Sequenced Fracturing Technique Improves Production from an Underperforming Lateral: An Interpretation Based on High Frequency Pressure Monitoring

Abstract

Well "A" was drilled as a horizontal unstimulated producer in the Kuparuk oil reservoir. Though fracturing was considered during the design phase, the operator wanted to evaluate the well's performance without stimulation. The well was completed with a liner with 10 perforated pups spaced evenly along the wellbore without annular isolation. When production from the well fell short of expectations, hydraulic fracturing was considered, but the completion limited the options to effectively stimulate the lateral. The chosen fracturing treatment was designed to balance maximum reservoir contact with economic considerations. In an attempt to place more than a single fracture at the weakest point of the 3,242 ft. lateral, it was decided to attempt eight fracturing stages separated by diversion pills. High-frequency (200 Hz) pressure transducers were used on the treating line. The data obtained from water hammers at the end of each stage allowed the estimation of diversion performance between fractures for each stage. The stimulation treatment was pumped in the middle of the arctic winter, placing 580,000 lbm of 16/20 mesh ceramic proppant. The amount and placement of sequenced fracturing diversion material, consisting of a composite fluid with multimodal degradable particles and fibers, was adjusted based upon the surface pressure responses throughout the treatment. High-frequency pressure monitoring data revealed a shift in the fracture initiation along the lateral, and post-fracturing production exceeded expectations at 1,500 BOPD and stabilized near 300 BOPD, which is on par with project expectations. High-frequency pressure monitoring applied to the evaluation of fracturing operations is still in its infancy, and there are limitations of this technique for wells with open hole completions. Combining high frequency pressure monitoring, ISIP data and post frac production data, it appears that sequencing fracturing diversion material can help to initiate more than one unique fracture.