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1.
黑龙江依兰地区变玄武岩及变堆晶辉长岩LA-ICP-MS锆石U-Pb年龄及其地质意义 总被引：2，自引：0，他引：2
对依兰地区黑龙江混杂岩中的变玄武岩、变枕状玄武岩及变堆晶辉长岩岩块中的锆石进行了LA-ICP-MS U-Pb同位素测定,结果表明,变玄武岩的锆石大量为捕获基底的锆石,其年龄范围大,从3172±24Ma到176±1Ma均有分布,其中具有基性岩典型的板状特征的锆石年龄为243±1Ma,代表了变玄武岩的原岩形成年龄;变枕状玄武岩及变堆晶辉长岩的年龄分别为251±1Ma和252±1Ma,分别代表各自原岩的形成年龄。本次锆石年龄的获得,证明晚二叠世佳木斯地块和松嫩-张广才岭地块之间存在古洋盆,为研究黑龙江杂岩的演化历史提供了重要的年代学依据。 相似文献
2.
In this paper we determined the chronology of Lower Paleozoic arc-related granitic rocks in the Cordón de Lila and Sierra de Almeida ranges, northern Chile, based on new U–Pb ages obtained by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) on single zircons. Plutonism lasted ∼30 m.y., spanning from 490 to 460 Ma (Lower to Mid Ordovician). The obtained ages correspond to the plutonic units' crystallization ages and fit well with the observed contact relationships with their country rocks and mutual intrusion relationships, and also with biostratigraphical data from the sedimentary country rocks. Our geochronological results on the granitic rocks of Cordón de Lila and Sierra de Almeida ranges broadly agree with the known ages of the plutonic rocks in the Argentinian Puna, strengthening the idea that they formed part of the same magmatic arc in the western border of west Gondwana during the Early to Middle Ordovician. 相似文献
3.
哀牢山构造带是青藏高原东南缘重要的边界构造带,其内出露的深变质岩系一直被认为是古老的变质基底岩石。利用LA-ICP-MS原位微区分析技术对哀牢山深变质岩系锆石进行U-Pb年龄、微量元素分析。结果表明深变质岩系的原岩有728±8Ma、727±3Ma、231±4Ma的花岗质岩石和其它年龄的碎屑岩,变质时代为27.8~23.7Ma。综合野外地质特征和分析结果,我们认为哀牢山深构造带在晚渐新世27.8~23.7Ma发生了大规模的地壳深熔作用,现今所见深变质岩系是由不同时代、不同岩性的原岩在晚渐新世(27.8~23.7Ma)变质形成,不全是古老的变质基底岩石。深熔过程中熔/流体发生了明显的迁移。哀牢山变质带具有混合岩化特征的岩石很可能是峰期变质作用后减压熔融的产物。晚渐新世地壳深熔作用与左行走滑剪切是哀牢山深变质带折返过程中近似同时发生的两种不同变质表现形式,两者相互影响、相互制约。 相似文献
4.
The Pelagonian Zone of Greece is the westernmost segment of the Internal Hellenides comprising widespread crystalline basement
exposures of granites and orthogneisses. We dated these basement rocks in order to identify the major crust-forming episodes
and to understand the evolutionary history of the area. In our study we investigated granites, gneisses, meta-rhyolites and
mylonites from the major occurrences of the Pelagonian Zone. We applied single-zircon dating techniques such as Pb–Pb evaporation,
conventional U–Pb and SHRIMP. The majority of the basement rocks gave Permo-Carboniferous intrusion ages, thus emphasizing
the importance of this crust-forming event for the Internal Hellenides of Greece. Triassic intrusion ages were obtained, however,
for a meta-rhyolite from the western Pelagonian Zone and two mylonites from the eastern Pelagonian Zone. These ages are interpreted
to reflect magmatism accompanying early rifting that led to the subsequent opening of the Pindos Ocean to the west and the
Meliata Ocean to the east of the Pelagonian Zone. The geochronological results demonstrate that the magmatic episodes during
which most of the Pelagonian Zone crystalline basement formed are predominantly pre-Alpine in age. 相似文献
5.
6.
7.
