This paper presents an Archimedean Screw Turbine (AST) based energy harvester designed to power wireless sensor system inside oil extraction or water injection wells. Numerical study has been carried out using CFD analysis to evaluate the performance of the harvester. Characteristics of the AST, including turbine length, blade pitch, and rotational speed were studied to determine the optimal geometry and operating conditions of the system. An AST prototype with a length of 85 mm and an outer diameter of 50 mm was fabricated through 3D printing and in-lab tests were conducted to validate the performance of the designed harvester. A maximum power output of 0.21 W was achieved under a constant pipe flow rate of 0.95 liter per second when an external resistive load of 10 Ω was connected to the harvester. Lastly, the experimental results were analyzed and compared to the CFD analysis.