Investigation of the Influence of Pressures and Proppant Mass on the Well Parameters after Hydraulic Fracturing

This paper considers the implementation of hydraulic fracturing in an oil field located in the Arkhangelsk region in Russia. During the exploitation, the production rates and injectivity of the injection wells in the field were intensively decreased. To increase well flow rates, hydraulic fracturing of the formation was carried out, and the evaluation of the efficiency was performed. Oil production rates after the fracturing increased ۳.۲ times and the productivity index increased twice. The influence of the geometrical sizes of fractures on the volume of injected proppant was investigated. An increase in the mass of the injected proppant from ۲ to ۳ tons per ۱ meter of formation thickness leads to an average increase in the crack width by ۰.۵ mm, and the half-length by ۴۰ m. Well work parameters after hydraulic fracturing of a reservoir were obtained as a function of the original parameters of the reservoir. It was observed that there is a sharp decrease in well production rates after fracturing in wells with low bottom hole pressures. When the pressure at the bottom of the well decreases from ۶۰ to ۲۰ MPa, it leads to an average decrease in the crack width by ۲ mm, and the half-length of the crack by ۵۰ m.  Direct correlation between the well productivity coefficients after fracturing and the values of bottom hole pressures was observed. The optimal conditions for fracturing were identified, which made it possible to significantly increase the efficiency of the operation.

Keywords:

Hydraulic fracturing , Productivity index , oil production , Permeability , pressure