Tight-gas and shale-gas systems can undergo significant depressurization during basin uplift and erosion of overburden due primarily to the natural leakage of hydrocarbon fluids. To date, geologic factors governing hydrocarbon leakage from such systems are poorly documented and understood. Here we show, in a study of produced natural gas from 1,907 petroleum wells drilled into a Triassic tight-...

US shale gas production is generally expected to continue its fast rise. However, a cautious evaluation is needed. Shale gas resource estimates are potentially overoptimistic and it is uncertain to which extent they can be produced economically. Moreover, the adverse environmental effects of ever more wells to be drilled may lead to a fall in public acceptance and a strengthening of regulation....

The shallow gas zone in the Pantai Pakam Timur (PPT) field, located in Northern Sumatra, Indonesia, has recently become an important target for development. However, only two wells were drilled in peripheral part of the field. In this situation the method of Geostatistics is hardly applied because of less control points, but there is a new suitable method to estimate reservoir properties under ...

This paper describes a prototype system for the prediction of parameters associated with a geological prospect, required for assessing the likelihood of hydrocarbons at the prospect. A principle characteristic of expert reasoning in this domain involves the recall and use of previous examples (`exemplars') of similar, already-drilled wells in addition to the use of general rules concerning know...

A large data base consisting of 40,679 well locations and 196,687 lithologic records was created from Illinois, Indiana, and Wisconsin well construction records for wells drilled during the period 1980-1997. The purpose of the database is to provide information for mapping the surface, thickness, transmissivity and hydraulic conductivity of the Quaternary, Silurian/Devonian, and Cambrian/Ordovi...

In the past 10–15 years, innovations in hydraulic fracturing and horizontal drilling have fueled a boom in the production of natural gas from geological formations that were previously unprofitable. The rapid deployment of fracking has been accompanied by concerns about negative externalities. In response, a regulatory regime has emerged that requires disclosure of chemical additives, but prese...

This paper describes a prototype system for the prediction of parameters associated with a geological prospect, required for assessing the likelihood of hydrocarbons at the prospect. A principle characteristic of expert reasoning in this domain involves the recall and use of previous examples (`exemplars') of similar, already-drilled wells in addition to the use of general rules concerning know...

In the this research, the hydrocarbon generation potential of the Gadvan Formation as a probable source rock was investigated in the central part of the Persian Gulf at the borders of Iran. Type and maturity level of kerogen were investigated in six wells using the results of Rock-Eval pyrolysis and compared with results yielded by the modelling software program known as Pars Basin Modeler (PBM...

Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are important in leaching uranium from source rocks and transporting it in low concentrations to a chemical redox interface where it is deposited in an ore zone typically...

A multiperiod MINLP model for offshore oilfield infrastructure planning is presented where nonlinear reservoir behavior is incorporated directly into the formulation. Discrete decisions include the selection of production platforms, well platforms and wells to be installed/drilled, as well as the drilling schedule for the wells over the planning horizon. Continuous decisions include the capacit...