Petrophysics Partnership with Aker BP: Advancing Subsurface Understanding

Understanding how fluids move through complex rocks is essential for safe and efficient subsurface operations. Through a close partnership with Aker BP, researchers at DTU Offshore are tackling this challenge head-on, combining laboratory measurements, logging data, and geomechanical testing to improve reservoir characterisation and modelling.

The collaboration brings together Postdoctoral Researchers Shohreh Iraji and Ermis Proestakis, supported by Professor Emerita Ida Lykke Fabricius and senior researcher Michael Welch, with Geoscience Advisor Birgitte Dalsgaard Larsen as Project Lead, blending experimental expertise with decades of experience in petrophysical interpretation. Together, they are translating advanced research into tangible results that support both scientific progress and industrial innovation.

The Diatomite Challenge: High Porosity Meets Low Permeability

At the heart of the Aker BP-DTU Offshore collaboration lies one of the most demanding geological challenges in the Norwegian North Sea: understanding unconventional reservoir formations.

These formations are characterised by extremely high porosity but very low permeability, meaning that while they can store significant volumes of fluid, those fluids move through the rock very slowly. “These rocks are fragile and behave differently from conventional reservoir,” explains Shohreh Iraji. “Every measurement we take contributes to understanding how these rocks store fluids, transmit them, and respond to changing conditions”

For the research team, the focus has been on integrating petrophysical data from multiple scales. “Petrophysics connects laboratory experiments with field measurements,” says Ermis Proestakis. “We investigate how rocks deform when pressure changes, whether from production or injection, and how acoustic signals can help us detect those changes in real time.”

This fundamental understanding is key to addressing industrial challenges in developing unconventional reservoirs and ensuring safe, sustainable subsurface operations.

Data-Rich Approach: From Core to Calibration

The Aker BP collaboration is built on a data-rich and method-driven approach, where laboratory experiments, borehole logging, and geomechanical testing come together to form a coherent understanding of rock behaviour.

Shohreh’s laboratory work is a backbone of the project. Using advanced analytical techniques, she measures a range of rock properties, including:

• Porosity and permeability
• Induced polarisation (IP) and electrical resistivity
• Nuclear magnetic resonance (NMR)
• Mercury injection capillary pressure (MICP)
• Cation exchange capacity (CEC)

“These methods give us quantitative insights into how fluids distribution and transport within the pore spaces,” Shohreh explains. “We can then integrate these results with Aker BP’s logging data to better interpret subsurface conditions.”

Geomechanical Testing and Acoustic Measurements

In collaboration with the company Geo, Ermis focuses on how stress and deformation affect rock integrity. “In fluid injection or production, reservoir pressure changes, and rocks deform,” he says. “In extreme cases, they can collapse. My work involves understanding how these siliceous rocks respond to stress and using acoustic wave propagation to model their mechanical behaviour.”

One of the project’s intriguing findings is that traditional helium porosity measurements underestimate the true pore space in the studied rocks. “We found that after drying, absorbed water significantly affects the results,” notes Shohreh. “Even a small difference in porosity estimates can have a major impact when you scale up to reservoir size.”