A comparative evaluation of fracturing techniques, relating economic benefits to alternative approaches in zonal isolation and selectivity

Advantages and cost / benefit evaluations associated with the decision to risk capital for the expectation of justifiable returns on fracturing and stimulation procedures have progressively improved in sophistication and accuracy of predictions. The evolution in software supporting the engineering disciplines, as well as the wealth of empirical data have combined to improve returns, both in procedural efficiencies and reductions of risk. This paper will review techniques relating to fracturing and stimulation procedures, evolving from the basic casing frac, through current alternatives in methods to improve efficiencies, introducing isolation and selectivity. Alternative methods to achieve isolation and selectivity are reviewed in the context of advantages and limitations, as well as reservoir characteristics and well geometry applicable to each. Economics of alternative methods are evaluated from the perspective of initial costs, procedural effectiveness, risk factors, and long term implications on well performance. Engineers can benefit from this discussion of historic to current methodology, having a better understanding in matching various techniques to applications and the risks / rewards associated with each alternative.