Abstract
An oil company faced the challenging task to perform multistage fracturing while all burst frac ports were preliminary opened. The objective of this work is to apply a non-intrusive methodology to confirm effectiveness of multistage fracturing operations with use of a chemical diverter on pre-opened unstimulated intervals.
A data-driven methodology is used for high frequency pressure monitoring and interpretation during the hammer signal distribution after pumps stop. An algorithm identifies the depth of fluid entry point and estimates the probability of the target zone stimulation. Before the main frac job, the hammer of injection test is analyzed, and the depth of fluid entry point is estimated. Depending on the probabilities of the fluid being injected into the target zone the decision is made whether to run another diverting pill or not.
Completion systems with several fracturing ports (burst or ball-activated) is a commonly used technique of horizontal wells stimulation in Western Siberia region. Frac ports in this case are stayed closed until a ball of specific diameter or excess of pressure open it to achieve an isolation of previously fractured intervals. Several hydraulic fracture stages were monitored following this methodology. For the first time, pre-opened fracturing ports were confirmed to be separately stimulated with application of chemical diverter and support of data-driven pressure monitoring algorithm. Diversion from all the previously stimulated intervals was confirmed. Planned formation fluid production target for such types of well completion was achieved.
This technique can create an additional value for oil and gas companies those objectives are related to multistage fracturing in pre-opened ports and refracturing after first multistage frac (burst or ball-activated, "plug and perf") to achieve effectiveness of chemical diverter application without a need of additional equipment and materials for mechanical isolation of stimulated intervals.
