Sensing and recording module within an untethered object acting as a pressure differential isolation of well fluid

1. A method comprising:

placing an untethered sensing object inside a well fluid of a wellbore,

whereby the untethered sensing object can perform sensing and data recording of well fluid and wellbore parameters, and

whereby the untethered sensing object includes at least one sensor and an external shell with at least one cross-sectional circular shape, and

wherein the external shell contains one or more connecting channels, wherein the one or more connecting channels connect the wellbore fluid to the sensor;

sensing and data recording of well fluid and wellbore parameters by the untethered sensing object while being in the well fluid;

conveying the untethered sensing object within the well fluid of the wellbore;

stopping the untethered sensing object at a previously placed plugging element inside the wellbore, wherein the plugging element comprises a cross-sectional restriction with a flow-through area, including a contact line matching the at least one cross-sectional circular shape of the external shell of the untethered sensing object; and

performing an isolation of well fluid across the contact line between the untethered sensing object and the plugging element.

2. The method of claim 1 , wherein performing an isolation of well fluid across the contact line between the untethered sensing object and the plugging element includes withstanding a pressure differential across the untethered sensing object and the plugging element, wherein the pressure differential is ranging from 100 psi to 20,000 psi [0.7 MPa to 140 MPa].

3. The method of claim 1 , wherein the plugging element inside the wellbore is a fracturing plug, a bridge plug, a seat, a sleeve seat, a packer, a liner hanger, or a tubing diameter restriction.

4. The method of claim 1 , wherein placing an untethered sensing object inside a well fluid of a wellbore, includes launching the untethered sensing object from surface or releasing it from a toolstring inside the wellbore.

5. The method of claim 4 , wherein the toolstring is conveyed via wireline, coiled-tubing, slick-line or tractor and provides the setting of the plugging element inside the wellbore, prior of having the untethered sensing object stopped by the set plugging element.

6. The method of claim 4 , wherein conveying the untethered sensing object within the well fluid of the wellbore includes gravity fall, wellbore fluid pumping or pushing by the toolstring.

7. The method of claim 1 , wherein the wellbore comprises tubing, cemented or non-cemented casing, or open-hole.

8. The method of claim 1 ,

wherein sensing and data recording of well fluid includes:

fluid pressure, fluid temperature, fluid flow, fluid properties like composition, density, resistivity, salinity, or pH; and

wherein sensing and data recording of wellbore parameters includes:

casing collar locator, casing thickness, cement bound, or formation properties like formation acoustic, resistivity, porosity, permeability, and natural radioactivity.

9. The method of claim 1 , wherein sensing and data recording of well fluid and wellbore properties comprises sensing and data recording on both sides, uphole and downhole, of the contact line between the untethered sensing object and the plugging element, inside the wellbore fluid.

10. The method of claim 1 , wherein the untethered sensing object or the plugging element includes a material dissolvable by well fluid.

11. The method of claim 10 , further comprising dissolving the external shell of the untethered sensing object inside the well fluid, wherein dissolving the external shell reduces the external dimension of the untethered sensing object and enables the remaining untethered sensing object to pass across the flow-through area of the plugging element.

12. The method of claim 11 , wherein the untethered sensing object is able to perform the sensing and data recording function while its external shell is dissolving.

13. An apparatus, for use inside a well fluid of a wellbore, comprising:

a plugging element including:

a cross-sectional restriction of the wellbore with a flow-through area, and

a contact line along the cross-sectional restriction; and

an untethered sensing object including:

at least one sensor,

an acquisition and data recording module, and

an external shell; and

wherein the at least one sensor senses the well fluid and wellbore properties and converts the measurement into an electrical signal;

wherein the acquisition and data recording module collects the electrical signal from the at least one sensor;

wherein the contact line along the cross-sectional restriction of the plugging element is a continuous edge around the flow-through area;

wherein the external shell of the untethered sensing object includes at least one cross-sectional circular shape able to stop on the contact line along the cross-sectional restriction of the plugging element;

wherein the external shell contains one or more connecting channels, wherein the one or more connecting channel connects the wellbore fluid to the sensor; and

wherein the contact line provides an isolation of well fluid able to ensure a pressure differential, between 100 and 20,000 psi, [0.7 MPa and 140 MPa] across the untethered sensing object and the plugging element inside the wellbore.

14. The apparatus of claim 13 , wherein the untethered sensing object is a ball, a dart, a pill, or an object having the external shell comprising a solid shape of revolution, including spherical, cylindrical or conical volumes.

15. The apparatus of claim 13 , wherein the untethered sensing object comprises at least two sensors positioned inside the untethered sensing object, whereby the position of the at least two sensors enables the simultaneous sensing of well fluid and wellbore parameters, both uphole and downhole of the isolation at the contact line between the untethered sensing object and the plugging element.

16. The apparatus of claim 15 , wherein the untethered sensing object is spherical, and wherein four sensors are positioned inside the spherical untethered sensing object, and wherein the four sensors have a tetrahedral configuration within the spherical untethered sensing object.

17. The apparatus of claim 13 , wherein the untethered sensing object comprises material dissolving inside well fluid.

18. The apparatus of claim 17 , wherein dissolving of the external shell of the untethered sensing object modifies both external dimension of the at least one circular cross-section of the external shell and the overall density of the remaining non-dissolved untethered sensing object, enabling the remaining of non-dissolved untethered sensing object to pass through the cross-sectional restriction of the plugging element as well as enabling the remaining non-dissolved untethered sensing object to float within the well fluid.