New constraints on the pyroclastic eruptive history of the Campanian volcanic Plain (Italy) 总被引：2，自引：0，他引：2
B. De Vivo G. Rolandi P. B. Gans A. Calvert W. A. Bohrson F. J. Spera H. E. Belkin 《Mineralogy and Petrology》2001,73(1-3):47-65
Summary The ∼ 150 km3 (DRE) trachytic Campanian Ignimbrite, which is situated north-west of Naples, Italy, is one of the largest eruptions in the
Mediterranean region in the last 200 ky. Despite centuries of investigation, the age and eruptive history of the Campanian
Ignimbrite is still debated, as is the chronology of other significant volcanic events of the Campanian Plain within the last
200–300 ky. New 40Ar/39Ar geochronology defines the age of the Campanian Ignimbrite at 39.28 ± 0.11 ka, about 2 ky older than the previous best estimate.
Based on the distribution of the Campanian Ignimbrite and associated uppermost proximal lithic and polyclastic breccias, we
suggest that the Campanian Ignimbrite magma was emitted from fissures activated along neotectonic Apennine faults rather than
from ring fractures defining a Campi Flegrei caldera. Significantly, new volcanological, geochronological, and geochemical
data distinguish previously unrecognized ignimbrite deposits in the Campanian Plain, accurately dated between 157 and 205 ka.
These ages, coupled with a xenocrystic sanidine component > 315 ka, extend the volcanic history of this region by over 200 ky.
Recent work also identifies a pyroclastic deposit, dated at 18.0 ka, outside of the topographic Campi Flegrei basin, expanding
the spatial distribution of post-Campanian Ignimbrite deposits. These new discoveries emphasize the importance of continued
investigation of the ages, distribution, volumes, and eruption dynamics of volcanic events associated with the Campanian Plain.
Such information is critical for accurate assessment of the volcanic hazards associated with potentially large-volume explosive
eruptions in close proximity to the densely populated Neapolitan region.
Received August 1, 2000; accepted November 2, 2000 相似文献
8.
Jian-Wei Li Paulo Vasconcelos Wei Zhang Xiao-Dong Deng Nurdan Duzgoren-Aydin Dai-Rong Yan Jian-Qiang Zhang Ming-An Hu 《Mineralium Deposita》2007,42(4):361-383
Supergene Mn-oxide deposits are widely distributed in Guangxi, Guangdong, Yunnan, and Hunan Provinces, South China, accounting
for 18% of the total Mn reserves in the country. Direct dating of supergene Mn enrichment, however, is lacking. In this paper,
we present high-resolution 40Ar/39Ar ages of Mn oxides from the Xinrong Mn deposit, western Guangdong, to place numerical constraints on the timing and duration
of supergene Mn enrichment. A total of ten cryptomelane samples, spanning a vertical extent of 67 m, were dated using the
40Ar/39Ar laser incremental heating technique, with seven samples yielding well-defined plateau or pseudo-plateau ages ranging from
23.48 ± 0.91 to 2.06 ± 0.05 Ma (2σ). One sample yields a staircase spectrum that does not reach a plateau; the spectrum, however, indicates the presence of
two or more generations of Mn oxides in the sample, whose ages are best estimated at 22.34 ± 0.31 and 10.2 ± 0.86 Ma, respectively.
The remaining two samples gave meaningless or uninterpretable results due to significant 39Ar recoil and contamination by old phases. The 40Ar/39Ar data thus reveal a protracted history of weathering and supergene Mn enrichment that started at least in the end of the
Oligocene or beginning of Miocene and extending into the latest Pliocene. Staircase-apparent age spectra, resulting from banded
or botryoidal samples, yield an average growth rate of Mn oxides at 0.6–0.7 × 10−3 mm kyr−1. The values indicate that a 1-mm grain of Mn oxides may host minerals precipitated during a time span of ca. 1.5 m.y., and
accumulation of Mn oxides to form economic deposits under weathering environments may take millions of years. The distribution
of weathering ages shows that the oldest Mn oxides occur on the top of the profile, whereas the youngest minerals are found
at the bottom, suggesting downward propagation of weathering fronts. However, two samples located at the intermediate depths
of the profile yield ages comparable with those occurring at the highest elevations. Such a complexity of age distribution
is interpreted in terms of preferential penetration of Mn-rich weathering solutions along more permeable fault zones, or as
a result of multi stages of dissolution and re-precipitation of Mn oxides. A synthesis of geochronological and geological
data suggests that formation of the Xinrong deposit was a consequence of a combination of favorable lithological, climatic,
and structural conditions. Because the climatic and structural conditions are similar among the provinces of South China during
the Cenozoic, the geochronological results obtained at Xinrong may also have implications for the timing of supergene Mn enrichment
throughout South China. 相似文献
9.
