We develop a conceptual framework that connects biological heredity and organization. We refer to heredity as the cross-generation conservation of functional elements, defined as constraints subject to organizational closure. While hereditary objects are functional constituents of biological systems, any other entity that is stable across generations—and possibly involved in the recurrence of phenotypes—belongs to their environment. The central outcome of the organizational perspective consists in extending the scope of heredity beyond the genetic domain without merging it with the broad category (...) of cross-generation stability. After discussing some implications, we conclude with a reflection on the relationship between stability and variation. 1Introduction2From Extended Heredity to Cross-generation Stability 2.1Extending the scope of heredity: A brief state of the art2.2Rethinking heredity: Conceptual challenges3Biological Heredity in Light of Organization 3.1Biological organization within organisms and beyond3.2Extending organization in time3.3What is biological heredity?4Implications and Objections 4.1Heredity as a specific kind of cross-generation stability4.2Heredity at various levels of description4.3Non-functional and dysfunctional objects5Conclusions: From Conservation to Variation. (shrink)

In this paper, I argue that the increasing data about non-genetic inheritance requires the construction of a new conceptual framework that should complement the inclusive approaches already discussed in the literature. More precisely, I hold that this framework should be epistemologically relevant for evolutionary biologists in capturing the limits of extended inheritance and in reassessing the boundaries of biological systems that transmit traits to their offspring. I outline the first elements of an organizational account of extended inheritance. In this account, (...) the category of inherited factors is neither restricted to genes nor extended to stable resources related to trans-generational similarities. Instead, it includes persisting constitutive elements appearing as difference makers for heterogeneous organizational constraints, namely for heterogeneous constitutive parts whose specific role is to harness flows of matter and energy across generations of clearly delimited extended organized systems. This both inclusive and restrictive framework opens an additional way to apprehend how extended inheritance may affect evolutionary trajectories. (shrink)

In this paper two models for movement of respiratory gases in the insect trachea are presented. One model considers the tracheal system as a single flexible compartment while the other model considers the trachea as a single flexible compartment with gas exchange. This work represents an extension of Ben-Tal’s work on compartmental gas exchange in human lungs and is applied to the insect tracheal system. The purpose of the work is to study nonlinear phenomena seen in the insect respiratory system. (...) It is assumed that the flow inside the trachea is laminar, and that the air inside the chamber behaves as an ideal gas. Further, with the isothermal assumption, the expressions for the tracheal partial pressures of oxygen and carbon dioxide, rate of volume change, and the rates of change of oxygen concentration and carbon dioxide concentration are derived. The effects of some flow parameters such as diffusion capacities, reaction rates and air concentrations on net flow are studied. Numerical simulations of the tracheal flow characteristics are performed. The models developed provide a mathematical framework to further investigate gas exchange in insects. (shrink)

The concept of biological inheritance has recently been extended so as to integrate, among other elements, parts of organisms’ environments. The literature refers to the trans-generational reconstruction of these parts in terms of environmental or ecological inheritance. This article’s main objective is to clarify the different meanings of "environmental inheritance," to underline so far unnoticed theoretical difficulties associated to this polysemous notion and to consequently argue that inheritance, even when extended, should be theoretically distinguished from trans-generational environmental stability. After disentangling (...) the different meanings of environmental inheritance, I underline that studies dealing with this concept place themselves in the wake of earlier contributions about biological environment and elaborate on the role of organisms in the determination of their relevant developmental and selective surroundings. This leads me to question the legitimacy of the category shift operated by niche inheritance proponents—from environment to inheritance—and to explain why the very concept of inherited environment shows important and so far unnoticed theoretical limitations. In this context, I assert the necessity to distinguish two related but different research programs: the construction of a finer-grained theory of environment and the elaboration of an extended theory of inheritance. (shrink)

The paper outlines the contours of an organizational perspective on extended inheritance. Based on theoretical studies about biological organization and extended physiology, this perspective allows for the conception of extended biological legacies while keeping a theoretically indispensable distinction between biological systems and their environment. In this context, the line of demarcation between these systems and their surroundings is modelled on an organizational criterion and on the related conceptual distinction between organizational constraints, whose specific role is to harness flows of matter (...) and energy across generations of composite biological systems, and resources exploited by those systems. Biological legacies are restricted to persisting constitutive elements responsible for the reoccurrence of organizational constraints in a given environment. The case of symbiotic transmission is presented as a paradigmatic system illustrating the main proposed conceptual clarifications. (shrink)

This essay examines the risks of racialized science as revealed in the American mustard gas experiments of World War II. In a climate of contested beliefs over the existence and meanings of racial differences, medical researchers examined the bodies of Japanese American, African American, and Puerto Rican soldiers for evidence of how they differed from whites.

