Development of advanced mathematical models for analysis of hydraulic channel fracturing technique

Abstract

The channel fracturing technique is a Schlumberger's recent development in the area of hydraulic fracture stimulations, which allows for discontinuous proppant placement within the fracture opening. The discontinuous placement of proppant creates a highly conductive network of interconnected open channels, which can significantly increase the overall fluid conductivity of the fracture. Modelling, analysis and prediction of the fluid conductivity of openings created using the channel fracturing technique is of a great interest in both industrial and research contexts. Subsequently, the main objective of this research is to study the channel fracturing technique. Specific aims include the investigation of the effects of different confining stress, proppant placement patterns, and mechanical properties of the rock formation and proppant on the enhancement of the fluid conductivity. The general methodology adopted in this thesis is based on the Distributed Dislocation Technique, which is a powerful analytical tool for the analysis of fracture problems. To meet the main objective, a number of nonlinear mathematical models were developed to predict the fluid conductivity. These models are presented in separate chapters of this thesis. A number of case studies were considered for typical combinations of mechanical properties of rock and proppant, proppant placement patterns as well as confining stress conditions. It was demonstrated that an appropriate selection of proppant and its placement pattern within the openings can significantly increase the well production rates, which is essentially the ultimate goal of hydraulic fracture stimulations. From practical point of view, the outcomes of this thesis can provide a valuable guidance for designing efficient proppant injection schedules and selecting a suitable proppant type in order to maximise the well productivity, decrease environmental impact as well as to reduce the overall cost of oil and gas recovery, which are currently the main concerns for the relevant industries and government organisations. The main body of the thesis represents a compendium of papers submitted to or published in international journals or conference proceedings. These papers are united by the same topic as well as the research methodology mentioned above. The percentage and contribution of the candidate are specified in the Statement of Authorship for each article with more than one author.