The invention relates to the field of oil production, and in particular to the recovery of oil from deep wells.
Processes for increasing production in “the unit of time” (that is at a particular given time or over a specified time, e.g. barrels per day) and percentage of oil quantity obtained from oil-bearing deposits, used so far, may be divided into chemical, biological and mechanical processes. Chemical processes include the injection of various chemical agents in oil-bearing deposits and to decrease oil viscosity and facilitate it to flow into a bore hole or bore holes. Biological processes include the injection of microorganisms in oil-bearing deposits, where the replication and metabolism products thereof increase the oil deposit pressure and decrease the viscosity of oil. Mechanical processes include processes for the enlargement of the drainage zone, and for increasing the oil deposit pressure and devices for pumping the oil from bore holes. Processes for the enlargement of the drainage zone include hydraulic fracturing processes and making of horizontal bores. Processes for increasing deposit pressure are gas drive and water drive recovery. Devices used for recovery of oil from bore holes having pressure insufficient for natural flow are: bore hole pumps, bore hole centrifugal pumps, screw suction pumps, diaphragm suction pumps, and gas-driven lifting devices. Such gas-driven lifting devices may be of a permanent type, a periodical type, a type of piston lift, and a chamber lift and device for recovery of oil fluid from deep wells, such as disclosed in Croatian patent HR P920143.
A disadvantage of the fore-mentioned solutions, which include a device for recovery of oil fluid from deep wells, is that any of those solutions, used individually, does not increase production dynamics or percentage of oil quantity obtained from the oil-bearing deposits or maintain control over the production process. Additional disadvantages from the known device for recovery of oil fluid from deep wells are that installation is complex and the operation is continuous. Moreover, the quantity of oil obtained over a specified time is comparatively small and restricted by dynamic pressure, which is generated by such an operating regime without damaging the oil bearing deposit.
The aim of the solution according to this application is to construct such a device that will increase production over a specified time and increase the percentage of oil quantity obtained from the oil-bearing deposit, all while using very little energy and maintaining control over production.
The present invention relates to a gas turbine driven oil lifting device for obtaining oil from deep wells. The structural design of the gas turbine driven oil lifting device provides for the division of a production column-casing (or technical column) that has two parts or sections separated by a bypass packer. A gas turbine is fixed above the bypass packer. A tubing is fixed above the gas turbine. Above the turbine, a check valve is set within the tubing. Fixedly part of the tubing, but above the turbine and the check valve, is a plurality of spaced-apart valves for lifting the oil fluid. Each valve has various opening pressures in which each valve is installed on the tubing. The valve positioned closest to the gas turbine would have the lowest opening pressure. Each subsequent spaced-apart valve would have a slightly higher opening pressure. In the area (generally ring-shaped) between the tubing and the casing is a turbine supply tube, which is fixed to the tubing by at least one collar. The bottom end of the turbine supply tube is fixed to a rotor inlet of the gas turbine by a flexible hose.
Structural connection of elements, carried out in the afore-mentioned manner, allows gas to be driven by means of a compressor through the turbine supply tube to the gas turbine (via the inlet), thereby, starting to revolve the gas turbine. The gas is driven out from the gas turbine through a check valve entering a ring area defined as the area between the tubing and the casing. Turbine blades allow rotation of a rotor that contains a rotary pump. Rotation of a rotary pump, which is immersed in oil, drives oil upwards into the tubing.
Introduction of gas in the ring area causes a pressure increase in it and opens the bottom-most valve (closest to the check valve and gas turbine). The opening pressure of that bottom-most valve determines the difference between the turbine inlet and outlet pressures. Gas enters through it into the tubing, mixes with oil, and therewith facilitates the oil to be lifted.
These and other features and benefits will be discussed in further detail in the various figures of the attached drawings, the Brief Description of the Drawings, and the Best Mode for Carrying Out the Invention.
