Oil and gas companies worldwide strive to improve artificial lift efficiencies to minimize environmental footprint and lower operational expense. In order to lower artificial lift costs, the traditional rod pump must be replaced and improved upon. The present invention of the rodless pump and multi-sealing hydraulic sub is an optimized hydraulic pumping system that eliminates rod wear, lowers pump intake pressure, and extends the reserve life of oil and gas wells regardless of casing configuration or depth. Lowering the pump's intake pressure in an oil and gas well by using a positive displacement pump such as the present invention will allow maximum hydrocarbon reserves to be produced with minimal energy consumption to power the pump. The superior surface seals and smaller footprint of the rodless pump eliminate the possibility of surface hydrocarbon leaks, minimizing environmental impact.