Abstract
The principal objective of this letter is to explain the major importance of using geochemical water analysis in monitoring the wellbore integrity and recognising wells with wellbore problems. Every reservoir or aquifer water has a characteristic composition that can be used for its identification.
Geochemical water analysis can identify the water composition of a well, with diagrams being commonly used to identify such composition. One of these diagrams is the Tickler diagram, which is plotted to provide information on the source and type of formation water. In this report, a case study is presented about using this diagram when needed.
An important duty of the production engineer is to monitor the wellbore integrity of production and injection wells. It is the responsibility of the production engineer to recognise when a problem exists; diagnose the problem; and recommend remedial action so that wellbore integrity can restored, production/injection can continue, and corrosion damage can be minimised. Different tools are used to monitor the wellbore’s integrity, identify problem wells and diagnose the problem. One of these tools is the geochemical water analysis.
Introduction of different waters into the produced reservoir fluids will change its composition significantly. Comparison of the geochemical analysis with the previous well history can identify wellbore problems.
In the A and B fields, gradual reduction in the total dissolved solids (TDS) and chloride (Cl) with time is expected due to the dilution of the original reservoir water with injection W or seawater. The following recommendations have been made to enhance well integrity monitoring using geochemical water analysis:
Establishing an application that shows the history of the TDS, Cl, Mg & Ca in plots and monitoring the plot trend. This application can be used to verify the geochemical analysis before making the validation. It can also identify if there are any wellbore problems.
Developing field/reservoir/aquifer TDS maps. Receiving these maps constantly will help to monitor the wellbore integrity & water quality and depict the produced water composition changes.
