深井CO_(2)爆破致裂干热岩系统综合效应预评价

CO_(2)爆破致裂工艺为建造商业化EGS储层提供了新方案,有望突破深层地热能行业发展的技术瓶颈,但目前未见CO_(2)致裂技术用于干热岩系统的综合性能评价研究。基于此研究不足,借助数学建模定量科学评价其综合性能,解决此技术效果的不确定性和模糊性,填补深井地热系统综合评价体系的空白。考虑到深井CO_(2)爆破干热岩系统是一个多变、模糊、复杂的非线性系统,该文选取AHP-FCE优化数学模型,AHP对深井爆破干热岩系统复杂问题分层,构建递阶层次结构,通过Matlab将专家的定性判断定量化,进而确定FCE中各层评价指标权重大小,再通过FCE模糊关系合成原理,对多因素影响下的深井CO_(2)爆破致裂干热岩系统综合评分为83.36,预评价结果为较好,可考虑将CO_(2)爆破致裂器用于干热岩开采。评定结果可作为深井CO_(2)爆破致裂干热岩建设过程中的数据支撑,为地热开采工程提供一定的理论依据。

Depositional Environment and Lithofacies Analyses of Eocene Lacustrine Shale in the Bohai Bay Basin:Insights from Mineralogy and Elemental Geochemistry

The effect of various depositional parameters including paleoclimate,paleosalinity and provenance,on the depositional mechanism of lacustrine shale is very important in reconstructing the depositional environment.The classification of shale lithofacies and the interpretation of shale depositional environment are key features used in shale oil and gas exploration and development activity.The lower 3rd member of the Eocene Shahejie Formation(Es_(3)^(x)shale)was selected for this study,as one of the main prospective intervals for shale oil exploration and development in the intracratonic Bohai Bay Basin.Mineralogically,it is composed of quartz(avg.9.6%),calcite(avg.58.5%),dolomite(avg.7%),pyrite(avg.3.3%)and clay minerals(avg.20%).An advanced methodology(thin-section petrography,total organic carbon and total organic sulfur contents analysis,X-ray diffraction(XRD),X-ray fluorescence(XRF),field-emission scanning electron microscopy(FE-SEM))was adopted to establish shale lithofacies and to interpret the depositional environment in the lacustrine basin.Six different types of lithofacies were recognized,based on mineral composition,total organic carbon(TOC)content and sedimentary structures.Various inorganic geochemical proxies(Rb/Sr,Ca/(Ca+Fe),Ti/Al,Al/Ca,Al/Ti,Zr/Rb)have been used to interpret and screen variations in depositional environmental parameters during the deposition of the Es_(3)^(x)shale.The experimental results indicate that the environment during the deposition of the Es_(3)^(x)shale was warm and humid with heightened salinities,moderate to limited detrital input,higher paleohydrodynamic settings and strong oxygen deficient(reducing)conditions.A comprehensive depositional model of the lacustrine shale was developed.The interpretations deduced from this research work are expected to not only expand the knowledge of shale lithofacies classification for lacustrine fine-grained rocks,but can also offer a theoretical foundation for lacustrine shale oil exploration and development.

Reservoir characteristics of Datta Formation (Early Jurassic), Marwat-Khisor Ranges, sub-Himalayas, Pakistan

