The Experts below are selected from a list of 67077 Experts worldwide ranked by ideXlab platform
Longchen Duan - One of the best experts on this subject based on the ideXlab platform.
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An Analytical Solution of the Pseudosteady State Productivity Index for the Fracture Geometry Optimization of Fractured Wells
Energies, 2019Co-Authors: Hui Gao, Longchen DuanAbstract:The pseudosteady state Productivity Index is very important for evaluating the production from oil and gas wells. It is usually used as an objective function for the optimization of fractured wells. However, there is no analytical solution for it, especially when the proppant number of the fractured well is greater than 0.1. This paper extends the established fitting solution for proppant numbers less than 0.1 by introducing an explicit expression of the shape factor. It also proposes a new asymptotic solution based on the trilinear-flow model for proppant numbers greater than 0.1. The two solutions are combined to evaluate the pseudosteady state Productivity Index. The evaluation results are verified by the numerical method. The new solution can be directly used for fracture geometry optimization. The optimization results are consistent with those given by the unified fracture design (UFD) method. Using the analytical solution for the pseudosteady state Productivity Index, optimization results can be obtained for rectangular drainage areas with arbitrary aspect ratios without requiring any interpolation or extrapolation. Moreover, the new solution provides more rigorous optimization results than the UFD method, especially for fractured horizontal wells.
Barnabé Walheer - One of the best experts on this subject based on the ideXlab platform.
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Disaggregation of the cost Malmquist Productivity Index with joint and output-specific inputs ☆ ☆☆
Omega, 2018Co-Authors: Barnabé WalheerAbstract:Abstract In multi-output settings, different types of inputs are simultaneously used in the production process. On the one hand, some inputs are jointly used to produce all (or a subset of) the outputs. These inputs give rise to economies of scope, which constitutes a prime economic motivation to produce multiple outputs. On the other hand, some inputs are allocated to specific output productions. Using nonparametric output-specific modeling of the production process, we propose a new Productivity Index for cost minimizing producers in these multi-output settings. The new Index takes the form of a cost Malmquist Productivity Index. The output-specific modeling of the production process naturally allows us to define output-specific cost Malmquist Productivity Indexes and to disaggregate the cost Malmquist Productivity Index in terms of output-specific cost efficiency measurements. We also tackle the issue of input price availability and explain how to extend the cost Malmquist Productivity Index with partial input price information or without assuming observation of the input prices. In the latter case, we establish a duality with a technical Productivity Index that takes the form of a Malmquist Productivity Index. The new Indexes can be used to evaluate cost-Productivity and Productivity changes or can be fairly easily combined with existing extensions. We propose an application to the electricity plants.
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Cost Malmquist Productivity Index: an output-specific approach for group comparison
Journal of Productivity Analysis, 2017Co-Authors: Barnabé WalheerAbstract:The cost Malmquist Productivity Index (CMPI) has been proposed to capture the performance change of cost minimizing Decision Making Units (DMUs). Recently, two alternative uses of the CMPI have been suggested: (1) using the CMPI to compare groups of DMUs, and (2) using the CMPI to compare DMUs for each output separately. In this paper, we propose a new CMPI that combines both procedures. The resulting methodology provides group-specific Indexes for each output separately, and therefore offers the option to identify the sources of cost performance change. We also define our Index when input prices are not observed and establish, in that case, a duality with a new technical Productivity Index, which takes the form of a Malmquist Productivity Index. We illustrate our new methodology with a numerical example and an application to the US electricity plant districts.
Robert W. Payton - One of the best experts on this subject based on the ideXlab platform.
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Modification of the Productivity Index model
Soil & Tillage Research, 1999Co-Authors: Matthew K. Mulengera, Robert W. PaytonAbstract:Abstract A soil erosion–Productivity model which considers the effect of soil water storage capacity, crop evapotranspiration, soil chemical and physical properties important for crop growth has been modified. The model is shown to give good predictions and promises to be an improvement over the former Productivity Index (PI) because it accounts for weather and cropping conditions. It also promises to give more reliable results than the currently used insufficient models which consider only soil water storage capacity and crop evapotranspiration.
