Development of Hybrid Drilling Fluid and Enzyme–Acid Precursor-Based Clean-Up Fluid for Wells Drilled with Calcium Carbonate-Based Drilling Fluids

Abstract

Significant formation damage can occur during drilling operations because of the invasion of drilling fluid fines and filtrates that lead to pore blocking and saturation alteration mechanisms. This study demonstrates the ways to minimize drilling fluid-related damage and the removal of the deposited filter cake in the carbonate reservoir through judicious selection of bridging particles using “ideal packing theory” and formulation of an enzyme-based clean-up fluid with an acid precursor. The polymer-based drill-in-fluid with a mixed grade of CaCO 3 bridging particles resulted in a compact filter cake with reduced filtration loss preventing internal pore damage significantly. Several ester hydrolysis reaction kinetics were studied, and finally, one combination was chosen as the suitable acid precursor because of its ability to generate a required concentration of acid within the downhole condition. The return permeability of mud-damaged carbonate core plugs was higher than 95% after exposure to the clean-up solution. The corrosion rates were found to be significantly below the industry limits, and the use of acid corrosion inhibitors is eliminated.

Achieving Practical Venue Recycle of Waste Oil-Based Drilling Fluids with Vacuum Distillation Technology

“…The apparent viscosity (AV), plastic viscosity (PV), and yield point (YP) of drilling fluids prepared by recycled oil are similar to those prepared by 3# white oil, which can meet the desired requirements. However, it should be noted that the demulsification voltage of drilling fluids prepared by recycled oil is 731 V, which is lower than the 766 V of white oil drilling fluids, indicating that emulsion stability decreases slightly. , This may be due to some materials that are conducive to improving the emulsification of the drilling fluid are decomposed at high temperatures during the vacuum distillation process. , These materials mainly include the primary emulsifier PF-MOEMUL and co-emulsifier PF-MOCOAT, which both contain amide compounds. The decomposition of these materials at high temperatures could cause the amide-based compounds to follow the gas phase into the back end.…”

“… 28 , 29 This may be due to some materials that are conducive to improving the emulsification of the drilling fluid are decomposed at high temperatures during the vacuum distillation process. 30 , 31 These materials mainly include the primary emulsifier PF-MOEMUL and co-emulsifier PF-MOCOAT, which both contain amide compounds. The decomposition of these materials at high temperatures could cause the amide-based compounds to follow the gas phase into the back end.…”

Investigation of Filter Cake Evolution in Carbonate Formation Using Polymer-Based Drilling Fluid

“…For instance, in high-temperature formations, fluid viscosity, particle size, friction coefficient, and Young’s modulus are thermally degraded properties, resulting in ineffective sealing of the fractures . Moreover, particle size degradation occurs during the long-term process of drilling fluid circulation, also resulting in severe formation damage …”

“…16 Moreover, particle size degradation occurs during the long-term process of drilling fluid circulation, also resulting in severe formation damage. 17 Over the last few years, several researchers have examined the use of other options such as nanoparticles to design drilling fluids with enhanced properties that can endure extreme downhole environments, particularly under HP/HT conditions. Vryzas and Kelessidis summarized some of these nanoparticle additives used in drilling fluid and reported an enhancement in fluid properties and wellbore strengthening; however, there are still many challenges that should be addressed.…”

Experimental approach for assessing filter-cake removability derived from reservoir drill-in fluids

“…Various laboratory studies have been conducted to study the impact of different breakers systems on cleaning up the filter cakes (Mohamed et al 2020). Mostly a combination of three methods is found on the literature for evaluating breaker effectiveness, namely breakthrough, return permeability and weighing method (Ghosh et al 2020;Chandran et al 2020). In addition to the mentioned conventional methods for formation damage assessment, other techniques are used to evaluate the damage differently.…”