Research on the Secondary-Tertiary Combination Enhanced Oil Recovery Technology in Dual Ultra-High Stage Reservoir

The block J66-50 of Liaohe Jing'anpu Oilfield is a typical multi-layered sandstone high pour-point oil reservoir, which is developed by water flooding. After undergoing four development phases, it is currently in a stable production stage characterized by extra-high water cut and extra-high recovery. The current development status exhibits a “two-high, two-low” trend—high water cut, high recovery degree, low daily oil production, and low production rate. To improve development performance and solve the main contradictions in waterflood development, using such methods as reservoir engineering analysis and numerical simulation were formed the technologies of enhanced oil recovery for reservoirs within dual ultra-high stage. These technologies include: subdivision and reorganization of layer-series and well pat-terns, precision injection-production adjustment, chemical flooding (EOR) conversion. Through detailed reservoir characterization, defined the adjustment boundaries of the subdivision layer-series, the main oil reservoir of J66-50 is subdivided into three sets of layer systems. Adjustment is carried out through the combination of “precise water flooding + chemical flooding”, and the recovery factor is expected to increase by 12.2%.