澜沧江南段临沧花岗岩的锆石U-Pb年龄及构造意义 总被引：7，自引：5，他引：2
临沧花岗岩是滇西地区出露面积最大的复式岩基,它是特提斯构造域的重要组成单元,是研究古特提斯俯冲-碰撞的重要窗口。本文通过对澜沧江南段澜沧-景洪地区广泛出露的临沧花岗岩的岩石学、地球化学以及锆石年代学综合分析,系统阐述该区花岗岩的原岩性质以及其形成的构造背景。临沧花岗岩主要岩石类型为黑云母二长花岗岩和花岗闪长岩。锆石LA-ICP-MS U-Pb年代学结果表明,该区临沧花岗岩侵位时代为217~233Ma。前人在澜沧江北段花岗岩也获得相似的侵位年龄,表明临沧花岗岩的南段与北段在形成时代上具有一致性。继承锆石U-Pb年龄主要峰期集中在2494Ma、1832Ma、1382Ma、959Ma、774Ma、482Ma,指示临沧花岗岩具丰富的物质来源。全岩主微量元素分析结果显示,临沧花岗岩的Na2O/K2O比值低,铝饱和指数(A/NCK值)大于1,属高钾钙碱性系列,过铝质花岗质岩石。轻重稀土分异明显,轻稀土相对富集,具有明显的铕负异常(Eu/Eu*=0.39~0.63);相容元素Cr和Ni含量较低,富集大离子亲石元素Rb和Ba,亏损高场强元素Nb-Ta和Zr-Hf。地球化学特征显示,临沧花岗岩来源于地壳沉积物的部分熔融,属S型花岗岩,形成于古特提斯洋闭合后的构造伸展阶段。 相似文献
10.
Building of models in the Earth Sciences often requires the solution of an inverse problem: some unknown model parameters need to be calibrated with actual measurements. In most cases, the set of measurements cannot completely and uniquely determine the model parameters; hence multiple models can describe the same data set. Bayesian inverse theory provides a framework for solving this problem. Bayesian methods rely on the fact that the conditional probability of the model parameters given the data (the posterior) is proportional to the likelihood of observing the data and a prior belief expressed as a prior distribution of the model parameters. In case the prior distribution is not Gaussian and the relation between data and parameters (forward model) is strongly non-linear, one has to resort to iterative samplers, often Markov chain Monte Carlo methods, for generating samples that fit the data likelihood and reflect the prior model statistics. While theoretically sound, such methods can be slow to converge, and are often impractical when the forward model is CPU demanding. In this paper, we propose a new sampling method that allows to sample from a variety of priors and condition model parameters to a variety of data types. The method does not rely on the traditional Bayesian decomposition of posterior into likelihood and prior, instead it uses so-called pre-posterior distributions, i.e. the probability of the model parameters given some subset of the data. The use of pre-posterior allows to decompose the data into so-called, “easy data” (or linear data) and “difficult data” (or nonlinear data). The method relies on fast non-iterative sequential simulation to generate model realizations. The difficult data is matched by perturbing an initial realization using a perturbation mechanism termed “probability perturbation.” The probability perturbation method moves the initial guess closer to matching the difficult data, while maintaining the prior model statistics and the conditioning to the linear data. Several examples are used to illustrate the properties of this method. 相似文献
11.
V. A. Valencia J. Ruiz F. Barra G. Geherls M. Ducea S. R. Titley L. Ochoa-Landin 《Mineralium Deposita》2005,40(2):175-191
Uranium–lead zircon (laser ablation multi-collector ICP-MS spot analysis) ages from La Caridad porphyry copper deposit in
the Nacozari District, Northeastern Sonora, Mexico, suggest a short period of magmatism, between 55.5 and 52.6 Ma. Two U–Pb
ages from the mineralized quartz monzonite unit, showing different textural characteristics, yielded indistinguishable crystallization
ages (~54 Ma), and indicate that the intrusion responsible for the mineralization occurred as a single large complex unit,
instead of multiple pulses of magmatism. Some zircons analyzed also show inherited ages in cores recording dates of 112–124 Ma,
141–166 Ma and 1.4 Ga. The Re–Os molybdenite ages from the potassic and phyllic hydrothermal alteration veins yielded identical
ages within error, 53.6±0.3 Ma and 53.8±0.3 Ma, respectively (weighted average of 53.7±0.21 Ma), supporting a restricted period
for the mineralization. The geochronological data thus indicate a short-lived magmatic and hydrothermal system. The inherited
zircons of Precambrian and Late Jurassic-Mid Cretaceous age found in the intrusive rocks of La Caridad deposit, can be explained
considering two possible scenarios within the tectonic/magmatic evolution of the area. The first scenario considers the presence
of a Precambrian anorogenic granitic basement that is intruded by Mesozoic (Jurassic–Cretaceous) units present beneath the
La Caridad deposit. The second scenario suggests that the Mesozoic Glance Conglomerate Formation of Arizona underlies the
Paleocene volcanic-igneous pile in the La Caridad area. 相似文献
12.
