Actual Production Data Research Articles

Prediction of net-length distribution for global interconnects in a heterogeneous system-on-a-chip

A system-on-a-chip (SoC) contains several pre-designed heterogeneous megacells that have been designed and routed optimally. In this paper a new stochastic net-length distribution for global interconnects in a nonhomogeneous SoC is derived using novel models for netlist, placement, and routing information. The netlist information is rigorously derived based on heterogeneous Rent's rule, the placement information is modeled by assuming a random placement of terminals for a given net in a bounding area, and the routing information is constructed based on a new model for minimum rectilinear Steiner tree construction (MRST). The combination of the three models gives a priori estimation of global net-length distribution in a heterogeneous SoC. Unlike previous models that empirically relate the average length of the global wires to the chip area, the new distribution provides a complete and accurate distribution of net-length for global interconnects. Through comparison with actual product data, it is shown that the new stochastic model successfully predicts the global net-length distribution of a heterogeneous system.

Conditioning Stochastic Reservoir Models to Well-Test Data

Summary Generating realizations of reservoir permeability and porosity fields that are conditional to static and dynamic data are difficult. The constraints imposed by dynamic data are typically nonlinear and the relationship between the observed data and the petrophysical parameters is given by a flow simulator which is expensive to run. In addition, spatial organization of real rock properties is quite complex. Thus, most attempts at conditioning reservoir properties to dynamic data have either approximated the relationship between data and parameters so that complex geologic models could be used, or have used simplified spatial models with actual production data. In this paper, we describe a multistep procedure for efficiently generating realizations of reservoir properties that honor dynamic data from complex stochastic models. First, we generate a realization of the rock properties that is conditioned to static data, but not to the pressure data. Second, we generate a realization of the production data (i.e., add random errors to the production data). Third, we find the property field that is as close as possible to the uncalibrated realization and also honors the realization of the production data. The ensemble of realizations generated by this procedure often provides a good empirical approximation to the posteriori probability density function for reservoir models and can be used for Monte Carlo inference. We apply the above procedure to the problem of conditioning a three-dimensional stochastic model to data from two well tests. The real-field example contains two facies. Permeabilities within each facies were generated using a "cloud transform" that honored the observed scatter in the crossplot of permeability and porosity. We cut a volume, containing both test wells, from the full-field model, then scaled it up to about 9,000 cells before calibrating to pressure data. Although the well-test data were of poor quality, the data provided information to modify the permeabilities within the regions of investigations and on the overall permeability average.

A Two Stage Heuristic Approach for the Continuous Casting Planning

Continuous casting planning plays an important role in improving the production rate and energy saving in the iron and steel industry. In this paper, we study continuous casting planning arising in a major steel company in China. Due to the complication of the problem, a two-stage model mathematics model is set up to analyze the twin strand continuous casting planning. Since the model is NP-hard and very difficult to achieve satisfied solution, we develop two efficient methods (Genetic Algorithm and Tabu Search Method) to solve it. The precision of the model and the effectiveness of the algorithms are shown through simulation results on actual production data from the steel company.

Manufacturing flexibility: methods for measuring the impact of product variety on performance in process industries

AbstractProduct variety is often assumed to yield competitive advantage by offering products or services tailored to specific market segments. This strategy should result in more total sales volume or higher prices, and presumed profit, gained by meeting more specialized demands. However, achieving competitive advantage through increased product variety is heavily dependent on the proper alignment of the marketing and manufacturing strategies. This paper shows that adding product variety can have adverse cost and margin implications when marketing and manufacturing strategies are mis‐aligned. The critical strategic issues involve product pricing and manufacturing flexibility in product mix. We report methods that can be used to measure product mix flexibility and manufacturing performance in terms of costs and margins based on actual orders and production data. Such methods provide a means of empirically diagnosing the degree of strategic mis‐match using actual operating data. These methods are general in nature, and have been tested in field research on high volume batch processes that are representative of many firms in process industries. The results show that gaining competitive advantage through increased product variety requires a clear understanding of the process choice required to support the contemplated range of product volumes, and the cost and profitability trade‐offs involved.

