Data-Driven Sequence Stratigraphy of the Cretaceous Depositional System,Punjab Platform,Pakistan     

Perveiz Khalid  Farrukh Qayyum  Qamar Yasin 《Surveys in Geophysics》2014,35(4):1065-1088

The Punjab Platform is a gently dipping monocline that has been drilled since the 1960s with a low success ratio. Most of the drilling targets in the past were based on the structural interpretation. Furthermore, the exploration focus remained in Paleozoic sequences, and little attention has been paid to the Cretaceous systems. In this paper, a prograding Cretaceous (Sembar-Goru) mega-sequence is subdivided into three sequences using a semi-automated and integrated workflow. A data-driven chronostratigraphic chart is prepared, which revealed several regressive stages in the study area. The sands developed during these stages are laterally sealed by shales and claystones that form a stratigraphic play. The stratigraphic play area lies in a shoreface environment where shoreface sands are expected to be charged by underlying Lower Cretaceous black shales. A prominent gas cap above the proposed stratigraphic play further increases the confidence on the presence of a reservoir. This paper is the first attempt to study the Cretaceous deltaic sequences in the study area, which has remained unexplored for the last six decades.  相似文献   

High Ni Levels in Soil Can Modify Growth Performance and Mineral Status of Wheat Cultivars          下载免费PDF全文

Muhammad Sabir  Khalid Rehman Hakeem  Tariq Aziz  Muhammad Zia‐ur‐Rehman  Irfan Rashid  Munir Ozturk 《洁净——土壤、空气、水》2014,42(9):1263-1271

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Experimental evaluation of a glass curtain wall of a tall building          下载免费PDF全文

Wensheng Lu  Baofeng Huang  Khalid M. Mosalam  Shiming Chen 《地震工程与结构动力学》2016,45(7):1185-1205

The seismic demand parameters including the floor acceleration amplification (FAA) factors and the interstory drift ratios (IDRs) were acquired from the floor response in time history analysis of a tall building subjected to selected ground motions. The FAA factors determined in this way are larger than those given in most current code provisions, but the obtained IDRs are close to the values given in some code provisions. Imposing a series of in‐plane pre‐deformations to two glass curtain wall (CW) specimens mounted on a shaking table, the IDRs were reproduced and the FAA factors were satisfied through applications of computed floor spectra compatible motion time histories, whose peak accelerations corresponded to the FAA factors. The CW specimens performed well during the whole experimental program with almost no change in the fundamental frequencies. No visible damage was observed in the glass panels. The maximum stresses detected in each component of the CW system were smaller than the design strengths. The obtained component acceleration amplification factor approached 3.35, which is larger than the value given in the current code provisions. In conclusion, the performance of the studied CW system is seismically safe. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

A semi-analytical method for the wave-induced seabed response     

M. S. Rahman  Khalid El-Zahaby  John Booker 《国际地质力学数值与分析法杂志》1994,18(4):213-236

A general semi-analytical method is presented for the analysis of seabed response under wave action during a storm. The seabed is idealized as a poro-elastic medium filled with a single compressible fluid with anisotropic flow. The coupled process of fluid flow and deformation of soil skeleton is formulated in the framework of Biot's theory. The analysis for the response of homogeneous seabed of finite thickness under a plane progressive wave is developed first, followed by an extension for the case of a layered seabed. A generalization for three-dimensional response of seabed is also developed for a general wave field which provides the analyses for seabed response under short-crested or standing waves in the vicinity of a structure. Some numerical examples illustrating the proposed analyses are also presented.  相似文献   

Characteristics and alteration of pesticide residues in surface soils of agricultural fields and public parks     

Khalid F. Al-Mutlaq 《Environmental Geology》2006,51(4):493-497

Organic contents of agricultural soils are major sources of organic compounds and pesticides into atmosphere. Therefore, surface soil samples from different locations in the city of Corvallis, USA were collected over a course of 1 year (2004/2005). The samples were subject to chemical extraction and analysis by gas chromatography–mass spectrometry (GC–MS). The results of the chemical analysis showed pesticide residues were present in soils and varied seasonally. For example, the highest total relative concentration of pesticide residues in Canola field was 0.16% in January 2005, and was 0.56% in Wheat Field in August 2005, and was 0.14% in the River Front Park in December 2004 and was 0.33 in Rose Garden. Sometimes in the year, these pesticide residues were not detected in the same sites.  相似文献   

A new least-squares minimization approach to depth and shape determination from magnetic data     

El-Sayed M. Abdelrahman  Eid. R. Abo-Ezz  Khalid S. Essa  T.M. El-Araby  Khaled S. Soliman 《Geophysical Prospecting》2007,55(3):433-446

