oa The Evolution of Subsurface Data Acquisition Strategies of an Exploration Company Searching for Gas in Palaeozoic Format

Specific data acquisition strategies have been developed to address the challenges of deep wells in tight reservoirs in remote and harsh environments. Advanced Mud Logging technologies have helped SRAK to gain trust in mud logging data sets to such an extent that this technology is now the prime source of information for certain datasets. Comparison of mass spectrometer derived mud gas data with downhole sampled gas has shown a very good compositional match. The targeted use of Logging While Drilling has been a successful strategy. In tight gas reservoirs that are typically drilled with high overbalance, it is difficult to obtain high quality data before invasion occurs. The high overbalance often results in deep invasion that may lead to underestimation of gas and other hydrocarbons. The use of LWD could also be used for fluid typing and as a permeability indicator when used in several time-steps across the same interval. This talk will also show how SRAK's decision to core both reservoir and non-reservoir facies rocks has helped to integrate all available data, from gas samples to core plugs, to come up with relevant conclusions on charge history and migration paths.