Modeling rolling batch planning as vehicle routing problem with time windows

This paper considers the rolling batch planning problem of grouping and sequencing a given set of slabs into several rolling units in iron and steel industry. The existing mathematical methods often used for the problem are traveling salesman problem (TSP) and vehicle routing problem (VRP), but these methods are not precise, because the position limitation of some slabs in a rolling unit scheduling is not considered. Therefore we suggest a new model, vehicle routing problem with time window (VRPTW) to describe the rolling batch planning problem, in which the position limitation of slabs are quantified as the time constraints. Several solution methods including the genetic algorithm are presented for solving the problem and the computational results show that the genetic algorithm is superior to other methods. In this paper, the vehicle routing problem with time window (VRPTW) of combinational optimization is used to analyze and model the rolling batch planning problem. Genetic algorithm and heuristic are used to solve the problem. Simulation results based on the actual production data show that this model is precise and the genetic algorithm based method is very promising.

Economic Evaluation of Commercial‐Scale, Saltwater Pond Production of Florida Red Tilapia in Puerto Rico

AbstractAn economic analysis was performed of a proposed commercial‐scale 20‐ha saltwater pond culture operation for Florida red tilapia in Dorado, northern Puerto Rico. The analysis was based on actual cost and production data from a commercial‐scale hatchery, pilot‐scale grow‐out trials conducted in six 0.2‐ha saltwater (avg. = 22.7 ppt) ponds at the Dorado facility and on wholesale market prices ($4.96–5.18/kg) fetched by dressed‐out (gilled, gutted and scaled) product. The proposed 20‐ha growout facility is comprised of 25 0.8‐ha earthen ponds, each supplied with sea water, brackish well water, drainage and aeration, which account for 60.8% of the capital costs. Ponds are stocked with fingerlings (0.85 g avg. wt.) at a density of 3.0 fish/m2 (30,000/ha), and are harvested at 160 and 220 d, at an average weight of 545 g for a total yield of 11,445 kg/ha per crop. Imported feed ($0.55/kg), processing and distribution ($0.50/kg) and sex‐reversed fry ($0.11/fry) are the highest variable costs, accounting for 30.7%, 15.4% and 13.9%, respectively, of the total annual costs. Salaries and benefits, and depreciation represent the highest fixed costs, accounting for 8.4% and 5.5%, respectively, of the total annual costs. Under these conditions, a wholesale price of $4.55/kg results in a positive cash flow by year eight, and a breakeven price, internal rate of return (IRR), net present value (NPV) and discounted payback period (DPP) of $4.08/kg, 7.6%, ($235,717) and >10 yr, respectively, suggesting that the proposed 20‐ha operation is not economically feasible under these conditions. The proposed enterprise is marginally feasible if stocking density is increased to 3.5 fish/m2 while at 4.0 fish/m2 economic outlook is favorable. Costs can be lowered considerably by targeting production and market variables most sensitive to profitability indices, using locally‐prepared feeds, and vertically integrating hatchery and growout operations.

Limitation of the signal pin density on wiring boards

A practical limit of the signal pin density on wiring boards is investigated from the wireability point of view. The wireability problem can be expressed as a supply and demand model of two resources, i.e. wiring channels and via-holes. The limit of the signal pin density is assumed to be determined by the shortage of either of these two resources. As a measure of pin density, the average distance between adjacent signal pins, s/sub T/, is introduced. The practical limit of s/sub T/ is estimated by analyzing the actual product data and experimental data. The lower bound of s/sub T/, normalized by the grid spacing, can range from 1.5 to 2.0. These results are applied as a guideline to estimate the footprint area per LSI, and to do design tradeoffs among different packaging technologies such as multichip modules (MCM).

The impact of a constraint buffer in a flow shop

This article presents the findings from a simulation using actual production data comparing the material requirements planning (MRP) scheduling method with that of drum-buffer-rope (DBR) from the theory of constraints (TOC), previously called OPT. The simulation is based on production information from a diesel engine factory currently using MRP. The same data were then used under DBR procedures. Care was taken to utilize the DBR method in the manner suggested in the TOC literature. A buffer-modified MRP was also modeled. This environment used MRP scheduling with a buffer inserted prior to the constraining operation. An analysis of variance of the results of all scenarios indicates that the constraint buffer used in DBR was successful in increasing output from the system.

