The ability to determine diverter effectiveness quickly, cost effectively, as well as being operationally noninvasive has been troublesome for the industry. However, a unique approach that represents a significant change in evaluating diversion effectiveness has been developed using offset pressure measurements, enabling a process to help design a completion strategy to fully stimulate each stage, enhance cluster efficiency, and improve fluid distribution across the stage. The knowledge of diverter effectiveness provided by this approach shall lead to a better understanding of the diversion process and enable real-time optimization, where the results of a diverter stage are used to adjust treatment design for subsequent stages. These diagnostic measurements shall augment and enhance other diagnostic methods currently in practice.
The new fracture diagnostic technology is the first pressure-based fracture monitoring solution to be introduced to the market for analysis of fracture geometry, diversion effectiveness, cluster efficiency, and reservoir drainage. The pressure-based method enables a consistent comparison of completion design success for numerous wells, because the cost is drastically lower than other technologies, as well as its nonintrusiveness to field operations, since the data acquisition folds into existing completion plans.
This method enables computation of fracture growth over the treatment interval, providing fracture growth patterns before and after diversion placement. Diversion effectiveness is quantified using these fracture growth patterns, which are classified into four categories: successful in stopping dominant fracture growth, impeding the dominant fracture growth, diversion having no impact, and adverse effects of diversion in accelerating dominant fracture growth.
This paper describes a case study with the application of pressure data acquired from isolated "monitor" stages on offset wells during treatment of adjacent wells, and the results of rapid evaluation of diverter effectiveness and adjustment of diversion techniques. In real-time optimization, the results of a diversion are used to adjust the completions of the next stage.
Along with offset pressure data, additional diagnostics were run to determine fracture geometries. Radioactive (RA) tracer was performed in conjunction with the offset pressure monitoring to reveal diversion effectiveness. In addition to the high-end diagnostics, treatment pressure data was analyzed as it is routinely available and used to diagnose diverter effectiveness.
Fracture geometries were computed to quantify the fracture growth patterns before and after individual diverter drops. Offset pressure monitoring evaluated near-field diverters on 17 stages, including single and double diverter drops per stage. Two stages had RA tracer analysis, with both diagnostics demonstrating the same effects of diversion. Results indicated wide variations in the success of a given diversion per stage, ranging from 68﹪ of diverter drops being successful (stopped or impeded primary fracture growth), 27﹪ of the drops being ineffective (no impediment primary fracture growth), and to 5﹪ of cases accelerating the primary fracture growth. Near realtime analysis permitted rapid modifications of the use of diverter to adjust and identify techniques that provided consistent diversion.