The present work has been accomplished to carry out a detailed study of the characteristics of the Early Jurassic Datta Formation of Trans-Indus Ranges, Pakistan. The discovery of Saib well-1 (Gas and condensate discovery from Jurassic limestone) in the study basin takes an active interest in carrying out extensive exploration activities in the same basin. Jurassic rocks especially Datta Sandstone and Samana Suk Limestone are acting as good reservoirs. The study unit consists of variegated sandstone interbedded with siltstone, carbonaceous clay, and shale and coal stringer. For the current work, two stratigraphic sections (Pezu and Abbo Wanda) have been measured. To examine its sedimentology, depositional environment, diagenetic settings, and reservoir characteristics, a detailed study was conducted and various laboratory techniques have been utilized. About 95 rock samples from the bottom to the top of both sections were collected, and 50 rock samples have been selected for thin section analysis and were examined under a polarizing microscope to show their mineralogical composition, diagenesis, and their reservoir characteristics. XRD (X-ray diffraction), Cathodoluminescence (CL), SEM (Scanning electron microscope) with EDS (Energy-dispersive spectroscope), and Core plug porosity and permeability analysis have been used to interpret its chemical and mineralogical composition and its reservoir characteristics, respectively. Based on field observations and thin section analysis, four depositional facies and six lithofacies have been established. The sedimentary structures, depositional facies, and lithofacies indicate that Datta Formation was deposited in a deltaic environment. Compactions, cementation, fracturing and dissolution can greatly affect the quality of reservoir rock. Based on thin section and SEM analysis, large numbers of primary pores, fracture and secondary pores were observed and connectivity between the pores is good, and at some places, these pores were filled through the authigenic clay minerals like kaolinite, mixed layers illite/smectite and chlorite that influences the reservoir characteristics. Primary pores (thin section) and secondary pores (dissolution pores) and core plug porosity and permeability data (porosity 13.23%-26.89% and permeability 0.12 to 149 mD) shows that Datta Formation has a good reservoir quality.

Modeling of a Sn-Based HTM-Free Perovskite Solar Cell Using a One-Dimensional Solar Cell Capacitance Simulator Tool

Tin(Sn)-based perovskite solar cells(PSCs)have received increasing attention in the domain of photovoltaics due to their environmentally friendly nature.In this paper,numerical modeling and simulation of hole transport material(HTM)-free PSC based on methyl ammonium tin triiodide(CH_(3) NH_(3) SnI_(3))was performed using a one-dimensional solar cell capacitance simulator(SCAPS-1D)software.The eff ect of perovskite thickness,interface defect density,temperature,and electron transport material(ETM)on the photovoltaic performance of the device was explored.Prior to optimization,the device demonstrated a power conversion effi ciency(PCE)of 8.35%,fi ll factor(FF)of 51.93%,short-circuit current density(J_(sc))of 26.36 mA/cm 2,and open circuit voltage(V_(oc))of 0.610 V.Changing the above parameters individually while keeping others constant,the obtained optimal absorber thickness was 1.0μm,the interface defect density was 1010 cm-2,the temperature was 290 K,and the TiO 2 thickness was 0.01μm.On simulating with the optimized data,the fi nal device gave a PCE of 11.03%,FF of 50.78%,J_(sc) of 29.93 mA/cm 2,and V_(oc) of 0.726 V.Comparing the optimized and unoptimized metric parameters,an improvement of~32.10%in PCE,~13.41%in J_(sc),and~19.02%in V_(oc) were obtained.Therefore,the results of this study are encouraging and can pave the path for developing highly effi cient PSCs that are cost-eff ective,eco-friendly,and comparable to state-of-the-art.

地热储层单裂隙岩体渗流传热数值模拟研究

研究地热储层裂隙岩体中的渗流传热过程对干热岩地热资源的开采具有重要的意义。本文以干热岩地热工程为背景,采用COMSOL Multiphysics数值模拟软件对地热储层单裂隙岩体中渗流传热机理进行了研究,并分析了流体注入速度和温度对岩体温度场的影响及其对干热岩地热工程的影响。研究发现流体参数对岩体温度场的影响主要体现在2个方面:一方面是对岩体温度场受扰动区域以及幅度的影响,另一方面是对岩体温度场达到稳态所需要时间的影响。流体注入速度的提升会降低系统的寿命和寿命期的出口法向总热量值,当考虑出口法向总热通量时,存在最佳流体注入速度,本研究中最佳流体注入速度为0.011 m/s。流体注入温度的提升会增加系统的寿命和系统的出口法向总热通量和总热量。研究为干热岩自热资源的开发与利用提供了理论依据,为工程运行参数的设计提供了参考依据。

Concomitant-chemoradiotherapy-associated oral lesions in patients with oral squamous-cell carcinoma

