Liquid-Free CO2/Sand Stimulations: An Overlooked Technology - Production Update

Abstract The U.S. Department of Energy (DOE) supported the demonstration of a unique liquid-free hydraulic stimulation technology (CO2/Sand) in the water sensitive Devonian Shale's of eastern Kentucky in 1993. The initial production results from four wells which were stimulated with two-stage CO2/Sand stimulations indicated a significant advantage over N2 gas and N2 foam stimulations. The nine-month production responses from a 15 well (30 stages) study group were presented in SPE paper #29191 "Analysis of Production Response to CO2/Sand Fracturing: A Case Study" and reported a measured production benefit of CO2/Sand stimulations over N2 gas and N2 foam of 1.9 and 4.9 respectively. This updated review includes: the 5-year production from those wells, the addition of three more single-stage CO2/Sand stimulation treatments, and the elimination of the early-time "flush" production from the analysis. The production responses for 21 wells (37 stages) is comprised of: CO2/Sand - 7 wells (11 stages), N2 gas - 9 wells (17 stages), and N2 foam - 5 wells (9 stages) are presented.