Applying Biological Enzyme to Remove Plugging in Screen Pipe Completed Horrizontal Wells in Vocanic Gas Reservior

Since the grade I reservoir in Changshen volcanic gas field has high natural deliverability. Horizontal wells completed with screen pipe were applied to develop this type of reservoir. However, the severe mud pollution during drilling badly damaged the formation, which reduced the well deliverability greatly. In order to remove the mud cake near well bore and restore the reservoir permeability, a new plugging relief technology of biological enzyme was developed. According to the situation of screen completed horizontal wells and the degradation characteristics of the enzyme, laboratory experiments and field applications were conducted. The results show that biological enzyme can remove the reservoir pollution and recover the natural production of screen completed horizontal wells in Jilin volcanic gas field. It provided a new way to develop the grade I reservoir in Changshen volcanic rock gas field.