METHOD FOR MONITORING SALINITY WITHIN AN UNDERGROUND FORMATION
First Claim
1. A method of exploiting and/or of monitoring the exploitation of a fluid such as a hydrocarbon fluid present in at least one geologic layer of an underground formation, at least one well being drilled through at least the layer of the formation, by means of at least one graph representative of the evolution of the electrokinetic coupling coefficient as a function of salinity for the layer, wherein the salinity within at least the layer is determined at least at one measurement point located in the well and at the level of the layer for at least one predefined time Ti of the exploitation of the fluid, by carrying out at least the following steps:
- a) measuring a pressure at the measurement point for at least the time Ti, a time Ti−
1 preceding the time Ti and a time Ti+1 following the time Ti,b) measuring a spontaneous potential at the measurement point for the times Ti−
1, Ti and Ti+1,c) from the pressure measurements and the spontaneous potential measurements for the times Ti−
1, Ti and Ti+1 at the measurement point, determining the slope of a curve showing the evolution of the spontaneous potential gradient as a function of the pressure gradient between the times Ti−
1 and Ti+1, andd) from the slope and the graph, determining a value for the salinity at the measurement point and at the time Ti,and in that the fluid is exploited and/or the exploitation of the fluid is monitored by taking account of the value of the salinity.
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Accused Products
Abstract
Method of exploiting and/or of monitoring the exploitation of a fluid such as a hydrocarbon fluid present in at least one geologic layer of an underground formation.
From consecutive pressure and spontaneous potential measurements taken at least at one measurement point in at least one well drilled through at least the geologic layer of interest, the slope of a curve showing the evolution of the spontaneous potential gradient as a function of the pressure gradient is determined. Then, from this slope and from a graph representative of the evolution of the electrokinetic coupling coefficient as a function of the salinity for the layer considered, a salinity value is determined at the measurement point.
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Citations
6 Claims
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1. A method of exploiting and/or of monitoring the exploitation of a fluid such as a hydrocarbon fluid present in at least one geologic layer of an underground formation, at least one well being drilled through at least the layer of the formation, by means of at least one graph representative of the evolution of the electrokinetic coupling coefficient as a function of salinity for the layer, wherein the salinity within at least the layer is determined at least at one measurement point located in the well and at the level of the layer for at least one predefined time Ti of the exploitation of the fluid, by carrying out at least the following steps:
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a) measuring a pressure at the measurement point for at least the time Ti, a time Ti−
1 preceding the time Ti and a time Ti+1 following the time Ti,b) measuring a spontaneous potential at the measurement point for the times Ti−
1, Ti and Ti+1,c) from the pressure measurements and the spontaneous potential measurements for the times Ti−
1, Ti and Ti+1 at the measurement point, determining the slope of a curve showing the evolution of the spontaneous potential gradient as a function of the pressure gradient between the times Ti−
1 and Ti+1, andd) from the slope and the graph, determining a value for the salinity at the measurement point and at the time Ti, and in that the fluid is exploited and/or the exploitation of the fluid is monitored by taking account of the value of the salinity. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification