The Overlooked Perils of Heterogeneous Oil and Gas

Chapter 2 details the differences and similarities among twenty-first-century petroleum resources and distinguishes conventional from unconventional resources. The chapter argues that, while these definitions are muddled, there is value to understanding and parsing unconventional oil and gas. Numerous different oil and gas resources are then surveyed, including shale gas, ultradeep gas, Arctic gas, tight gas, coalbed methane, biogas, acid gas, geopressurized gas, methane hydrates, condensates, light tight oil, extra-heavy oil, ultradeep oil, Arctic oil, depleted oil, kerogen, biofuels, gas-to-liquids, and coal-to-liquids. Estimates are provided of cumulative industry greenhouse gas emissions for conventional versus unconventional oil and gas resources. The chapter concludes with a discussion of hydrogen—the ultimate unconventional resource—and its production pathways.

Unified Assessment of Unconventional Resource Plays – Implications for Global Exploration and Development

Unconventional resource plays, herein referred to as source rock plays, have been able to significantly increase the supply of hydrocarbons to the world. However, majority of the companies developing these resource plays have struggled to generate consistent positive cash flows, even during periods of stable commodity prices and after successfully reducing the development costs. The fundamental reasons for poor financial performance can be attributed to various reasons, such as; rush to lease acreage and drill wells to hold acreage, delayed mapping of sweet spots, slow acknowledgement of high geological variability, spending significant capital in trial and errors to narrow down optimal combinations of well spacing and stimulation designs. The objective of this paper is to present a systematic integrated multidisciplinary analysis of several unconventional plays worldwide which, if used consistently, can lead to significantly improved economics. We present an analysis of several unconventional plays in the US and Argentina with fluid systems ranging from dry gas to black oil. We utilize the publicly available datasets of well stimulation and production data along with laboratory measured core data to evaluate the sweet spots, the measure of well productivity, and the variability in well productivity. We investigate the design parameters which show the strongest correlation to well productivity. This step allows us to normalize the well productivity in such a way that the underlying well productivity variability due to geology is extracted. We can thus identify the number of wells which should be drilled to establish geology driven productivity variability. Finally, we investigate the impact of well spacing on well productivity. The data indicates that, for any well, first year cumulative production is a robust measure of ultimate well productivity. The injected slurry volume shows the best correlation to the well productivity and "completion normalized" well productivity can be defined as first year cumulative production per barrel of injected slurry volume. However, if well spacing is smaller than the created hydraulic fracture network, the potential gain of well productivity is negated leading to poor economics. Normalized well productivity is log-normally distributed in any play due to log-normal distribution of permeability and the sweet spots will generally be defined by most permeable portions of the play. Normalized well productivity is shown to be independent of areal scale of any play. We show that in every play analyzed, typically 20-50 wells (with successful stimulation and production) are sufficient to extract the log-normal productivity distribution depending on play size and target intervals. We demonstrate that once the log-normal behavior is anticipated, creation of production profiles with p10-p50-p90 values is quite straightforward. The way the data analysis is presented can be easily replicated and utilized by any operator worldwide which can be useful in evaluation of unconventional resource play opportunities.

A Computational Scheme for Evaluating the Stress Field of Thermally and Pressure Induced Unconventional Reservoir

The fluid flow connecting the hydraulic fracture and associated unconventional gas or oil reservoir is of great importance to explore such unconventional resource. The deformation of unconventional reservoir caused by heat transport and pore pressure fluctuation may change the stress field of surrounding layer. In this paper, the stress distribution around a penny-shaped reservoir, whose shape is more versatile to cover a wide variety of special case, is investigated via the numerical equivalent inclusion method. Fluid production or hydraulic injection in a subsurface resource caused by the change of pore pressure and temperature within the reservoir may be simulated with the help of the Eshelby inclusion model. By employing the approach of classical eigenstrain, a computational scheme for solving the disturbance produced by the thermally and pressure induced unconventional reservoir is coded to study the effect of Biot coefficient and some other important factors. Moreover, thermo-poro transformation strain and arbitrarily orientated reservoir existing within the surrounding layer are also considered.

Hydraulic Fracture Characterization Using Rapid Simulation

The purpose of this paper is to present a technique to estimate hydraulic fracture (HF) length, fracture conductivity, and fracture efficiency using simple and rapid but rigorous reservoir simulation matching of historical production, and where available, pressure. The methodology is particularly appropriate for analysis of horizontal wells with multiple fractures in tight unconventional or unconventional resource plays. In our discussion, we also analyze the differences between the results from decline curve analysis (DCA) approach and the Science Based Forecasting (SBF) results that this work proposes. When we characterize fracture properties with SBF, we can do a better job of forecasting than if we randomly combine fracture properties and reservoir permeability together in a decline-curve trend. The forecasts are significantly different with SBF, therefore fracture characterization plays an important role and SBF uses this characterization to produce different (and better) forecasts.

Identification of thermally mature TOC-rich layers in shale formations using an effective machine learning approach

We develop a support vector machine (SVM) method that relies on core-measured data as well as gamma ray, deep resistivity, sonic and density wireline well log data in identifying thermally mature TOC-rich layers at depth intervals with missing geochemical data in unconventional resource plays. We first test the SVM method using the Duvernay shale formation data. The SVM method successfully classifies the TOC data set into TOC-rich, TOC-poor classes and the Tmax data set into thermally mature and thermally immature classes, when optimal features are selected. To further test the SVM approach, we generate depth-separated training and test data sets from a well in the Duvernay shale formation and successfully use the approach to identify thermally mature TOC-rich intervals. We also demonstrate the successful cross-basin application of the SVM approach in predicting TOC using data from the Barnett and Duvernay shale formations as the training and test data sets respectively.

Potential of garnet sand as an unconventional resource of the critical high-technology metals scandium and rare earth elements

Scandium is a critical raw material that is essential for the EU economy because of its potential application in enabling technologies such as fuel cells and lightweight materials. As there is currently no secure supply of Sc, several projects worldwide evaluate potential Sc sources. While elsewhere in Europe emphasis is placed upon secondary resources such as red mud, we investigated the potential of industrial garnet sand and its waste products. Since Sc readily substitutes for Mg and Fe in the crystal lattice of garnet, the garnet minerals almandine and pyrope, in particular, may show high Sc concentrations. Garnet sand, after being used as an abrasive in the cutting and sandblasting industry, is recycled several times before it is finally considered waste which eventually must be disposed of. Extraction of Sc (and rare earth elements, REE) from such garnet sand may generate added value and thereby reduce disposal cost. The studied garnet sands from different mines in Australia, India and the U.S., and industrial garnet sands commercially available in Germany from different suppliers show average Sc concentrations of 93.7 mg/kg and 90.7 mg/kg, respectively, i.e. similar to red mud. Our data also show that “fresh” and recycled garnet sands yield similar Sc concentrations. Within the framework of a minimum-waste approach, it may be feasible to utilize the industrial waste-product “garnet sand” as an unconventional source of Sc and REE, that reduces disposal cost.

WAYS TO IMPROVE ENERGY EFFICIENCY IN CIVIL BUILDINGS

As a result of theoretical and experimental experiments carried out in this research paper, specificaspects of the temperature field in the parts of the canopy in terms of the thermal characteristics of its outer wall for improving energy efficiency in civil buildings are determined. Also, taking into account the fact that there is currently an increased demand for energy in buildings, it is advisable to use new innovative technologies. Therefore, this conducted experiment gave a positive result.Keywords:heat, insulation, ventilation, primary energy, external barriers, reserve, unconventional, resource, material, capacity, demand, fuel, consumption, air, indicator