Areas of Southwestern Energy's Fayetteville Shale asset were identified as candidates for optimized completions by analyzing the y-axis intercept of the Rate Transient Analysis (RTA) square root time plot, an indicator of skin, and looking for those wells with values above the field average. It is hypothesized that the increase in the y-intercept from the typical average across the asset is due to proppant embedment in the formation and through optimized completions a reduction in the y-intercept, or skin, can be achieved.
The initial test program started in Q4 2014 and the area of interest (AOI) was established by conducting rate transient analysis on all Southwestern Energy Fayetteville Shale wells and then mapping the variable across the play. The initial test pads were located in areas where y-intercept values exceeded average and included 6 pads, 19 wells, with completion designs using 30 - 50% more sand/stage and 7 pads, 24 wells, with 30 - 50% reduction in fluid volume/stage versus the standard Southwestern Energy Fayetteville Shale completion. Success or failure was determined by comparing normalized pressure and well performance to the 9-section area of the test pad.
The wells with 30 - 50% more sand/stage have an average EUR/CLAT improvement of 4% and exhibit a reduction of 24% in the y-intercept. The wells with 30 - 50% reduction in fluid volume have an average EUR/CLAT improvement of 6% and exhibit a reduction of 68% in the y-intercept and the economics are more favorable due to the reduced costs of the completion.
Given the success of the initial test program in the AOI, more pads are being evaluated to have optimized completions. As the program progresses, the y-intercept will be used in conjunction with data analysis of the more than 3,500 wells currently in the Fayetteville Shale to further optimize completions in specific areas.