MXPA97005651A - Use of at least two separate wells for the extraction of hydrocarbons, for the extraction of geoterm energy - Google Patents

Abstract

The present invention relates to the use of at least two separate wells for the extraction of hydrocarbons, for the extraction of geothermal energy, together with at least one new well section, which interconnects the lower sections of each of the old wells, the old wells being used for the transport of a heat exchange fluid from bottom to top respectively of the new well section, so that the new well section is adapted to transport the heat exchange fluid from a well to the ot

Description

PERFORATION ON EARTH FOR TRANSFER OF GEOTHERMAL ENERGY TO A LIQUID THAT BRINGS ENERGY AND A METHOD FOR THE PRODUCTION OF DRILLING DESCRIPTION OF THE INVENTION The invention relates to a hole in the earth to transfer geothermal energy from the earth around the borehole to an energy carrying fluid which is introduced into the borehole. In US 4 290 266 it is disclosed that a pipe circuit can be placed in a hole with no outlet in the earth and that a fluid can pass down into the earth by means of the first section of the pipe circuit and upstream of the pipeline. earth by means of a second section of the pipe circuit. The disadvantage of this prior art technique is that the sections of the pipe circuit extend very close to each other where the hot fluid flowing upwards is cooled by the fluid flowing down cold, with the result that the overall efficiency it is low. In addition, it is known that there are a number of deep hole drilling or wells which have been used or are being used for the recovery of oil or gas together with associated facilities above ground. As a consequence of the difficulties in the environment, in which these facilities are often represented, and demands have been increased for such facilities to be removed or dismantled and the wells sealed after the extraction of oil or gas has ceased , which is a very expensive process. The object of the invention is to provide a perforation of the aforementioned type wherein the aforementioned disadvantages can be avoided. The characteristics of the perforation according to the invention are represented by the characteristic configurations indicated in the claims. The invention will be described in more detail with reference to the drawings whose schematic figure only illustrates a perforation according to the invention. As illustrated in the figure, a platform 1 is located at the bottom of the sea, the upper section of which projects upwards from the surface of the sea 6. From the sea bed 5 near the platform two substantially vertical drilling sections extend, viz, a first section 2 of the perforation and a third section 4 of the perforation to locations 7 and 8 respectively in the formation of the earth from which the oil or gas has been extracted and carried upwards by means of sections 2, 4 of the perforation. Instead of removing the platform and sealing sections 2, 4 of the perforation after the recovery of the oil or gas has finished, it is proposed according to the invention that a second or additional section 3 of the perforation must be perforated which connects the locations 7 and 8 to each other, thereby providing a drilling circuit comprising the first, second and third drilling sections 2, 3 and 4 respectively. By passing a suitable fluid, such as water, down into the first section 2 of the perforation, this fluid can flow through the second section 3 of the perforation, where it is heated by the surrounding earth, and subsequently towards up through the third section 4 of the perforation, without the heated fluid in the third section 4 of the perforation being cooled by the cold water flowing down which passes downwards in the first section 2 of the perforation. If the substantially vertical perforation sections 2 and 4 extend from the same platform 1 as illustrated in the figure, the additional section 3 of the perforation may extend in a relatively large circuit away from location 7 before it extends. to the second section 8, wherein it is ensured that the fluid is heated to the near temperature of the earth around the second section 3 of the bore before it flows up and out of the third section 4 of the borehole, even though the fluid velocity is high. It can be provided on the platform, a known per se installation (not shown) where the heat energy can be converted to another form of available energy, for example electrical energy, and supplied to a consumer. This installation may comprise, for example, heat exchangers, turbines, generators, etc., and it is assumed that this will be familiar to some person skilled in the art. As will be understood, the invention allows a reuse of the facilities and wells, the seizure of which has been linked at higher expense by the owner. The invention provides energy whose release does not pollute the environment, and which is obtained from an almost inexhaustible source. In order to illustrate the costs involved by the amount of energy that has been provided, the following information is provided.

The temperature on the ground is approximately 110 - 180 ° C at a depth of between 3500 m and 6000 m below the sea floor. Two boreholes of holes each having a length of about 3000 m to extract oil or gas present costs of approximately 150 million NOK. An original deviated drilling which has a length of approximately 1000 m and which connects these two hole drilling costs approximately NOK 20 million. For example, the field of Statfjord B drilling in the North Sea comprises approximately 40 wells which together with the platform will probably be closed around 2003. Applying the invention, however, these pozos can be part of 20 circuits of perforations for the production of geothermal energy, and the platform can be used as the installation location for the aforementioned installation. It will be understood that pipelines in which the fluid can flow may be inserted into the perforation sections. For this oil field the following examples can be used: Diameter of internal pipe 0.215 m Water volume 700 m3 / h Water velocity 5.32 m / s Inlet temperature of the upstream water pump 20 ° C Outlet temperature of the downstream water pump 40 ° C Exhaust water outlet temperature 110 ° C Length of drilling 7000 m Pump power 1.72 MW Thermal energy 40 MW As a preliminary estimate, this thermal energy can provide an effective output of approximately 5 MW. The 20 drilling circuits in this oil field can thus be able to provide a total output of 100 MW of electricity, subtracting the realization of the pump 20 x 1.75 MW = 34.4 MW, which gives a total of 65.6 MW of electricity. Although it has been established in the above description of the invention that the two perforation sections have been interconnected by means of an additional perforation section, it will be understood that more than two sections of perforations can be interconnected.

Claims (1)

1. The use of at least two separate wells which have previously been used for the extraction of hydrocarbons, for the extraction of geothermal energy, together with at least one new well section which interconnects the lower sections of each of the wells old, old wells that have been used to transport an exchange of heat from a fluid downward and upward respectively of the new well section and through a pipeline that runs continuously through the old wells and the new well section , where the new well section is adapted to transport the heat exchange fluid from one well to the other, and then to a geothermal power plant.