Appraisal Of Underbalanced Perforation Technology And Deliverability

Perforated completion is a very important link in the system engineering of exploration and development, high or low of perforated efficiency direct influence the deliverability of oil and gas well. In the past few years, with continuously work in the exploration and development of field, the improvement and development of perforated completion technologic were concerned more and more by people, Perforated completion had been developed from opening simply oil and gas lay to emancipating and defending oil and gas lay, underbalanced perforation is a kind of means of defending oil and gas lay.Underbalanced perforation is one that down hole fluid column pressure is lower than reservoir pressure when perforation. Because underbalance pressure differential can cause an opposite direction backflow and flush perforated hole while underbalanced perforating, which formation may avoid to be damaged by hole plugging and perforation fluid, and which also can reduce compaction degree. So underbalanced perforation is perforated means that can defend foemation, raise the deliverability, cost cutting. However on the one hand, this guarantee hole to be cleaned and wash out tiny grain around hole from broken skin, which is min underbalance pressure . On the other hand, underbalance perforation with over pressure differential can cause fine migration, plugging hole in bad formation and make unconsolidated formation to sand flow and slough, this can cause greater formation damage, this is max underbalance pressure. Only choosing correct underbalance pressure differential during perforation can avoid harmful fluid invasion and create stronger backflow to flush hole and reduce compaction degree, and then raise the deliverability. So choosing correct underbalance pressure differential is key factor for underbalance perforation design. It is necessity to research underbalance perforation effect, not only defend formation, but also guarantee work safety.After this subject study, it can give the effect of underbalance perforation to deliverability, after applying in situ, and then this action from underbalance perforation to deliverability was analysed.