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Determination of well locations and their operational settings (controls) such as injection/production rates in heterogeneous subsurface reservoirs poses a challenging optimization problem that has a significant impact on the recovery performance and economic value of subsurface energy resources. The well placement optimization is often formulated as an integer-programming problem that is typically carried out assuming known well control settings. Similarly, identification of the optimal well settings is usually formulated and solved as a control problem in which the well locations are fixed. Solving each of the two problems individually without accounting for the coupling between them leads to suboptimal solutions. Here, we propose to solve the coupled well placement and control optimization problems for improved production performance. We present an alternating iterative solution of the decoupled well placement and control subproblems where each subproblem (e.g., well locations) is resolved after updating the decision variables of the other subproblem (e.g., solving for the control settings) from previous step. This approach allows for application of well-established methods in the literature to solve each subproblem individually. We show that significant improvements can be achieved when the well placement problem is solved by allowing for variable and optimized well controls. We introduce a well-distance constraint into the well placement objective function to avoid solutions containing well clusters in a small region. In addition, we present an efficient gradient-based method for solving the well control optimization problem. We illustrate the effectiveness of the proposed algorithms using several numerical experiments, including the three-dimensional PUNQ reservoir and the top layer of the SPE10 benchmark model. 相似文献
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Behnam Haidari Alireza Riyahi Bakhtiari Vhid Yavari Ali Kazemi Golshan Shirneshan 《洁净——土壤、空气、水》2013,41(2):166-173
Vanadium and nickel are two important indicators of oil pollution. Lengthy exposure to these elements causes serious harmful effects in human health, different harsh allergies being examples. The accumulation of two heavy metals (Ni and V) in sediment and the soft and hard tissues of Saccostrea cucullata were analyzed at three sampling sites along the coast of Lengeh Port, Persian Gulf. Results indicated at all the sampling sites; the Ni levels in soft tissues (STs) were higher than in the shells (SHs) and sediments, whereas the V levels were higher in the sediments. In addition, meaningful relationship (r = 0.65; p < 0.05) was observed across Ni levels in ST of S. cucullata and sediment, while for V concentrations a strong relationship (r = 0.83; p < 0.01) was found in SH of S. cucullata and sediment. This indicates that ST and SH of oyster can be considered as a biomonitoring agent for Ni and V levels, in coastal waters, respectively. The exposure of the consumer is compared directly to minimal risk level and provisional maximum tolerable daily intake. Result indicated that levels of Ni and V were within the safety limits for human consumption. 相似文献
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Behnam Salimi Kamyar Mehranzamir Zulkurnain Abdul-Malek 《Asia-Pacific Journal of Atmospheric Sciences》2014,50(2):133-137
Lightning is an electrical discharge during thunderstorms that can be either within clouds (Inter-Cloud), or between clouds and ground (Cloud-Ground). The Lightning characteristics and their statistical information are the foundation for the design of lightning protection system as well as for the calculation of lightning radiated fields. Nowadays, there are various techniques to detect lightning signals and to determine various parameters produced by a lightning flash. Each technique provides its own claimed performances. In this paper, the characteristics of captured broadband electric fields generated by cloud-to-ground lightning discharges in South of Malaysia are analyzed. A total of 130 cloud-to-ground lightning flashes from 3 separate thunderstorm events (each event lasts for about 4–5 hours) were examined. Statistical analyses of the following signal parameters were presented: preliminary breakdown pulse train time duration, time interval between preliminary breakdowns and return stroke, multiplicity of stroke, and percentages of single stroke only. The BIL model is also introduced to characterize the lightning signature patterns. Observations on the statistical analyses show that about 79% of lightning signals fit well with the BIL model. The maximum and minimum of preliminary breakdown time duration of the observed lightning signals are 84 ms and 560 us, respectively. The findings of the statistical results show that 7.6% of the flashes were single stroke flashes, and the maximum number of strokes recorded was 14 multiple strokes per flash. A preliminary breakdown signature in more than 95% of the flashes can be identified. 相似文献
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Construction of predictive reservoir models invariably involves interpretation and interpolation between limited available data and adoption of imperfect modeling assumptions that introduce significant subjectivity and uncertainty into the modeling process. In particular, uncertainty in the geologic continuity model can significantly degrade the quality of fluid displacement patterns and predictive modeling outcomes. Here, we address a standing challenge in flow model calibration under uncertainty in geologic continuity by developing an adaptive sparse representation formulation for prior model identification (PMI) during model calibration. We develop a flow-data-driven sparsity-promoting inversion to discriminate against distinct prior geologic continuity models (e.g., variograms). Realizations of reservoir properties from each geologic continuity model are used to generate sparse geologic dictionaries that compactly represent models from each respective prior. For inversion initially the same number of elements from each prior dictionary is used to construct a diverse geologic dictionary that reflects a wide range of variability and uncertainty in the prior continuity. The inversion is formulated as a sparse reconstruction problem that inverts the flow data to identify and linearly combine the relevant elements from the large and diverse set of geologic dictionary elements to reconstruct the solution. We develop an adaptive sparse reconstruction algorithm in which, at every iteration, the contribution of each dictionary to the solution is monitored to replace irrelevant (insignificant) elements with more geologically relevant (significant) elements to improve the solution quality. Several numerical examples are used to illustrate the effectiveness of the proposed approach for identification of geologic continuity in practical model calibration problems where the uncertainty in the prior geologic continuity model can lead to biased inversion results and prediction. 相似文献
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Sajjad Abbasi Behnam Keshavarzi Farid Moore Hossein Delshab Naghmeh Soltani Armin Sorooshian 《Environmental Earth Sciences》2017,76(23):798
