Child-Child Fracture Driven Interactions Analysis and their Application with Field Case Studies

Abstract

AbstractFor unconventional shale reservoirs, understanding the relationship between well spacing, fracture dimensions and extensions are key components for achieve optimal oil and gas production without leaving undrained areas. The analysis of Fracture Driven Interactions (FDI) will contribute with this understanding. Pressure interference data, in a pad with several new wells (child-child) or between parent and child pads (parent-child), are obtained with gauges connected at the wellheads that record pressure continuously, while the sequence of hydraulic stimulations is carried out.Following the development of unconventional fields in Argentina, this type of information has been acquired more frequently and has become more relevant for the characterization of the different subsurface effects going on between adjacent wells (parent and child-child) during fracturing.These pressure connections between active and passive wells are not necessarily negative, and a certain level of communication may be desired since the total absence of interaction could be interpreted as volumes of rock unstimulated and, therefore, unproduced. Part of the initial process described in this work involves the steps to collect and process, simply and efficiently, all the child-child interaction data; to generate a reliable database that can be analyzed and integrated with other field observations.In this work, we present case studies where the child-child FDI data were analyzed using different tools, with the main objective of characterizing the hydraulic fractures generated with different stimulation designs and understanding their relationship with the vertical (different landing) and horizontal (same landing) spacing. Also, we present cases showing examples where child-child interferences are integrated with other field data acquisition (chemical tracers, microseismic, etc.) to improve and complement the understanding of the subsurface effects occurring during hydraulic fracturing operations.Finally, the main conclusions are:Stronger interferences were detected between wells located in the same landing zone, and vertical interactions tended to be weaker. The depletion regions from parent wells have an influence on the FDI responses between child wells. The "parent-child" condition produced irregular responses on the child-child FDI that are interpreted to be associated with possible asymmetrical growth of the fracture lengths. Fluid volume per cluster (fracture design parameter) shows a relevant impact on the child-child FDI responses, demonstrating that this variable is an important driver for these interferences. Cocina wells tend to have more and stronger interactions (longer fracture lateral growth or more interconnection among natural fractures) that the Lower Organic ones. Data integration between child-child FDI and other data acquisitions (e.g., chemical tracer and microseismic) helps to understand and conclude about subsurface characteristics.