Challenges and opportunities of wireline formation testing in tight reservoirs: a case study from Barmer basin, India

摘要

Tight reservoir exploration in Barmer basin has huge potential with possible in place volumes of multi billion barrels in reservoirs across the Mesozoic to Cenozoic stratigraphic levels. These tight reservoirs (permeability in the range of 0.01–10?mD) are ideal fraccing candidates for commercial production. One of the critical challenges in tight reservoir exploration is early assessment of permeability and reservoir fluid type identification through wireline formation testing (WFT) to determine flow behavior, frac optimization and expected deliverability after fraccing. The most prospective Barmer Hill (BH) and Fatehgarh (FAT) tight formations from the basin have been tested with new 3D radial probe WFT tool providing significant time and cost optimization opportunities. Good quality fluid samples with very low contamination levels were extracted with less rig time and operational costs from very low permeable BH formation (0.18?mD/cP mobility) and FAT formation (0.35?mD/cP mobility) in 150 and 200?min respectively. 3D radial probe and dual packer module based WFT job were compared for their efficiencies in similar environment. The results show that 3D radial probe has less inflation time (~1/5th), quick fluid detection (~1/10th time), quick and reliable packer deployment, focused fluid flow regime to address the formation heterogeneity and minimum hole sticking issues due to mechanical arms around the probe. In short, 3D radial probe can address both the uncertainties of WFT in tight reservoirs and optimized well testing and frac design for cost effective field development.