Apparatus and method for measuring concentrations of scale-forming ions
First Claim
1. A method of monitoring the concentrations of scaling ions in a fluid, wherein the scaling ions are selected from the group consisting of Ca2+, Ba2+ and Sr2+ ions, the method comprising;
- bringing the fluid into contact with a membrane which is permeable to the scaling ions and is located between the fluid and a ligand which selectively binds scaling ions, wherein the ligand comprises a portion binding a scaling ion and a redox-active group attached thereto and the binding of the scaling ions to the ligand alters the electronic configuration of the ligand;
applying varying potential to electrodes placed in the vicinity of the ligand and thereby causing redox reaction of the redox active group, where alterations in the electronic configuration through binding of a scaling ion change the flow of current in response to applied potential,measuring the current flowing in response to applied potential, and thereby measuring alterations in the electronic configuration of the ligand; and
,determining the concentration of said scaling ion from the measurements of current flow.
0 Assignments
0 Petitions
Accused Products
Abstract
This invention relates to methods and apparatus for determination of ion concentrations, particularly in downhole water from hydrocarbon wells, aquifers etc. It is useful in a wide range of applications, including predicting the formation of scale and fingerprinting waters from different sources. More particularly, the invention relates to the use of ligands whose electronic configuration is altered by the binding of the scaling ions within a water sample. These alterations are detected electrochemically by applying varying potential to electrodes and measuring current flow as potential is varied, from which is derived the concentration of scaling ions in the fluid.
14 Citations
9 Claims
-
1. A method of monitoring the concentrations of scaling ions in a fluid, wherein the scaling ions are selected from the group consisting of Ca2+, Ba2+ and Sr2+ ions, the method comprising;
-
bringing the fluid into contact with a membrane which is permeable to the scaling ions and is located between the fluid and a ligand which selectively binds scaling ions, wherein the ligand comprises a portion binding a scaling ion and a redox-active group attached thereto and the binding of the scaling ions to the ligand alters the electronic configuration of the ligand; applying varying potential to electrodes placed in the vicinity of the ligand and thereby causing redox reaction of the redox active group, where alterations in the electronic configuration through binding of a scaling ion change the flow of current in response to applied potential, measuring the current flowing in response to applied potential, and thereby measuring alterations in the electronic configuration of the ligand; and
,determining the concentration of said scaling ion from the measurements of current flow. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
Specification
-
- Resources
-
Current AssigneeSchlumberger Technology Corporation (Schlumberger NV)
-
Original AssigneeSchlumberger Technology Corporation (Schlumberger NV)
-
InventorsJiang, Li, Jones, Timothy Gareth John, Meredith, Andrew, Pagels, Markus, De Silva, Amilra Prasanna
-
Primary Examiner(s)Sines, Brian J
-
Application NumberUS12/820,363Publication NumberTime in Patent Office1,792 DaysField of Search436/79, 436/73, 436/174, 436/177, 436/178, 422/50, 422/68.1, 422/62, 422/63US Class Current436/79CPC Class CodesG01N 17/008 Monitoring foulingG01N 33/1853 hardness of waterY10T 436/21 HydrocarbonY10T 436/25 including sample preparationY10T 436/25375 Liberation or purification ...Y10T 436/255 including use of a solid so...