Controls on supergene enrichment of porphyry copper deposits in the Central Andes: A review and discussion 总被引：1，自引：1，他引：1
The Central Andes host some of the world’s largest porphyry copper deposits. The economic viability of these deposits is dependent
on the size and quality of their supergene enrichment blanket. Published models that have strongly influenced exploration
policy suggest that supergene enrichment ceased at 14 Ma due to an increase in aridity. Here we discuss these models using
published geochronological, geomorphological and geological data. Geochronological data indicate that supergene oxidation
and enrichment has been active between 17 and 27°S across the forearc of northern Chile and southern Peru from 44 to 6 Ma,
and on the Bolivian Altiplano and Eastern Cordillera of Argentina from 11 Ma to present. There is evidence for cessation at
20, 14 and 6 Ma. However, a major problem is that as more geochronological data become available the age ranges and periods
of enrichment increase. This suggests that the full spectrum of enrichment ages may not have been sampled. The relationship
between supergene enrichment and the age of regional pediplain surface development is not well constrained. Only in two areas
have surfaces related to enrichment been directly dated (southern Peru and south of 26°S in Chile) and suggest formation post
14 Ma. Sedimentological data indicate that a fluctuating arid/semi-arid climate prevailed across the Atacama Desert until
between 4 and 3 Ma, climatic conditions that are thought to be favourable for supergene enrichment. The balance between uplift,
erosion, burial and sufficient water supply to promote enrichment is complex. This suggests that a simple model for controlling
supergene enrichment is unlikely to be widely applicable in northern Chile. General models that involve climatic desiccation
at 14 Ma related to rainshadow development and/or the presence of an ancestral cold-upwelling Humboldt Current are not supported
by the available geological evidence. The integration of disparate sedimentological, geomorphological and supergene age data
will be required to fully understand the controls on and distribution of supergene oxidation and enrichment in the Central
Andes. 相似文献
13.
中国东北地区显生宙花岗岩的成因一直是中亚造山带东段研究的热点之一,尤其是小兴安岭-张广才岭地区的花岗岩其成因及形成的大地构造背景一直存在较大争议。本文新获得小兴安岭-张广才岭铁力和依兰地区的二长花岗岩LA-ICP-MS锆石U-Pb年龄分别为188±1 Ma和257±3 Ma。地球化学数据显示,两地区的二长花岗岩均为Ⅰ型花岗岩并且富集大离子亲石元素(Th和U等)和轻稀土元素,亏损高场强元素(Nb和Ta等)和重稀土元素具有弧岩浆岩的地球化学特征。锆石Hf同位素数据显示,铁力地区二长花岗岩的岩浆源区可能来自于中新元古代的下地壳部分熔融。综合前人在小兴安岭-张广才岭地区已发表的花岗岩类岩石的地质年代学和地球化学数据,初步推测小兴安岭-张广才岭地区在晚古生代至中生代期间处于活动大陆边缘环境。同时,小兴安岭-张广才岭地区晚古生代至中生代的岩浆岩具有自东向西形成时代逐渐变年轻的趋势,这可能是由于东侧的牡丹江洋在晚古生代至中生代期间俯冲角度逐渐变缓造成的。 相似文献
14.
