Hydraulic Fracturing Evolution in Block 61: TSO, Channel Fracturing and Waterflooding

Abstract Block 61 in Ecuador, one of the most productive assets in the Oriente Basin, started a redevelopment phase in 2015 where the introduction of waterflooding in 2017 and hydraulic fracturing campaigns have substantially enhanced oil production. This study starts with an introduction to Block 61 history and reservoir characteristics. A timeline is presented with the highlights in the evolution of hydraulic fracturing technology and waterflooding for the two fracturing campaigns executed since 2015. A comparison of the conventional tip screen out (TSO) and current channel fracturing (CF) is discussed to highlight the differences in fracture design. Formation damage is a continuous challenge in Block 61, that is observed during drilling, completion, workover operations and waterflooding demonstrated by the coreflooding studies. Typical geomechanical properties are outlined by using a type well with fracture jobs in Lower U Sandstone and Lower T Sandstone. This section includes recommendations on channel fracturing candidate selection based on Young's modulus and closure pressure. With the advances in channel fracturing significant improvements were achieved like a reduction in early screenout from 24% to 0% along with the KPIs that demonstrate the overall success of the project. Examples for wells fractured in waterflooding influenced areas are provided to understand the production scenarios where both technologies are combined. A summary of hydraulic fracturing candidate selection for wells in waterflooded influenced areas is included. Finally, the project is evaluated using three key performance indicators, oil production before and after fracturing, inflow performance relationship and historical oil production after capex intervention. All key performance indicators show not only productivity increase, but it can be sustained over time with an according waterflooding and reservoir management strategy. Hydraulic fracturing in Block 61 resulted in more than 7,000 stb/d (approximately 10% of the total oilfield production comes from the nine wells presented in this study) and other highlights like the development of a new horizon, Upper T Sandstone, and the two biggest fracture jobs in Ecuador so far.