The concept of biological inheritance has recently been extended so as to integrate, among other elements, parts of organisms’ environments. The literature refers to the trans-generational reconstruction of these parts in terms of environmental or ecological inheritance. This article’s main objective is to clarify the different meanings of "environmental inheritance," to underline so far unnoticed theoretical difficulties associated to this polysemous notion and to consequently argue that inheritance, even when extended, should be theoretically distinguished from trans-generational environmental stability. After disentangling (...) the different meanings of environmental inheritance, I underline that studies dealing with this concept place themselves in the wake of earlier contributions about biological environment and elaborate on the role of organisms in the determination of their relevant developmental and selective surroundings. This leads me to question the legitimacy of the category shift operated by niche inheritance proponents—from environment to inheritance—and to explain why the very concept of inherited environment shows important and so far unnoticed theoretical limitations. In this context, I assert the necessity to distinguish two related but different research programs: the construction of a finer-grained theory of environment and the elaboration of an extended theory of inheritance. (shrink)

In this article I scrutinise a crucial tension in understanding the debate over shale gas production in Europe. On the one hand, analyses predominantly grasp the debate in terms of pro-and-con dialectics, as if the pro-shale gas camp faced the anti-shale gas camp in a dyadic clash of opposing voices. On the other hand, it is commonly recognised that this debate is driven by multi-party and multi-position argumentative dynamics. In this broader context, I focus on one pivotal contribution to the (...) debate – Gazprom’s press release from October 2013 outlining Russia’s energy giant’s strategy of dealing with unconventional gas production. I employ concepts and methods of argumentative discourse analysis to contend that an arguer to a multi-party debate – argumentative polylogue – faces a number of constraints and opportunities that cannot be adequately grasped in terms of dyadic pro-and-con dialectics. The analysis reveals how Gazprom needs to simultaneously design its discourse to address a number of other parties who might also disagree among themselves: from Greenpeace to European Union governments to shale gas companies. I show why and how a stakeholder analysis used in organisational communication might lead to a better understanding of this form of multi-party public argumentation. (shrink)

In the Abu Madi Formation of the Nile Delta Basin, false bright spots may be misinterpreted as being indicative of hydrocarbons due to mixed clastics and carbonates. However, rock-physics analysis of well logs in a particular prospect area where such ambiguity exists suggests that attributes derived using extended elastic impedance inversion may help identify hydrocarbons because they better show anomalous behavior in particular directions that are readily related to pore fluids and lithology. The EEI attributes calculated from well logs correlate (...) extremely well to lithology and fluid properties, thereby differentiating amplitude anomalies caused by gas-bearing sandstones encased in shale from similar amplitudes caused by juxtaposition of high-impedance carbonates over lower impedance water-filled sandstones. Comparing seismically derived EEI attributes to well logs from a productive well and a nonproductive well indicates that seismic inversion can successfully identify lithologies such as shales, sandstones, carbonates, and anhydrite and distinguish gas-bearing from water-bearing sandstones. The technique can thus potentially be used to better delineate and risk prospects in the area, as well as assisting exploration efforts in other locations where similar ambiguities in amplitude interpretation exist. (shrink)

This is an expansion of the author's 1991 work which investigates the implications of Gödel's writings on Einstein's theory of relativity as they relate to the fundamental questions of the nature of time and the possibilities for time travel.

The thesis of this paper is that individual emitters, in contrast to governments, may be justified in employing excusable ignorance as an excuse after 1990 and even well into the future. Although it may at first seem counterintuitive, this is not only true of individuals with extremely limited access to information but potentially also of highly educated individuals with almost boundless access to data, reports, and analyses. I develop the argument based on an influential account of excusable ignorance and discuss (...) and reject an objection from expert testimony. (shrink)

In his historical novel from 1835, Prince Otto of Denmark and his Time, the poet Bernhard Severin Ingemann established the unknown, yet historical character, Prince Otto of Denmark as the hero of the novel. This choice has puzzled critics ever since, due to the fact that Prince Otto seems less a potential king than his brother Valdemar IV who actually became a king of Denmark. Georg Brandes claimed that Otto mirrored Ingemann’s persona as weak and feminine, a “monk” not suited (...) for kingship. In his ridicule of Prince Otto and Ingemann, Brandes reveals his ideas about gender, masculinity and femininity, but as this article seeks to show, such ideas are tied to time and place. Read from the distance of 2019, Ingemann’s feminine medieval hero might seem more modern and progressive than Brandes would have him. In this sense, the article is a piece of “queer medievalism”. (shrink)

What are the common denominators for success when we consider increasing gas efficiency and enhancing creativity in organizations? As an analogy, the principles of increasing gas efficiency are applicable to enhancing creativity in organizations: Plan activities in advance, allocate sufficient time, resources, and set a SMART goal with clear priority and focus. Identify talent in ourselves and others and do not fall into the temptation of following others. Big ideas take time. Maintain momentum, avoid interruptions, incorporate new technologies, information, and (...) feedback, and modify action to achieve goals. We have 100% control of our thoughts and action. Stop idling, take action, and do it now. If everyone contributes just a little, the cumulative effect over time can be huge. If we have the knowledge, skills, and abilities (KSA) for doing the right things that will benefit humanity and the whole world, but fail to do them, is this ethical? We, the managers, need to focus on what we have done and what we have failed to do, change our thinking, change our behavior, and accomplish our goals. (shrink)

We have estimated the seismic attenuation in gas hydrate and free-gas-bearing sediments from high-resolution P-cable 3D seismic data from the Vestnesa Ridge on the Arctic continental margin of Svalbard. P-cable data have a broad bandwidth, which is extremely advantageous in estimating seismic attenuation in a medium. The seismic quality factor, the inverse of seismic attenuation, is estimated from the seismic data set using the centroid frequency shift and spectral ratio methods. The centroid frequency shift method establishes a relationship between the (...) change in the centroid frequency of an amplitude spectrum and the Q value of a medium. The SR method estimates the Q value of a medium by studying the differential decay of different frequencies. The broad bandwidth and short offset characteristics of the P-cable data set are useful to continuously map the Q for different layers throughout the 3D seismic volume. The centroid frequency shift method is found to be relatively more stable than the SR method. Q values estimated using these two methods are in concordance with each other. The Q data document attenuation anomalies in the layers in the gas hydrate stability zone above the bottom-simulating reflection and in the free gas zone below. Changes in the attenuation anomalies correlate with small-scale fault systems in the Vestnesa Ridge suggesting a strong structural control on the distribution of free gas and gas hydrates in the region. We argued that high and spatially limited Q anomalies in the layer above the BSR indicate the presence of gas hydrates in marine sediments in this setting. Hence, our workflow to analyze Q using high-resolution P-cable 3D seismic data with a large bandwidth could be a potential technique to detect and directly map the distribution of gas hydrates in marine sediments. (shrink)

We model a piece of text of human language telling a story by means of the quantum structure describing a Bose gas in a state close to a Bose–Einstein condensate near absolute zero temperature. For this we introduce energy levels for the words used in the story and we also introduce the new notion of ‘cogniton’ as the quantum of human thought. Words are then cognitons in different energy states as it is the case for photons in different energy states, (...) or states of different radiative frequency, when the considered boson gas is that of the quanta of the electromagnetic field. We show that Bose–Einstein statistics delivers a very good model for these pieces of texts telling stories, both for short stories and for long stories of the size of novels. We analyze an unexpected connection with Zipf’s law in human language, the Zipf ranking relating to the energy levels of the words, and the Bose–Einstein graph coinciding with the Zipf graph. We investigate the issue of ‘identity and indistinguishability’ from this new perspective and conjecture that the way one can easily understand how two of ‘the same concepts’ are ‘absolutely identical and indistinguishable’ in human language is also the way in which quantum particles are absolutely identical and indistinguishable in physical reality, providing in this way new evidence for our conceptuality interpretation of quantum theory. (shrink)

Pore- and fracture-filling gas hydrates were identified from the core samples at several sites during the second Guangzhou Marine Geological Survey expedition. Well logs indicated that gas hydrate occurred in three distinct layers at site GMGS2-08. The gas hydrate saturations calculated from well-log data and the seismic responses for the three gas hydrate-bearing layers, especially within the middle carbonate layer, were poorly known. We estimated gas hydrate saturations using isotropic and anisotropic models based on the mineral composition of the sediments (...) and the effective medium theory. In the upper and lower gas hydrate-bearing layers, saturations estimated from anisotropic models are close to those estimated from pressures cores and chlorinity data. The average saturation using an anisotropic model in the upper hydrate layer is approximately 10% with a maximum value of 25%. In the lower layer, the horizontal and vertical gas hydrate-filled fractures and visible gas hydrate were formed with a maximum saturation of approximately 85%. For the middle layer, well logs show high P-wave velocity, density, high resistivity as well as low gamma ray, porosity, and drilling rate, together indicating a carbonate layer containing gas hydrate. The hydrate saturations calculated from isotropic models assuming hydrate formed at grain contacts are less than 20%, which fit well with two values calculated from chlorinity data for this layer. The upper gas hydrate layer shows no clear seismic response and probably consisted of small fractures filled with gas hydrate. The middle carbonate and lower fracture-filled gas hydrate-bearing layers show pull-up reflections, with the carbonate layer exhibiting relatively higher amplitudes. Pore-filling gas hydrate was also identified just above the depth of the bottom-simulating-reflector from the GMGS2-05 drill site. Below the BSR, the push-down reflections, polarity reversal, and enhanced reflections indicate the occurrence of free gas in the study area. (shrink)

As global warming continues to attract growing levels of attention, various stakeholders have put climate change on corporate agendas and expect firms to disclose relevant greenhouse gas information. In this paper, we investigate the consistency of the GHG information voluntarily disclosed by French listed firms through two different communication channels: corporate reports and the Carbon Disclosure Project. More precisely, we contrast the amounts of GHG emissions reported and the methodological explanations provided in each channel. Consistent with a stakeholder theory perspective, (...) we find that GHG amounts are significantly lower in the CR than in the CDP. We also find that firms increase the CR figures’ traceability when there is a discrepancy between disclosures in the two channels. We suggest that the aim of this greater traceability is to enhance information credibility across the different channels used. (shrink)

Because shale gas content plays a very important role in the evaluation of gas shale potential, its calculation and prediction become obligatory. We used two predictive models, namely, the Langmuir and Ambrose models, to calculate the shale gas content. The parameters involved in these two models are calculated by various experiments and analytic methods, including indirect prediction, the isothermal adsorption test, X-ray diffraction analysis, total organic carbon measurement, pyrolysis, and porosity measurement. Then, a new calculation model that is applicable to (...) shales in the Kuqa Depression, Tarim Basin, is established. Further research on influential factors of gas content in well YN2 is implemented. The result indicates that the gas content of terrestrial shales is more influenced by TOC abundance than by the content of clay minerals and quartz. The main parameters in the new calculation model are the TOC, depth, porosity, and gas saturation. The Jurassic shale gas in well YN2 is speculated to be mainly adsorption gas, with a dominant proportion of 75%–90% in the total gas content. As the formation depth increases, the free-gas content rises continuously, whereas the adsorption gas content first increases and then approaches the equilibrium value or even tends to decrease slightly. Based on the foregoing results, the target layer, the Yengisar Formation, is predicted to possess an enormous amount of shale gas potential, with an average total gas content of [Formula: see text]. (shrink)

We model a piece of text of human language telling a story by means of the quantum structure describing a Bose gas in a state close to a Bose–Einstein condensate near absolute zero temperature. For this we introduce energy levels for the words used in the story and we also introduce the new notion of ‘cogniton’ as the quantum of human thought. Words are then cognitons in different energy states as it is the case for photons in different energy states, (...) or states of different radiative frequency, when the considered boson gas is that of the quanta of the electromagnetic field. We show that Bose–Einstein statistics delivers a very good model for these pieces of texts telling stories, both for short stories and for long stories of the size of novels. We analyze an unexpected connection with Zipf’s law in human language, the Zipf ranking relating to the energy levels of the words, and the Bose–Einstein graph coinciding with the Zipf graph. We investigate the issue of ‘identity and indistinguishability’ from this new perspective and conjecture that the way one can easily understand how two of ‘the same concepts’ are ‘absolutely identical and indistinguishable’ in human language is also the way in which quantum particles are absolutely identical and indistinguishable in physical reality, providing in this way new evidence for our conceptuality interpretation of quantum theory. (shrink)

Lattice-gas cellular automaton (LGCA) and lattice Boltzmann (LB) models are promising models for studying emergent behaviour of transport and interaction processes in biological systems. In this chapter, we will emphasise the use of LGCA/LB models and the derivation and analysis of LGCA models ranging from the classical example dynamics of fluid flow to clotting phenomena in cerebral aneurysms and the invasion of tumour cells.

