This study proposes a methodology to diagnose the root causes of failures in the domain of oil well drilling. The idea is to combine a Bayesian network, which is generated based on an expert knowledge, with situation-specific knowledge of past failure cases. A causal chain is viewed as a temporal sequence. To test the model’s capability, six failure cases from the study’s application domain (oi...

Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance, pH, electrical conductivity (EC(e)), s...

The costs associated with drilling and completing wells are a major factor in determining the economic feasibility of producing energy from geothermal resources. In EGS power plants, estimates place drilling costs as accounting for 42%-95% of total power plant costs (Tester et al., 1994) depending on the quality of the EGS reservoir. An earlier correlation first developed by Milora and Tester (...

Data is generally expected to continue its exponential growth the next five to ten years. However, it is commonly agreed that the amount of data that currently exist is abundant and that there is still much to achieve with it. The industry, in general, has recognized both the growth and the need to analyze the data. This is also the case with oil well drilling operations. Currently, operators m...

The problem of slow drilling in deep shale formations occurs worldwide causing significant expenses to the oil industry. Bit balling which is widely considered as the main cause of poor bit performance in shales, especially deep shales, is being drilled with water-based mud. Therefore, efforts have been made to develop a model to diagnose drilling effectivity. Hence, we arrived at graphical cor...

OBJECTIVES There are no recognized analytical methods for measuring oil mist and vapours arising from drilling fluids used in offshore petroleum drilling industry. To inform the future development of improved methods of analysis for oil mist and vapours this study assessed the inter- and intra-laboratory variability in oil mist and vapour analysis. In addition, sample losses during transportati...

a r t i c l e i n f o The use of high-volume horizontal hydraulic fracturing (fracking) has increased substantially over the past five years in the United States. Use of this drilling technology to extract natural gas from hitherto impermeable shale is expected to increase even more in coming decades. Two institutions, integration contracts and well spacing requirements, evolved to mitigate the...

Recently, we have seen falling oil prices combined with sticky costs at a high level in the petroleum industry. This cause cost cuts and project postponements, thus challenging reserve replacement of oil companies and security of supply for consumers. Costs are particularly high for drilling. High rig rates are obviously important. In new contracts for high-spec semi rigs on the Norwegian Conti...

In the oil industry, the measurement-while-drilling (MWD) systems are usually used to provide the real-time position and orientation of the bottom hole assembly (BHA) during drilling. However, the present MWD systems based on magnetic surveying technology can barely ensure good performance because of magnetic interference phenomena. In this paper, a MWD surveying system based on a fiber optic g...