Increase the length scale for permeability answers away from the wellbore

Permeability data is typically obtained in the near-wellbore area from core analysis, nuclear magnetic resonance (NMR) logs, and pretest buildup investigations conducted with a wireline formation testing tool.

However, reservoir heterogeneity is best represented using permeability values on a much larger scale. Reservoir modeling studies, geostatistical models, and reservoir simulation grid blocks require horizontal permeability (k_h) measurements from tens to hundreds of feet into the formation. Corresponding vertical permeability (k_v) values are also needed.

Precise flow rate delivers pressure data

The MDT modular formation dynamics tester performs these critical k_v and k_h measurements by using its flow control module to produce a 1,000-cm³ volume of formation fluid. The precise surface-controlled flow rate is recorded for interpretation of pressure data. For tests requiring larger fluid volumes, the pumpout module or sample chamber may also be used.

Deeper testing for deeper understanding

Because interference tests measure significantly deeper into the formation than pretests, they don’t necessarily measure identical values. For example, differences in vertical communication could indicate a permeability barrier. The increased DOI of interference testing that the MDT tester provides is invaluable for understanding permeability anisotropy in your reservoir characterization.