Departure Curves Research Articles

MULTISTAGE ANALYSIS OF HYDROLOGIC ALTERATIONS IN THE YELLOW RIVER, CHINA

ABSTRACTNatural river flow regimes provide an array of ecological and social functions by sustaining the health of riverine ecosystems. To identify the hydrologic alterations in the lower Yellow River basin caused by natural factors and human activities, we developed multistage hydrologic analysis to investigate the temporal variability of the river's flow regimes. We used a cumulative departure curve and Mann–Whitney–Pettitt nonparametric tests to determine possible change points based on hydrologic data from 1950 to 2006. We then used the range of variability approach to characterize and to quantify the temporal variability of the hydrologic regimes that were associated with perturbations such as dam operation, flow diversions or intensive conversion of land use within the watershed. In the case study, three stages in hydrologic alterations of the flow regime were found: a stage without human impacts, a stage with excessive human impacts and a reservoir‐regulation stage. Our results indicated that (i) after 1997, dam operation efficiently achieved flood control using sediment regulation activities; (ii) although effective in flood control, the Xiaolangdi Reservoir could not handle situations with extremely low flow, such as during droughts; and (iii) under the arid climate of the Yellow River basin, water consumption by agriculture was the main cause of water shortages. The current study shows that multistage hydrologic analysis can greatly assist regional water resources management and the restoration of riparian eco‐environmental systems affected by dam construction under a changing environment. Copyright © 2012 John Wiley & Sons, Ltd.

Agent-based Simulation of the 2011 Great East Japan Earthquake/Tsunami Evacuation: An Integrated Model of Tsunami Inundation and Evacuation

The 2011 Great East Japan Earthquake/Tsunami was a magnitude 9.0 Mw event that destroyed most structural tsunami countermeasures. However, approximately 90% of the estimated population at risk from the tsunami survived due to rapid evacuation to higher ground or inland. In this paper, we introduce an evacuation model integrated with a numerical simulation of a tsunami and a casualty estimation evaluation. The model was developed in Netlogo, a multi-agent programming language and modeling environment for simulating complex phenomena. GIS data are used as spatial input information for road and shelter locations. Tsunami departure curves are used as the start time for agents deciding to evacuate in the model. Pedestrians and car drivers decide their own goals and search for a suitable route through algorithms that are also used in the video game and artificial intelligence fields. Bottleneck identification, shelter demand, and casualty estimation are some of the applications of the simulator. A case study of the model is presented for the village of Arahama in the Sendai plain area of Miyagi Prefecture in Japan. A stochastic simulation with 1,000 repetitions of evacuation resulted in a mean of 82.1% (SD=3.0%) of the population evacuated, including a total average of 498 agents evacuating to a multi-story shelter. The results agree with the reported outcome of 90% evacuation and 520 sheltered evacuees in the event. The proposed model shows the capability of exploring individual parameters and outcomes. The model allows observation of the behavior of individuals in the complex process of tsunami evacuation. This tool is important for the future evaluation of evacuation feasibility and shelter demand analysis.

The Morning Commute Problem with Coarse Toll and Nonidentical Commuters

This paper studies the morning commute problem under a flat peak-period toll (coarse toll) within the context of heterogeneous commuters. All the possible cumulative departure curves resulting from different choices of toll level and charging period are examined. The optimal toll schemes are then derived from minimizing the total travel cost of all commuters, excluding toll cost. We prove that at the optimum there will be no queue or capacity waste at the bottleneck at both the starting and ending points of the charging period for the type of Value-Of-Time (VOT) distribution considered in the paper. Moreover, the optimal coarse toll scheme is pareto-improving. Different from the homogeneous case, which can be regarded as a special case of the heterogeneous case, price discrimination occurs when commuters have different VOT. The optimal solution depends on the units in which the system cost is measured and we find that commuters in the middle pack of the VOT distribution are worse off by higher toll charges if the system cost is measured in money instead of time. A numerical example is provided at the end for demonstration.

