Using Causal Inference in Field Development Optimization: Application to Unconventional Plays     

Bertoncello  Antoine  Oppenheim  Georges  Cordier  Philippe  Gourvénec  Sébastien  Mathieu  Jean-Philippe  Chaput  Eric  Kurth  Tobias 《Mathematical Geosciences》2020,52(5):619-635

Mathematical Geosciences - In the current era of big data and machine learning, a strong focus exists on prediction and classification. In industrial applications, however, many important questions...  相似文献   

Holocene recurrent explosive activity at Chimborazo volcano (Ecuador)     

Diego Barba  Claude Robin  Pablo Samaniego  Jean-Philippe Eissen 《Journal of Volcanology and Geothermal Research》2008

Ice-capped Chimborazo is one of the large composite Ecuadorian volcanoes whose recent eruptive activity is poorly known. This paper presents the characteristics and the ages of a newly discovered Holocene sequence of pyroclastic deposits on the east and north sides of the cone. Lying upon a moraine of the Late-Glacial period, the most complete section of ~ 4.5 m in thickness is located 5 km from the present summit crater. It consists of seven massive or diffusely stratified ash flow layers and four fallout layers interbedded with seven paleosoils.  相似文献   

Geochemical and petrological constraints on rear-arc magma genesis processes in Ecuador: The Puyo cones and Mera lavas volcanic formations   总被引：1，自引：0，他引：1  

Géraldine Hoffer  Jean-Philippe Eissen  Bernardo Beate  Erwan Bourdon  Michel Fornari  Jo Cotten 《Journal of Volcanology and Geothermal Research》2008

The Puyo scoria cones and the Mera lava flows, two newly recognized volcanic formations dated between Late Pliocene to Middle Pleistocene, extend the limits of the Ecuadorian rear-arc volcanic province some 100 km to the south. The Puyo scoria cones have erupted K-rich absarokites containing olivine, diopside and phlogopite, whereas the Mera lava flows display a basic andesite composition, with olivine and minor augite phenocrysts. In addition to high contents in LILE, LREE and HFSE, the Puyo absarokites exhibit many characteristics of primitive melts, namely high Cr (590–310 ppm) and Ni (330–154 ppm) contents, high Mg# (64–70) and they contain forsteritic olivine (Fo_82–89). The composition of the most primary Puyo absarokite was used in petrogenetic models, in order to constrain the genesis of these high-K magmas. Major and trace elements models, as well as isotopic data, indicate that the source of Puyo magmas is a hydrated phlogopite- and garnet-bearing lherzolite. Phlogopite crystallization in the mantle wedge is triggered by the metasomatism by 3–5% of a SiO₂-, H₂O-rich liquid generated by slab melting. Partial melting of the subducted oceanic crust beneath Ecuador is allowed by the subduction of the young and warm Carnegie Ridge, which modifies the thermal regime of the Benioff zone. A low degree (1–4%) of partial melting of the metasomatized mantle wedge, leaving a variable garnet (4–7%) ± phlogopite (0–4%) lherzolitic residual assemblage, leads to the compositions of the entire Puyo absarokite series and is consistent with previous petrogenetic models developed for the Ecuadorian volcanic arc. Indeed, the homogeneity of isotopic data across the arc suggests a similar source for the whole Ecuadorian magmas.  相似文献   

Pre-eruptive physical conditions of El Reventador volcano (Ecuador) inferred from the petrology of the 2002 and 2004–05 eruptions     

Pablo Samaniego  Jean-Philippe Eissen  Jean-Luc Le Pennec  Claude Robin  Minard L. Hall  Patricia Mothes  Deborah Chavrit  Joseph Cotten 《Journal of Volcanology and Geothermal Research》2008

A petrological study of the eruptive products of El Reventador allowed us to infer the magmatic processes related to the 2002 and 2004–05 eruptions of this andesitic stratovolcano. On November 3, 2002, El Reventador experienced a highly explosive event, which was followed by emplacement of two lava flows in November–December 2002. Silica contents range from 62 to 58 wt.% SiO₂ for the November 3 pyroclastic deposits to 58–56 and 54–53 wt.% SiO₂ for the successive lava flows. In November 2004 eruptive activity resumed supplying four new lava flows (56–54 wt.% SiO₂) between November 2004 and August 2005.  相似文献   

Co-registration and correlation of aerial photographs for ground deformation measurements     