O. A. Levchenkov V. I. Levitskii N. G. Rizvanova V. P. Kovach N. A. Sergeeva L. K. Levskii 《Petrology》2012,20(1):86-92
New geochronological (U-Pb, Pb-LS, Sm-Nd) studies were carried out for minerals from metamorphic rocks (aluminous plagiogneisses
with sillimanite (kinzigites) and potassium shadow migmatites) to establish the sequence of metamorphic events in the Irkut
block of the Prisayan marginal uplift of the Siberian platform basement. Obtained data permit the distinguishing of two main
stages of regional metamorphism under the granulite and amphibolite facies conditions: 2480–2560 and 1860–1900 Ma. New age
data in general are consistent with previously published zircon estimates of the Neoarchean and Paleoproterozoic ages of the
granulite-facies metamorphism of the Irkut block. This gives grounds to consider the geochronological studies of garnet and
monazite as promising tool for distinguishing age boundaries of metamorphic transformations in the areas of polycyclic evolution. 相似文献
15.
Although zircon is the most widely used geochronometer to determine the crystallisation ages of granites, it can be unreliable for low-temperature melts because they may not crystallise new zircon. For leucocratic granites U–Pb zircon dates, therefore, may reflect the ages of the source rocks rather than the igneous crystallisation age. In the Proterozoic Capricorn Orogen of Western Australia, leucocratic granites are associated with several pulses of intracontinental magmatism spanning ~800 million years. In several instances, SHRIMP U–Pb zircon dating of these leucocratic granites either yielded ages that were inconclusive (e.g., multiple concordant ages) or incompatible with other geochronological data. To overcome this we used SHRIMP U–Th–Pb monazite geochronology to obtain igneous crystallisation ages that are consistent with the geological and geochronological framework of the orogen. The U–Th–Pb monazite geochronology has resolved the time interval over which two granitic supersuites were emplaced; a Paleoproterozoic supersuite thought to span ~80 million years was emplaced in less than half that time (1688–1659 Ma) and a small Meso- to Neoproterozoic supersuite considered to have been intruded over ~70 million years was instead assembled over ~130 million years and outlasted associated regional metamorphism by ~100 million years. Both findings have consequences for the duration of associated orogenic events and any estimates for magma generation rates. The monazite geochronology has contributed to a more reliable tectonic history for a complex, long-lived orogen. Our results emphasise the benefit of monazite as a geochronometer for leucocratic granites derived by low-temperature crustal melting and are relevant to other orogens worldwide. 相似文献
16.
Patrick J. Applegate Nathan M. Urban Klaus Keller Thomas V. Lowell Benjamin J.C. Laabs Meredith A. Kelly Richard B. Alley 《Quaternary Research》2012,77(2):293-304
The statistical distributions of cosmogenic nuclide measurements from moraine boulders contain previously unused information on moraine ages, and they help determine whether moraine degradation or inheritance is more important on individual moraines. Here, we present a method for extracting this information by fitting geomorphic process models to observed exposure ages from single moraines. We also apply this method to 94 10Be apparent exposure ages from 11 moraines reported in four published studies. Our models represent 10Be accumulation in boulders that are exhumed over time by slope processes (moraine degradation), and the delivery of boulders with preexisting 10Be inventories to moraines (inheritance). For now, we neglect boulder erosion and snow cover, which are likely second-order processes. Given a highly scattered data set, we establish which model yields the better fit to the data, and estimate the age of the moraine from the better model fit. The process represented by the better-fitting model is probably responsible for most of the scatter among the apparent ages. Our methods should help resolve controversies in exposure dating; we reexamine the conclusions from two published studies based on our model fits. 相似文献
17.
Andreas S. Stordal Hans A. Karlsen Geir Nævdal Hans J. Skaug Brice Vallès 《Computational Geosciences》2011,15(2):293-305
The nonlinear filtering problem occurs in many scientific areas. Sequential Monte Carlo solutions with the correct asymptotic
behavior such as particle filters exist, but they are computationally too expensive when working with high-dimensional systems.
The ensemble Kalman filter (EnKF) is a more robust method that has shown promising results with a small sample size, but the
samples are not guaranteed to come from the true posterior distribution. By approximating the model error with a Gaussian
distribution, one may represent the posterior distribution as a sum of Gaussian kernels. The resulting Gaussian mixture filter
has the advantage of both a local Kalman type correction and the weighting/resampling step of a particle filter. The Gaussian
mixture approximation relies on a bandwidth parameter which often has to be kept quite large in order to avoid a weight collapse
in high dimensions. As a result, the Kalman correction is too large to capture highly non-Gaussian posterior distributions.
