As the development of hydrocarbon from shale resources increases exponentially globally, it is essential to have a clear understanding of the key variables for evaluating shale reservoirs and to define the best methods for effectively stimulating wells. However, this is not easy considering that each tool has both advantages and drawbacks with respect to technical, methodological, and economic matters. That is why, for shale projects, it is necessary to know the vital variables to optimize the collection of information, costs, and, of course, the validity of final results and interpretations. For initial characterization, reference information from previously fractured horizontal wells in the same formation should be considered and a holistic approach using characterization from petro-physical, geomechanical, mineralogy, and geochemical analysis should be considered during the determination of the best zones to be fractured. Analysis and use of diagnostic fracture injection testing (DFIT) and minifrac testing is also to be reviewed for the final calibration of fracture models before execution of the operation. Interpretation of micro-seismic monitoring during fracturing has great importance for obtaining models to optimize completions of wells and the development of a reservoir after an initial approach. This work analyzes and evaluates different sources of information and studies performed. Several factors and effects during the design stage are presented, such as using regional stress studies to estimate possible interference between the fracture stages and its effect on final fracture space determination. All in all, using this information is recommended for the initial approach during fracture design for the first wells in a new formation, proving to be a novel methodology to optimize and accelerate the development of a basin that can be applied later to following wells, helping save both time and resources.

Unconventional reservoirs (UNC) are considered those that do not produce at economic flow rates and cannot be cost-effectively produced without applying stimulation, fracturing, and recovery. They are located in predominantly extensive regional accumulations, which, in most cases, is independent of the stratigraphic and structural traps. This requires using special technology for extraction, either by its oil properties or the characteristics of the rock that contains it. Today, these reservoirs represent an interesting source of income, because many of them are found in deposits that were considered to be exhausted or non-economic by traditional recovery methods, and it is estimated that they are present in large volumes. The recently exploited shale plays are typically constituted by a matrix of very fine grain rock (size clay, shale or marl might be), with varying proportions of clay, silica, and carbonate, which act as source rock, and reservoir seals at the same time. They have very low permeability and often require massive stimulation to produce hydrocarbon. Generally, resource shale reservoirs must meet a series of requirements to make them economically viable. These conditions are: Organic richness (> 2% COT for shale gas and shale oil variable)Thermal maturity (> 0.7% Ro)Thickness (> 30 m) and areal extentAdsorption capacity (mainly in shale gas)Fracturability (clay content < 40%)OverpressureDepthSurface facilities