塔中地区碳酸盐岩裂缝综合预测技术及其应用

塔中地区碳酸盐岩裂缝复杂多变,对储层的储渗性能、烃类运聚、产能起着至关重要的作用。针对塔中奥陶系裂缝发育的特点,形成了相干处理、应变量分析、数值模拟3种裂缝预测技术。高相干相表示较致密地层的反映;低相干相表示可能是岩溶或裂缝发育反映;极低值相干相表示各级断层的反映。应变量分析则是通过钻井标定,同时考虑地层厚度、岩性、裂缝发育方向等参数,对多期构造运动产生的裂缝的密度进行预测。数值模拟是利用应变量、曲率或其他地震属性做约束,应用随机模拟方法,确定裂缝的平面展布与发育程度。根据岩心观察裂缝的切割关系、充填成分以及充填序次,结合测井资料和以上3种技术的裂缝预测结果及区域构造应力场的分析,对塔里木盆地塔中16—塔中30井区奥陶系碳酸盐岩裂缝发育带进行了预测,这三项技术预测的结果与井区内实际钻井奥陶系碳酸盐岩岩心裂缝参数统计值基本吻合,证实了利用相干体、应变量分析和数值模拟技术综合预测塔中地区碳酸盐岩裂缝发育带是实用的,也是有效的。

Application of Prediction Techniques in Carbonate Karst Reservoir in Tarim Basin

Carbonate karst reservoir is the emphases of Tarim＇s carbonate exploration. However, it is buried at a large depth, which results in Weak seismic reflection signal and low S/N ratio. In addition, the karst reservoir contains great heterogeneity, so reservoir prediction is very difficult. Through many years of research and exploration, we have established a suite of comprehensive evaluation technology for carbonate karst reservoir using geophysical characteristics and a geological concept model, including a technique for reconstructing the paleogeomorphology of buried hills based on a sequence framework, seismic description of the karst reservoir, and strain variant analysis for fracture estimation. The evaluation technology has been successfully applied in the Tabei and Tazhong areas, and commercial production of oil and gas has been achieved. We show the application of this technology in the Lunguxi area in North Tarim in this paper.

Numerical analysis of multicomponent responses of surface-hole transient electromagnetic method

We calculate the multicomponent responses of surface-hole transient electromagnetic method. The methods and models are unsuitable as geoelectric models of conductive surrounding rocks because they are based on regular local targets. We also propose a calculation and analysis scheme based on numerical simulations of the subsurface transient electromagnetic fields. In the modeling of the electromagnetic fields, the forward modeling simulations are performed by using the finite-difference time-domain method and the discrete image method, which combines the Gaver–Stehfest inverse Laplace transform with the Prony method to solve the initial electromagnetic fields. The precision in the iterative computations is ensured by using the transmission boundary conditions. For the response analysis, we customize geoelectric models consisting of near-borehole targets and conductive wall rocks and implement forward modeling simulations. The observed electric fields are converted into induced electromotive force responses using multicomponent observation devices. By comparing the transient electric fields and multicomponent responses under different conditions, we suggest that the multicomponent-induced electromotive force responses are related to the horizontal and vertical gradient variations of the transient electric field at different times. The characteristics of the response are determined by the varying the subsurface transient electromagnetic fields, i.e., diffusion, attenuation and distortion, under different conditions as well as the electromagnetic fields at the observation positions. The calculation and analysis scheme of the response consider the surrounding rocks and the anomalous field of the local targets. It therefore can account for the geological data better than conventional transient field response analysis of local targets.

Strain rate effects on sand and its quantitative analysis

Strain rate effects on the stress-strain behavior of sand were investigated by performing special plane strain and triaxial compression tests on saturated and air-dried sand specimens. In these tests, the loading strain rate was changed many times by a factor of up to 1 000 during otherwise monotonous loading at a constant axial strain rate. Test results show that the stress jump upon a stepwise change in the strain rate decays with an increase in the irreversible strain when monotonous loading continues at the changed strain rate and the amount of stress jump is essentially proportional to the instantaneous stress. Based on the amount of these stress jumps, a parameter fl called the rate-sensitivity coefficient is introduced to represent the quantity of the observed viscous properties of sand, which equals 0.021 3 and 0.024 2 respectively for Hostun and Toyoura sands. Further analyses on the results indicate that the effect of the presence of pore water is deemed to be negligible with sand and the fl value is rather independent of loading method, wet condition and confining pressure.

