Method, a system, and a probe for determining in-situ an oxidation-reduction potential in a formation having a surface

Abstract

Aspects of the present disclosure are directed to a system for determining in-situ oxidation-reduction potential in a formation having a surface separating the formation from an ambient atmosphere. The system may measure the oxidation-reduction potential in-situ, and thereby provide the most precise measurement of the oxidation-reduction potential. The formation surface may be the interface between the ambient atmosphere and the uppermost layer of the formation. The system may comprise a probe for a penetration into the formation. a reference electrode for placing on the formation surface, and a controller configured to communicate with the probe. The controller may be configured to communicate with the reference electrode, determine the oxidation-reduction potential as a potential difference between the reference electrode and the oxidation-reduction electrode, and communicate with the probe, the oxidation-reduction electrode, the reference electrode or any other device by a wire or wireless or a combination of wire and wireless.

Claims

1. A method of determining an oxidation-reduction potential in a formation having a surface, the method including the following steps: placing a reference electrode at the surface; penetrating by direct push drilling a probe carrying an oxidation-reduction electrode into the formation, while the reference electrode is at the surface; determining the oxidation-reduction potential as a potential difference between the reference electrode and the oxidation-reduction electrode, wherein the step of determining is performed during the penetrating step.

2. The method according to claim 1, wherein the act of penetrating is performed by directing the probe as a function of time.

3. The method (1000) according to claim 1, wherein the act of penetrating includes establishing a penetration of the probe into the formation; and wherein the act of determining the oxidation-reduction potential is performed as a function of the penetration.

4. The method (1000) according to claim 1, further including the steps of retracting the probe from the formation and performing a direct current resistivity measurement during retraction.

5. The method according to claim 1, further including the steps of: using a meter of the probe to measure a direct current resistivity, and determining resistivity as a function of time, penetration, or both time and penetration.

6. A system for determining in situ oxidation-reduction potential in a formation having a surface separating the formation from an ambient atmosphere, the system (20) comprising: a probe including a probe body and an oxidation-reduction electrode, the probe configured and arranged to penetrate into the formation; a reference electrode external to the probe configured and arranged for placement on the surface of the formation; and a controller configured and arranged to communicate with the probe and the reference electrode; determine the oxidation-reduction potential as a potential difference between the reference electrode and the oxidation-reduction electrode; wherein the oxidation-reduction electrode is a metal electrode substantially encapsulated in and galvanically isolated from the probe body, and the oxidation-reduction electrode includes an electrode body encapsulating the metal electrode, wherein the electrode body includes a protrusion and the probe body includes a throughgoing recess in the probe body, and the protrusion is complementary to the throughgoing recess, the protrusion has an outer face with an exposed part of the metal electrode.

7. The system according to claim 6, further including a penetrometer communicatively coupled with the controller, the controller further configured and arranged to determine the oxidation-reduction potential as a function of the probe penetration into the formation.

8. The system according to claim 6, further including a timer communicatively coupled with the controller, the controller further configured to determine the oxidation-reduction potential as a function of time.

9. The system according to claim 6, wherein the probe further includes a meter configured and arranged for measuring a direct current resistivity, and the controller is further configured and arranged to determine resistivity as a function of time, penetration, or both time and penetration.

10. The system according to claim 6 to perform the method of determining the oxidation-reduction potential according to claim 1.

11. A computer-readable medium having stored thereon the computer program of claim 10.

12. The system according to claim 6, wherein the probe is further configured and arranged to retract out of the formation and while the probe is retracting the controller circuitry is further configured and arranged to perform a direct current resistivity measurement.

13. The system according to claim 6, wherein the probe further includes a meter configured and arranged for measuring a direct current resistivity.

14. A probe for a penetration into a formation, the probe comprising: a probe body including a probe front configured and arranged for penetrating the formation, and a throughgoing recess, an oxidation-reduction electrode, supported by the probe body, and an electrode body including a protrusion complementary to the throughgoing recess in the probe body, the protrusion having an outer face with an exposed part of the oxidation-reduction electrode, wherein the oxidation-reduction electrode is a metal electrode, substantially encapsulated in and galvanically isolated from the probe body by the electrode body.

15. Use of the probe according to claim 14 for determining an oxidation-reduction potential in a formation having a surface.