Objective:Oral squamous-cell carcinoma(OSCC)accounts for >90% of oral cancers affecting adults mostly between the fourth to seventh decades of life.The most common OSCC treatment is concomitant chemoradiotherapy(CCRT)having both locoregional and distant control,but CCRT has acute and chronic toxic effects on adjacent normal tissue.This study aimed to determine the side effects of CCRT on the oral mucosa and to characterize the clinicopathology of oral lesions in patients with OSCC.Methods:This descriptive,cross-sectional study was certified by the Ethical Review Committee(UHS/Education/126-12/2728)of the University of Health Sciences,Lahore,Pakistan.OSSC patients(n=81)with various histological subtypes,grades,and stages were recruited,and findings on their oral examination were recorded.These patients received 70,90,and 119 Gy of radiotherapy dosages in combination with the chemotherapy drugs cisplatin and 5-fluorouracil.Data were analyzed using SPSS 20.0.Results:The most common presentation of OSCC was a nonhealing ulcer(63%) involving tongue(55.6%).Clinical findings included mucositis(92.6%)and xerostomia of mild,moderate,and severe degrees in 11.1%,46.9%,and 35.8% cases,respectively.Ulcers(87.7%),palpable lymph nodes(64.2%),limited mouth opening(64.2%)and fistula(40.7%) were also observed.In females,the association of radiotherapy dosage with limited mouth opening,xerostomia,and histological grading was statistically significant(P<0.05).The association of chemotherapy drugs with xerostomia(P=0.003)was also statistically significant.Conclusions:CCRT induced mucositis,xerostomia,and trismus in patients with OSCC.

Early selection of bread wheat genotypes using morphological and photosynthetic attributes conferring drought tolerance

Genetic diversity is the base of any genetic improvement breeding program aimed at stress breeding.The variability among breeding materials is of primary importance in the achievements of a good crop production.Herein,105 wheat genotypes were screened against drought stress using factorial completely randomized design at seedling stage to determine the genetic diversity and traits association conferring drought tolerance.Analysis of variances revealed that all the studied parameters differed significantly among all genotypes,indicating the significance genetic variability existed among all genotypes for studied indices.The 10 best performance genotypes G1,G6,G11,G16,G21,G26,G39,G44,G51,and G61 were screened as drought tolerant,while five lowest performance genotypes G3,G77,G91,G98,and G105 were screened as drought susceptible.Root length,chlorophyll a,chlorophyll b,and carotenoid contents were significantly correlated among themselves which exhibited the importance of these indices for rainfed areas in future wheat breeding scheme.Shoot length exhibited non-significant and negative association with other studied traits,and its selection seems not to be a promising criteria for this germplasm for drought stress.Best performance genotypes under drought stress conditions will be useful in future wheat breeding program and early selection will be effective for developing high yielding and drought tolerant wheat varieties.

Pore size distribution,their geometry and connectivity in deeply buried Paleogene Es1 sandstone reservoir,Nanpu Sag,East China

The study or pore characteristics is or great importance in reservoir evaluation,especially in deeply buried s andstone.It controls the storage mechanism and reservoir fluid properties of the permeable horizons.The first member of Eocene Shahejie Formation(Esl)sandstone is classified as feldspathic litharenite and lithic arkose.The present research investigates the pore characteristics and reservoir features of the deeply buried sandstone reservoir of Esl member of Shahejie Formation.The techniques including thin-section petrography,mercury injection capillary pressure(MICP),scanning electron microscopy and laser scanning confocal microscope images were used to demarcate the pores including primary intergranular pores and secondary intergranular,intragranular,dissolution and fracture pores.Mercury injection test and routine core analysis were led to demarcate the pore network characteristics of the studied reservoir.Pore size and pore throat size distribution are acquired from mercury injection test.Porosity values range from 0.5%to 30%,and permeability ranges 0.006-7000 mD.Pore radii of coarse-grained sandstone and fine-grained sandstone range from 0.2 to>4μm and 1 nm to 1.60μm,respectively,by MICP analysis.The mineral composition also plays an important role in protecting the pores with pressure from failure.Fractured sandstone and coarse-grained sandstone consist of large and interconnected pores that enhance the reservoir porosity and permeability,whereas fine-grained sandstone and siltstone consist of numerous pores but not well interconnected,and so they consist of high porosity with low permeability.

