Abstract

Accurate fracture characterization has a huge impact on production forecasts and evaluation of projects in Naturally Fractured Carbonate fields. Pulse/Interference Tests can give valuable information about fracture network by providing additional constraint for spatial fracture distribution between wells, which can be honored with application of geologically consistent trends (Levchenko et.al, 2017). However, operational execution of the Pulse/Interference tests is very challenging. Therefore, usually limited data are available from the planned surveillance jobs leaving large sections of the reservoir without information from Pulse/Interference tests, which could be used for calibration of the Fracture Model.

Lack of Interference data can be resolved by examining already available measurements, which are generally used for other purposes. For example, the primary purpose of Pressure Transient Tests (PTTs) is obtaining kh and skin values, while Permanent Downhole Gauges (PDHG) are mostly utilized for recording reservoir pressure, which is used for conventional History Matching process. As it was found from this study, historical data from both PTTs and PDHGs could be a source of additional high value information of Interference tests occurring in the field, which nobody was aware of.

Properly designed Pulse/Interference Tests are very difficult to execute in the field with high production deliverability requirements. However, examining historical data can reveal a lot of good quality Interference Tests, which were recorded and stored for decades, but not used for Fracture Model characterization. Additional information from Interference tests were applied to calibrate a full-field simulation model, significantly improving quality of the history match in comparison with previous models, and improved confidence in the production forecasts.

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