A novel diagnostic fracture injection test workflow considering natural fractures

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Date

2021-05-03

Authors

Bruno, Jonathan

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Abstract

Applications of diagnostic fracture injection test (DFIT) are used in unconventional reservoirs to determine reservoir characteristics for future fracture design and production. DFIT consists of creating a minifrac by pumping small amounts of water and monitoring the pressure response. The presence of natural fractures can heavily influence the pre- and post-shut in pressure data obtained from DFIT. Traditional DFIT models do not capture the complexity of hydraulic and natural fracture networks into an integrated workflow. This work uses an embedded discrete geometry simulation (EDGS) and embedded discrete fracture model (EDFM) to add natural fracture complexity into a new DFIT model. Incorporating fracture modeling tools will enhance the existing reservoir model by creating a more accurate representation of an unconventional reservoir for future development strategies. The new DFIT model workflow can capture complex natural fractures and reservoir properties for unconventional reservoirs. The pressure data from the DFIT analysis can be separated into two parts: before-closure analysis (BCA) and after-closure analysis (ACA). Past models have analyzed BCA and ACA independently, which can lead to misinterpretation. To understand the properties of an unconventional reservoir, the new DFIT model combines the BCA and ACA while including complex natural fractures into a single workflow. Data from the lower Eagle Ford formation was used to validate the model by accurately matching the same field data with the new workflow. The workflow consists of identifying random natural factures connected to the generated minifrac to observe the true pressure response during DFIT. The new DFIT model implemented hydraulic and natural fractures characterization for a more accurate representation of unconventional reservoirs. The model accurately estimates reservoir properties using a single workflow by interpreting the pressure data coherently. A comparison between the traditional DFIT model and the new integrated model shows that traditional DFIT model may overestimate the true reservoir characteristics. The results from the new DFIT model workflow show that the reservoirs’ complexity can be captured. The pressure fall response can be estimated using the new DFIT workflow. The new DFIT model gave a better representation of an unconventional reservoir to determine the reservoirs characteristics and geomechanics for future fracture designs

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