AN INSTALLATION AND A METHOD FOR PUMPING UP FLUID FROM THE EARTH'S CRUST

Abstract: Installation for pumping up liquids from the earth's crust, comprising: a screw pump lowered into the earth which is provided with a first screw member and a counter-screw member, drive means arranged on or close to the earth's surface for driving the screw member which in turn drives the counter-screw member; and transmission means for transmitting the drive produced by the drive means, which transmission means extend from the drive means on or close to the earth's surface to the lowered screw pump.

Description: AN INSTALLATION AND A METHOD FOR PUMPING UP FLUID FROM THE EARTH'S CRUST Liquids from the earth's crust such as petroleum are usually pumped up either with a suction pump (for in¬ stance a so-called nodding donkey) or with a pump lowered into a drilled hole and having a screw-like member. Such a pump for this purpose usually comprises a screw member (rotor) of metal which is rotatably drivable relative to a statically arranged member (stator) of rubber or plas¬ tic-like material. In particular oil fields a viscous petroleum type which may also be hot, for instance in the order of 150- 300°C, can cause a high degree of wear, particularly of the rubber or plastic-like stator. Since such a lowered pumping means can be situated at considerable depth, for example up to 1000-2000 m into the earth's crust, mainte- nance of such pumps is laborious, time-consuming and therefore costly due to standstill losses in petroleum production. Known from the European patent application EP-A- 0168366 is an apparatus for pumping up oil wherein both the pump and the drive means are immersed in the oil or other liquids. When in this known apparatus maintenance of the drive means has to be carried out, the whole apparatus must be raised from the bore hole to above the ground surface, which is time-consuming and whereby oil extraction must be interrupted. This apparatus further makes use of balancing collars, whereby the bearing construction will be subject to wear due to sand or dirt occurring in the liquid, while this bearing construction is also complicated and play can easily occur therein. Further known from the German Offenlegungsschrift DE-A-3718863 is a screw pump for use in an automobile which, if only because of the dimensions, is not suitable for pumping up oil or other liquids from the earth's crust. The present invention provides an installation for pumping up liquids from the earth's crust, comprising: - a screw pump lowered into the earth which is provided with a first screw member and a counter-screw member; - drive means arranged on or close to the earth's surface for driving the screw member which in turn drives the counter-screw member; and - transmission means for transmitting the drive produced by the drive means, which transmission means extend from the drive means on or close to the earth's surface to the lowered screw pump. Because the drive means are disposed close to the earth's surface and the driving movement is transmitted to the lowered screw pump via transmission means, mainte¬ nance of the drive means can be performed easily and large standstill losses can be avoided. The screw member and/or the counter-screw member are preferably provided with slide bearings, wherein lubrica- tion can take place by the liquid for pumping up. This also prevents the screw member and/or the counter-screw member from lying against the housing of the pump, so that wear is limited to a minimum. It is anticipated that the lifespan of a screw pump according to the present invention will amount to a minimum of 10,000 hours before maintenance thereon has to be carried out. Two or more screw pumps are preferably lowered into the earth in series. If in this preferred embodiment both screw pumps are designed to produce a pumping pressure of 30 bar, in total 60 bar, it may occur that due to small differences in dimensioning of each of the screw pumps one of the two screw pumps produces in the first instance a pressure greater than 30 bar. After a time the pressure build-up by this first screw pump will decrease slightly due to a certain degree of wear, wherein this decrease is however compensated by the second screw pump, so that the total required 60 bar is maintained. The present invention further provides a method for pumping liquids from the earth's crust, wherein one or more screw pumps, each comprising a screw member and a counter-screw member, is lowered into a hole drilled in the earth's surface, wherein the first screw member is driven close to or above the earth's surface and the counter-screw member is driven by the screw member and wherein the liquid is pumped up between the screw member and the second screw member. Further advantages, features and details of the present invention will become apparent in the light of the following description with reference to the annexed drawings, in which: fig. 1 shows a sectional view under the earth's surface of a first preferred embodiment of an installa¬ tion according to the present invention for performing the method according to the present invention; fig- 2 shows a side view along line II-II of the installation of fig. 1; fig. 3 is a sectional view above the lower screw pump of a second preferred embodiment of the installation according to the present invention; fig. 4 shows a view in cross section of detail IV of fig. 1; fig. 5 shows a view in cross section of detail V of fig. 1; and fig. 6 is a view along line VI-VI in fig. 5. A first preferred embodiment of an installation 1 according to the present invention (fig. 1, 2, 5 and 6) contains drive means 8 disposed on the ground S and provided with a connecting flange 2 for connection to a drain pipe 3 for the pumped-up oil. Driven by drive means 8 is a tube, rod or shaft 4 which transmits the drive power to a depth of for instance 1000 or 2000 metres in the ground to an assembly of two screw pumps 5 and 6. Each of the screw pumps, for instance screw pump 6, comprises a driven screw member 7 and a counter-screw member 9 which is driven by the associated screw member. Screw member 7 and counter-screw member 9 are mutually adapted such that the liquid is transported between the helical grooves and helical ridges, while the counter- screw member follows precisely the movement of the screw member. The screw member and the counter-screw member are preferably manufactured from hardened stainless steel which can withstand temperatures of 300°C and is little subject to wear. It can further be seen, particularly in fig. 1, 2 and 6, that the drive rod 4 and the screw pumps 5 and 6 can be received in a closed housing which has for instance a largest diameter d of about 15 cm so that the installation can be applied in a bore hole with such a dimension which may or may not be provided with a cement- ed casing. At a length in the order of magnitude of 1 metre a pressure of about 30-40 Bar can be produced by the above described screw pump shown in the figures, so that the petroleum can be pumped from a considerable depth, for instance 1000-3000 metres. When a number of screw pumps are placed in series in the manner shown it is possible to work at still greater depth. The screw members and counter-screw members are preferably provided in each case with axial and radial bearing elements 30, 31, respectively 32, 33, 34 and 35 (fig. 5) of ceramic material which are lubricated by the petroleum for pumping up. Fig. 3 shows a second preferred embodiment of an installation for performing the method according to the present invention, wherein a first pump 10 is lowered to great depth while a second screw pump 11 is situated clo.se to the surface at ground level S. If maintenance has to be carried out on this second screw pump 11 the drive rod 4' does not have to be withdrawn completely from the bore hole. The rights applied for are not limited by the above described preferred embodiments, but are defined in the first instance by the following claims. It is recommended that two or more screw pumps are lowered along the bore hole in interspaced manner, wherein the upper screw pump is situated at a minimum of for instance 300 metres below ground level and no pressures higher than 30 bar will occur in the installation.