Effect of asymmetric rolling under high friction coefficient on recrystallization texture and plastic anisotropy of AA1050 alloy

In asymmetric rolling(ASR) the circumferential velocities of the working rolls are different. This yields a complex deformation mode with shear, compression and rigid body rotation components. The main microstructural modification is on crystallographic texture, and, for aluminium alloys, this may improve the deformability after recrystallization. This work correlated the process variables, thickness reduction per pass(TRP) and velocity ratio between the upper and bottom rolls, with the texture development and the plastic properties after annealing. Finite element(FE) simulations were performed to quantify the influence of the strain components. Experimental data on texture, and plastic anisotropy were analyzed. In the sheet centre a crystallographic rotation of the compression components about the TD(transverse direction) axis was obtained, which yielded the development of {111}//ND(normal direction) texture components. On the surfaces the local variation of the velocity gradients caused an extra rotation component about ND. This yielded the increment of rotated cube components. After annealing the main texture components at the sheet centre were maintained and the texture intensity decreased. The planar anisotropy(△r) was reduced but the normal anisotropy and deep drawability obtained by the Erichsen test were similar for all conditions. The most favourable reduction of △r was obtained at a velocity ratio of 1.5 and TRP of 10%.

Plant Communities and Factors Responsible for Vegetation Pattern in an Alpine Area of the Northwestern Himalaya

The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species distribution.We placed random plots covering different habitats and altitude to record species composition and environmental variables.Vegetation was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with Canonical Correspondence Analysis.Four communities,each in alpine shrub and meadows were delineated and well justified in the ordination plots.Indicator species for the different communities were identified.Maximum species richness and diversity were found in community IV among shrub communities and community II among the meadows.Studied environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in meadows.Soil variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and meadows.Altitude,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum variation.About 40% variations left unexplained.Latitude and species diversity among the other variables had significant correlation with ordination axes.Study showed that altitude and C/N ratio played a significant role in species composition.Extensive sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.

MINING INDUCED INFLUENCE ON THE ROADWAYS IN WEAK SURROUNDING ROCK AND ITS CONTROLLING MEASURES

The application of destressing method can change the distribution patterns of the stress field in the weak rock surrounding openings. locate the openings in the zone of low stress level, thus improve their loading and maintaining conditions. Such method is considered as a new way of opening maintenance in weak rock and has caused extensive interests in mining industry both at home and abroad. The results of theoretic research and lab experiments of utilizing top-destressing trough to maintain the opening affected by mining activities in weak rock, as well as its practical application in a coal mine are introduced in this paper. The research results indicate that the deformation and floor heaving of the opening in weak rock can be effectively controlled, and long-term stability of the opening can be realized by applying destressing method as long as the destressing plan and concerned parameters are carefully determined.

A local and global statistics pattern analysis method and its application to process fault identification

Traditional principal component analysis （PCA） is a second-order method and lacks the ability to provide higherorder representations for data variables. Recently, a statistics pattern analysis （SPA） framework has been incorporated into PCA model to make full use of various statistics of data variables effectively. However, these methods omit the local information, which is also important for process monitoring and fault diagnosis. In this paper, a local and global statistics pattern analysis （LGSPA） method, which integrates SPA framework and locality pre- serving projections within the PCK is proposed to utilize various statistics and preserve both local and global in- formation in the observed data. For the purpose of fault detection, two monitoring indices are constructed based on the LGSPA model. In order to identify fault variables, an improved reconstruction based contribution （IRBC） plot based on LGSPA model is proposed to locate fault variables. The RBC of various statistics of original process variables to the monitoring indices is calculated with the proposed RBC method. Based on the calculated RBC of process variables＇ statistics, a new contribution of process variables is built to locate fault variables. The simula- tion results on a simple six-variable system and a continuous stirred tank reactor system demonstrate that the proposed fault diagnosis method can effectively detect fault and distinguish the fault variables from normal variables.

Bayesian Lasso for Screening Experiments

The purpose of variable selection is to identify important predictors for response variables. Although there are many varieties of variable selection methods, almost all of them have a problem of not accounting for the relationship between predictors. Therefore it would well happen that the selected subset of identified predictors leads to hard-to-interpret model consisted of only interaction terms. In design of experiments, the analysis is driven by the effect heredity principle which governs the relationship between an interaction and its corresponding main effects. In this paper, the authors extend the variable selection method the Lasso with effect heredity principle to its Bayesian version. In the example, the authors analyze the data obtained from typical screening design Plackett-Bunnan design and compare the result from the ordinary Bayesian Lasso and proposed method.