We have developed a least‐squares minimization approach to depth determination using numerical second horizontal derivative anomalies obtained from magnetic data with filters of successive window lengths (graticule spacings). The problem of depth determination from second‐derivative magnetic anomalies has been transformed into finding a solution to a non‐linear equation of the form, f(z) = 0. Formulae have been derived for a sphere, a horizontal cylinder, a dike and a geological contact. Procedures are also formulated to estimate the magnetic angle and the amplitude coefficient. We have also developed a simple method to define simultaneously the shape (shape factor) and the depth of a buried structure from magnetic data. The method is based on computing the variance of depths determined from all second‐derivative anomaly profiles using the above method. The variance is considered a criterion for determining the correct shape and depth of the buried structure. When the correct shape factor is used, the variance of depths is less than the variances computed using incorrect shape factors. The method is applied to synthetic data with and without random errors, complicated regionals, and interference from neighbouring magnetic rocks. Finally, the method is tested on a field example from India. In all the cases examined, the depth and the shape parameters are found to be in good agreement with the actual parameters.  相似文献   

Characteristics of moisture flux convergence in Central Southwest Asia     

Khalid M. Malik  Peter A. Taylor  Kit Szeto 《Theoretical and Applied Climatology》2015,120(3-4):643-659

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Study of Shoreline Changes Through Digital Shoreline Analysis System and Wave Modeling: Case of the Sandy Coast of Bou-Ismail Bay,Algeria     

Kaddour  Said  Hemdane  Yacine  Kessali  Nasser  Belabdi  Khalid  Sallaye  Miloud 《Ocean Science Journal》2022,57(3):493-527

Ocean Science Journal - This work aims to analyze the evolution of Bou-Ismail coastline in Algeria using aerial photographs and quick-bird satellite image during the elapsed period from 1959 to...  相似文献   

Waterflood management using two-stage optimization with streamline simulation   总被引：1，自引：0，他引：1  

Tailai Wen  Marco R. Thiele  David Echeverría Ciaurri  Khalid Aziz  Yinyu Ye 《Computational Geosciences》2014,18(3-4):483-504

Waterflooding is a common secondary oil recovery process. Performance of waterfloods in mature fields with a significant number of wells can be improved with minimal infrastructure investment by optimizing injection/production rates of individual wells. However, a major bottleneck in the optimization framework is the large number of reservoir flow simulations often required. In this work, we propose a new method based on streamline-derived information that significantly reduces these computational costs in addition to making use of the computational efficiency of streamline simulation itself. We seek to maximize the long-term net present value of a waterflood by determining optimal individual well rates, given an expected albeit uncertain oil price and a total fluid injection volume. We approach the optimization problem by decomposing it into two stages which can be implemented in a computationally efficient manner. We show that the two-stage streamline-based optimization approach can be an effective technique when applied to reservoirs with a large number of wells in need of an efficient waterflooding strategy over a 5 to 15-year period.  相似文献   

3D analysis of kinematic behavior of granular materials in triaxial testing using DEM with flexible membrane boundary   总被引：2，自引：2，他引：0  

Mehmet B. Cil  Khalid A. Alshibli 《Acta Geotechnica》2014,9(2):287-298

This paper describes the constitutive behavior and particle-scale kinematics of granular materials in three-dimensional (3D) axisymmetric triaxial testing using discrete element method (DEM). PFC3D code was used to run the DEM simulations using a flexible membrane boundary model consisting of spherical particles linked through flexible contact bonds. The overall deformation behavior of the specimen was then compared with the specimen with rigid boundary and experimental measurements. Computed tomography was used to track the evolution of particle translation and rotation within a laboratory triaxial specimen in 3D. The DEM model of the flexible membrane specimen successfully predicted the stress–strain behavior when compared with laboratory experiment results at different confining pressures. The DEM results showed that the rigid specimen applies a uniform deformation and leads to non-uniformities in the confining stress along the particle-boundary interface in the lateral direction. In contrast, the flexible specimen better replicates the uniformly applied confining stress of a laboratory triaxial experiment. The 3D DEM simulations of the specimen with flexible membrane overpredicted particle translation and rotation in all directions when compared to a laboratory triaxial specimen. The difference between the particle translation and rotation distributions of DEM specimens with rigid and flexible membrane is almost negligible. The DEM specimen with flexible membrane produces a better prediction of the macroscopic stress–strain behavior and deformation characteristics of granular materials in 3D DEM simulations when compared to a specimen with rigid membrane. Comparing macroscale response and particle-scale kinematics between triaxial simulation results of rigid versus flexible membrane demonstrated the significant influence of boundary effects on the constitutive behavior of granular materials.  相似文献