids-laden drilling fluids.

2. Description of Related Art

The prior art discloses a wide variety of centrifugal pumps; systems that employ them; and systems with such pumps for pumping drilling fluid laden with drilled solids and other solid components; for example, and not by way of limitation, see U.S. Pat. Nos. 5,456,580; 5,662,807; 5,846,440; 6,096,228; 6,170,580; 6,179,071; 6,276,824; 6,345,672; 6,406,255; and 6,808,354, all of said patents incorporated fully herein for all purposes.

Pumping systems which employ centrifugal pumps are used to pump mixtures and slurries that contain solids. In certain particular aspects, such systems pump fluids used in the drilling of earth wellbores, tunneling and excavating. Drilling fluids can contain hazardous material, oil, solids, debris, rock, and shale cuttings.

The safe and efficient handling of drilling fluid and its proper disposal result in significant expense in drilling a wellbore.

There has long been a need, recognized by the present inventors, for effective and efficient systems employing centrifugal pumps for pumping mixtures with solids therein. There has long been a need, recognized by the present inventors, for effective and efficient systems for pumping solids-laden drilling fluids.

The present invention discloses, in certain aspects, systems for pumping mixtures with solids therein. In certain aspects, such systems include a container or tank for receiving and holding the mixture; apparatus for moving the mixture within and from the container; and one or more centrifugal pumps for transferring the mixture from the container to storage or disposal (and/or to mix the mixture within the container to make it homogeneous).

In certain aspects the mixture contained within a container is a slurry which includes a fluid or fluids and solids in the fluid. In one particular aspect, the mixture is a slurry of drilling fluid from a wellbore with solids (e.g. drilled cuttings, drilled debris, etc.) therein.

In certain particular aspects, the present invention discloses a centrifugal pump with a packing structure for a pump shaft. The packing structure includes seals that act as containment barriers to prevent outside contamination from entering a pump housing and contacting the shaft and other parts. In certain aspects, the packing structure is sealed within a non-vented space below bearings, a space in which a positive pressure is maintained. Also, with seals isolated and under pressure, and located in a non-vented space, as temperature builds up during operation, lubricant adjacent the seals expands, increasing pressure as compared to pressure external to the packing structure, which contributes to maintaining the seals in isolation and to prohibiting contaminants from entering the system and flowing to the bearings. Thus, the life of parts, e.g. shafts and bearings, can be extended.

In certain aspects, the present invention discloses pumping systems for pumping a drilling mixture containing liquid drilling fluid and solids (e.g., debris, drilled cuttings, etc.) entrained in the liquid drilling fluid, the pumping systems including: a container for receiving and holding the drilling mixture; centrifugal pump apparatus for transferring the drilling mixture from the container, the centrifugal pump apparatus including a pump shaft, a motor to drive the pump shaft, a packing structure around the pump shaft and bearing apparatus around the pump shaft, a housing, the housing comprising an enclosed non-vented structure; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

The present invention discloses, in certain aspects, centrifugal pump apparatus including: a pump shaft; a motor to drive the pump shaft; a packing structure around the pump shaft; bearing apparatus for the pump shaft; a non-vented housing able to contain lubricant and/or grease under pressure; and the packing structure, bearing apparatus and part of the pump shaft within the housing.

In certain aspects, the present invention discloses methods for pumping a mixture containing liquid and solids (in one particular aspect, a mixture of drilling fluid and drilled solids), the method including: feeding the mixture from a container for receiving and holding the mixture to a centrifugal pump apparatus for transferring the mixture from the container, the centrifugal pump apparatus being any according to the present invention; and with the centrifugal pump, pumping the mixture from the container.

The present invention discloses, in certain aspects, pumping systems for pumping a mixture containing liquid and solids, the pumping systems including: a container for receiving and holding the mixture; centrifugal pump apparatus for transferring the mixture from the container; the centrifugal pump apparatus including a non-vented housing that is able to hold pressure.

What follows are some of, but not all, the objects of this invention. In addition to the specific objects stated below for at least certain preferred embodiments of the invention, there are other objects and purposes which will be readily apparent to one of skill in this art who has the benefit of this invention\'s teachings and disclosures. It is, therefore, an object of at least certain preferred embodiments of the present invention to provide:

New, useful, unique, efficient, non-obvious pumping systems; methods of their use; and centrifugal pump apparatus for use with them;

Such pumping systems with a pump having an isolated packing structure with a relatively high internal pressure which effectively prevents contaminants from entering the system and flowing to items above the packing structure, e.g. preserving vital parts, e.g. bearings and shafts;

Such pumping systems and methods in which a packing structure is located in a non-vented space; and

In certain aspects, such a pump in which lubricant heated during operation increases pressure on the packing structure.

Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.

The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention\'s realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of certain preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent\'s object to claim this invention no matter how others may later attempt to disguise it by variations in form, changes, or additions of further improvements.