Understanding the Applicability and Economic Viability of Refracturing Horizontal Wells in Unconventional Plays

Abstract

Oil prices have fallen to lows not seen in years. These low oil prices and sustained low gas prices have drastically reduced the number of new wells being drilled in US unconventional plays as oversupply from these plays has reached an all-time high in US storage levels. One alternative to drilling new wells is to hydraulically refracture older wells to enhance production and gain additional economic returns. With each successful refracturing operation, service companies are improving on methods to divert refracturing fluid and proppant without the use of mechanical diversion techniques. To ensure success and meet economic hurdles, refracturing requires thorough preparation, proper candidate selection, and effective diversion techniques. The authors of this paper studied the economic potential and applicability of refracturing in six different unconventional plays across the US, including the Haynesville, Fayetteville, Barnett, Woodford, Eagle Ford, and Bakken plays. The expected rates of return for refracturing were compared to the economics of new wells to determine which alternative is a better use of capital spending and how the economics vary by play. Major challenges with refracturing horizontal laterals are highlighted, along with criteria for picking the best refracturing candidates to reduce risk and help meet economic hurdles. We carefully searched through over 20,000 laterals completed since the second half of 2013 in the US and found more than 100 horizontal wells refractured by chemical diversion means based on public records. The production results of these wells were evaluated to identify the best basins for economic success. The Haynesville and Eagle Ford show the best rates of return, whereas other basins will require higher market prices, changes to current refracturing techniques, and/or identification of the best refracturing candidates to minimize the associated risks. The number of economic horizontal refracture candidates across the various basins will vary with fluctuations in oil and gas prices.

Well Performance Simulation and Parametric Study for Different Refracturing Scenarios in Shale Reservoir

“…It is the most common method to promote pumping rate, fluid volume, and proppant concentration in the previous successful refracturing jobs [29][30][31][32]. On the one hand, a higher pumping rate helps to reduce proppant collection at the bottom of the wellbore [6]. On the other hand, higher proppant concentration and large-scale treatment size are helpful to restore or increase hydraulic fracture conductivity so as to increase gas production, as shown in Figure 7.…”

“…Compared to drilling and completing of infill wells, refracturing is an economical alternative to promote well productivity when the right candidate is selected [12][13][14][15][16]. The refracturing process has been developed and applied to Barnett, Haynesville, Bakken, Fayetteville, Eagle Ford, and Woodford shale reservoirs in recent years [6,15].…”

Parent Well Refracturing: Economic Safety Nets in an Uneconomic Market

“…Many papers have been written discussing this occurrence and principles as to how fracture hits may happen (Diakhate et al 2015;Lindsay et al 2016;Malpani et al 2015;Marongio-Porcu et al 2015;Martinez et al 2012;Morales et al 2016;Roussel and Sharma 2010;Roussel and Sharma 2012). The depletion effects during the life of the original parent well create localized pressure sinks.…”

“…Refracturing with chemical diverters has been discussed in other papers (Kraemer et al 2014, Lindsay et al 2016, Malpani et al 2015. The intended outcome is to sequentially pump fracturing fluid and proppant into existing perforation clusters, reenergizing and growing fracture networks already in place.…”

“…With a proper understanding, single-well refracturing may be used to benefit offset wells if fracture communication tends to increase production in that particular reservoir area. To understand the economic success of a refracturing treatment, the original wells production decline is forecasted out past the anticipated refracture date, creating a ЉbaselineЉ to compare refracture results to (Lindsay et al 2016). Any refracture production over that baseline is the incremental production from the refracturing treatment.…”