Claims: CLAIMS 1. Installation for pumping up liquids from the earth's crust, comprising: - a screw pump lowered into the earth which is provided with a first screw member and a counter-screw member; - drive means arranged on or close to the earth's surface for driving the screw member which in turn drives the counter-screw member,* and - transmission means for transmitting the drive produced by the drive means, which transmission means extend from the drive means on or close to the earth's surface to the lowered screw pump. 2. Installation as claimed in claim 1, wherein the transmission means comprise one or more shafts. 3. Installation as claimed in claim 1 or 2, provided with one or more slide bearings for bearing mounting of the first screw member and/or the counter-screw member. 4. Installation as claimed in claim 3, wherein the slide bearings comprise one or more axial ceramic bear- ings. 5. Installation as claimed in claim 3 or 4, wherein the slide bearings comprise one or more radial ceramic bearings. 6. Installation as claimed in any of the foregoing claims, wherein the first screw member and/or the second counter-screw member are manufactured from a heat-resis¬ tant and hard material. 7. Installation as claimed in claim 6, wherein the material is hardened stainless steel. 8. Installation as claimed in any of the foregoing claims, wherein two or more screw pumps are placed in series under the earth's surface. 9. Method for pumping liquids from the earth's crust, wherein one or more screw pumps, each comprising a screw member and a counter-screw member, is lowered into a hole drilled in the earth's surface, wherein the first screw member is driven close to or above the earth's surface and the counter-screw member is driven by the screw member and wherein the liquid is pumped up between the screw member and the second screw member. 10. Method as claimed in claim 9, wherein bearings for the screw member and the counter-screw member are lubricated by the liquid for pumping up.

Inventors: BERKHOFF HENDRIK GEERT CORNELI, VAN DEN BOOGAARD ENGELBERT JOS, BERKHOFF, HENDRIK, GEERT, CORNELIS, VAN DEN BOOGAARD, ENGELBERT, JOSEPHUS
Applicants: BERKHOFF HENDRIK GEERT CORNELI, DEN BOOGAARD ENGELBERT JOSEPHU, HOUTTUIN BEHEER BV, BERKHOFF, HENDRIK, GEERT, CORNELIS, HOUTTUIN BEHEER B.V., VAN DEN BOOGAARD, ENGELBERT, JOSEPHUS
Application year: 1995
Main classification: F04C11
IPC codes: F04C13