The organic-rich Lower Silurian Longmaxi and Upper Ordovician Wufeng Shale is one of the most important marine shale gas plays in southern China, with relatively high thermal maturity and complex structural evolution. The delineation of the Jiaoshiba shale gas play has been highly successful for the LSLUOWS in the Fuling area of southeastern Sichuan Basin. The drilling targets the basal part of the LSLUOWS, where the approximately 38–45 m of organic-rich section corresponds to a maturity range around 2.2%–3.0% Ro, with (...) high brittle mineral content. The produced shale gas displays a clear reversal in the stable carbon isotopes. The shale gas play zone is between the overlain mudstone in the Middle-Upper Longmaxi Formation and the underlain Upper Ordovician tight limestone in the Jiancaogou Fm. The shale gas reservoir is overpressured, with an average pressure coefficient of 1.55. From December 2013 to late 2014, results of production tests determined relatively stable pressure and production curves. Fifty prolific gas wells have been completed to date in the Jiaoshiba Shale Gas Field in Fuling. Preliminary study revealed several characteristics of this structurally complex shale play that are distinctly different from those in the United States, including an anticlinal structure with mild deformation, abundant free gas, and very short gas migration through microfractures, the natural fracture network formed by the two fault systems, and the slip parallel to the layer in the basal LSLUOWS. Movement along strike-slip faults has gone through up into the Quaternary, which is considered to be a significant factor in the establishment and preservation of the overpressured region in the LSLUOWS. (shrink)

As gas hydrate energy assessment matures worldwide, emphasis has evolved away from confirmation of the mere presence of gas hydrate to the more complex issue of prospecting for those specific accumulations that are viable resource targets. Gas hydrate exploration now integrates the unique pressure and temperature preconditions for gas hydrate occurrence with those concepts and practices that are the basis for conventional oil and gas exploration. We have aimed to assimilate the lessons learned to date in global gas hydrate exploration (...) to outline a generalized prospecting approach as follows: use existing well and geophysical data to delineate the gas hydrate stability zone, identify and evaluate potential direct indications of hydrate occurrence through evaluation of interval of elevated acoustic velocity and/or seismic events of prospective amplitude and polarity, mitigate geologic risk via regional seismic and stratigraphic facies analysis as well as seismic mapping of amplitude distribution along prospective horizons, and mitigate further prospect risk through assessment of the evidence of gas presence and migration into the GHSZ. Although a wide range of occurrence types might ultimately become viable energy supply options, this approach, which has been tested in only a small number of locations worldwide, has directed prospect evaluation toward those sand-hosted, high-saturation occurrences that were presently considered to have the greatest future commercial potential. (shrink)

As a special type of lithologic body, gas-bearing strata, composed of rhyolite, an igneous rock with a volcanic composition, are characterized by deep burial, complex lithology, poor stratification, and a complicated gas-bearing distribution. These characteristics lead to difficulties in the prediction of gas-bearing reservoir parameters and thus restrict the exploration and exploitation of such reservoirs. The unique and complex volcanic model contains different types of facies and subfacies because the volcanic eruption usually experiences different explosion-effusion periods. Our study focuses on (...) the vertical and lateral gas-bearing reservoir distribution in a volcanic environment in the Cretaceous Yingcheng Formation of the Songnan Gas Field, using seismic facies-controlled nonlinear stochastic inversion to integrate the volcanic facies information. First, we built the volcanic facies model for the Songliao Basin to introduce the comprehensive characteristics of the volcanic facies during a volcanic eruption and analyzed the well-tie logging facies and seismic facies to guide the facies analysis of the target layer. Then, based on this facies analysis, we depicted the gas-bearing reservoir in detail through the use of seismic facies-controlled nonlinear random inversion. Finally, we predicted the distribution of the gas-bearing reservoir by the inversion results. The predicted results were found to agree well with the actual drilling data. The inversion method effectively predicts the velocity distribution of the gas-bearing reservoir, which provides a good foundation for the subsequent description of gas-bearing reservoirs in the Yingcheng Formation. (shrink)