Origin of Quartz Cement in the Paleogene Sandstone Reservoir of Shahejie Formation,Bohai Bay Basin,China

The precipitation of authigenic quartz plays a significant role to reduce the reservoir characteristics and enhance the stiffness of the rock.The Es_(1) sandstone of Shahejie Formation is acting as a significant hydrocarbon producing rock in the Nanpu Sag.Various methods like thin section petrography,cathodoluminescence(CL),scanning electron microscope(SEM,with EDS),and electron microprobe analysis has been used to reveal the origin of quartz cement as well as to evaluate the effect of quartz cement on reservoir quality.The studied sandstone is classified as immature to mature feldspathic litharenite and lithic arkose and consists of quartz,feldspar,rock fragments and micas.Petrographic studies and SEM analysis shows that the authigenic quartz is acting a significant cement that reduces the reservoir quality.Whereas clay minerals(kaolinite and mixed layer illite to smectite)are dominant in the Es_(1) sandstone,that can reduce the reservoir quality.SEM,CL and thin section analysis reveal that there are two stages of quartz cement in the studied samples;that are pore filling authigenic cement and quartz overgrowth cement.Fluid inclusion homogenization temperatures shows that stages of quartz cement were developed with continuous process from 70℃ to 130℃.Quartz cements were generally originated from I/S reaction,feldspar dissolution,conversion of rock fragments and pressure solution.Feldspar dissolution(K-feldspar)and kaolinite to illite reaction is an insignificant silica source for the silica cement which is internally precipitated in a close system with diffusion transporting mechanism.Overall,quartz cement significantly enhance the rock strengthen and brittleness effectively as well as it reduce the overall reservoir quality.

Loan growth and bank solvency:evidence from the Pakistani banking sector

Background:The dramatic loan growth and changes in the Pakistani banking system in mid-2000s have led to significant research attention on borrowers and lenders.This expansion and diversification in financial sector was driven by structural reforms,political stability and significant economic growth.Against this background,this study investigates the loan growth and risk-taking behavior of the banks during the expansionary periods of lending.Method:This study used dynamic two-step system generalized method of moment’s estimation technique,based on data taken from 32 banks in Pakistan over 2006-2014.Result:Loan growth has a significant effect on bank-specific and macroeconomicspecific variables.Loan growth in the previous year raises non-performing loans and decreases the solvency of banks with a time lag of many years.The driving force behind this phenomenon is weak prudential regulation among competitors,the asymmetric information of the borrowers,and,most importantly,that banks underestimate the risk of lending during credit booms.Conclusion:More regulatory measures are required to ensure a strong financial system when the volume of non-performing loan grows significantly.An increase in the capital requirement policy for rapidly growing banks is also needed because the problem of abnormal loan growth cannot be detected at the current time.At the same time,strong supervision is necessary to avoid the adverse consequences of borrower selection.

Electromagnetic Response Studies of the Antenna for Deep Water Deep Target CSEM Environments

The Controlled Source Electromagnetic Method (CSEM) is used for offshore hydrocarbon exploration. Hydrocarbon detection in seabed logging (SBL) is a very challenging task for deep hydrocarbon reservoirs. The electromagnetic field response of an antenna is unable to detect deep hydrocarbon reservoirs due to a weak electromagnetic signal response in the seabed logging environment. This work premise deals with the comparison of the electromagnetic signal strength of a new antenna with a straight antenna and the orientation of an antenna for deep target hydrocarbon exploration. Antenna position and orientation (Tx and Ty) was studied using Computer Simulation Technology software (CST) for deep targets in marine CSEM environments. The model area was assigned as (40 ′ 40 km) to replicate the real seabed environment. From the results, the new dipole antenna shows an 804% and 278% increase in electric and magnetic field strength than the straight antenna. An electric (E) and magnetic (H) field component study was done with and without the presence of a hydrocarbon reservoir. Ex and Hz field component responses with the new antenna at the1 kmtarget were measured in a deep water environment. It was analyzed that the antenna shows 53.10% (Ex) and 83.13% (Hz) field difference in deep water with and without a hydrocarbon reservoir at the30 mantenna position from the sea floor. From the antenna orientation results, it was observed that, the electric field Ex and magnetic field Hz responses decreased from 18% to 12% and 21% to 16%, respectively but was still able to detect the deep target hydrocarbon reservoir at the4 kmtarget depth. This EM antenna may open new frontiers for the oil and gas industry for deep target hydrocarbon detection (HC).

