Development of an organic shale resource relies on the combination of a targeted drainage area and an adequately sized stimulation treatment. While increasing fracturing treatment size might improve productivity for a lateral standalone, well spacing must be considered as an additional constrain when moving to pad development.
Work proposes to evaluate numerically pad optimization using a reservoir-centric approach, modelling explicitly the hydraulic fracture geometry and coupling it directly to a production simulator. Model calibration is performed by reproducing observed facture geometry events (such as fracture net pressure level and microseismic events) and history matching production of existing laterals in the Vaca Muerta shale. Different scenarios are then considered to evaluate the interaction of the hydraulic fracturing, the reservoir properties, fluid type and well spacing to be optimized in a single process.
Hydraulic Fracture dimensions must match well spacing. At stage level, hydraulic treatment volume should be adjusted to ensure that no excessive resources are used to cover the targeted volume and limit overlap between fracturing treatments of different wells. At perforation cluster level, stress shadow and natural fractures impact the geometry of each different fracture. Variation of fracture geometry along the lateral should be accounted for to evaluate well spacing and prevent the excessive growth of one single facture within a given stage. Completion design can be engineered by adjusting hydraulic fracture treatments to increase the overall consistency of the resulting fracture geometry and reduce effect of production interference between laterals of a given pad.
Novelty of the proposed methodology relies on the explicit description of the hydraulic fracturing geometry and direct coupling with reservoir simulation, not only for a single well, but considering a whole pad of horizontal wells to be applied to the development of the Vaca Muerta shale.
The Vaca Muerta shale is located in the Neuquén basin, Argentina, and is characterized by its areal extent, high gross thickness and high organic content (Maretto et al 2002, Sagasti et al 2014) then ranking amongst the top of world resources for shale oil and gas (US Energy Information Agency 2016). First well was drilled and completed in 2010 and even if the basin counts more than 500 wells to date, the Vaca Muerta shale history is relatively recent compared with other known shale plays.