Abstract: The open-hole well area of the old oilfield in Block X was developed using open-hole completions relying on natural depletion development because of the limitations of early drilling technology and production costs. At present, most wells in the area are approaching the economic limit of oilfield development. Due to the small size of the well site and the complexity of the wellbores, these wells cannot meet the requirements of large-scale reservoir stimulation operations. In order to effectively utilize the economically recoverable reserves of old oilfields and maximize the acquisition of underground oil resources, a horizontal well pilot test was conducted in the open-hole well area of the old oilfield in Block X. Two platforms, A and B, were selected respectively for on-site testing of horizontal wells natural energy development technology and multi-well mixed three-dimensional well network development technology. Practice has shown that by establishing a multi-well mixed three-dimensional well network mainly consisting of horizontal wells, supported by large-scale volumetric fracturing technology for comprehensive reservoir stimulation, and supplemented with targeted energy replenishment measures, effective recovery of remaining oil in the open-hole well area can be achieved. With wide promotion and application of this technology system, the total number of wells in the area can be effectively reduced, the recovery rate can be improved, and the oilfield development strategy of "less wells, more oil, and higher recovery rate" can be achieved.