In this paper, we have extended the Gaussian mixture filter (Hoteit et al., Mon Weather Rev 136:317–334, 2008) and also made the connection to particle filters more transparent. In particular, we introduce a tuning parameter for the
importance weights. In the last part of the paper, we have performed a simulation experiment with the Lorenz40 model where
our method has been compared to the EnKF and a full implementation of a particle filter. The results clearly indicate that
the new method has advantages compared to the standard EnKF. 相似文献
18.
The HMX (harmonic mixing) mixing calculation program, originally developed to solve geological problems, provides a solution fora posteriori multicomponent mixing problems, i.e., for computations of the proportions of components contributing to a mixture in such cases where the compositions of components and mixture are known. Naturally, these problematics are not restricted to geosciences, but occur throughout all disciplines of natural sciences. The method applied is a harmonic least-squares regression analysis in combination with an optimization technique known as the variable metric method. This procedure guarantees a least-squares regression solution for those real mixing problems, where all data treated are subject to error. In these cases, the application of graphical or least-squares methods for linear regression, as they were used previously, will give significantly different, probably distorted, results. 相似文献
19.
In this paper we present a review of sedimentological, geomorphological, lithological, geochronological and geophysical data from major, minor and satellite basins of the Baikal Rift Zone (BRZ) and discuss various aspects of its evolution. Previously, the most detailed sedimentological data have been obtained from the basins of the central BRZ, e.g., Baikal, Tunka and Barguzin, and have been used by many scientists worldwide. We add new information about the peripheral part and make an attempt to provide a more comprehensive view on BRZ sedimentation stages and environments and their relations to local and regional tectonic events. A huge body of sedimentological data was obtained many years ago by Soviet geologists and therefore is hardly accessible for an international reader. We pay tribute to their efforts to the extent as the format of a journal paper permits. We discuss structural and facial features of BRZ sedimentary sequences for the better understanding of their sedimentation environments. In addition, we review tectono-sedimentation stages, neotectonic features and volcanism of the region. Finally, we consider the key questions of the BRZ evolution from the sedimentological point of view, in particular, correlation of Mesozoic and Cenozoic basins, bilateral growth of the Baikal rift, Miocene sedimentation environment and events at the Miocene/Pliocene boundary, Pliocene and Pleistocene tectonic deformations and sedimentation rates. The data from deep boreholes and surface occurrences of pre-Quaternary sediments, the distribution of the Pleistocene sediments, and the data from the Baikal and Hovsgol lakes sediments showed that 1) BRZ basins do not fit the Mesozoic extensional structures and therefore hardly inherited them; 2) the Miocene stage of sedimentation was characterized by low topography and weak tectonic processes; 3) the rifting mode shifted from slow to fast at ca. 7–5 Ma; 4) the late Pleistocene high sedimentation rates reflect the fast subsidence of basin bottoms. 相似文献
20.
Reduced-order optimal control of water flooding using proper orthogonal decomposition 总被引：1，自引：0，他引：1
Jorn F. M. van Doren Renato Markovinović Jan-Dirk Jansen 《Computational Geosciences》2006,10(1):137-158
Model-based optimal control of water flooding generally involves multiple reservoir simulations, which makes it into a time-consuming
process. Furthermore, if the optimization is combined with inversion, i.e., with updating of the reservoir model using production
data, some form of regularization is required to cope with the ill-posedness of the inversion problem. A potential way to
address these issues is through the use of proper orthogonal decomposition (POD), also known as principal component analysis,
Karhunen–Loève decomposition or the method of empirical orthogonal functions. POD is a model reduction technique to generate
low-order models using ‘snapshots’ from a forward simulation with the original high-order model. In this work, we addressed
the scope to speed up optimization of water-flooding a heterogeneous reservoir with multiple injectors and producers. We used
an adjoint-based optimal control methodology that requires multiple passes of forward simulation of the reservoir model and
backward simulation of an adjoint system of equations. We developed a nested approach in which POD was first used to reduce
the state space dimensions of both the forward model and the adjoint system. After obtaining an optimized injection and production
strategy using the reduced-order system, we verified the results using the original, high-order model. If necessary, we repeated
the optimization cycle using new reduced-order systems based on snapshots from the verification run. We tested the methodology
on a reservoir model with 4050 states (2025 pressures, 2025 saturations) and an adjoint model of 4050 states (Lagrange multipliers).
We obtained reduced-order models with 20–100 states only, which produced almost identical optimized flooding strategies as
compared to those obtained using the high-order models. The maximum achieved reduction in computing time was 35%. 相似文献