Like reference numerals are used to designate like parts throughout the several views of the drawings, wherein:
Referring to
The device operates as follows: gas under pressure is driven from the compressor though a supply tube of the turbine (2), which is connected by a flexible pipe (7) to the opening (20) of the upper head (34), then enters the cylinder (23) of the gas turbine (9), and activates the blades (24) that rotate the rotor (32). Rotary pump (25), which is immersed in oil, rotates together with the rotor (32). By its rotation, rotary pump (25) drives oil from the bottom part of casing (1) into tubing (17). Gas leaves the cylinder (23) through an opening (28) in the lower head (30), and enters the ring area (18) within casing (1). The ring area is preferably hermetically closed on its upper and lower sides. An increase of gas pressure in the ring area (18) opens valves (3), (4), (6), (8). The uppermost valve (illustrated as valve (8) also serves as a regulator of difference between the turbine pressure and flow through the turbine. It is adjusted to the lowest opening pressure. Possible further increase of pressure in the ring area (18) opens in turn: valves (6), then (4), and last, valve (3).
The valves preferably open and close automatically depending on opening pressures, to which they are adjusted. Opening of the valves in this manner (and as described in the paragraph above) allows gas to enter from the ring area (18) into the tubing (17) and thereby lift oil while decreasing the pressure of the oil affecting the gas turbine (9) and the rotary pump (25). Gas turbine (9) starts to rotate faster and lifts larger quantities of oil. When the supply of gas through the turbine supply tube (2) stops, the turbine (9) momentarily stops to operate.
Check valve (16), which has been open during the turbine operation, closes owing to pressure of hydrostatic column in the tubing (17). This action hermetically separates the area of low pressure in section (12), created by turbine operation (9), from the upper part of the tubing (17). Owing to pressure differential, oil flows from the distant parts of the oil deposit(s) to the area of lower pressure (12) created by turbine operation. After a certain time, owing to inflow of oil to the area of lower pressure (12), the pressure in area (12) increases. If the pressure in area (12) exceeds the pressure of hydrostatic column in the tubing (17), the check valve (16) opens and allows free flow of oil through the turbine (9). With new introduction of gas in the turbine (9), the turbine (9) starts to operate and the cycle repeats.
Check valve (10) at the turbine outlet (28) prevents fluid from entering the turbine during the well completion process.
In industrial applications of the invention, the invention is intended to increase the recovery of liquids from liquid-bearing geological deposits, such as recovery of oil or water from deep wells. This is particularly the case where partial depletion of deposits is present and where, owing to the deposit low pressure, natural flow is missing. The intention is to increase the quantity of oil obtained from the deposit in a specified time and to increase the percentage of total quantity of liquid obtained from the deposit, all while using the least energy possible.
The application of the technical solution according to this invention includes usual procedures, equipment, and material, provided that the staff is additionally trained for controlling and handling of the equipment.
Safety working measures are of standard type, and are not environmentally dangerous.
This solution provides for periodical turbine operation on high velocity rotation resulting in a large quantity of liquid recovered in a short period of time and creation of low pressure in bore hole areas, extending to oil bearing deposits.
The illustrated embodiments are only examples of the present invention and, therefore, are non-limitive. It is to be understood that many changes in the particular structure, materials, and features of the invention may be made without departing from the spirit and scope of the invention. Therefore, it is the Applicant's intention that its patent rights not be limited by the particular embodiments illustrated and described herein, but rather by the following claims interpreted according to accepted doctrines of claim interpretation, including the Doctrine of Equivalents and Reversal of Parts.
Number | Date | Country | Kind |
---|---|---|---|
PCT/HR02/00047 | Oct 2002 | WO | international |
P20010739A | Oct 2001 | HR | national |
This application claims priority to PCT International Application Serial No. PCT/HR02/00047, filed Oct. 11, 2002, and entitled “Gas Turbine For Oil Lifting,” which claims priority to Croatian application P20010739A, filed Oct. 12, 2001.