Validating the Incremental Queue Accumulation Method for Left-Turn Delay Estimation

This paper examines the proposed incremental queue accumulation (IQA) method for the analysis of traffic flow at signalized intersections. The paper considers the formulation of the IQA method for protected plus permitted left turns. Validation of the model is presented by using the NGSIM high-resolution vehicle trajectory data set developed for an arterial in Atlanta, Georgia. A comparison of the existing Highway Capacity Manual (HCM 2000) method with the IQA method shows that the IQA approach produces delay estimates that are closer to field measurements. Several issues associated with the arrival and departure curves produced by the IQA method are examined.

A reverse causal-effect modeling approach for signal control of an oversaturated intersection

A novel approach is presented in which signalized intersections are treated as normal highway bottlenecks for improved computational efficiency. It is unique in two ways. First, it treats the signalized intersections as common freeway bottlenecks by a reversed cause and effect modeling approach. Both traffic arrivals and departures are modeled by smooth continuous functions of time as if there were no interruptions to traffic flows from signals. The use of smooth continuous functions for departure curves instead of commonly used step functions makes it easy to apply differential calculus in optimization and future extension to a system of intersections. Second, a dynamic linear programming (LP) model is then developed to maximize the total vehicular output from the intersection during the entire period of congestion subject to prevailing capacity and other operational constraints. The continuous optimal departure flow rate (the effect) is then converted to signal timing parameters (the cause) that can be readily implemented. Two numerical examples are presented to demonstrate the properties of the proposed algorithm and examine its performance.

Microscopic and Macroscopic Approaches to Delay Estimation with Oversaturated Conditions

Chapter 16 of the 2000 Highway Capacity Manual (HCM) contains a widely recognized and well-accepted procedure for calculating per-vehicle control delay at signalized intersections. Appendix F of that chapter discusses the relationship between various components of control delay using cumulative arrival and departure curves. The delay obtained from these curves has certain limitations that need to be recognized if proper conclusions are to be drawn. To illustrate these limitations, a comparison is made between the delay obtained from cumulative curves and the delay obtained through a detailed analysis of vehicle trajectories. A comparison of the control delay obtained from trajectory analysis and that obtained from cumulative arrival–departure curves shows that the cumulative curves omit certain valid portions of the control delay, while including other portions of time that are not delay at all. Taking a macroscopic approach to oversaturated delay estimation, the HCM procedures for dealing with oversaturated conditions are described and their shortcomings are explored using an example of a multiperiod analysis of an oversaturated approach to a signal. It is demonstrated that the current HCM equations can overestimate multiperiod delay and that the assumption of a capacity that is constant from cycle to cycle can underestimate delay at high values of the volume-to-capacity ratio.

Shock Wave and Cumulative Arrival and Departure Models: Partners Without Conflict

The shock wave and cumulative arrival and departure curve techniques are staples of traffic analysis, particularly for the modeling of freeway congestion, but the literature contains numerous suggestions that they are not compatible. Three numerical examples illustrate that although the two models define queue lengths in different ways, they are compatible, yield identical estimates of travel time and delay, and provide additional insight into the nature of freeway congestion when used together instead of individually.

Dynamic Analyses on Network Traffic Flow

This paper summarizes dynamic network analyses utilizing cumulative arrival and departure curves under point as well as physical queues. First, a relationship between the cumulative curve under point and physical queue concepts and time-space diagram is explained. Second, dynamic traffic assignments with three principles of DUO (Dynamic User Optimal), DUE (Dynamic User Equilibrium), and DSO (Dynamic System Optimal) are formulated. Finally, theoretical past research outcomes on departure time choice, which is as important as route choice, are reviewed.

An effect of pine volatiles on departure of Bursaphelenchus xylophilus (Nematoda : Aphelenchoididae) from Monochamus alternatus (Coleoptera : Cerambycidae)

To clarify the effect of the volatiles of Pinus densiflora on the temporal pattern of departure of Bursaphelenchus xylophilus from Monochamus alternatus adults (nematode departure curve), autoclaved or normal pine twigs were provided to the beetles. Monoterpenoids were not detected from the air of rearing containers with autoclaved pine twigs. A Kolmogorov-Smirnov test showed that there were significant differences in the averaged nematode departure curve between the 2 beetle groups supplied with different foods. The time of 50% nematode departure was shorter in the beetles supplied with autoclaved twigs. The proportion of nematodes which remained in the bodies of 5l-day-old M. alternatus was significantly smaller in the beetles supplied with autoclaved pine twigs. Consequently, it is suggested that B. xylophilus had a trait of spontaneous departure from M. alternatus and that the volatiles from excised normal P. densiflora twigs repressed B. xylophilus departure from M. alternatus.