16. The probe of claim 14, wherein the probe further includes a meter configured and arranged for measuring a direct current resistivity.

17. The probe of claim 14, wherein the probe is further configured and arranged to retract out of the formation and perform a direct current resistivity measurement during retraction.

Description

DESCRIPTION OF THE DRAWING

(1) Embodiments of the invention will be described in the figures, whereon:

(2) FIG. 1 illustrates a method of determining an oxidation-reduction potential [in situ] in a formation;

(3) FIG. 2 illustrates a determined oxidation-reduction potential as a function of penetration;

(4) FIG. 3 illustrates a system for determining in-situ oxidation-reduction potential in a formation;

(5) FIG. 4 illustrates a system for determining in-situ oxidation-reduction potential in a formation as a function of penetration;

(6) FIG. 5 illustrates a system for determining in-situ resistivity in a formation;

(7) FIG. 6 illustrates a system for determining in-situ resistivity in a formation as a function of penetration;

(8) FIG. 7 illustrates a system with a Wenner configuration for determining in-situ resistivity in a formation;

(9) FIG. 8 illustrates a system with a Wenner configuration for determining in-situ resistivity in a formation as a function of penetration;

(10) FIG. 9 illustrates a system for determining in-situ oxidation-reduction potential in a formation using a probe having an auger;

(11) FIG. 10 illustrates an oxidation-reduction electrode (A) and cross-section of a probe body having an oxidation-reduction electrode (B);

(12) FIG. 11 illustrates a probe having a meter with four electrodes (A) and a probe having a meter with two resistivity electrodes (B);

(13) FIG. 12 illustrates a probe with an oxidation-reduction electrode; and

(14) FIG. 13 illustrates an oxidation-reduction potential as a function of penetration and a resistivity measurement as a function of penetration.

DETAILED DESCRIPTION OF THE INVENTION

(15) TABLE-US-00001 Item No Formation 10 Surface 12 Ambient atmosphere 16 Redox interface 18 System 20 Controller 30 Communication 32 Probe 40 Probe body 42 Probe front 44 Oxidation-reduction potential 50 Reference electrode 52 Oxidation-reduction electrode 54 Electrode body 55 Oxidation-reduction electrode holder 56 Protrusion 58 Outer face 59 Penetrometer 60 Penetration 62 Meter 70 Resistivity electrode 72 Current electrode 74 Resistivity 76 Plastic ring 80 Plastic tube 82 Method 1000 Placing 1100 Penetrating 1200 Retracting 1300 Determining 1400 Establishing 1500

(16) FIG. 1 illustrates a method 1000 of determining an oxidation-reduction potential 50 in a formation 10 having a surface 12.

(17) The method 1000 comprises the act of placing 1100 a reference electrode 52 at the surface 12. There is a further act of penetrating 1200 or retracting 1300 a probe 40 carrying an oxidation-reduction electrode 54 into the formation 10. There is a further act of determining 1400 the oxidation-reduction potential 50 as the potential difference between the reference electrode 52 and the oxidation-reduction electrode 54.

(18) As an example, the reference electrode 52 is placed at the surface of the formation 10. Afterwards a drilling mechanism will perform the act of penetrating 1200 the probe 40 into the formation 10. The probe 40 carries an oxidation-reduction electrode 54. A controller 30, being in wireless or wired communication 32 with the oxidation-reduction electrode 54 and the reference electrode 52, will perform the act of determining 1400 the oxidation-reduction potential 50 as the potential difference between the reference electrode 52 and the oxidation-reduction electrode 54.

(19) In FIGS. 3, 4 and 9 a system 20 has executed the above mentioned method 1000, wherein the act of determining 1400 the oxidation-reduction potential 50 is performed whilst penetrating 1200.

(20) FIG. 2 illustrates a determined oxidation-reduction potential 50 as a function of penetration 62.

(21) The method 1000 comprises an act of placing 1100 a reference electrode 52 at the surface 12. There is a further act of penetrating 1200 or retracting 1300 a probe 40 carrying an oxidation-reduction electrode 54 into the formation 10. Wherein the act of penetrating 1400 or retracting 1300 involves an act of establishing 1500 a penetration 62 of the probe 40 into the formation 10; and wherein the act of determining 1400 the oxidation-reduction potential 50 is performed as a function of the penetration 62.

