Abstract: Aiming at the problem that it is difficult to adapt the varying parameters of XX block in G oilfield to the heterogeneous reservoirs conditions of this area, single well controlled reserves calculation has been applied to include oil-sand layers with similar effective reservoir thickness, physical properties and oil feature in a single well calculation unit. Horizontal and vertical differences of heterogeneous oil-sand parameters as well as the oil recovery have also been taken into account. Ultimately the single well controlled geological reserves, technically recoverable reserves and remaining recoverable reserves of each oil-sand layer have been obtained. By using single-well controlled recoverable reserves to analyze distribution diagrams of single-well remaining recoverable reserves and remaining oil, horizontal and vertical residual oil enrichment regions, layers and their forms are given, in addition, the residual oil exploration scale, extent, location, and enrichment amount of the target layers have been provided, making it evident the way for the further exploration of residual oil and efficiently development of the oilfield.