Environmental ethicists have not reached a consensus about whether or not individuals who contribute to climate change have a moral obligation to reduce their personal greenhouse gas emissions. In this paper, I side with those who think that such individuals do have such an obligation by appealing to the concept of integrity. I argue that adopting a political commitment to work toward a collective solution to climate change—a commitment we all ought to share—requires also adopting a personal commitment to reduce (...) one’s emissions. On these grounds, individuals who contribute to climate change have a prima facie moral duty to lower their personal greenhouse gas emissions. After presenting this argument and supporting each of its premises, I defend it from two major lines of objection: skepticism about integrity’s status as a virtue and concerns that the resulting moral duty would be too demanding to be morally required. I then consider the role that an appeal to integrity could play in galvanizing the American public to take personal and political action regarding climate change. (shrink)

The purpose of this paper is to provide further clarity to the technical and policy difficulties associated with mitigating greenhouse gas emissions from agriculture by identifying and distilling the core tensions which propagate and animate them. We argue that these complexities exist across four critical dimensions: the epistemological, the ethical, the political, and the practical. Adequately confronting the challenge of agricultural emissions will require improved transparency in emissions measurement, increased science communication, enhanced public participatory mechanisms, and the integration of ethical (...) deliberation in scientific and policy discussions. (shrink)

Comprehensive analysis of proteins to evaluate their genetic diversity, study their differences, and respond to the tensions is the main subject of an interdisciplinary field of study called proteomics. The main objective of the proteomics is to detect and quantify proteins and study their post-translational modifications and interactions using protein chemistry, bioinformatics, and biology. Any disturbance in proteins interactive network can act as a source for biological disorders and various diseases such as Alzheimer and cancer. Most current computational methods for (...) discovering protein complexes are usually based on specific topological characteristics of protein-protein networks. To identify the protein complexes, in this paper, we, first, present a new encoding method to represent solutions; we then propose a new clustering algorithm based on the genetic algorithm, named PPI-GA, employing a new multiobjective quality function. The proposed algorithm is evaluated on two gold standard and real-world datasets. The result achieved demonstrates that the proposed algorithm can detect important protein complexes, and it provides more accurate results compared with state-of-the-art protein complex identification algorithms. (shrink)

We model a piece of text of human language telling a story by means of the quantum structure describing a Bose gas in a state close to a Bose–Einstein condensate near absolute zero temperature. For this we introduce energy levels for the words used in the story and we also introduce the new notion of ‘cogniton’ as the quantum of human thought. Words are then cognitons in different energy states as it is the case for photons in different energy states, (...) or states of different radiative frequency, when the considered boson gas is that of the quanta of the electromagnetic field. We show that Bose–Einstein statistics delivers a very good model for these pieces of texts telling stories, both for short stories and for long stories of the size of novels. We analyze an unexpected connection with Zipf’s law in human language, the Zipf ranking relating to the energy levels of the words, and the Bose–Einstein graph coinciding with the Zipf graph. We investigate the issue of ‘identity and indistinguishability’ from this new perspective and conjecture that the way one can easily understand how two of ‘the same concepts’ are ‘absolutely identical and indistinguishable’ in human language is also the way in which quantum particles are absolutely identical and indistinguishable in physical reality, providing in this way new evidence for our conceptuality interpretation of quantum theory. (shrink)

The gas hydrate petroleum system approach, which has been used to characterize gas hydrates in nature, uses three distinct components: a methane source, a methane migration pathway, and a reservoir that not only contains gas hydrate, but also acts as a seal to prevent methane loss. Unlike GHPS, a traditional petroleum system approach further distinguishes between the reservoir, a unit with generally coarser sediment grains, and a separate overlying seal unit with generally finer sediment grains. Adopting this traditional PS distinction (...) in the GHPS approach facilitates assessments of reservoir growth and production potential. The significance of the seal for the formation of a gas hydrate reservoir as well as for efficiency in methane extraction from the reservoir as an energy resource is evident in findings from recent offshore field expeditions, such as India’s second National Gas Hydrate Program expedition. In regard to gas hydrate-bearing reservoir formations, the NGHP-02 gas chemistry data indicate a primarily microbial methane source. Fine-grained seal sediment in contact with coarser grained reservoir sediment can facilitate that microbial methane production. Logging-while-drilling and sediment core data also indicate that the overlying fine-grained seal sediment is less permeable than the underlying, highly gas hydrate-saturated reservoir sediment. The overlying seal’s capacity to act as a low-permeability boundary is important not only for preventing methane migration out of the reservoir over time, but also for preventing water invasion into the reservoir during methane extraction from the reservoir. Ultimately, the presence of an overlying, fine-grained, low-permeability “seal” influences how gas hydrate initially forms in a coarse-grained reservoir and dictates how efficiently methane can be extracted as an energy resource from the gas hydrate reservoir via depressurization. (shrink)