Guided and Direct Wave Evaluation of Controlled Source Electromagnetic Survey Using Finite Element Method

Deep target hydrocarbon detection is still challenging and expensive. Direct hydrocarbon indicators (DHIs) in seismic data do not correspond to economical hydrocarbon exploration. Due to unreliability in seismic data for the detection of DHIs, new methods have been investigated. Marine controlled source electromagnet (MCSEM) or Sea bed logging (SBL) is new method for the detection of deep target hydrocarbon reservoir. Sea bed logging has also the potential to reduce the risks of DHIs in deep sea environment. Modelling of real sea environment helps to reduce the further risks before drilling the oil wells. 3D electromagnetic (EM) modelling of seabed logging requires more accurate methods for the detection of hydrocarbon reservoir. Finite element method (FEM) is chosen for the modelling of seabed logging to get more precise EM response from hydrocarbon reservoir below 4000 m from seabed. FEM allows to investigate the total electric and magnetic fields instead of scattered electric and magnetic fields, which shows accurate and precise resistivity contrast below the seabed. From the modelling results, It was investigated that Hz field shows higher magni- tude with 342% than the Ex field. It was observed that 0.125 Hz frequency can be able to show better resistivity contrast of Hz field (31.30%) and Ex field (16.49%) at target depth of 1000 m below seafloor for our proposed model. Hz and Ex field delineation was found to decrease as target depth increased from 1000 m to 4000 m. At the target depth of 4000 m, no field delineation response was seen from the current electromagnetic (EM) antenna used by the industry. New EM antenna has been used to see the EM response for deep target hydrocarbon detection. It was investigated that novel EM antenna shows better delineation at 4000 m target depth for Ex and Hz field up to 10.3% and 15.1% respectively. Novel EM antenna also shows better Hz phase response (128.4%) than the Ex phase response (38.3%) at the target depth of 4000 m below the seafloor.

Crystalline order and disorder in dusty plasmas investigated by nonequilibrium molecular dynamics simulations

The particle structure of a complex system has been explored through a unique Evans' s homogenous nonequilibrium molecular dynamics(HNEMD) simulation technique. The crystalline order–disorder structures(OD-structures) and the corresponding energies of three-dimensional(3 D) nonideal complex systems(NICSs) have been measured over a wide range of plasma states(■, κ) for a body-centered cubic(BCC) structure. The projected technique provides accurate ODstructures with fast convergence and applicable to very small size effect for different temperatures(≡ 1/■) and constant force field(F~*) values. The OD-structure obtained through HNEMD approach is found to be reasonable agreement and more reliable than those earlier identified by simulation approaches and experimental data of NICSs. New simulations of OD-structures show that dusty plasma remains in crystalline(strongly coupled) state at lower temperature and constant F*values, for the whole simulation runs. Our investigations show that the crystalline structure is changed and the particle structure switches from intermediate to disorder(nonideal gaseous) state with an increase of the system's temperature. It has been shown that the long range order shifts toward lower temperature with increasing κ. The presented technique exhibits that the potential energy has a maximum value when the dusty plasma remains in crystalline states(low temperatures),which confirms earlier 3 D simulation results.

