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Abstract The hundreds of Duvernay wells near Fox Creek, Alberta, Canada are usually fracture stimulated with either slickwater or hybrid slickwater-crosslinked water treatments with a large acid spearhead. There is a 14.6% higher 3-year average cumulative production total for slickwater treated wells versus hybrid fluid system treated wells. Additionally, the slickwater systems have an average 53.8% lower frac chemical cost compared to the 50/50 slickwater-crosslinked water hybrids frac stimulation systems. There is a very linear trend between the total volume of fluid pumped to the total 2 year BOE production; the higher the treatment fluid volume, the greater the stimulated reservoir volume (SRV) and the higher the resulting production. The production case study shows that wells treated with an average of 25,000 m of water have an 80% higher average 2-year cumulative production result compared to wells that only use an average of 13,000 m. The average proppant tonnage per stage varies with 140 tonnes per stage outperforming 100 tonnes per stage by 31.6% cumulative BOE production per stage at 2 years. However larger tonnes per stage showing a diminishing benefit when looking at the 2 year BOE production totals. The total production versus total proppant used (1000 tonnes to 3500 tonnes per well) is also examined showing an overall total well production benefit. Comparing the total proppant placed versus cumulative BOE is shows a positive. It does appear that the more proppant that is placed the higher the production rate and total long term production.
Abstract The burgeoning development of shale and unconventional formations in the face of a limited supply of guar, the primary gellant for fracturing fluids, created a demand for an alternative fluid. The new fluid, a modified friction reducer, capable of generating high viscosity with increased loadings and containing unique chemistry to facilitate breaking of the fluid provides a cost effective way of proppant transport. Since 2011, it has been used together with different types of proppant to treat various formations in the United States, both conventional and unconventional. Even with a wide technological acceptance, this fluid is not a solution for all situations. This study presents the application results, positive and negative, which are equally important for the continuous improvement of fracturing stimulation. Mining an in-house treatment database, this study collects treatment designs and operation parameters for all fracturing jobs performed in the following five major unconventional plays: Bakken/Threeforks, Eagle Ford, Marcellus, Utica and Wolfcamp. By using the publicly available FracFocus database, offset wells nearby the wells of interest were identified and their basic treatment information was collected, analyzed and normalized based on geography. Production performance metrics such as peak production and cumulative production in near and long term were used to evaluate the production performance of wells included. This study shows that this technology has been successfully deployed in temperatures up to 300°F. Many wells treated in the Bakken have measured depths (MD) over 20,000 ft and true vertical depths (TVD) over 11,000 ft. Proppant with various mesh sizes from 100 to 20/40 are carried by this type of fracturing fluid. Due to the complex nature of unconventional formations and a long list of designing and operating parameters, it demonstrates outstanding performance in certain cases and may show why it has unfavorable results in others. In comparison to other studies, this evaluation incorporates the near and long term results. The detailed analysis of this fracturing fluid technology and how its production performance sheds light on some questions that completion engineers are longing to answer: In which formation does this fluid have the best results and what types of formations should be avoided? What can be modified in job design to improve its performance?
Slick water hydraulic fracturing treatments are the preferred method for stimulation of tight hydrocarbon plays as these treatments enhance the complexity of fracture networks, increase fracture lengths, reduce formation damage and decrease treatment costs. These characteristics of a slick water treatment are critical to produce economic wells in unconventional formations. Even though these treatments are effective, they also have disadvantages that can limit production and increase treatment costs. With slight modifications to the treatment design of traditional slick waters - the addition of a novel chemical and 5% nitrogen - the limitations can be reduced. The performance of the slick water treatment is improved by modifying the proppant's surface properties. A novel surfactant preferentially adsorbs onto the surface of the proppant (for both quartz and ceramic), hydrophobically modifying the surface of the solids. The enhanced surface properties create an attraction between the proppant surface and nitrogen gas, in effect, surrounding the particle with a thin layer of gas and thus increasing the buoyancy of the proppant in water. These enhanced properties allow for improved proppant distribution, deeper proppant penetration within the complex fracture network, increased proppant pack volume, and increased maximum proppant concentration that can be placed. Improving proppant placement and increasing the volume that the proppant occupies within the fracture enhances the conductivity of the fracture network, therefore improving the productivity of the well. Laboratory studies of polymer adsorption, sand pack column flow analysis, crush resistance and brine compatibility testing will be presented to complement laboratory analyses previously published. Case studies of field treatments will also be provided. The first case study uses pad wells and compares the new system to traditional fracturing fluids. It will show that, without changing any other variables in the treatment design, production is enhanced significantly. The other two case studies will illustrate how production has been increased in two formations in the Western Canadian Sedimentary Basin.
Gawad, A. A. (Apache/Qarun Petroleum Company) | Long, J.. (Apache/Qarun Petroleum Company) | El-Khalek, T.. (Apache/Qarun Petroleum Company) | Bashandy, R.. (Apache/Qarun Petroleum Company) | Mabrouk, T.. (Apache/Qarun Petroleum Company) | Shaaban, A.. (Schlumberger) | Mathur, A.. (Schlumberger) | Yosry, M.. (Schlumberger) | Kraemer, C. C. (Schlumberger) | Bernechea, J. M. (Schlumberger)
Abstract This paper describes the application for the first time of a novel channel fracturing technique combined with rod-shaped proppant in selected production targets in several fields in the Egyptian western desert. The channel fracturing technique introduces channels within the proppant pack that increase conductivity and effective half-length leading to increased productivity (Gillard et al. 2010). Rod-shaped proppant when used as tail-in in fracturing treatments increases near-wellbore fracture conductivity and prevents proppant flowback due to its particular geometry (McDaniel et al. 2010). The western desert fields in the Qarun concession area in Egypt are characterized as complex, thin-bedded sequences with heterogeneous laminated sandstones producing mainly from the Abu Roash and Upper Bahariya formations. Hydraulic fracturing has traditionally been employed to produce hydrocarbons from these marginal reservoirs. The channel-fracturing technique was first introduced in the Amana fields in late 2012 combined with rod-shaped proppant for flowback control and conductivity enhancement. Early-time normalized production of the wells fractured with this technique increased by 89% over offset wells fractured conventionally, and the application of the channel fracturing technique eliminated the incidence of premature screen-outs in all fields. The positive results from implementation of this combined stimulation technique have led to a vigorous expansion of its utilization throughout Egypt's western desert area, including a refracturing campaign for older wells where conventional fracturing techniques did not yield the desired results.