stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. in all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. the dependency of per...

Abstract Nuclear magnetic resonance (NMR) logs can provide information on some critical reservoir characteristics, such as permeability, which are rarely obtainable from conventional well logs. Nevertheless, high cost and operational constraints limit the wide application of NMR logging tools. In this study, a machine learning (ML)-based procedure is developed for fast accurate estimation NMR-d...

Stress waves contain useful information about the properties of porous materials; they can be recovered through different non-destructive testing methods such as crosswell, vertical seismic profile, borehole logging as well as sonic tests. In all these methods, it is crucial to assess the effects of frequency on wave attributes including velocity and intrinsic attenuation. The dependency of per...

Carbon dioxide has been used commercially to recover oil from reservoir by enhanced oil recovery technologies for over 40 years. Currently, the CO2 flood is the second most applied enhanced oil recovery (EOR) processes in the world behind steam flood. Water alternating gas (WAG) injection has been a popular method to control mobility and improve volumetric sweep efficiency for CO2 flooding. The...

Background The most essential requirements for a geothermal reservoir are sufficient temperature and permeability (e.g. Jung et al. 2002; Paschen et al. 2003; Schulz 2011; Schulz et al. 2009). Whereas the geothermal gradient for a given region is commonly constrained to a sufficient degree, estimates of porosities, fracture systems, permeabilities, and therefore the achievable convective heat f...

Permeability is an important parameter connected with oil reservoir. In the last two decades, artificial intelligence models have been used. The current best prediction model in permeability prediction is extreme learning machine (ELM). It produces fairly good results but a clear explanation of the model is hard to come by because it is so complex. The aim of this research is to propose a way o...

Reservoir heterogeneities exist at several length scales. Reservoir properties will depend on the scale that we are analysing on the reservoir (from core to grid block). Facies are normally identified in cores and classified based on microscopic and small scale features such as lithology, grain size, texture, sedimentary structure, colour and fossil content. However, facies information is only ...

Analysis and forecasting of well performance data in unconventional reservoirs is and will likely remain problematic as there is considerable uncertainty related to our current lack of understanding of the fluid flow phenomenon in low/ultra-low permeability reservoir systems.There are many unknowns which are the primary sources of the uncertainty on production performance.To name a few, these c...

We discuss petrophysical analysis of wireline logs, methods for formation evaluation and issues in evaluating tight sandstone formations. The main concerns of log interpretation in tight gas sandstones include porosity interpretation, understanding the effect of clay on the log responses, accurate computation of water saturation, and permeability determination (Kukal et al., 1985). Moreover, va...

Several methods have been developed in the past for analyzing the porosity and other types of well logs for large-scale porous media, such as oil reservoirs, as well as their permeability distributions. We developed a method for analyzing the porosity logs ϕ(h) (where h is the depth) and similar data that are often nonstationary stochastic series. In this method one first generates a new statio...