In this study, statistical models which incorporate the techniques of linear, non-linear and multiple regression were employed to determine the relationship among corrosion variables such as temperature, corrosion rate, pH and flow rate. The data used in this statistical analysis were obtained from published experimental tests.
Correlation equations were developed showing the relationship among the corrosion variables such as temperature, pH and flow rate, and the rate of corrosion for static and dynamic filtration of drilling fluids, based on mud loop experimental data. Using field data, other correlation equations were developed relating the corrosion variables for drilling, completion and workover corrosive fluids. Because the relationship among these corrosion variables are non-linear in most cases, the statistical models provided linearization of these parameters by correlation.
The intensive corrosion often encountered in deep gas and geothermal wells, as well as in thermal oil recovery wells, can be minimized if adequate corrosion control measures are taken while formulating and treating: drilling, completion and workover fluids. Low pH of these fluids in the acid range, within the wellbore string, will initiate and promote chemical corrosion. The existence, in sufficient amounts of soluble acidic compound in the wellbore fluids will reduce the pH of those fluids enough to generate corrosion. Acid compound gases such as carbon dioxide and hydrogen sulfide in the presence of water and other corrosive agents cause chemical corrosion and must be dealt with in formulating; drilling, completion and workover fluids.