ExTra: A FORTRAN program to calculate resistivity departure curves with a quasi-exponential transition zone

In borehole geophysics it is important to determine accurately the physical parameters of the formation. For electrical methods in oil exploration one of the most important being the true resistivity of the formation. This information helps to assess the recoverability of the oil and the economic viability of the oil field. An interactive computer program ExTra is presented in the paper. The source code is written in standard FORTRAN 77. ExTra computes the forward model response for borehole resistivity sounding for two electrode (normal) configuration. The earth model consists of three cylindrical layers of infinite extent, which is an ideal setup for response computation in one-dimension (1-D). These layers consist of borehole mud, the innermost layer, the flushed zone, and invaded zone. The outermost layer is of infinite radial extent and termed an uncontaminated zone. The dc (direct current) boundary value problem is solved analytically. Resistivity values in the different zones are considered to be uniform except in the invaded zone where the value changes radially. Analytical derivation has been cited for a quasi-exponential transition in resistivity in the invaded zone. Gauss quadrature is used for numerical evaluation of the infinite integral. To achieve higher efficiency, 1-D spline interpolation is introduced for computation of the kernel function at desired values of the integration variable. All the results are expressed as dimensionless quantities. Apparent resistivity response for other known arrays (electrode configurations) can be computed using this program with minor and necessary changes in the code. Solution for infinite bed thickness is shown which can be extended for finite bed thickness where the effect from the vertical inhomogeneity is negligible. The invasion profile presented here is realistic from the point of the actual borehole environment and physical model studies.

Normal and lateral log response for a 2-D borehole model

Direct current resistivity responses for two-dimensional (2-D) borehole model with cylindrical symmetry are computed using the finite difference method (FDM). The effects of shoulder beds, borehole mud, flushed zone, invaded zone, and uncontaminated zone are taken together to compute the normal and lateral log responses. The invasion zone is assumed to be a transitional zone. The effects of target bed thickness, resistivity of the invaded zone, radius of invasion and resistivity of the shoulder beds on the 2-D resistivity departure curves (RDCs) are demonstrated. Sensitivities in the 2-D RDCs remains up to the electrode separation (L) equal to the target bed thickness. For L ³ 5H, the target bed thickness), the entire information comes from the shoulder beds. This 2-D forward problem can be used for 2-D inversion to determine the resistivity of the uncontaminated zone and radius of invasion.

Borehole dc resistivity response for a transitional invaded zone

A borehole direct‐current resistivity boundary value problem for normal and lateral elctrode configuratin is soved assuming axial symmetry. The borehole mud, a flushed zone, an invaded zone, and an unciontaminated zone are all assumed to be present. A linear transition in resistivity is assumed for the invaded zone. Frobenius extended power series and the method of separation of variables are used to solved the 1-D problem. Single-run borehole resistivity sounding and solution of the inverse problem are suggested fo estimatingthe resisitivity of the uncontaminated zone and the radius of invasion. Finite‐difference modeling is dione to estimate the effect of shoulder beds ion borehole sounding. Some of the computed 1-D and 2-D model apparent reisivity curves are compared with the existing scale model data. The analysis reveals that the mud cake effect is negligible for normal and lateral electrode array and the invasion zone thickness is feflected in the forward models. Apparent resistivity curves with and without a transitional invaded zone are well separated. Resistivity departure curves are well separated for fixed resistivity and variable resistivity invaded zone models. A normal electrode configuration can feel the presence of the shoulder bed in a 2-D model when the bed thickness is about 12 time the electrode separation. One‐dimensional ridge regression inversion the synthetic forward model data is presented to suggest an alternative approach for determining the resistivey of the uncontaminated zone ([Formula: see text]) and the radius of invasion [Formula: see text]. We conclude that (1) a single run borehole sounding with 10 or 12 data points from a normal or lateral log may be used, rather than 3 points from a dual laterolog [Formula: see text] tool, for better estimation of [Formula: see text], and (2) a borehole forward model should include a transitional invaded zone. Finally, an alternative approach for the estimation of the radius of invasion is proposed.

