Tight reservoir means reservoir of low porosity and low permeability. Many tight formations are extremely complex, produced from multiple layers with different permeability that is often enhanced by natural fracturing. The complicity of these reservoirs is attributed to a) Low porosity and low permeability reservoir, b) The presence of clay minerals like illite, kaolin and micas in pores, c) Th...

China has vast reserves of shale gas. Currently, shale gas is one of the focuses of the unconventional reservoir. Well logs play an import role in shale gas production, and it is the bridge connecting geology, geophysics and petroleum engineering. In the exploration stage, well logs are used to identify lithology, evaluate the parameters of mineral types and compositions, total organic carbon (...

Analysis of heterogeneous gas sand reservoirs is one of the most difficult problems. These reservoirs usually produce from multiple layers with different permeability and complex formation, which is often enhanced by natural fracturing. Therefore, using new well logging techniques like NMR or a combination of NMR and conventional openhole logs, as well as developing new interpretation methodolo...

A stochastic Bayesian approach for combining well logs and geophysical surveys for enhancing subsurface characterization is presented. The main challenge we face is in creating the bridge to link between ambiguously related geophysical surveys and well data. The second challenge is imposed by the disparity between the scale of the geophysical survey and the scale of the well logs. Our approach ...

Conventional Imtrltiple regression for permeability estimation from well logs requires a functional relationship to be presumed. Due to the inexact nature of the relationship between petrophysical variables, it is not always possible to identify the underlying functional form between dependent and independent variables in advance. When large variations in metrological properties arc exhibited, ...

Well logs are principal sources of subsurface geological information. They provide significant information on mineralogical composition, texture, sedimentary structures and petrophysical properties such as porosity and permeability. By compiling data from various well logs, one can discriminate sedimentary units with comparable log characteristics. Sedimentary units with similar fluid flow and ...