In vitro antiproliferative and apoptosis inducing effect of a methanolic extract of Azadirachta indica oil on selected cancerous and noncancerous cell lines

Objective: To find the cytotoxic and apoptotic effects of neem oil extract on the selected cancerous(A-549, PC-3 and DU-145) and noncancerous(NIH3T3 and CCD-18Co) cell lines.Methods: Viability and cytotoxic effect induced by the extract was measured by using MTT assay and apoptotic effect of the extract was evaluated by using Hoechst 33342 and propidium iodide dual staining through a fluorescent microscope and activity of caspases 3, 8 and 9 through colorimetric assay kits. Results: The results showed that neem oil extract significantly reduced the viability in all selected cancer cells treated with varying concentrations of extract as compared with untreated cells and had less effect on noncancerous cell lines. It significantly increased the percentage of necrotic and apoptotic cells, and caspases 3, 8 and 9 activities in all cancer cells treated with extract as compared with untreated cells whereas no effect on noncancerous cell lines. It suggested that neem oil extract exerted a higher cytotoxic effect on cancer cells than normal cells and lower concentration induced apoptosis only in cancer cells.One of the apoptosis-inducing mechanism was through the activation of caspases signaling pathways. Conclusion: Conclusively, it implies that neem oil extract may contain one or more potential agents that can be used as a safe and effective anticancer therapy.

A Machine Learning Approach for Expression Detection in Healthcare Monitoring Systems

Expression detection plays a vital role to determine the patient’s condition in healthcare systems.It helps the monitoring teams to respond swiftly in case of emergency.Due to the lack of suitable methods,results are often compromised in an unconstrained environment because of pose,scale,occlusion and illumination variations in the image of the face of the patient.A novel patch-based multiple local binary patterns(LBP)feature extraction technique is proposed for analyzing human behavior using facial expression recognition.It consists of three-patch[TPLBP]and four-patch LBPs[FPLBP]based feature engineering respectively.Image representation is encoded from local patch statistics using these descriptors.TPLBP and FPLBP capture information that is encoded to find likenesses between adjacent patches of pixels by using short bit strings contrary to pixel-based methods.Coded images are transformed into the frequency domain using a discrete cosine transform(DCT).Most discriminant features extracted from coded DCT images are combined to generate a feature vector.Support vector machine(SVM),k-nearest neighbor(KNN),and Naïve Bayes(NB)are used for the classification of facial expressions using selected features.Extensive experimentation is performed to analyze human behavior by considering standard extended Cohn Kanade(CK+)and Oulu–CASIA datasets.Results demonstrate that the proposed methodology outperforms the other techniques used for comparison.

Sign Language to Sentence Formation:A Real Time Solution for Deaf People

Communication is a basic need of every human being to exchange thoughts and interact with the society.Acute peoples usually confab through different spoken languages,whereas deaf people cannot do so.Therefore,the Sign Language(SL)is the communication medium of such people for their conversation and interaction with the society.The SL is expressed in terms of specific gesture for every word and a gesture is consisted in a sequence of performed signs.The acute people normally observe these signs to understand the difference between single and multiple gestures for singular and plural words respectively.The signs for singular words such as I,eat,drink,home are unalike the plural words as school,cars,players.A special training is required to gain the sufficient knowledge and practice so that people can differentiate and understand every gesture/sign appropriately.Innumerable researches have been performed to articulate the computer-based solution to understand the single gesture with the help of a single hand enumeration.The complete understanding of such communications are possible only with the help of this differentiation of gestures in computer-based solution of SL to cope with the real world environment.Hence,there is still a demand for specific environment to automate such a communication solution to interact with such type of special people.This research focuses on facilitating the deaf community by capturing the gestures in video format and then mapping and differentiating as single or multiple gestures used in words.Finally,these are converted into the respective words/sentences within a reasonable time.This provide a real time solution for the deaf people to communicate and interact with the society.