(22) As an example, the reference electrode 52 is placed at the surface of the formation 10. Afterwards, a drilling mechanism will perform the act of penetrating 1200 the probe 40 into the formation 10. The probe 40 carries an oxidation-reduction electrode 54. A penetrometer 60 for measuring a penetration 62 of the probe is in connection with the probe 40. A controller 30, which is in wireless or wired communication 32 with the oxidation-reduction electrode 54, the reference electrode 52, will perform the act of determining 1400 the oxidation-reduction potential 50 as the potential difference between the reference electrode 52 and the oxidation-reduction electrode 54. The controller 30 is also in wireless or wired communication 32 with the penetrometer 60 and the oxidation-reduction potential 50 as a function of the penetration 62 into the formation 10 is therefore determined.

(23) In FIG. 4 a system 20 has executed the above mentioned method 1000, wherein the act of determining 1400 the oxidation-reduction potential 50 as a function of the penetration 62 into the formation 10 is performed whilst penetrating 1200.

(24) FIG. 3 illustrates a system 20 for determining in-situ oxidation-reduction potential 50 in a formation 10. The formation 10 has a surface 12 which separates the formation 10 from the ambient atmosphere 16.

(25) The system 20 comprises a probe 40 for penetration 62 into the formation 10. The probe comprises an oxidation-reduction electrode 54. The oxidation-reduction electrode 54 may be a metal electrode or noble metal electrode or a platinum electrode.

(26) The system can comprise any drilling mechanism and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(27) The system 20 further comprises external to the probe 40 a reference electrode 52. The reference electrode 52 is placed at the surface 12 of the formation 10.

(28) The system 20 further comprises a controller 30, which is configured to communicate 32 by wire or wirelessly with: the probe 40; and the reference electrode 52.

(29) The controller 30 is further configured to perform an act of determining 1400 the oxidation-reduction potential 50 as a potential difference between the reference electrode 52 and the oxidation-reduction electrode 54.

(30) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is penetrating 1200 the formation 10.

(31) The oxidation-reduction electrode 54 is crossing a dashed line in the figure, which indicates the redox interface 18.

(32) A sketch of graph is disclosed, where the first axis has arbitrary units and the second axis is the determined oxidation-reduction potential 50 and the redox interface 18 is indicated by a large change in potential.

(33) FIG. 4 illustrates a system 20 for determining in-situ oxidation-reduction potential 50 in a formation as a function of penetration 62. The formation 10 has a surface 12 which separates the formation 10 from the ambient atmosphere 16.

(34) The system 20 comprises a probe 40 for a penetration 62 into the formation 10. The probe comprises an oxidation-reduction electrode 54.

(35) The system can comprise any drilling mechanism and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(36) The system 20 further comprises external to the probe 40 a reference electrode 52.

(37) The reference electrode 52 is placed at the surface 12 of the formation 10.

(38) The system 20 further comprises a penetrometer 60 for determining a penetration 62 of the probe 40.

(39) The penetrometer 60 is a string potentiometer.

(40) The system 20 comprises a controller 30 which is configured to communicate 32 by wire or wirelessly with The probe 40; The reference electrode 52; and The penetrometer 60.

(41) The controller 30 is further configured to determining 1400 the oxidation-reduction potential 50 as a potential difference between the reference electrode 52 and the oxidation-reduction electrode 54 as a function of the penetration 62 into the formation 10.

(42) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is penetrating 1200 the formation 10.

(43) The oxidation-reduction electrode 54 is crossing a dashed line in the figure which indicates the redox interface 18.

(44) A sketch of graph is disclosed, where the first axis is the penetration 62 and the second axis is the determined oxidation-reduction potential 50 and the redox interface 18 is indicated by a large change in potential.

(45) FIG. 5 illustrates a system 20 for determining in-situ resistivity 76 in a formation 20. The formation 10 has a surface 12 separating the formation 10 from the ambient atmosphere 16.

(46) The system 20 comprises a probe 40 for penetration 62 into the formation 10. The probe comprises a meter 70 having two resistivity electrodes 72 for measuring a potential/measuring a direct current (DC).

(47) The system can comprise any drilling mechanism, and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(48) The system 20 further comprises a pair of current electrodes 74, 74 for providing a direct current. The current electrodes 74, 74 are placed at the surface 12 of the formation 10.

