Impact of sedimentary environment on pore parameters of thermally mature Permian shale: A study from Kommugudem Formation of Krishna Godavari Basin, India

2021 ◽  
pp. 105236
Author(s):  
Shubhangi Kala ◽  
Venkata Yasaswy Turlapati ◽  
J. Devaraju ◽  
M.A. Rasheed ◽  
N. Sivaranjanee ◽  
...  
Keyword(s):  
Sedimentary Environment ◽  
Godavari Basin

THE MODERN SEDIMENTARY ENVIRONMENT AND TRANSPORT TRENDS IN JIULONGJIANG ESTUARY

2010 ◽  
Vol 30 (2) ◽  
pp. 35-42 ◽  
Author(s):  
Jianyong FANG ◽  
Jian CHEN ◽  
Aijun WANG ◽  
Dongyi LI ◽  
Caibin HUANG
Keyword(s):  
Sedimentary Environment

scholarly journals Production behavior evaluation on multilayer commingled stress-sensitive carbonate gas reservoir

2020 ◽  
pp. 014459872096415
Author(s):  
Jianlin Guo ◽  
Fankun Meng ◽  
Ailin Jia ◽  
Shuo Dong ◽  
Haijun Yan ◽  
...  
Keyword(s):  
Early Stage ◽  
Sedimentary Environment ◽  
Production Performance ◽  
Total Production ◽  
Inversion Algorithm ◽  
Gas Reservoir ◽  
Hole Pressure ◽  
Bottom Hole Pressure ◽  
Bottom Hole ◽  
Production Behavior

Influenced by the complex sedimentary environment, a well always penetrates multiple layers with different properties, which leads to the difficulty of analyzing the production behavior for each layer. Therefore, in this paper, a semi-analytical model to evaluate the production performance of each layer in a stress-sensitive multilayer carbonated gas reservoir is proposed. The flow of fluids in layers composed of matrix, fractures, and vugs can be described by triple-porosity/single permeability model, and the other layers could be characterized by single porosity media. The stress-sensitive exponents for different layers are determined by laboratory experiments and curve fitting, which are considered in pseudo-pressure and pseudo-time factor. Laplace transformation, Duhamel convolution, Stehfest inversion algorithm are used to solve the proposed model. Through the comparison with the classical solution, and the matching with real bottom-hole pressure data, the accuracy of the presented model is verified. A synthetic case which has two layers, where the first one is tight and the second one is full of fractures and vugs, is utilized to study the effects of stress-sensitive exponents, skin factors, formation radius and permeability for these two layers on production performance. The results demonstrate that the initial well production is mainly derived from high permeable layer, which causes that with the rise of formation permeability and radius, and the decrease of stress-sensitive exponents and skin factors, in the early stage, the bottom-hole pressure and the second layer production rate will increase. While the first layer contributes a lot to the total production in the later period, the well bottom-hole pressure is more influenced by the variation of formation and well condition parameters at the later stage. Compared with the second layer, the scales of formation permeability and skin factor for first layer have significant impacts on production behaviors.

scholarly journals Geochemistry of the black rock series of lower Cambrian Qiongzhusi Formation, SW Yangtze Block, China: Reconstruction of sedimentary and tectonic environments

2021 ◽  
Vol 13 (1) ◽  
pp. 166-187
Author(s):  
Hao Liu ◽  
Chan Wang ◽  
Yong Li ◽  
Jianghong Deng ◽  
Bin Deng ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Sedimentary Environment ◽  
Hydrothermal Fluids ◽  
Early Cambrian ◽  
Rock Series ◽  
Yangtze Block ◽  
Tectonic Environment ◽  
Weathering Intensity ◽  
Black Rock Series ◽  
Tectonic System

Abstract The black rock series in the Qiongzhusi Formation contains important geochemical information about the early Cambrian tectonic and ecological environment of the southwestern Yangtze Block. In this paper, major, trace, and rare earth element data are presented in an attempt to reveal the sediment source during the deposition of the early Cambrian Qiongzhusi Formation and to reconstruct the sedimentary tectonic environment and weathering intensity during that time. The basin primarily received continental clastic material with neutral-acidic igneous rocks from a stable source and with a moderate level of maturity during the depositional period of the Qiongzhusi Formation. Furthermore, the strata were weakly influenced by submarine hydrothermal fluids during diagenesis. The reconstruction of the sedimentary environment and weathering intensity shows that P2O5 enrichment and water body stratification occurred due to the effects of upwelling ocean currents during the depositional period of the Qiongzhusi Formation. The combination of upwelling and bottom-water hydrothermal fluids led to environmental changes in the study area, from dry and hot to moist and warm. Last, the reconstruction of the tectonic environment of the Qiongzhusi Formation indicates that deposition occurred in continental slope and marginal marine environments associated with a continental arc tectonic system. These findings provide an essential basis for the comprehensive reconstruction of the early Cambrian sedimentary environment of the Yangtze Block.

