An in-depth study compares incremental workover cost and lost-time cash flows in the years following hydraulic fracturing stimulations using 100% frac sand as the proppant versus a curable resin-coated proppant tail-in for proppant flowback control. All wells in the study are vertical wells and were artificially lifted by rod pumping. The wells are located in the AWP field, McMullen County, Texas, in the Olmos formation.
An operator offered well data to this technical paper's authors with the understanding the operator's name not be disclosed. The data include 46 vertical wells during a 10-year time frame from the early 90s through May 2013. The authors compared the difference in workover cost and the lost production cost of 23 wells stimulated with 100% frac sand and 23 wells stimulated with a curable resin-coated tail-in at an average 10.5% of the total volume. The proppant cost for a curable resin-coated tail-in well was $20,000 higher compared with the proppant cost for a 100% frac sand well for these hydraulic fracturing jobs.
The study's technical contributions reveal the long-term economic value of preventing proppant flowback into the wellbore to reduce workover cost. By using a curable resin-coated proppant tail-in to prevent proppant flowback, this study documents an operator can pay for the proppant through lower workover cost and increased well uptime.
The net present value (NPV) of the difference in the compared groups for the total workover cost equals $2,770,419. This is assuming a 10% discount rate. By subtracting the cost difference of the two proppant types from the NPV of the total workover cost, we see the operator experienced a net value gain of $2,310,419.
Looking at the sample size, the 100% frac sand wells experienced lost production of 24,837 hr, equating to lost production of one well for 2.8 yr. The curable resin-coated proppant wells experienced lost production of 11,413 hr, equating to lost production of one well for 1.3 yr. The difference between these two groups of wells equals an increase of 13,424 hr that is equivalent to one well's production for 1.5 yr, proving the long-term economic value of proppant flowback control.