(49) The system 20 further comprises a controller 30, which is configured to communicate 32 by wire or wirelessly with: The probe 40 with the meter 70; and The pair of current electrodes 74, 74.

(50) The controller 30 is configured to determine the resistivity 76 of the formation, based on applied direct current and potential between the resistivity electrodes 72.

(51) The pair of current electrodes 74, 74 is positioned on each side of the probe 40.

(52) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is retracting 1300 from the formation 10.

(53) A dashed line in the figure indicates the redox interface 18.

(54) A sketch of graph is disclosed, where the first axis is in arbitrary units and the second axis is the determined resistivity 76.

(55) FIG. 6 illustrates a system 20 for determining in-situ resistivity 76 in a formation 10 as a function of penetration 62. The formation 10 has a surface 12 separating the formation 10 from the ambient atmosphere 16.

(56) The system 20 comprises a probe 40 for a penetration 62 into the formation 10. The probe comprises a meter 70, having two resistivity electrodes 72 for measuring a potential/measuring a direct current (DC).

(57) The system can comprise any drilling mechanism and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(58) The system 20 further comprises a pair of current electrodes 74, 74 for providing a direct current. The current electrodes 74, 74 are placed at the surface 12 of the formation 10.

(59) The system 20 further comprises a penetrometer 60 for determining a penetration 62 of the probe 40.

(60) The penetrometer 60 is a string potentiometer.

(61) The system 20 further comprises a controller 30 which is configured to communicate 32 by wire or wirelessly with: The probe 40 with the meter 70; The pair of current electrodes 74, 74; and The penetrometer 60.

(62) The controller 30 is further configured to determine the resistivity 76 of the formation based on applied direct current and potential between the resistivity electrodes 72 as a function of penetration 62.

(63) The pair of current electrodes 74, 74 is positioned on each side of the probe 40.

(64) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is retracting 1300 from the formation 10.

(65) A dashed line in the figure indicates the redox interface 18.

(66) A sketch of graph is disclosed, where the first axis is the penetration 62 in arbitrary units and the second axis is the determined resistivity 76.

(67) FIG. 7 illustrates a system 20 with a Wenner configuration for determining in-situ resistivity 76 in a formation 10.

(68) The formation 10 has a surface 12 separating the formation 10 from the ambient atmosphere 16.

(69) The system 20 comprises a probe 40 for penetration 62 into the formation 10. The probe comprises a meter 70 having two resistivity electrodes 72 for measuring a potential/measuring a direct current (DC) and two current electrodes 74 for providing a direct current.

(70) The electrodes 72, 74 of the meter are in a Wenner configuration and the electrodes 72, 74 are ring electrodes.

(71) The system can comprise any drilling mechanism, and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(72) The system 20 further comprises a controller 30, which is configured to communicate 32 by wire or wirelessly with the probe 40 with the meter 70.

(73) The controller 30 is configured to determine the resistivity 76 of the formation, based on applied direct current and potential between the resistivity electrodes 72.

(74) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is retracting 1300 from the formation 10.

(75) A dashed line in the figure indicates the redox interface 18.

(76) A sketch of graph is disclosed, where the first axis is in arbitrary units and the second axis is the determined resistivity 76.

(77) FIG. 8 illustrates a system 20 with a Wenner configuration for determining in-situ resistivity 76 in a formation 12 as a function of penetration 62.

(78) The formation 10 has a surface 12 separating the formation 10 from the ambient atmosphere 16.

(79) The system 20 comprises a probe 40 for penetration 62 into the formation 10. The probe comprises a meter 70 having two resistivity electrodes 72 for measuring a potential/measuring a direct current (DC) and two current electrodes 74 for providing a direct current.

(80) The electrodes 72, 74 of the meter are in a Wenner configuration and the electrodes 72, 74 are ring electrodes.

(81) The system can comprise any drilling mechanism and the drilling mechanism is therefore disclosed as a rectangle next to the probe 40.

(82) The system 20 further comprises a penetrometer 60 for determining a penetration 62 of the probe 40.

(83) The penetrometer 60 is a string potentiometer.

(84) The system 20 further comprises a controller 30 which is configured to communicate 32 by wire or wirelessly with: The probe 40 with the meter 70; and The penetrometer 60.