Modelling long-term dependence based on cumulative departures of annual flow series

This paper investigates the suitability of Sen's approach in modelling hydrologic time series and in particular the generation of synthetic flow series. It was found that several problems exist with the method as proposed. These include too many parameters in the model, difficulties in modelling skewed series, and finding a suitable stochastic model for the residuals between the original and the fitted cumulative departure curves. On the other hand, it has been found that Sen's method is effective in preserving the Hurst phenomenon and is especially suited for modelling time series with a relatively high Hurst coefficient but low lag-one serial correlation coefficient. Also, with some modifications to the suggested procedure some of the stated problems can be somewhat overcome.

Trans4: a FORTRAN program for computing apparent resistivity departure curves for an infinitely thick bed with transitional invaded zone in borehole geophysics

In petroleum exploration it is necessary to measure the resistivities of the formation units along the borehole wall once a well is drilled. It is necessary to estimate the true resistivity of the formation ( R t) away from the borehole wall for assessment of movable oil and life of the oil field. In this paper the program TRANS4 is presented as a forward model for borehole resistivity sounding for a two electrode (normal) configuration. The source code is written in FORTRAN 77. The earth model consists of a cylinder of borehole mud surrounded by coaxial cylinders of flushed zone, invaded zone, and uncontaminated zone. The direct current potential boundary value problem is solved using the methods of separation of variables and Frobenius extended power series. In this problem invaded zone resistivity (or conductivity) is assumed to differ linearly with radial distance. To avoid algebraic singularity the problem was divided into two different parts. Resistivity (when R t < R xo) and conductivity (when σ t < σ xo) models are solved separately. Here R t and σ t are the true resistivity and conductivity of the uncontaminated zone and R xo and σ xo are the resistivity and conductivity of the flushed zone respectively. Apparent resistivity is computed using 7 point Gauss quadrature. Spline interpolation is introduced for calculation of the kernel function at desired values of the integration variable which are used in numerical integration. Computed apparent resistivity with and without application of spline interpolation are presented to show the reduction in computation time. Results are expressed in a nondimensional form. The program can be used for computation of apparent resistivities for other electrode configurations with minor and necessary modifications. This forward model is solved for infinite bed thickness. This solution will be valid for finite bed thickness where shoulder bed effect is negligible. The forward model algorithm could be used as a subroutine for 1-D inversion where a realistic transitional invaded zone model is assumed.

Response Transforms From Comparative Study of Commercial Pulsed-Neutron-Capture Logging Systems

Summary Three generations of Schlumberger's Thermal Decay Time (TDTSM) logging devices—viz., TDT-K, TDT-M, and TDT-P—along with an Atlas Wireline PDK-100SM system were run in a Saudi Aramco well. The wellbore (8½ in. with 7-in. casing) penetrated a sequence of clean sand, shaly sand, and shale streaks as exhibited by the openhole natural gamma ray log. The initial wellbore fluid was diesel. The fluid was then changed to brines of 42, 000 and 176, 000 ppm NaCl, respectively. Three repeat passes at a logging speed of 900 ft/hr were obtained by each device for each borehole liquid. As a result of this extensive comparative study, a set of departure curves and mathematical transforms was developed primarily for standardizing the various Schlumberger tools to a common reference logging system and/or borehole environment. The transforms were used beneficially to determine residual oil saturation (ROS) from time-lapse logs in a Saudi Aramco reservoir.

Logging in deep water wells in central Jutland, Denmark

During a search for unpolluted resources, new wells have been drilled to a deep confined aquifer in central Jutland. Since little is known about the extent and vulnerability of the deep reservoir, geophysical logging was used to supplement hydraulic well‐testing. Gamma‐ray, SP and resistivity logs were recorded in the boreholes. Gamma‐logs were also recorded in two cased wells. Analysis of the logs, combined with information from samples, shows an unconfined aquifer of quartz and mica sand to a depth of about 55 m at Grindsted. Below this level there is a 40 m thick aquitard with an apparent southerly dip. The aquitard is composed of interbedded sand, silt and clay. The deep confined aquifer extends from 95 to 110 m below the surface at Grindsted. Both the aquitard and the deep aquifer are provisionally dated as Early/Middle Miocene. The electrical logs discriminate well between sand, silt and clay beds. If a suitable mud is used in the well it is possible to calculate the formation water resistivities in good agreement with water samples obtained after completion. From the resistivity logs formation factors were calculated in the range 3–5 using no‐invasion departure curves. The high content of heavy mineralsin the Tertiary deposits makes it impossible to obtain precise lithological information from the gamma‐ray log. On the other hand this log provides clear markers for identifying the hydrogeological units in the well‐bores.