Economic Analysis of a Commercial-Scale Recirculating, Brackish Water Hatchery for Florida Red Tilapia

An economic analysis was performed on a commercial- scale, recirculating, brackish water hatchery for Florida red tilapia located on Lee Stocking Island (LSI), a privately-owned island in the Bahamas, using actual design criteria and production data collected from 1987-1992. Results were compared with a hypothetical facility based in the city of Freeport, on Grand Bahama Island, Bahamas. At annual production levels of 1.0-2.5 million sex-reversed fry, breakeven prices ranged from $0.16-0.07/fry at LSI and from $0.14-0.06/fry at Freeport. Salaries and benefits represented the largest fixed costs, accounting for 34.6% and 39.1% of annual production costs at LSI and Freeport, respectively. Air-freight shipping to Miami, Florida represented the largest variable cost at both locations, with private air charter from LSI accounting for 16% of the annual operating cost and commercial air freight from Freeport accounting for 6.1% of the total annual costs. At annual sales of 2 million sex-reversed fry, internal ra...

Performance of infra-plant overtime policies

Abstract Production quotas smooth production in order to synchronize inter-plant production networks. To meet quotas, plants work overtime whenever they're behind. In addition to this 'mandatory' overtime required to satisfy the quota of finished product at the end of the line, many plants run selected stations within the plant overtime to fill critical buffers within the plant. We call this intra-plant overtime 'preventive' overtime because by spending a little overtime this shift on critical stations, the plant can avoid massive overtime next shift. We describe this real production control problem currently facing industry. The problem arises because of (often underestimated or ignored) production variability. We exhibit actual production data that shows the degree of variability often inherent in current manufacturing processes. We describe four policies and compare them using simulation.

Net revenues of potatoes rotated with other crops

Using actual potato production data from Aroostook County, Maine, we investigate the possibility of producers increasing net revenues by modifying rotation practices. By examining rotations as a whole, and incorporating yield effects and changes in production costs across rotations, more realistic pictures of net revenues for each rotation develop than if net revenue for each crop within a rotation is considered independently. Our analyses indicate producers can alter their production practices within the range of rotations used locally to increase net revenues. A key finding confirms the synergistic interaction between grains underseeded with a green manure crop and round-white potato varieties, resulting in decreased production costs, greater potato yields, and increased net revenues.

Core tests help prevent formation damage in horizontal wells : Beatty, T; Hebner, B; Hiscock, R; Bennion, D B Oil Gas JV91, N31, Aug 1993, P64–70

Simulating drilling mud invasion in cores helped determine and eliminate the damaging effects of various mud systems prior to the drilling of a horizontal well in Canada. Formation damage is highly reservoir specific. General damage classifications according to rock and fluid type can be postulated, but specific tests are necessary to evaluate precisely the primary potential mechanisms of damage for each lithofacies. Proper testing and core preparation procedures must be followed to ensure that results are representative. This article outlines core displacement test methodology and presents the results of two core displacement studies. The findings of these studies are substantiated by actual production data. These results illustrate that although damage from a drilling fluid cannot be eliminated in horizontal drilling, it can be minimized.

Simulation of the Jigging Process

Jigging is one of the most important separation methods used in coal preparation plants. The process is very complicated and is affected by many factors. In order to estimate and predict the optimum production performance, the process is modelled as a Markov technique and simulations are carried out. The Markov technique is a stochastic process. The probability vectors in the transition matrix are non-stationary in this case and are determined from actual production data. Results of simulations using the Markov technique show that predicted and actual data are almost identical. The method of development is simple and is easily carried out. In addition, some problems in production may be analysed through simulation of the jigging process.

Inter-process synchronization in steel production

SUMMARY The development of strategies for sequencing slabs through the reheat furnace and rolling mill of a modern steel production facility is complicated by multiple, and often conflicting production objectives. Optimal energy efficiency through the reheat furnace may lead to inefficient rolling sequences or less than desirable product delivery schedules. Not only is model formulation complicated, but the combinatorial nature of the problem precludes optimal solution. A heuristic procedure for solving this multi-objective product sequencing problem has been developed and tested under production conditions in a Danish steel mill. The methodology, which is based on a modified ‘greedy’ algorithm is presented and results using actual production data are discussed

Review of Reserves, Production, and Desorption Data of the Original 23 Coal Bed Methane Wells at Oak Grove, Alabama: Are We Underestimating Coal Bed Methane Reserves in All Coal Basins?

