The paper presents an innovative wellbore methodology for sustainable hydrogen production from natural gas, focusing on promoting economic and climate benefits. The methodology involves at-source wellbore gasification of methane for hydrogen production while simultaneously sequestering carbon in situ. By conducting the gasification within a wellbore completion tool deep within the well, the process takes advantage of the surrounding fluid-connected geology's elevated temperatures and pressures. This approach reduces excess energy input from the surface and minimizes feedstock consumption, offering significant energy and cost savings compared to traditional surface-based methane reformation facilities. The proposed system is designed to be independent of electricity and fuel costs, as both are provided in situ through heat recovery and reserves. Additionally, the process aims to eliminate the production of carbon to the surface, thereby reducing greenhouse gas emissions. The methodology avoids the expenses associated with downstream CO2 recapture from traditional methane combustion processes. Utilizing the NREL's H2A template for economic analysis, the study indicates that the proposed wellbore methodology can achieve hydrogen production costs below 1 USD/kg H2, making it a cost-competitive alternative to existing steam methane reformation facilities. The economic analysis considered various scenarios, ensuring the robustness of the proposed system's economic advantages. Overall, the paper highlights the potential of this innovative approach for sustainable hydrogen production and its positive implications for the energy transition and climate impact.