Numerical Simulation of Application of Horizontal Wells in Old Heavy Oil Area

Remaining oil distribution in the late period of huff and puff in the vertical wells in Block Qi -40 in Liaohe oil field was studied by using field testing and selective injection data and a numerical simulation method.Based on these studies,the combination pattern of horizontal wells with the existing vertical wells, the recovery methods and the injection - production parameters were optimized by taking economic indicators as the object function.The results showed that during huff and puff,remaining oil saturation in the upper part of perforation interval was 49.9% ~ 52. 3%,in the lower part was 54.7 % ~ 62.0%, stream injection recovery factor in horizontal well groups can be 12.68% higher than that in vertical well groups, and heat-oil ratio increases 0.2627Kg/Kj.