François Ayoub  Sébastien Leprince  Jean-Philippe Avouac 《ISPRS Journal of Photogrammetry and Remote Sensing》2009,64(6):551-560

We describe and test a procedure to accurately co-register and correlate multi-temporal aerial images. We show that this procedure can be used to measure surface deformation, and explore the performance and limitations of the technique. The algorithms were implemented in a software package, COSI-Corr (available from the Caltech Tectonics Observatory website). The technique is validated on several case examples of co-seismic deformation. First, we measure co-seismic ground deformation due to the 1992, Mw 7.3, Landers, California, earthquake from 1 m resolution aerial photography of the National Aerial Photography Program (United States Geological Survey). The fault ruptures are clearly detected, including small kilometric segments with fault slip as small as a few tens of centimeters. We also obtained similar performance from images of the fault ruptures produced by the 1999 Mw 7.1 Hector Mine, California, earthquake. The measurements are shown to be biased due to the inaccuracy of the Digital Elevation Model, film distortions, scanning artifacts, and ignorance of ground displacements at the location of the tie points used to co-register the multi-temporal images. We show that some of these artifacts can be identified and corrected.  相似文献   

A novel platform to evaluate the dampening of water and solute transport in an experimental channel under unsteady flow conditions     

Samer Majdalani  Roger Moussa  Jean-Philippe Chazarin 《水文研究》2020,34(4):956-971

This paper presents a novel platform to study the dampening of water and solute transport in an experimental channel under unsteady flow conditions, where literature data are scarce. We address the question about what could be the smallest size of experimental platform that is useful for research, project studies, and teaching activities and that allows to do rational experiments characterized by small space occupation, short experimental duration, high measurement precision, high quality and reproducible experimental curves, low water and energy consumption, and the possibility to test a large variety of hydrograph scenarios. Whereas large scale hydraulic laboratories have focused their studies on sediment transport, our platform deals with solute transport. The objectives of our study are (a) building a platform that allows to do rational experiments, (b) enriching the lack of experimental data concerning water and solute transport under unsteady state conditions, and (c) studying the dampening of water and solute transport. We studied solute transport in a channel with lateral gain and lateral loss under different experimental configurations, and we show how the same lateral loss flow event can lead to different lateral loss mass repartitions under different configurations. In order to characterize water and solute dampening between the input and the output of the channel, we calculate dampening ratios based on peak coordinates of time flow curves and time mass curves and that express the decrease of peak amplitude and the increase of peak occurrence time between the input and output curves. Finally, we use a solute transport model coupling the diffusive wave equation for water transfer and the advection–diffusion equation for solute transport in order to simulate the experimental data. The simulations are quite good with a Nash–Sutcliffe efficiency NSE > 0.98 for water transfer and 0.84 < NSE < 0.97 for solute transport. This platform could serve hydrological modellers because it offers a variety of measured parameters (flow, water height, and solute concentration), at a fine time step under unsteady flow conditions.  相似文献   

Sensitivity to domain size of mid-latitude summer simulations with a regional climate model   总被引：1，自引：1，他引：0  

Martin Leduc  René Laprise  Mathieu Moretti-Poisson  Jean-Philippe Morin 《Climate Dynamics》2011,37(1-2):343-356

The issue of Regional Climate Model (RCM) domain size is studied here by using a perfect-model approach, also known as the Big-Brother experiment. It is known that the control exerted by the lateral boundary conditions (LBC) on nested simulations increases when reducing the domain size. The large-scale component of the simulation that is forced by the LBC influences the small-scale features that develop along the large-scale flow. Small-scale transient eddies need space and time to develop sufficiently however, and small domains can impede their development. Our tests performed over eastern North America in summer reveal that the small-scale features are systematically underestimated over the entire domain, even for domain as large as 140 by 140 grid points. This result differs from that obtained in winter where the small scales were mainly underestimated on the west (inflow) side of the domain. This difference is due to the circulation regime over Eastern Canada, which is characterized by weak and variable flow in summer, but strong and westerly flow in winter. For both seasons, the small-scale transient-eddy amplitudes are systematically underestimated at higher levels, but this problem is less severe in summer. Overall the model is more skilful in regenerating the small scales in summer than in winter for comparable domain sizes, which can be related to the weaker summer flow and stronger physical processes occurring in this season.  相似文献   

