Trends in Vaca Muerta Horizontal Wells Stimulation

Abstract Until the recent crude and gas price decrease in late 2015, development in the Vaca Muerta shale experienced profitable production through improved methods, efficiency, and economics control. To combine public domain hydrocarbon production datasets with detailed proprietary drilling information, operators and service companies can use completion, logging, and well stimulation data. These data enable analysis of trends and improvements that occur during drilling, fracturing, and production of horizontal wells targeting both shale oil and gas in the Vaca Muerta and help provide economic, efficiency, and productivity improvements. In recent years, more than 500 wells have been drilled in the Neuquén basin in the Vaca Muerta, the majority of which are located in the Loma Campana field. Other areas under development include El Orejano, La Amarga Chica, Aguada Pichana, Sierras Blancas, Cruz de Lorena, Bandurria, Aguada Federal, La Invernada, Bajo del Choique, and Puesto Silva Oeste. As of January 2016, Vaca Muerta monthly production of oil and gas was 6.7 million bbl and 13 million barrels of oil equivalent (BOE), respectively, representing 12 and 5% of total Neuquén basin production. A database was created including 47 records of horizontal stimulated wells that target the Vaca Muerta. Each register includes information related to location [well name, latitude, longitude, ground level, total depth (TD)]; production (operator, first oil date, effective time on, monthly oil, gas and water production); drilling (casing, liner, shoes, cementing); completion (directional survey, stages, clusters, perforations, plugs); fracturing [pump time, pressure, instantaneous shut-in pressure (ISIP), fracture gradient, horsepower, fluid type, injection rate, fluid volume, proppant type, proppant mesh, proppant mass, injection rate]; and production (cumulatives, rates, decline rate, recovery estimates, flow regime). Several correlations and crossplots between variables were developed and analyzed to identify trends and establish normal and anomalous behavior. The validity of using early production to estimate longer periods was confirmed, enabling creation of a complementary series of production data with modeled forecasts and estimated ultimate recoveries. Production data were then standardized by stages, horizontal length, proppant sacks (100 lbm) pumped, and fluids injected; after this, the records were sorted by productivity to determine average standardized production and typical completion and stimulation. Observing these values over time highlights trends toward longer wells with more stages and smaller sized proppant. Simultaneously, a recent shift to shale gas objectives located slightly basinward is indicated by deeper wells, where less fluid and more horsepower were used during stimulation.