The first large-scale pattern of vertical wells to drain methane gas from a single coal bed began in 1976 as a joint project with US Bureau of Mines and US Steel Corporation (now USX Corporation) at Oak Grove Mine in Jefferson County, Alabama. Through June 1990, the 23 wells have produced over 3.5 bcf of coal-seam gas, or an average of about 154 million ft{sup 3} per well. Initial reserve calculations indicated methane reserves of about 104 mmcf per well. Review of the information obtained from two core holes, drilled in 1988 as a joint US Bureau of Mines and Gas Research Institute, and actual production data from the 23 wells indicates that we indeed are underestimating the potential coal-bed methane reserves in all coal basins and specifically in the Appalachian coal basin.

Formation Temperature and Formation Pressure Influence the Oil and Gas Distribution in Tertiary Gulf Coast Sediments: ABSTRACT

ABSTRACT Oil and gas distribution is generally influenced by both formation temperature and formation pressure, and this paper provides an analytical study of these parameters. From our in-depth studies in the clastic Tertiary Gulf Coast sediments, we concluded that the highest concentration of all hydrocarbons is encountered near the onset of abnormally high formation pressure regimes. This conclusion is based on pressure and temperature data recorded in more than 12,000 wells and actual production data taken from approximately 33,000 well completions. Similar observations are presented for the Tertiary clastic sediments offshore Malaysia and for the Pliocene reservoirs under development in the West Turkmen depression in the USSR.

Parameter Estimation for Hyperbolic Decline Curve

The problem of estimating the nonlinear parameters associated with the hyperbolic decline curve equation is considered in this paper. Estimation equations are developed to estimate these nonlinear parameters. The condition under which the results can be used to predict future oil productions is examined using actual field data. An approximate linear term is obtained from the nonlinear hyperbolic equation through Taylor’s series expansion, and the optimum parameter values are determined by employing the method of least squares through an iterative process. The estimated parameters are incorporated into the original hyperbolic decline equation to provide realistic forecast function. This method does not require any straight line extrapolation, shifting, correcting and/or adjusting scales in order to estimate future oil and gas predictions. The method has been successfully applied to actual oil production data from a West Cameron Block 33 Field in South Louisiana. The results obtained are provided in Fig. 1.

Evaluation of CO2 Flood Performance: North Coles Levee CO2 Pilot, Kern County, California