scholarly journals Striking forest revival at the end of the Roman Period in north-western Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. Lambert ◽  
A. Penaud ◽  
M. Vidal ◽  
C. Gandini ◽  
L. Labeyrie ◽  
...  
Keyword(s):  
North Atlantic ◽  
Western Europe ◽  
Anthropogenic Activities ◽  
Sedimentary Environment ◽  
Pollen Grains ◽  
Roman Period ◽  
Freshwater Microalgae ◽  
Environmental Signals ◽  
The North ◽  
North Western

AbstractThe Holocene period (last 11,700 years BP) has been marked by significant climate variability over decadal to millennial timescales. The underlying mechanisms are still being debated, despite ocean–atmosphere–land connections put forward in many paleo-studies. Among the main drivers, involving a cluster of spectral signatures and shaping the climate of north-western Europe, are solar activity, the North Atlantic Oscillation (NAO) varying atmospheric regimes and North Atlantic oceanic gyre dynamics. Over the last 2500 years BP, paleo-environmental signals have been strongly affected by anthropogenic activities through deforestation and land use for crops, grazing, habitations, or access to resources. Palynological proxies (especially pollen grains and marine or freshwater microalgae) help to highlight such anthropogenic imprints over natural variability. Palynological analyses conducted in a macro-estuarine sedimentary environment of north-western France over the last 2500 years BP reveal a huge and atypical 300 year-long arboreal increase between 1700 and 1400 years BP (around 250 and 550 years AD) that we refer to as the ‘1.7–1.4 ka Arboreal Pollen rise event’ or ‘1.7–1.4 ka AP event’. Interestingly, the climatic 1700–1200 years BP interval coincides with evidence for the withdrawal of coastal societies in Brittany (NW France), in an unfavourable socio-economic context. We suggest that subpolar North Atlantic gyre strengthening and related increasing recurrence of storminess extremes may have affected long-term coastal anthropogenic trajectories resulting in a local collapse of coastal agrarian societies, partly forced by climatic degradation at the end of the Roman Period.

scholarly journals Characteristics of Mineralogy, Lithofacies of Fine-Grained Sediments and Their Relationship with Sedimentary Environment: Example from the Upper Permian Longtan Formation in the Sichuan Basin

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3662
Author(s):  
Hongzhi Yang ◽  
Liangbiao Lin ◽  
Liqing Chen ◽  
Yu Yu ◽  
Du Li ◽  
...  
Keyword(s):  
Mineral Composition ◽  
Sichuan Basin ◽  
Sedimentary Environment ◽  
Organic Matter Content ◽  
Upper Permian ◽  
Carbonaceous Shale ◽  
Carbonate Minerals ◽  
Thin Sections ◽  
Terrestrial Input ◽  
The Sichuan Basin

The Longtan Formation of the Upper Permian in the Sichuan Basin has become a significant target for shale gas exploration in recent years. Multiple methods, including outcrop observations, thin sections, total organic matter content, X-ray diffraction and scanning electron microscopy were used to investigate the mineralogy, shale lithofacies assemblages and their relationships with the deposition environment. The mineral composition of the Longtan Formation has strong mineral heterogeneity. The TOC values of the Longtan Formation have a wide distribution range from 0.07% to 74.67% with an average value of 5.73%. Four types of shale lithofacies assemblages of the Longtan Formation could be distinguished, as clayey mudstone (CLS), carbonaceous shale (CAS), siliceous shale (SS) and mixed shale (MS) on the basis of mineral compositions. The TOC values of various types of shale lithofacies assemblages in the Longtan Formation varied widely. The shore swamp of the Longtan Formation is most influenced by the terrestrial input and mainly develops CLS and MS. The tidal flat is influenced by the terrestrial input and can also deposit carbonate minerals, developing CLS, CAS and MS. The shallow water melanged accumulation shelf develops CAS and MS, dominated by clay and carbonate minerals. The deep water miscible shelf develops CLS and SS, whose mineral composition is similar to that of the shore swamp, but the quartz minerals are mainly formed by chemical and biological reactions, which are related to the Permian global chert event. The depositional environment of the Longtan Formation controls the shale mineral assemblage of the Longtan Formation and also influences the TOC content.

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