Apparatus for controlling injection pressure for the assisted recovery of oil using polymer

Abstract

An apparatus for controlling the injection pressure of an aqueous polymeric solution in an oil well is formed by: at least one pressure modulation valve, allowing, per valve, a maximum pressure loss of 5 bars practically without any mechanical deterioration, the one or more valves being connected in line with; a tube containing vortex modules, each creating a maximum pressure loss of 5 bars, practically without any mechanical deterioration, a vortex module being a section of tube, which is closed at one of its ends by a cap perforated with a hole, and which can be inserted into the detachable tube. The purpose of the apparatus is the ability to reduce the pressure to 100 bars with total mechanical deterioration of less than 10%. A method for using the apparatus is also contemplated.

Claims

1. An apparatus for controlling an injection pressure of an aqueous polymeric solution in an oil well, said apparatus comprising: at least one pressure modulation valve allowing a maximum pressure loss of 5 bars per valve, said one or more valves being connected in line with; a single tube of continuous inside diameter containing a plurality of vortex modules, each vortex module creating a maximum pressure loss of 5 bars, each vortex module being a section of tube, which is closed at one end thereof by an end wall perforated with a hole, and each vortex module being insertable into the single tube of continuous inside diameter containing the plurality of vortex modules; whereby the apparatus is able to reduce the injection pressure to 100 bars with total mechanical deterioration of the aqueous polymeric solution of less than 10%.

2. The apparatus according to claim 1, wherein the hole in the end wall has a diameter of between 10 and 25 mm depending on recommended injection flowrates.

3. The device according to claim 1, wherein the valves are needle valves.

4. The device according to claim 1, wherein a length of each vortex module is between 10 and 20 cm.

5. The apparatus according to claim 1, wherein the single tube of continuous inside diameter contains between 4 and 12 vortex modules.

6. The apparatus according to claim 1, comprising at least two pressure modulation valves.

7. The apparatus according to claim 1, wherein an outside diameter of each of the vortex modules is 1 mm smaller than the inside diameters of the single tube.

8. A method for reducing an injection pressure of an aqueous polymeric solution depending on a pressure of a well, using the device according to claim 1, in an enhanced oil recovery method.

9. The method according to claim 8, wherein a pressure loss created in a valve or in a vortex module is at most 5 bars.

10. The method according to claim 8, wherein said method is an offshore method.

11. The method according to claim 8, wherein a pressure loss created in a valve or in a vortex module is between 1 and 5 bars.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 represents a schematic view of the pressure regulation apparatus that can be connected in line with the main pipeline. The apparatus successively comprises two valves (1) enabling a maximum pressure reduction of 5 bars each, two pressure gauges (2) for monitoring pressure, and a detachable tube (3) containing 10 vortex modules (4), each allowing a maximum pressure reduction of 5 bars. In total, this apparatus is capable of regulating the pressure by a maximum of 60 bars.

(2) FIG. 2 represents a schematic view of one part of the detachable module (3) with inside diameter of 60 mm containing two vortex modules (4) with a length of 100 mm, outside diameter of 59 mm, inside diameter of 50 mm, each having a central orifice 14 mm in diameter.

DETAILED DESCRIPTION OF THE INVENTION

(3) Using the same wells as in example 1 of patent US2016/0168954 and the same polymer, the following results were obtained.

Example

(4) Four wells are fed with a water pump at 160 bars, in which the polymer is mixed at a dose of 500 ppm by pumping, with a triplex pump and injection after the water pump.

(5) The flow rate per well is fixed at 19 m.sup.3/hour, measured with an electromagnetic flowmeter.

(6) A pressure reducer is constructed comprising: Two 2-inch needle valves with pressure gauges enabling adjustment between 1 and 5 bars of pressure loss; A tube with inside diameter of 60 mm able to receive modules with outside diameter of 59 mm and inside diameter of 50 mm. The caps are perforated with a 14 mm passage to create a vortex pressure loss of 5 bars for 19 m.sup.3/hour.

(7) For the 130 bars well, 5 modules are placed in the tube, and the pressure can be modulated with the 2 valves from 125 to 135 bars.

(8) For the 125 bars well, 6 modules are placed in the tube, and we can modulate from 120 to 130 bars.

(9) For the 120 bars well, 7 modules are placed in the tube, and we can modulate from 115 to 125 bars.

(10) For the 110 bars well, 9 modules are placed in the tube, enabling modulation from 105 to 115 bars.

(11) As in the preceding tests, the deterioration noted is less than 5% even with a pressure difference of 50 bars.

(12) In the event a well would experience increased pressure over time, as is often the case, the tube would be dismantled and a module removed, which is a simple operation.

(13) This simple, compact and low-cost system meets the current demands of oil producers.