Summary CO2 injection began on June 1, 1981, in the Main Western (MW) III interval of the North Coles Levee field Kern County CA, to test the tertiary potential of the reservoir to CO2. The pilot test was designed to inject continuously a 40 %-HCPV slug of CO2 into two inverted 5-acre [2.02-ha] 5-spot patterns and one 10-acre [4.05-ha] linedrive pattern. The injection was switched to water near the end of CO2 injection because of the CO2 source loss. Overall pilot test performance varied; oil production increased above secondary decline in some wells, but not in others. A simulation study was initiated to determine the dominant mechanisms controlling pilot performance. The simulation study investigated the influence of reservoir description, gravity override, communication with other producing horizons. and production strategy. Simulation results indicate that a random permeability description with Zone MWIII in communication with upper zones is most appropriate. Gravity override of CO2 into the upper zones dominated displacement efficiency. These results indicate that dual injection of CO2 low in MWIII and of water high in MWIII would greatly enhance sweep efficiency. Further analyses with oil and CO2 production data from individual wells and a post-CO2 tracer test showed that the test was a technical success in wells that responded to CO2 and that grouping and analyzing all pilot wells together masks the true incremental oil response to CO2. This is true mainly because some wells that never responded to CO2 experienced well problems that severely curtailed their production and that offset increased production from wells that did respond to CO2. The pilot test patterns are badly out of balance, possibly because of operational patterns are badly out of balance, possibly because of operational imbalance, directional permeability or a combination of the two. Introduction EOR by CO2 injection in watered-out reservoirs has been proven in several reservoirs throughout the world. This paper documents an analysis of the first application of CO2 injection in the Kern River Valley, Kern County. CA. Although California is well known for EOR by application of thermal methods to viscous oil reservoirs, it also has many deep, light-oil reservoirs discovered in the 1930's and 1940's that are approaching their economic limits from waterflooding. The North Coles Levee field is typical. A pilot study was initiated to test the potential of CO2 in three patterns on field spacing. Many problems have plagued the project, especially mechanical problems in wells that did not respond to CO2. The primary purpose of this study is to determine the technical success of the pilot test and to identify the dominant mechanisms controlling the process. The pilot test was analyzed by attempting to identify mechanisms that could account for the response to CO2 injection by use of reservoir simulation and a detailed well-by-well analysis of actual field production, injection, and tracer data. The lack of data-especially fluid saturations, pressure distribution, and a pilot-wide reservoir description-hinder a detailed simulation, but controlling processes can be qualitatively derived. Field and Pilot History The North Coles Levee reservoir is a large oil pool located in the Stevens sand interval about 10 miles [16.1 km] west of Bakersfield, CA, in the Kern River Valley (Fig. 1). Table 1 summarizes reservoir properties. The reservoir is mature and approaching its economic properties. The reservoir is mature and approaching its economic limit from waterflooding. The field was discovered in Nov. 1938 and produced by gas-cap expansion until Nov. 1942, when fluid withdrawal produced by gas-cap expansion until Nov. 1942, when fluid withdrawal was balanced by gas injection to preserve reservoir pressure. This included injection of make-up gas and gas cycling. A controlled blowdown of gas was started in 1965 because the economics favored gas sales over continued gas injection, allowing reservoir pressure to drop below 1,000 psi [6895 kPa]. A pilot alternating propane with water and dry chase gas was tried in 1964, but was unsuccessful because of early breakthrough and a diminishing supply of propane. A waterflood pilot was started in 1967. A fieldwide waterflood was started in 1970 pilot was started in 1967. A fieldwide waterflood was started in 1970 and continues to the present. Water preferentially enters the gas-swept region, while fluid withdrawals come mainly from the lower regions of the reservoir. This has led to a higher pressure, greater than 5,000 psi [34 475 kPa], in Zone MWI compared with 4,500 psi [31 027 kPa] in Zones MWII and -III. Because of underbalanced withdrawals in Zone MWIII, the waterflood was infill-drilled at 20- and 10-acre [8.09- and 4.05-ha] spacing (Fig. 2). Some patterns were converted to linedrive or irregular configurations later in the waterflood. Rod pumps were used for artificial lift on most producing wells. Gas lift was used on the remaining wells.

間欠ガスリフト井の挙動解析について

In the Kubiki oil field, oil is extracted by the intermittent gas lift system. Our concern is to reduce operating cost because of the present low price of oil. So as to optimize the intermittent gas lift system, the time taken to inject gas and the cycle frequency have been determined through trial and error and other means. If production volume can be predicted, operating cost can be reduced.The flowing bottom hole pressure curves were analyzed to calculate the productivity index, reservoir pressure and fall back volume. Our prediction is based on these three statistics.We used this method of statistical analysis to predict the amount of oil that was extracted from one of our wells and the prediction closely corresponded with the actual production data. Therefore our statistical method seems to be successful.

Estimation of Productivity of Lobo 6 Sand, Lower Wilcox, Texas, by Identifying Diagenetic Clays With Well Log Data

Summary The laminated, structural, and grain-coating primary clays in the Lower Wilcox Sand, Lobo 6, tend to be potassium-bearing illite and some smectite, whereas diagenetic clays, the cause of pore-throat plugging, are largely potassium-deficient kaolinite and chlorite. These diagenetic clays largely control reservoir permeability, depending on the degree of pore-throat plugging. This paper presents different methods for qualitative and quantitative evaluation of these diagenetic clays, which are related to productivity of the Lobo 6 sand. Qualitative evaluation consists of crossplot techniques using natural spectral gamma ray and other log data plus selected computed reservoir parameters. For quantitative evaluation, a sophisticated clay-analysis program that uses log-derived cation exchange capacity (CEC) and hydrogen index (HI) values is used. The average volume of different clay types in the zones of interest is calculated, presented, and correlated with production and core data. This approach was used on eight wells on which production data are available to evaluate the presence of diagenetic clays and to estimate productivity of the Lobo 6 sand. The reliability of the log-derived method applied is verified by the excellent correlation with actual production data.