Sławomir Klatka - One of the best experts on this subject based on the ideXlab platform.
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Aplication of Soil Productivity Index after Eight Years of Soil Reclamation with Sewage Sludge Amendments
Environmental Management, 2021Co-Authors: Wiktor Halecki, Sławomir KlatkaAbstract:Remediation methods are gaining acceptance as effective and inexpensive techniques used in the reclamation of degraded areas. The reclamation of post-mining sites has become important for the conservation of soil and vegetation. An assessment of potential Productivity of plants based on the depth of their root zone is crucial for the validation of properties of post-mining soils. Our aim was to present soil Productivity parameters that would facilitate assessment of various post-mining objects. Soil Productivity Index (SPI) was calculated to assess soil quality, mainly in areas degraded by hard coal mining. It is based on an equation determining the relationship between the Productivity Index and the physical, chemical, and hydrological properties of soil. Our study demonstrated the positive effects of enriched sewage sludge with amendments on newly formed soil and plants. The soil Productivity Index was 0.81, demonstrating the suitable condition of the initial soil resulting from reclamation. This parameter might be important for post-industrial reclamation, such as wasteland intended to be transformed into woodland. Considering the composition of sewage sludge amendments, it can be successfully used as an effective method of restoring and improving both the physical and chemical properties of soils, thus effectively replacing mineral fertilisers. The use of sewage sludge in soil reclamation will be an important method of managing this waste material in post-mining areas.
Salam Al-rbeawi - One of the best experts on this subject based on the ideXlab platform.
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Practical solution for stabilized pseudo-steady state Productivity Index of multiple vertical wells depleting closed reservoirs
Petroleum, 2020Co-Authors: Salam Al-rbeawi, Fadhil Sarhan KadhimAbstract:Abstract The objective of this paper is introducing practical solutions for stabilized pseudo-steady state Productivity Index and pressure behaviors and flow regimes of multiple vertical wells depleting closed rectangular reservoirs. It introduces full understanding of reservoir performance during transient and pseudo-steady state flow using pressure and pressure derivative patterns and Productivity Index and Productivity Index derivative schemes. The practical solutions proposed in this study are relied on a new approach for accurate estimation of starting time of pseudo-steady state flow and stabilized Productivity Index by applying Productivity Index derivative that converges mathematically to zero at the beginning of this flow. It is also an attempt for pointing out the optimal reservoir configuration that can give maximum stabilized pseudo-steady state Productivity Index for different wellbore types and distributions in the drainage area. Several analytical models are used in this study for describing pressure drop and Productivity Index behavior of multiple vertical wells considering different reservoir configurations and different wellbore types and locations. These wells were assumed either fully or partially penetrate the formations. These pressure models are justified to generate two pressure derivatives, one represents the derivative of time dependent pressure drop and the second represents the derivative of time-invariant pressure drop. The two derivatives are used for determining the starting time of pseudo-steady state flow and stabilized Productivity Index when both converge and mathematically become identical. These models are used also to generate several plots for time-invariant or stabilized pseudo-steady state Productivity Index for different reservoir geometries considering different wellbore conditions. The maximum stabilized Productivity Index is illustrated in these plots and several analytical models for the expected flow regimes are developed using pressure and pressure derivative behaviors of different reservoirs and wellbore conditions. The outcomes of this study are summarized in: 1) Developing new analytical solutions for pressure distribution in porous media drained by multiple vertical wells. 2) Developing new practical solution for estimating stabilized pseudo-steady state Productivity Index. 3) Understanding pressure, pressure derivative, and Productivity Index behavior of finite acting reservoir depleted by multiple vertical wells during transient and pseudo-steady state production. 4) Investigating the impacts of different reservoir configurations and wellbore sizes and locations as well as partial penetration on stabilized pseudo-steady state Productivity Index. The novel points in this study are: 1) The optimum reservoir configuration that gives the maximum stabilized Productivity Index is the rectangular shape reservoir with reservoir length to width ratio of ( 2 − 4 ) . 2) Starting time of pseudo-steady state and stabilized Productivity Index are impacted by wellbore numbers, sizes, and locations. 3) Starting time of pseudo-steady state flow is not affected by partial penetration ratio, however, stabilized Productivity Index is affected by this ratio. 4) Five spots pattern gives the maximum Productivity Index compared with other wellbore distribution patterns. 5) Productivity Index of diagonally distributed wellbores is greater than the Index of wellbores distributed along reservoir length.
