The initial high cost of exploitation of the sustained, increasingly growing development of unconventional resources in Argentina has resulted in concentrating all efforts to increase well productivity while reducing construction and completion costs. The optimization of hydraulic fracture (HF) treatments is vitally important. It is the primary strategy used to achieve an optimal reservoir drainage area, consequently characterizing the fracture geometry, including the height, for the continuous improvement of HF treatment and planning.
Several types of technologies and methodologies are used to estimate fracture height during and after a hydraulic stimulation treatment. These technologies can provide information about the fracture geometry and extension in the near-wellbore (NWB) and far-field areas. The determination of a reliable correlation between those methodologies represents a challenge as a result of formation complexity, heterogeneity, and limitations of evaluation technologies. It is well-known that some areas in the Vaca Muerta formation contain layers that can act as fracture barriers and are responsible for fracture containment.
This paper presents a fast and simple methodology that uses conventional well logs [gamma ray (GR), sonic, and density] from pilot wells to identify potential fracture barriers. This approach establishes a means to evaluate the degree to which the rock will have the ability to control fracture height growth. This methodology was determined useful for planning perforation intervals or clusters placement, particularly in those formations with stress profile showing reduced stress contrast and, when complemented with geological information, this method also provides useful information for horizontal well trajectory. Case studies are provided to illustrate examples of the proposed fracture barrier index (FBI) being calibrated or compared to other fracture height assessment. Additionally, the benefits of adding this new approach to current methodologies and technologies to aid completion design optimization and decision making is discussed.
Analytically-derived criteria are presented for the orientation of fracture initiation from horizontal wellbores drilled in porous-permeable (poroelastic) media. This involves drilling-induced tensile fractures (DITFs) from non-perforated wellbores and completion-induced hydraulic fractures (CIHFs) from perforated wellbores with cylindrical perforation geometry. The criteria are developed considering the tangential stresses on two points (extremes) around the base of the perforation; one for the initiation of longitudinal fractures and another for the initiation of transverse fractures, with respect to the wellbore. In-situ stress state, wellbore pressure, and the formation's mechanical and poroelastic properties are independent variables that are shown to control the orientation of the initiated hydraulic fractures; the dependent variable.
The DITF orientation can be used to constrain the magnitude of the maximum horizontal stress; the most difficult aspect of the in-situ stress tensor to constrain. Transverse CIHF initiation only occurs over a narrow wellbore pressure-at-breakdown window, while longitudinal initiation occurs at comparatively higher wellbore pressures. However, transverse CIHF initiation occurs more frequently than transverse DITFs, because the presence of perforations aids transverse fracture initiation. The region of the in-situ stress states where transverse initiation is promoted is shown in dimensionless plots for perforated and non-perforated wellbores. Fracture initiation criteria for specific cases presented can be used to predict the orientation of fracture initiation in oilfield operations.
The orientation of CIHFs controls the productivity of hydrocarbon reservoirs. Productivity from low permeability formations is greatly improved having multiple fractures oriented transversely rather than longitudinally, relative to a horizontal wellbore. Fracture initiation often follows a plane different to the final fracture propagation plane. Stress re-orientation in the near-wellbore region may promote fracture initiation of different orientation than the orientation dictated by the far-field stresses. The range of in-situ stress states in which transverse fracture initiation is promoted increases as Biot's poroelastic coefficient,
Data Analytics is progressively gaining traction as a viable resource to improve forecasts and reserve estimations in most prospective US shale plays. Part of those learnings has been tested for the reserves and resources estimation of the next worldwide top-class shale play, Vaca Muerta formation in Argentina. In this work, we rely on advanced artificial intelligence methods to automate workflows for production forecasting and reserve estimation in the Vaca Muerta formation. To achieve this goal, we develop a computational platform capable of integrating several sequential operations into a single automated workflow: (1) data gathering; (2) data preparation; (3) model fitting and forecasting and, (4) EUR estimation. As new data becomes available, each of these steps is performed automatically. The proposed platform also integrates with advanced business intelligence tools that aid at facilitating graphical interpretation and communication among specialists and decision makers. Hence, the suggested workflow can deliver production forecasts several magnitudes faster than traditional workflows while maintaining accurate and engineering sound results. Having fast and reliable forecast turnarounds allow for timely tracking key differences and commonalities among multiple shale plays to facilitate informed decision strategies in unconventional field evaluation and development.
Fast-declining, older, unconventional oil wells require artificial lift experts to deal with and explore a population of miles-long horizontal wells that do not follow the established rules of thumb. After Gustavo Astie, executive manager for unconventionals at YPF, presented what he thought was an aggressive growth plan for the coming year to YPF management, he was asked: Would it be possible to go faster? A drive down a gravel road in the Loma Campana follows the steep early learning curve in the Vaca Muerta. It is easy to fixate on what it will take to extract huge volumes of oil and gas from the nearly impermeable rock within the Vaca Muerta. Añelo is a small town in an arid, sparsely populated area with a new supermarket, police station, bank, skate park, hotel, and hospital.
Last year, the SPE Board of Directors approved a new 5-year Strategic Plan, a blueprint to provide guidance on how the association can meet the needs and expectations of its members and the industry over the next several years. Late December/early January is the time of year when industry outlooks are announced, revealing company spending plans, oil price predictions, and potential stumbling blocks. The most recent report from the United Nation’s Intergovernmental Panel on Climate Change and December’s international conference on climate change held in Katowice, Poland, show that the world is not coming close to reaching the targets set in the landmark Paris Agreement of 2015. SPE is launching a new online publication and newsletter on data science and digital engineering and a new monthly newsletter on the unconventionals oil and gas sector. Slow uptake of innovation and new technology is an oft-repeated criticism of the oil and gas industry.
This paper covers the staged field-development methodology, including analysis and evaluation of various development concepts, that enabled the company to optimize both completion design and artificial-lift selection, reducing downtime and lowering operating costs by nearly 50%. The First Eocene is a multibillion-barrel heavy-oil carbonate reservoir in the Wafra field, located in the Partitioned Zone between Saudi Arabia and Kuwait. After more than 60 years of primary production, expected recovery is low and provides a good target for enhanced-oil-recovery processes. This paper studies the technical and economic viability of this EOR technique in Eagle Ford shale reservoirs using natural gas injection, generally after some period of primary depletion, typically through long, hydraulically fractured horizontal-reach wells. This paper provides a robust methodology for miscible CO2 WAG experimental-data acquisition and history matching.
Unconventional development has made it clear to Erdal Ozkan that conventional theory overlooks a lot of potentially productive rock. He talks about looking for ways to do better as part of JPT’s tech director report. The industry has figured out how much opportunity lies in the Permian Basin’s Delaware subbasin, and the Delaware play is now dominating US unconventional oil activity, Citigroup’s Jeff Sieler told the SPE Gulf Coast Section reservoir group recently. Unconventional Resources: Will Shale Oil Ever Make Money? This well-established oilfield consultancy explains why 2020 might be a big year for the unconventional sector.
The state-owned firm is looking within its home country, around Southeast Asia, and to the Americas—including shale—in an effort to maintain its forecast average yearly production of 1.7 million BOE/D over the next 5 years. Vaca Muerta production is on the upswing. Will increasing activity propel the Argentine play to the ranks of US shale? Data suggest it is both already there and has a ways to go. Wells are starting to come on stronger than expected, which is putting a new emphasis on orginizing all the other ingredients needed for shale production: more rigs, roads, pipelines, water, and sand.