Challenges of Pore Pressure Prediction for Unconventional Reservoirs in Active Operational Settings
I. Eggenkamp and A. Summitt
Event name: Second EAGE Workshop on Pore Pressure Prediction
Session: Pore and Fracture Pressure Uncertainties I
Publication date: 19 May 2019
Info: Extended abstract, PDF ( 901.09Kb )
Price: € 20
Pore pressure prediction in unconventional plays presents a unique set of challenges and uncertainties. These are the result of uncertainty in the measurements, the low permeability of the reservoir, and changes caused by industry activity. Slow pressure changes during production tests or diagnostic fracture injection tests (DFITs) require significant extrapolation to obtain the reservoir pressure. A third source of data comes from the mud weight required to control a kick. Unconventional reservoirs are often drilled underbalanced and if the kick is the result of encountering a natural fracture, the mud weight required may be lower than the reservoir pressure due to the limited hydrocarbon volume of the fracture. The uncertainty in the measurements result in a wide range of pressures that can make it difficult to identify important outliers caused by geological differences or by industry activity in the area. Kicks close to lithostatic pressure can be encountered when drilling into a hydraulic fracture of a nearby well. This can have major safety and financial implications. Regulations have been put in place requiring operators to identify offset wells that could be affected by hydraulic fracturing operations and work together with their competitors to stay safe.