Coaxial progressive cavity pump

Abstract

This invention relates a progressive cavity pump with a central feed-through for supplying steam, gas or liquids to the supply side of the pump. For the oil industry this invention enables single well stimulation. Steam can be supplied from the surface to the production zone or below through the central feed-through, heating or pressurizing oil and the surrounding formation, and facilitating production. In heavy oil fields solvents can be pumped down as well. Oil can be pumped up by the progressive cavity pump through the annulus of the connecting coaxial pipe.

Description

TECHNOLOGY

[0001] The invention is to be applied as pump, with an internal channel through the rotor of the pump, for supplying heating or pressure by steam to the supply side of the pump.

[0002] 1. Objects of the Invention

[0003] Old, almost depleted, oil wells can be revived if steam is injected. Previously at least one additional steam injection well would be necessary. With this solution single wells can be continuously stimulated by steam injection through, and below, the pump, to heat the formation and to heat the produced oil, thus keeping the viscosity low and the oil flowing more freely. With the same reasoning, the pump can be applied for tarsand and other heavy oil wells.

[0004] 2. Background of the Invention

[0005] The US alone has over 500,000 oil wells, with an average production in 2010 of only 10 barrels/day. About 300,000 wells are marginal wells with an average of about only 2 bbl/day production. Still just the marginal fields together produce about 700 million bbl/year, about half the imports from Saudi-Arabia. Doubling the marginal field production would be helping energy independence, as well as an economic stimulus.

[0006] A non-Moineau progressive cavity pump is known from my patent NL 2004120 (20, Jul. 2011). This pump can be used with all metal parts, at much higher rpm's, and with much better balancing, thus much less vibrations. The pump is based as on a central oval rotor, and sections of housing with 2 rockers, helically spiraling around this rotor, thus creating 8 progressing cavities.

[0007] A feature not obvious from above patent is the lack of need for an universal joint or gear, as needed with Moineau pumps. And as such it is not obvious a simple opening inside the rotor can act as feed-through for steam, gas or liquid. Thus steam can be pumped below the pump, heating the formation, letting oil flow more freely, and keeping oil flowing more freely up the well. For this the pump has to be connected to a coaxial pipe, with the inner pipe transporting hot steam or solvent through the rotor, and the annulus transporting pumped oil.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 front view of hollow elliptical rotor and two straight-edged rockers

[0009] FIG. 2 exploded view with most of the housing sections removed

DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 shows a cross-section of a machine comprising in essence of one rotor (3), two rockers (2) and a housing (1), creating inside the housing eighth separate variable volumes. The hollow rotor (3) has a cavity (4) which allows transport through the rotor, for example for injecting hot steam from the surface below the pump.

[0011] FIG. 2 shows an exploded view with all but 5 housing sections removed. It shows how the rockers are wrapped around the rotor.

Claims

1. A progressive cavity pump consisting of in essence one axially uniform rotor of oval shape and sets of two rockers with straight-edged shape and housing, with an isolated cavity through the rotor connecting both sides of the pump, to be used for supplying gas or liquid to the supply side of the pump.

2. A progressive cavity pump consisting of in essence one axially uniform rotor of oval shape and two rockers with straight-edged shape and one housing, with an isolated cavity through the rotor connecting both sides of the pump, to be used for supplying gas or liquid to the supply side of the pump.

3. A progressive cavity pump of claim 1 or 2, where the shape of the rotor changes in axial direction to allow for compression or decompression.