Water production is one of the largest waste streams during hydrocarbon production. The demand for sustainable water management is becoming more challenging in-terms of treatment and water disposal especially in an off-shore environment. Producing a barrel of water requires more energy that creates major economic impact on the profitability of an oil-field project. This paper presents a pilot case study for down-hole water shut off treatment in one of Malaysia oilfield; Field A (Well B03-SS) with a novel relative permeability modifier known as Nano-Clay. The main pilot objective was to assess the Nano-Clay performance as part of production enhancement effort to reduce water production from 90 to 50 (water cut) and to accelerate the oil production. We discussed the overall workflow, series of laboratory experiments such as core flooding tests, numerical simulation, pilot execution, post treatment results, challenges, and best practices. Nano-Clay injection strategy consists of bull-heading a pill of pre-flush of treated sea water for injectivity test and well conditioning, Nano-Clay injection, post flush with treated sea water, Nano-Clay soaking for about 24 to 48 hours, flowing back the well, monitoring and demobilization. The pilot execution at Well B03-SS was completed successfully and safely. Early post treatment results showed water cut trending has reduced to ~50 as compared to pre-job water cut at ~80. Post Nano-Clay treatment indicated instantaneous oil gain of about 219 stb/day from 171 stb/d to 390 stb/day. After one and a half year of monitoring, the water cut maintained with expected water cut reduction range in between 10 to 50 from the baseline. The application of Nano-Clay at Field A concluded the overall pilot success and replications at other fields is currently in progress. Copyright 2024, Society of Petroleum Engineers.