This study aimed to (1) investigate microrubbers (MRs) for the first time and identify microplastics (MPs) in street dust, (2) determine the physicochemical and mineralogical characteristics and morphology of dust particles, (3) understand the concentration and the possible source(s) of heavy metals/metalloids, (4) identify the chemical speciation and mobility potential of trace metals in urban street dusts, and (5) determine adverse health effects of street dust on children and adults living in the city of Bushehr in southwestern Iran. Generally, twenty four street dust samples were collected and analyzed. Calculated enrichment factors indicate high levels of contamination. Statistical analysis reveals that the two main sources of trace elements include road traffic emissions (Cu, Zn, Sb, Hg, Pb, Mo) and re-suspended soil particles (Al, Mn, Ni, Ti, Cd, Co). BCR sequential extraction results indicated that As, Zn, Cu, and Pb mainly occur in the exchangeable fraction and hence are highly bioavailable. X-ray powder diffraction analysis revealed the presence of calcite, dolomite, quartz, and magnetite. The size distribution of dust particles was also investigated using a scanning electron microscope (SEM), while elemental distribution was analyzed using an attached energy dispersive X-ray spectrometer (SEM–EDS) unit. Dust particles from heavy traffic areas are much finer compared with other investigated areas. MPs and MRs, mostly fibers and fragments, were detected in all samples [ranging from 210 to 1658 (MPs) and 44 to 782 (MRs) items/10 g dust] using fluorescence microscopy. The hazard index for As is higher than 10?4 for children and adults indicative of high risk. According to the calculated potential ecological risk index, Hg indicated moderate ecological risk in the street dust of the study area. 相似文献
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The overall structure of collapsible soils collapses by moister absorption. This is also makes their stabilization and modification necessary with an additive which is often cement. However, a new modification additive, XPS-Cement Mixture, was utilized in this study in order to improve compression characteristics of a simulated collapsible soil. The soil used in this study is named ML in the unified classification system and the reason why it was used is because of its low plasticity index. This parameter is one of the most essential factors of collapsible soils so that makes their stabilization necessary. In the present study, the collapsibility potential (CP) of a simulated modified soil was evaluated by adding different percentage of cement to it. More than 120 tests were carried out in a three-cell consolidation apparatus. Based on information obtained, by adding XPS-Cement mixture up to a specified content CP decreases. However, by further addition no remarkable decrease would be observed. In addition, changes in the collapsibility index were investigated versus the changes in the vertical stress for two types of samples; modeled natural soil and improved soil. Of particular significance of this part is the result which exhibits the drastic effect of high levels of stress on the compression behavior of collapsible soils. 相似文献
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Compressed History Matching: Exploiting Transform-Domain Sparsity for Regularization of Nonlinear Dynamic Data Integration Problems 总被引：1，自引：1，他引：0
Behnam?JafarpourEmail author Vivek?K.?Goyal Dennis?B.?McLaughlin William?T.?Freeman 《Mathematical Geosciences》2010,42(1):1-27
In this paper, we present a new approach for estimating spatially-distributed reservoir properties from scattered nonlinear
dynamic well measurements by promoting sparsity in an appropriate transform domain where the unknown properties are believed
to have a sparse approximation. The method is inspired by recent advances in sparse signal reconstruction that is formalized
under the celebrated compressed sensing paradigm. Here, we use a truncated low-frequency discrete cosine transform (DCT) is
redundant to approximate the spatial parameters with a sparse set of coefficients that are identified and estimated using
available observations while imposing sparsity on the solution. The intrinsic continuity in geological features lends itself
to sparse representations using selected low frequency DCT basis elements. By recasting the inversion in the DCT domain, the
problem is transformed into identification of significant basis elements and estimation of the values of their corresponding
coefficients. To find these significant DCT coefficients, a relatively large number of DCT basis vectors (without any preferred
orientation) are initially included in the approximation. Available measurements are combined with a sparsity-promoting penalty
on the DCT coefficients to identify coefficients with significant contribution and eliminate the insignificant ones. Specifically,
minimization of a least-squares objective function augmented by an l
1-norm of DCT coefficients is used to implement this scheme. The sparsity regularization approach using the l
1-norm minimization leads to a better-posed inverse problem that improves the non-uniqueness of the history matching solutions
and promotes solutions that are, according to the prior belief, sparse in the transform domain. The approach is related to
basis pursuit (BP) and least absolute selection and shrinkage operator (LASSO) methods, and it extends the application of
compressed sensing to inverse modeling with nonlinear dynamic observations. While the method appears to be generally applicable
for solving dynamic inverse problems involving spatially-distributed parameters with sparse representation in any linear complementary
basis, in this paper its suitability is demonstrated using low frequency DCT basis and synthetic waterflooding experiments. 相似文献
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Abbas Rajabifard Behnam Atazadeh Mohsen Kalantari 《International journal of geographical information science》2018,32(10):2098-2122
Three-dimensional (3D) spatial information models are increasingly being adopted to help communicate the spatial dimensions of complex built environments. Land administration practices in multi-owned developments include the subdivision, registration and management of legal interests associated with private, communal and public properties, which are often located along the vertical dimension. The spatial structure of each legal interest is normally composed of invisible spaces, defined as the inside and outside of multi-owned developments, as well as physically built structures. Additionally, a wide variety of legal boundary types mark out the spatial limits of the individual parts of each legal interest. These legal boundaries are typically delineated by either relying on fixed surveying measurements or referencing physically existent objects. This article provides a critical assessment of 3D spatial information models in terms of their capabilities for modelling legal interests and legal boundaries defined in the Victorian jurisdiction. We classify these models into three categories: purely legal, purely physical and integrated. This assessment provides the basis for developing a new 3D spatial information model, which would subsequently support a pathway towards realising the Victorian land administration system in a 3D digital environment. 相似文献
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