Maximizing sustained well productivity from smart multilateral wells in heterogeneous reservoir completed with Inflow Control Device completion (ICD) and smart completion requires effective filter-cake cleanup to ensure uniform inflow contribution from entire horizontal section. The specially designed reversible invert emulsion Reservoir Drilling Fluid (RDF) along with filter-cake cleanup agent were utilized in drilling and completion of Kuwait's first Level-4 smart multilateral well in Burgan reservoir of west Kuwait. Further the reservoir is having vertically stacked thin channel sands associated with complex fault network makes drilling and completion of multilateral wells challenging and necessitated an innovative Reservoir Drilling Fluid and effective filter-cake cleanup to maximize the completion efficiency. Moreover the combination of high water mobility due to hydrocarbon viscosity ranging from 40 to 60 cP at reservoir conditions and fault network connected to aquifer causes severe premature water breakthrough. The smart multilateral wells have addressed premature water breakthrough problem and enhanced well productivity by facilitating the adequate reservoir management. The horizontal sections of smart multilateral wells were drilled with invert emulsion reservoir drilling fluid and achieved gauged hole which facilitated trouble free ICD completion installation along with large quantity swell packers. Novel filter cake cleanup agent was pumped immediately after running the ICD completion to change filter cake wettability from oil-wet to water-wet for uniform cleanup and thereby regained original reservoir permeability. This has eliminated the risk of formation impairment, ICD screen and nozzle plugging and established excellent well productivity. The well has achieved significantly increased sustained well productivity by having low wellbore skin. The paper covers the selection and design of reversible invert emulsion drilling fluid along with filter-cake cleanup system, well completion operations and long term well performance results.