(85) The controller 30 is further configured to determine the resistivity 76 of the formation based on applied direct current and potential between the resistivity electrodes 72 as a function of penetration 62.

(86) The arrow below the probe 40 indicates the movement of the probe 40 and in this figure, the probe 40 is retracting 1300 from the formation 10.

(87) A dashed line in the figure indicates the redox interface 18.

(88) A sketch of graph is disclosed, where the first axis is the penetration 62 in arbitrary units and the second axis is the determined resistivity 76.

(89) FIG. 9 illustrates a system 20 for determining in-situ oxidation-reduction potential 50 in a formation 10 using a probe 40 having an auger. FIG. 7 only differs from FIG. 3 by the probe having an auger.

(90) FIG. 10 illustrates an oxidation-reduction electrode 54 (A) and cross-section of a probe body 42 having an oxidation-reduction electrode (B).

(91) The oxidation-reduction electrode 54 comprises an electrode body 55. The electrode body 55 encapsulates the metal electrode. The electrode body 55 comprises a protrusion 58 complementary to a through going recess 46 in the probe body 42, see FIG. 10B. The protrusion 58 has an outer face 59 with an exposed part of the metal electrode.

(92) The reference line for the oxidation-reduction electrode 54 points to the metal electrode.

(93) The oxidation-reduction electrode 54 has a curved part adapted for engaging with the cylindrical shape of the probe body 42.

(94) The protrusion 58 has an extent such that the outer face 59 and probe body 42 form a flush surface.

(95) The electrode body 55 has a back side (not shown) which is to engage with an oxidation-reduction electrode holder.

(96) The oxidation-reduction electrode holder 56 has a substantially cylindrical shape with a slit towards a central recess, where the slit and central recess are adapted for engaging the oxidation-reduction electrode 54 when the oxidation-reduction electrode 54 and the oxidation-reduction electrode holder is positioned inside the probe body 42 as seen in FIG. 10B. The entire connection is very sturdy, such that the oxidation-reduction electrode 54 can experience large forces or pressures without drifting and thereby either reducing the resolution, or in worse case, corrupting the data completely.

(97) FIG. 11A illustrates a probe 40 having a meter 70 with four electrodes 72, 74 (A). The two resistivity electrodes 72 and the two current electrodes 74 are all ring electrodes and positioned in a Wenner configuration.

(98) The electrodes 72, 74 are to be isolated from the rest of the probe 40 by plastic rings 80 positioned between the electrodes 72, 74 and a plastic tube 82.

(99) FIG. 11B illustrates a probe 40 having two resistivity electrodes 72. In this case current electrodes 74 (not shown) are to be placed at a surface 12 of a formation 10.

(100) The resistivity electrodes 72 are ring electrodes.

(101) The resistivity electrodes 72 are to be isolated from the rest of the probe 40 by plastic rings 80 positioned between the electrodes 72 and a plastic tube 82.

(102) FIG. 12 illustrates probe 40 with an oxidation-reduction electrode 54.

(103) The probe 40 has a probe body 42 with a probe front 44. Where the probe front 44 has a pointed end for easing the penetration. The probe 40 has another probe body 42′ with an oxidation-reduction electrode 54 to be connected to the probe body 42 with the probe front 44.

(104) The oxidation-reduction electrode 54 comprises an electrode body 55. The electrode body 55 encapsulates the metal electrode. The electrode body 55 comprises a protrusion 58 complementary to a through going recess 46 in the probe body 42. The protrusion 58 has an outer face 59 with an exposed part of the metal electrode.

(105) FIG. 13 illustrates an oxidation-reduction potential 50 as a function of penetration 62 (A) and a resistivity 76 measurement as a function of penetration 62 (B).

(106) FIG. 13A discloses a graph of a formation 10, which is reduced as the measured oxidation-reduction potential 50 at all penetrations 62 is negative, thus, this formation supports or could support bacteria capable of denitrification.

(107) FIG. 13B discloses a graph of a formation 10, which has been studied using Direct current. The resistivity 76 measurement is plotted as function of the penetration 62. The lithography of the formation 10 can be determined from the resistivity 76. Since water-bearing layers such as sand have different oxidation-reduction potentials 50 compared to non-water-bearing layers, the lithography of the formation 10 is important when interpreting any oxidation-reduction potential surveys.