A Real-Time Automatic Translation of Text to Sign Language

Communication is a basic need of every human being;by this,they can learn,express their feelings and exchange their ideas,but deaf people cannot listen and speak.For communication,they use various hands gestures,also known as Sign Language(SL),which they learn from special schools.As normal people have not taken SL classes;therefore,they are unable to perform signs of daily routine sentences(e.g.,what are the specifications of this mobile phone?).A technological solution can facilitate in overcoming this communication gap by which normal people can communicate with deaf people.This paper presents an architecture for an application named Sign4PSL that translates the sentences to Pakistan Sign Language(PSL)for deaf people with visual representation using virtual signing character.This research aims to develop a generic independent application that is lightweight and reusable on any platform,including web and mobile,with an ability to perform offline text translation.The Sign4PSL relies on a knowledge base that stores both corpus of PSL Words and their coded form in the notation system.Sign4PSL takes English language text as an input,performs the translation to PSL through sign language notation and displays gestures to the user using virtual character.The system is tested on deaf students at a special school.The results have shown that the students were able to understand the story presented to them appropriately.

Traditional Herbal Medicine and Its Clinical Relevance: A Need to Preserve the Past for the Future

Herbal medicines have been gaining popularity worldwide. They are an integral component of alternative medical care and provide a rich source for innovative drug discovery. However, the rapid increase in the demand for herbal medicines and products has led to the rapid depletion of herbal plants. In addition, rapid population growth, industrialization, and global climate change have endangered these medicinal plants. Given the imminent threat associated with the loss of medicinal plant diversity, this review highlights the need to protect these threatened plant species and avoid the loss of their therapeutic value. The aim of the study was to conserve resources and link them with current research activities and projects to develop novel and more effective drugs in the future.

MASW Survey with Fixed Receiver Geometry and CMP Cross-Correlation Technique for Data Processing: A Case Study of Wadi Fatima, Western Saudi Arabia

Multichannel analysis of surface waves is a noninvasive technique for subsurface shear wave velocity imagining. This method is one of the most effective geophysical tools for geotechnical investigations. In this paper, we present multichannel surface wave data acquisition in a non-conventional manner in alluvium deposits. Fixed receiver and multi-source offset geometry were applied to obtain field data. The data processing comprised of generating CMP cross-correlated traces and then inversion to obtain dispersion curves. The inversion of dispersion curves is achieved by employing a genetic algorithm to obtain subsurface shear wave velocity. Finally, the one-dimensional shear wave models are obtained. The multi-source offset data acquisition with fixed receiver geometry technique in combination with CMP cross-correlation gathers for data processing worked in a quite efficient way to obtain subsurface shear wave model.

Modeling of Antenna for Deep Target Hydrocarbon Exploration

Nowadays control source electromagnetic method is used for offshore hydrocarbon exploration. Hydrocarbon detection in sea bed logging (SBL) is a very challenging task for deep target hydrocarbon reservoir. Response of electromagnetic (EM) field from marine environment is very low and it is very difficult to predict deep target reservoir below 2 km from the sea floor. This work premise deals with modeling of new antenna for deep water deep target hydrocarbon exploration. Conventional and new EM antennas at 0.125 Hz frequency are used in modeling for the detection of deep target hydrocarbon reservoir. The proposed area of the seabed model (40 km ′ 40 km) was simulated by using CST (computer simulation technology) EM studio based on Finite Integration Method (FIM). Electromagnetic field components were compared at 500 m target depth and it was concluded that Ex and Hz components shows better resistivity contrast. Comparison of conventional and new antenna for different target depths was done in our proposed model. From the results, it was observed that conventional antenna at 0.125 Hz shows 70%, 86% resistivity contrast at target depth of 1000 m where as new antenna showed 329%, 355% resistivity contrast at the same target depth for Ex and Hz field respectively. It was also investigated that at frequency of 0.125 Hz, new antenna gave 46% better delineation of hydrocarbon at 4000 m target depth. This is due to focusing of electromagnetic waves by using new antenna. New antenna design gave 125% more extra depth than straight antenna for deep target hydrocarbon detection. Numerical modeling for straight and new antenna was also done to know general equation for electromagnetic field behavior with target depth. From this numerical model it was speculated that this new antenna can detect up to 4.5 km target depth. This new EM antenna may open new frontiers for oil and gas industry for the detection of deep target hydrocarbon reservoir (HC).