ABSTRACT
Extensive data were gathered during the pumping and flowback of a nitrogen foam stimulation treatment on a Devonian Shale gas well in eastern Kentucky. Subsequent analysis of these data revealed that 1) duplicate monitorinc equipment, properly calibrated, yielded nearly identical data, 2) the job execution, largely because of extensive quality control, closely followed job design. 3) friction loss in the pumping annulus could be calculated at all stages of the treatment, and 4) both perforation friction loss and the number of holes open could be estimated throughout the job.
As part of the Comprehensive Study Well program sponsored by the Gas Research Institute (GRI). this fracture treatment design, planning, execution, and analysis involved cooperation.among several GRI contractors, the service company, and the operator. On-site monitoring equipment included densiometers. pressure gauges and transducers, and various types of flowmeters. Two control vans monitored real-time data and permitted adjustment to one of three tentative pumpinc schedules based on downhole treating pressures during the prepad stage. Direct measurements led to real-time calculations of foam quality, foam rate, and downhole proppant concentration.
When the data were analyzed, the wealth of data coupled with the redundancy allowed various calculations to be made with confidence. Direct comparisons between the two sets of monitoring equipment showed near-perfect agreement. Similarly, the actual data matched the desien estimates. Recently published results dealing with discharge coefficient change and hole enlargement formed the basis of our analysis of perforation friction.
This analysis has been performed on one other set of data from an offset well and led to similar conclusions. Comparable data is being acquired from other wells and may eventually provide a valuable database for fracture design in the Devonian Shales.