Stresses Analysis on a Rail Part

The EFVM （Vitoria Minas Railroad） is one of the main railways in Brazil. It transports freight trains of ore, 220 wagons each. These wagons have 2 boogies of 2 axles each and 32 metric tons on metre gauge. Elastic strains were measured on a special part of this railway due to these trains. The main load to evaluate stresses and strains was a G 16 Locomotive, a C-C kind from Vale, a Brazilian Company. The measurements were obtained by dynamic deflectometer installed on a main line of this railway, near Ipatinga, a city from Minas Gerais, one of Brazil states. This track was equipped to obtain stresses under an equal repeated static load A simulation of the stresses was made under critical strain by Ferrovia 1.0 software. It was also made an evaluation of unequal results from neighbor sleepers taking in comparison two equipped parts of this railway, one with compacted ballast and no compaction to the other. The results were strain limited, avoiding breakage or damage to the studied rails. This work analyses these measurements focusing on the improvement of track quality.

Genetic Variations and Gene Effect Controlling Grain Yield and Some of Its Components in Maize

Diallel cross analysis among seven diverse pure lines of maize, （IK8, IK58, ZP-707, OH40, UN44052, DKI7 and HS） with their nonreciprocal 21 crosses, were carried out for estimating the nature and magnitude of gene effects through component and graphic analysis for characters： number of days to tasseling, number of days to silking, plant height, ear height, number of rows per ear, number of grains per row, 300 grain weight and grain yield per plant. The results showed highly significant mean square of genotypes for all studied characters. Additive and dominance variances were found to be significant from zero for all the eight characters except number of days to tasseling and silking for which additive genetic variance was no significant. Dominance variance estimation was relatively higher than the additive variance for all characters. The graphic analysis suggested the presence of epistatic gene effects （non-allelic interaction） for number of days to tasseling, number of days to silking, plant height, number of grains per row and grain yield per plant. The estimates of narrow sense heritability varied from 1.85% for 300 grain weight to 49.88% for ear height, it was moderate in case of ear height and low for the remainder characters.

Analytical investigation for stress measurement with the rheological stress recovery method in deep soft rock

Due to the difficulty and weakness of current stress measurement methods in deep soft rock, a new rheological stress recovery method of the determination of the three-dimensional(3D) stress tensor is proposed. It is supposed that rock stresses will recovery gradually with time and can be measured by embedding transducers into the borehole. In order to explore the applicability and accuracy of this method, analytical solutions are developed for stress measurement with the rheological stress recovery method in a viscoelastic surrounding rock, the rheological properties of which are depicted as both the Burger's model and a 3-parameter solid model. In such conditions, explicit analytical expressions for predicting time-dependent pressures on the transducer are derived. A parametric analysis is then adopted to investigate the influences of the grout solidification time and the mechanical properties of the grout layer. The results indicate that this method is suitable for stress measurement in deep soft rock, the characteristics of which are soft, fractured and subjected to high geo-stress.

Feature Screening for Nonparametric and Semiparametric Models with Ultrahigh-Dimensional Covariates

This paper considers the feature screening and variable selection for ultrahigh dimensional covariates. The new feature screening procedure base on conditional expectation which is used to differentiate whether an explanatory variable contributes to a response variable or not, without requiring a specific parametric form of the underlying data model. The authors estimate the marginal condi- tional expectation by kernel regression estimator. The proposed method is showed to have sure screen property. The authors propose an iterative kernel estimator algorithm to reduce the ultrahigh dimensionality to an appropriate scale. Simulation results and real data analysis demonstrate the proposed method works well and performs better than competing methods.

Experimental investigation and numerical modeling for elastoplastic notch-root stress/strain analysis under monotonic loadings

Experimental investigation and numerical modeling on elasto-plastic notch-root stress/strain distributions under monotonic loadings of both the Ni-based directionally solidified(DS)superalloy and Titanium alloy were carried out simultaneously.For measuring inhomogeneous deformation fields at notch roots,an optical-numerical full-field surface deformation measurement system was developed based on the digital image correlation(DIC)method.The obtained strain distributions were then verified with reasonable accuracy by finite element simulation,where an anisotropic elastic-viscoplastic constitutive model was developed for DS superalloy and a simple isotropic stress-strain relationship was adopted for Titanium alloy.Meanwhile,factors affecting elasto-plastic notch-root stress/strain distributions were systematically investigated numerically,where the emphasis was placed on temperature,loading stress rate,sample shape,anisotropy and notch features.The results show that stress/strain behavior at notch root is significantly affected by the mentioned factors,which are concretely embodied in the distribution of tensile stress/strain,equivalent stress and accumulative equivalent plastic strain.

Generalized Multivariate Gumbel Distributions——Dependence,Aging Properties and Applications

This paper introduces a generalized multivariate Gumbel(GMG) distribution using a survival copula.Various dependence properties of the GMG distribution and some analytical properties of the generators of the GMG distribution are studied.Furthermore,the authors also investigate the dependence behavior of the residual lifetime vector of the GMG distribution.As an illustration,the GMG distribution is applied to fit a real data set.