东日本大地震启示     

Jean-Philippe Avouac  韩立波 《国际地震动态》2011,(8):16-18

一组高质量的数据记录了2011年3月东日本大地震的震前、地震发生时以及震后的地表形变。但目前还没有适当的模型可以利用类似数据来对地震和海啸危险性进行评估。随着基于空间的测量板块构造边界和大型断层表面形变技术的发展,地震科学已经跨入一个全新的时代。日本在实施这些技术方面一直走在前列,特别是随着大约15年  相似文献   

Sources of groundwater pumpage in a layered aquifer system in the Upper Gulf Coastal Plain, USA     

Yun Huang  Bridget R. Scanlon  Jean-Philippe Nicot  Robert C. Reedy  Alan R. Dutton  Van A. Kelley  Neil E. Deeds 《Hydrogeology Journal》2012,20(4):783-796

Understanding groundwater-pumpage sources is essential for assessing impacts on water resources and sustainability. The objective of this study was to quantify pumping impacts and sources in dipping, unconfined/confined aquifers in the Gulf Coast (USA) using the Texas Carrizo-Wilcox aquifer. Potentiometric-surface and streamflow data and groundwater modeling were used to evaluate sources and impacts of pumpage. Estimated groundwater storage is much greater in the confined aquifer (2,200?km³) than in the unconfined aquifer (170?km³); however, feasibility of abstraction depends on pumpage impacts on the flow system. Simulated pre-development recharge (0.96?km³/yr) discharged through evapotranspiration (ET, ～37%), baseflow to streams (～57%), and to the confined aquifer (～6%). Transient simulations (1980–1999) show that pumpage changed three out of ten streams from gaining to losing in the semiarid south and reversed regional vertical flow gradients in ～40% of the entire aquifer area. Simulations of predictive pumpage to 2050 indicate continued storage depletion (41% from storage, 32% from local discharge, and 25% from regional discharge capture). It takes ～100?yrs to recover 40% of storage after pumpage ceases in the south. This study underscores the importance of considering capture mechanism and long-term system response in developing water-management strategies.  相似文献   

Chironomid assemblages in cores from multiple water depths reflect oxygen-driven changes in a deep French lake over the last 150 years     

Victor Frossard  Laurent Millet  Valérie Verneaux  Jean-Philippe Jenny  Fabien Arnaud  Michel Magny  Jérôme Poulenard  Marie-Elodie Perga 《Journal of Paleolimnology》2013,50(3):257-273

We sampled modern chironomids at multiple water depths in Lake Annecy, France, before reconstructing changes in chironomid assemblages at sub-decadal resolution in sediment cores spanning the last 150 years. The lake is a large, deep (z_max = 65 m), subalpine waterbody that has recently returned to an oligotrophic state. Comparison between the water-depth distributions of living chironomid larvae and subfossil head capsules (HC) along three surface-sediment transects indicated spatial differences in the influence of external forcings on HC deposition (e.g. tributary effects). The transect with the lowest littoral influence and the best-preserved, depth-specific chironomid community characteristics was used for paleolimnological reconstructions at various water depths. At the beginning of the twentieth century, oxygen-rich conditions prevailed in the lake, as inferred from M. contracta-type and Procladius sp. at deep-water sites (i.e. cores from 56 to 65 m) and Paracladius sp. and H. grimshawi-type in the core from 30 m depth. Over time, chironomid assemblages in cores from all three water depths converged toward the dominance of S. coracina-type, indicating enhanced hypoxia. The initial change in chironomid assemblages from the deep-water cores occurred in the 1930s, at the same time that an increase in lake trophic state is inferred from an increase in total organic carbon (TOC) concentration in the sediment. In the 1950s, an assemblage change in the core from 30 m water depth reflects the rapid expansion of the hypoxic layer into the shallower region of the lake. Lake Annecy recovered its oligotrophic state in the 1990s. Chironomid assemblages, however, still indicate hypoxic conditions, suggesting that modern chironomid assemblages in Lake Annecy are decoupled from the lake trophic state. Recent increases in both TOC and the hydrogen index indicate that changes in pelagic functioning have had a strong indirect influence on the composition of the chironomid assemblage. Finally, the dramatic decrease in HC accumulation rate over time suggests that hypoxic conditions are maintained through a feedback loop, wherein the accumulation of (un-consumed) organic matter and subsequent bacterial respiration prevent chironomid re-colonization. We recommend study of sediment cores from multiple water depths, as opposed to investigation of only a single core from the deepest part of the lake, to assess the details of past ecological changes in large deep lakes.  相似文献