We have performed 2D and 3D gas hydrate petroleum systems modeling for the Pleistocene turbiditic sedimentary sequences distributed in the Daini-Atsumi area in the eastern Nankai Trough to understand the accumulation mechanisms and their spatial distribution related to geologic and geochemical processes. High-resolution seismic facies analysis and interpretations were used to define facies distributions in the models. We have created a new biogenic methane generation model based on the biomarker analysis using core samples and incorporated it into our model. Our (...) 2D models were built and simulated to confirm the parameters to be used for 3D modeling. Global sea level changes and paleogeometry estimated from 3D structural restoration results were taken into account to determine the paleowater depth of the deposited sedimentary sequences. Pressure and temperature distributions were modeled because they are the basic factors that control the GH stability zone. Our 2D modeling results suggested that the setting of biogenic methane generation depth is one of the most important controlling factors for GH accumulation in the Nankai Trough, which may be related to the timing of methane upward migration and methane solution process in pore water. Our 3D modeling results suggested that the distribution of sandy sediments and the formation dip direction are important controlling factors in the accumulation of GHs. We also found that the simulated amount of GH accumulation from the petroleum systems modeling compares well with independent estimations using 3D seismic and well data. This suggests that the model constructed in this study is valid for this GH system evaluation and that this type of evaluation can be useful as a supplemental approach to resource assessment. (shrink)

The Gulf of Mexico Joint Industry Project Leg 2 logging-while-drilling data in Walker Ridge Lease Block 313 in the Gulf of Mexico detected gas hydrate in both coarse- and fine-grained sediments at sites WR313-G and WR313-H. The coarse-grained units are thin and highly saturated while the fine-grained unit is thick with low-saturation and fracture-filling gas hydrate. Unlike its coarse-grained counterpart, the seismic character of the fine-grained unit does not clearly indicate the presence of gas hydrate, which likely would have remained (...) undiscovered in the absence of drilling. In this paper, through frequency-domain acoustic full waveform inversion of ocean-bottom seismometer data along a 2D multichannel seismic transect near Sites WR313-G and WR313-H, we detect and quantify gas hydrate in the fine-grained unit. Key results are as follows. First, the base of the gas hydrate stability zone, which is not obvious in the reflection profile, can be discerned in the FWI results. Second, the gas hydrate in the fine-grained unit is mainly confined to the area between two sets of opposite-dipping normal faults implying that the fault architecture may be partially responsible for this gas hydrate accumulation and distribution. (shrink)

A new 3D seismic reflection data volume acquired in 2012 has allowed for the detailed mapping and characterization of gas hydrate distribution in the Pearl River Mouth Basin in the South China Sea. Previous studies of core and logging data showed that gas hydrate occurrence at high concentrations is controlled by the presence of relatively coarse-grained sediment and the upward migration of thermogenic gas from the deeper sediment section into the overlying gas hydrate stability zone ; however, the spatial distribution (...) of the gas hydrate remains poorly defined. We used a constrained sparse spike inversion technique to generate acoustic-impedance images of the hydrate-bearing sedimentary section from the newly acquired 3D seismic data volume. High-amplitude reflections just above the bottom-simulating reflectors were interpreted to be associated with the accumulation of gas hydrate with elevated saturations. Enhanced seismic reflections below the BSRs were interpreted to indicate the presence of free gas. The base of the BGHSZ was established using the occurrence of BSRs. In areas absent of well-developed BSRs, the BGHSZ was calculated from a model using the inverted P-wave velocity and subsurface temperature data. Seismic attributes were also extracted along the BGHSZ that indicate variations reservoir properties and inferred hydrocarbon accumulations at each site. Gas hydrate saturations estimated from the inversion of acoustic impedance of conventional 3D seismic data, along with well-log-derived rock-physics models were also used to estimate gas hydrate saturations. Our analysis determined that the gas hydrate petroleum system varies significantly across the Pearl River Mouth Basin and that variability in sedimentary properties as a product of depositional processes and the upward migration of gas from deeper thermogenic sources control the distribution of gas hydrates in this basin. (shrink)