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The optimal reservoir configuration for maximum Productivity Index of gas reservoirs depleted by horizontal wells under Darcy and non-Darcy flow conditions
Journal of Natural Gas Science and Engineering, 2018Co-Authors: Salam Al-rbeawiAbstract:Abstract A new approach for estimating Productivity Index of horizontal wells depleting finite gas reservoirs is introduced in this paper. This approach focuses on using reservoir configurations and anisotropy as well as wellbore length for calculating Productivity Index at pseudo-steady state conditions when production time is no longer affects reservoir performance. The paper also aims to determine the optimal reservoir configurations that could give the maximum Productivity Index. For this purpose, new analytical models were developed for Productivity Index of gas reservoirs depleted by horizontal wells based on the solutions of the flow equation (Diffusivity equation) at pseudo-steady state condition. Gas flow in the porous media was considered obeying both Darcy and non-Darcy flow. These models were modified for bounded gas reservoirs when the pressure drawdown becomes time invariant and gas flow rate is constant. The study investigated the effects of reservoir boundaries, anisotropy, wellbore length, wellbore horizontal penetration ratio with respect to reservoir length, and the asymmetricity of wellbore in the formation on the Productivity Index. The outcomes of this study can be summarized in: 1) Productivity Index of gas reservoirs in pseudo-steady state is affected by the dominant flow type in the reservoirs: Darcy or non-Darcy flow. 2) Wellbore length, reservoir configuration, and anisotropy affect the Productivity Index as well as wellbore asymmetricity. 3) Productivity Index of Darcy flow is greater than non-Darcy flow. 4) Wellbore horizontal penetration ratio with respect to reservoir length may have significant impact on Productivity Index as well as reservoir width. The most interesting points in this study are: 1) The maximum Productivity Index could be reached for reservoir length of ( x e D = 0.55 − 0.65 ) regardless reservoir width. 2) The anisotropy may affect Productivity Index for short and moderate wellbores, however, it does not have significant effects in long wellbores. 3) Productivity Index might be affected by wellbore location with respect to reservoir width and length but not wellbore location in the vertical direction. 4) Pseudo-steady state Productivity Index can be estimated by the proposed models using reservoir configuration and wellbore length with a full consideration to the formation anisotropy and wellbore asymmetricity.
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The impact of hydraulic flow unit & reservoir quality Index on pressure profile and Productivity Index in multi-segments reservoirs
Petroleum, 2017Co-Authors: Salam Al-rbeawi, Fadhil Sarhan KadhimAbstract:Abstract The objective of this paper is studying the impact of the hydraulic flow unit and reservoir quality Index (RQI) on pressure profile and Productivity Index of horizontal wells acting in finite reservoirs. Several mathematical models have been developed to investigate this impact. These models have been built based on the pressure distribution in porous media, depleted by a horizontal well, consist of multi hydraulic flow units and different reservoir quality Index. The porous media are assumed to be finite rectangular reservoirs having different configurations and the wellbores may have different lengths. Several analytical models describing flow regimes have been derived wherein hydraulic flow units and reservoir quality Index have been included in addition to rock and fluid properties. The impact of these two parameters on reservoir performance has also been studied using steady state Productivity Index. It has been found that both pressure responses and flow regimes are highly affected by the existence of multiple hydraulic flow units in the porous media and the change in reservoir quality Index for these units. Positive change in the RQI could lead to positive change in both pressure drop required for reservoir fluids to move towards the wellbore and hence the Productivity Index.
