Evaluating the Implications of Lineaments on Petroleum Fields: South Sumatra, Indonesia

Declining oil prices has led to a reduction of petroleum exploration as oil production as no longer a lucrative area of investment as in the previous years. Current exploration activities are supported by field work which are intensive considering the resources required. There is need to develop low cost methods to delineate areas of potential hydrocarbon resources. This research uses Land Satellite (Landsat) 8 Operational Land Imager (OLI) for alteration extraction, Shutter Radar Topography Mission (SRTM) for lineament extraction, Geological maps to develop a low cost method of petroleum exploration. The results indicate high OH bearing alterations on the Gumai and Kasai formation, a seal rock. Extensional tectonics is responsible for the migration of petroleum from the subsurface. It is suggested that future exploration be concentrated on the Gumai and Kasai formation based on evidence of micro seepage.

Integrated petrophysical study to validate water saturation from well logs in Bahariya Shaley Sand Reservoirs, case study from Abu Gharadig Basin, Egypt

Water saturation is a key parameter in evaluating oil and gas reservoirs and calculating OIIP and GIIP for petroleum fields. The late Cretaceous Bahariya reservoir contains variable amounts of clay minerals. Bore hole logs are affected with those clay minerals particularly the density and resistivity logs. Several methods are acknowledged to determine the true water saturation from well logs in shaley sand reservoirs. Each method assumes a sort of corrections to amount of shale distributed in the reservoir. The scope of this petrophysical study is to integrate core analysis and bore hole logs to investigate the characteristics of water saturation in the Bahariya reservoirs. Comparison between most of the significant shaley sand methods is presented in this research. Reservoir lithology and mineralogy are explained by Elan-model while bore hole images are used for fine-tuning the electrofacies. Siltstone, shaley sand and clean sandstones are the main electrofacies that is characterizing the Bahariya reservoir rocks. For accurate saturation results, some core samples have been used for validating the log-derived water saturation. Dean stark and cation exchange capacity experiments are integrated with bore hole logs to calculate the error in water saturation for each method for best calibration. The successful integration between logs and core measurements led to convenient log evaluation and accurate understanding for the Bahariya reservoir in the prospective part of Abu Gharadig basin.

A regulator's perspective: well integrity considerations in decommissioning

With several petroleum fields in offshore Australia approaching the end of their economic life, it is widely recognised that there is an upcoming wave of well decommissioning. Decommissioning of wells (also known as ‘plug and abandonment’ or well abandonment) presents well integrity and, in some instances, well control challenges. Deferral of well abandonment is likely to make the task more difficult; wells are continually ageing and, meanwhile, the benchmark for what constitutes a compliant abandonment tends to get higher over time. It is a common objective of industry, government and society that wells are decommissioned properly so that they do not present future safety or environmental risk. Decommissioning a well safely requires that it has been maintained properly with a reliable dataset and documentation history. A clear framework for managing and monitoring well integrity in all phases of the well lifecycle is a prerequisite, as demonstrated in international standards and guidelines such as ISO 16530. Well decommissioning requires collaboration across industry partners to foster research and development, reduce risk and lower cost.