Customized Reperforating With New Technologies for Optimal Field Drainage and Productivity Enhancement: East Venezuela Applications

摘要

This paper describes a new methodology and technologies applied for re-perforating production wells in a development field in East Venezuela. Subsequent well tests and production logs demonstrated significant skin reductions and improved flow profiles, delivering up to threefold increase in productivity index and enhancing reservoir drainage efficiency. These results exceeded normal expectations for this type of job. El Furrial field is located in Northeast Venezuela. The wells typically produce from multiple intervals having widely heterogeneous flow capacities. In order to avoid asphaltene production and water-gas channeling, downhole pressure drawdown has to be limited leading to restricted production. These conditions are further complicated by severe formation damage caused by deep mud filtrate invasion and plugging of existing perforation tunnels with crushed rock material left over from conventional perforating. This environment motivated the team to try a novel re-perforating methodology to overcome these combined challenges. In these cases, rather than follow the common practice of treating all intervals as having the same average reservoir properties, the reperforation program was customized, taking into account the individual properties and skin of each layer. Post re-perforation analysis, presented in this paper, clearly shows that the two main causes of formation damage (skin) I.e.: deep mud filtrate invasion and perforation tunnels lined with crushed rock material, were effectively minimized by using new deeper penetrating charges and a controlled dynamic underbalance perforating technique. El Furrial field success has renewed interest in re-perforation as an important tool for optimizing reserves recovery. This new customized approach used by PDVSA has generated a much higher effective return on investment.