Induction Log Vertical Resolution Improvement in Vertical and Deviated Wells Using a Practical Deconvolution Filter

Summary Induction tool measurements can be affected as far as 30 ft from high-conductivity beds and the effect can be greater in deviated wells. A doconvolution filter was designed to improve the vertical response in both vertical and deviated wells. The filter described was tested on synthetic induction logs derived from formations of known resistivity. Several examples of deconvolved induction field logs are provided. The filter should not be used in areas where the general level of formation resistivities is less than about 3 ?·m; skin effects significantly alter the tool response in these areas. Introduction Thin-bed effects on the induction log have been well documented by the logging service companies, and correction charts1 have been available for many years. Examples are shown in Fig. 1. The charts are better suited to manual interpretation than foot-by-foot digital interpretation. The deep induction log has been used as the main resistivity device in Prudhoe Bay field on the North Slope of Alaska. This choice was made because very fresh muds were used and because modern laterologs were not available at the start of field development. Invasion is considered shallow because, in very thick beds, it has been observed that the deep induction log (ILD), LLD, LLS, LL8, and SFL tools all show similar readings. Formation resistivities of 1000 ?·m or more exist in parts of the field and have been confirmed by occasional deep laterologs. Resistivity ratios at bed boundaries of greater than 100:1 can occur and induction log resistivity anomalies are still present as far as 30 ft [9 m] from these bed boundaries (Fig. 2). These conditions obviously are not ideal or even recommended for the running of induction logs, yet the magnititude of the resistivities recorded in thick beds are of generally acceptable accuracy. The objective of this work was to find a mechanism for applying thin-bed corrections to digitized induction logs. The corrections were recquired to betechnically justified,applicable to continuous digital data, andapplicable at Prudhoe Bay conditions (e.g., hole deviation, formation resistivity range). A deconvolution-type filter was appropriate for these practical requirements. An introduction to deconvolution processing is given in the Appendix. Review of the Induction Log Response Several authors have discussed the induction log radial and vertical response characteristics following the pioneering work of Doll.2 Doll used the geometrical factor concept without skin effect correction to develop departure curves for beds of finite thickness. The influence of skin effect at bed boundaries was shown by Duesterhoeft et al.3,4 and Moran and Kunz.5 Inclusion of skin effect improves the vertical resolution of the coil array compared with the simpler Doll theory. In more recent years, radial response has been studied by Woodhouse et al.6,7 Radial and vertical responses have been studied by Gianzero and Anderson,8 Thadani et al.,9,10 and Anderson and Chang,11 who showed that absolute conductivity values and bed thickness both affect the vertical response characteristics. Modern chart hooks indicate the complexity of the vertical response by the need for multiple charts to correct for thin beds (Fig. 1). Except for Howell and Fisher,12 little attention has been given to the analysis of the dipping beds and deviated hole problem. The substantial radial depth of investigation of the tool means that deviated holes or dipping beds influence induction log measurements more than the comparable horizontal bed and vertical hole case.

Directional Survey and Proximity Log Analysis of a Downhole Well Intersection

Summary A relief well was drilled to intersect the casing of a blowout well at 13,500 ft (4115 m) total vertical depth (TVD). During drilling, numerous directional surveys were run on the relief well. These surveys have been analyzed to determine the error associated with each. Both systematic and random errors were found in the surveys. The systematic errors caused much larger position errors than did the random errors. Magnetic and position errors than did the random errors. Magnetic and resistivity proximity logs were run to determine the distance between the blowout well and the relief well. Comparison with the directional survey data indicated that the magnetic proximity log could detect casing at least 42 ft (13 m) away and gave reasonably accurate distance and direction to it. The resistivity logs gave qualitative indications of casing when the wells were 100 ft (30 m) apart. but the quantitative interpretation was not as good as the magnetic log. Introduction The R.L. Bergeron 1 was being drilled as a Tuscaloosa development well in the Moore-Sams field near Baton Rouge, LA, when it blew out at a depth of 18,562 ft (5658 m). The Bergeron 2 relief well was designed to intersect the blowout well at 9,500 ft (2896 m) TVD and to parallel it to a depth of 13,500 ft (4115 m) TVD. This parallel it to a depth of 13,500 ft (4115 m) TVD. This was estimated to be the shallowest depth that a successful kill could be made because of the high pressure in Bergeron 1, as indicated by the kick data. Since Bergeron 1 was cased at 13,500 ft (4115 m), it was necessary that the relief well be within a few inches (centimeters) of the original casing for perforation. The relief well was to be back to vertical and parallel to Bergeron 1 at 9,500 ft (2896 m), thus taking advantage of the relatively clean shale through this interval for proximity log analysis. This plan allowed 4,000 ft (1219 m) in which to locate Bergeron 1 and to position Bergeron 2 within perforating distance. The shallow intersection plan also took advantage of the reduced uncertainty of plan also took advantage of the reduced uncertainty of the bottomhole location of Bergeron 1 at the shallower depth. The proposed well plans for Bergeron 2, as well as a wellbore schematic of Bergeron 1, are shown in Fig. 1. The original Bergeron 2 is referred to as Bergeron 2-A, with the first and second sidetracks designated Bergeron 2-B and 2-C, respectively. Methods of Determining Proximity to Bergeron 2 The plan for drilling Bergeron 2 depended on the ability to detect the casing in Bergeron 1 because directional surveys alone would not be sufficient to get the wells close enough. Two commercially available proximity logging techniques were accessible for homing in on Bergeron 1 after the wells were reasonably close together. A long-spaced electric log was to be used as the primary means of detecting the presence of casing. The primary means of detecting the presence of casing. The electric log, which gives information about distance but does not indicate direction, previously had been used successfully by Amoco Production Co. in the U.S. gulf coast area. The technique uses known formation resistivity from conventional resistivity logs to make a layered resistivity model of the formation in the vicinity of the intercept point. This layered model can be used to predict the expected response of the long-spaced electric predict the expected response of the long-spaced electric log when no casing effects are present. The observed log resistivity will be lower than the model predictions because of the short-circuiting effect of the casing when the blowout well is near the relief well. The ratio of the observed log resistivity to the predicted resistivity can be used to determine the distance between wellbores. Ref. 1 explains the technique in more detail and gives departure curves for converting the resistivity ratio to distance. JPT P. 2351

ON SOME RESISTIVITY LOG INTERPRETATION CHARTS*

AbstractThe paper relates primarily to the borehole and the side bed correction charts for Latero‐logs 3 and 7. Versions of some of these charts published by different companies—or even by the same company in different years—exhibit significant variations. Usually, such publications do not contain adequate information on how the charts were constructed and do not explain why discrepancies occur.Because of these reasons, an attempt has been made in this paper to reconstruct the borehole correction chart for Laterolog 7 and the shoulder bed correction charts for Latero‐logs 3 and 7. For the latter two, the results found differ substantially from those published earlier.The paper demonstrates how departure (response) curves and correction charts for the lateral and the Laterolog 7 sondes can be computed from those for the normal sonde. An apparent resistivity formula is suggested for Laterolog 7 in which all currents that exist in the ground at the time of measurement and that produce the signal are monitored and used. Response curves and correction charts for Laterolog 7, based on such a formula, are presented as illustrations.

High pressure differential thermal analysis (HPDTA) of fatty acid methyl esters and triglycerides

AbstractWhen using high pressure differential thermal analysis to study the stability of a fatty methyl ester or triglyceride in an atmosphere of air, a departure from the base line in the exothermic curve is observed. The point where an extension line from the base line intersects a tangent line to the departure curve was selected as the transition point in the exothermic curve. For each sample studied, temperature at this transition point showed good reproducibility. The influence of sample container and air pressure upon the temperature of the transition point in the exothermic curve (TTE) was examined. A linear correlation between the number of double bonds in the sample and TTE was observed.