scholarly journals A New Approach for Determining the Control Volumes of Production Wells considering Irregular Well Distribution and Heterogeneous Reservoir Properties

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Cheng Lu ◽  
Ling Chen ◽  
Xiaodong Wang ◽  
Wanjing Luo ◽  
Yue Peng ◽  
...  
Keyword(s):  
Control Volume ◽  
Computational Cost ◽  
Real Field ◽  
Well Performance ◽  
Production Well ◽  
Reservoir Model ◽  
Reservoir Properties ◽  
New Approach ◽  
Production Wells ◽  
Control Volumes

The oil and gas fields are commonly developed with a group of production wells. Therefore, it can be essential for the industries to predict the performance of the production wells in order to optimize the development strategies. In practice, it frequently happens that we only hope to study the performance of a single production well. In such cases, it can be time consuming to run the reservoir simulation with the entire reservoir model to study the well performance. Hence, it can be preferred to determine the control volume (or drainage volume) of the target well from the entire reservoir and run the simulation with the small control volume to reduce the simulation cost. However, an irregular layout of the production wells and the heterogeneity of reservoir properties, which can be commonly observed in real field cases, can induce a stringent barrier for one to determine the control volumes. At present, we are still lacking a method to determine the control volumes of the production wells considering well distribution and reservoir heterogeneities. In order to overcome such a barrier, the authors proposed a new approach to divide the entire reservoir into small control volumes on the basis of the fast marching method (FMM). This approach is validated by comparing the simulation outputs of the target well calculated only with the determined control volume to those calculated with the entire reservoir model. The calculated results show that using the control volume that is determined with the proposed method to calculate the well performance can yield results that agree well with the results that are calculated with the entire reservoir model. This indicates that this proposed method is reliable to determine the control volume of the production wells. In addition, the calculated results in this work show that changing fracture length exerts a slight influence on the control volumes if the length of all fractures is increased, whereas, if only one of the fracture lengths is increased, the control volume of the corresponding well will be significantly increased. The number of the production wells and the distribution of the production well can noticeably influence the control volumes of the production wells. The findings of this study can help for optimizing the well spacing, estimating the ultimate recovery, and reducing the computational cost.

A New Approach to Load Balance for Parallel/Compositional Simulation Based on Reservoir-Model Overdecomposition

SPE Journal ◽  
2013 ◽  
Vol 19 (02) ◽  
pp. 304-315 ◽  
Author(s):  
Yuhe Wang ◽  
John E. Killough
Keyword(s):  
Dynamic Load ◽  
Execution Time ◽  
Static Load ◽  
Computational Cost ◽  
Hydrocarbon Composition ◽  
Reservoir Model ◽  
Compositional Simulation ◽  
New Approach ◽  
Load Imbalance ◽  
Load Balancer

Summary The quest for efficient and scalable parallel reservoir simulators has been evolving with the advancement of high-performance computing architectures. Among the various challenges of efficiency and scalability, load imbalance is a major obstacle that has not been fully addressed and solved. The causes of load imbalance in parallel reservoir simulation are both static and dynamic. Robust graph-partitioning algorithms are capable of handling static load imbalance by decomposing the underlying reservoir geometry to distribute a roughly equal load to each processor. However, these loads that are determined by a static load balancer seldom remain unchanged as the simulation proceeds in time. This so-called dynamic imbalance can be exacerbated further in parallel compositional simulations. The flash calculations for equations of state (EOSs) in complex compositional simulations not only can consume more than half of the total execution time but also are difficult to balance merely by a static load balancer. The computational cost of flash calculations in each gridblock heavily depends on the dynamic data such as pressure, temperature, and hydrocarbon composition. Thus, any static assignment of gridblocks may lead to dynamic load imbalance in unpredictable manners. A dynamic load balancer can often provide solutions for this difficulty. However, traditional techniques are inflexible and tedious to implement in legacy reservoir simulators. In this paper, we present a new approach to address dynamic load imbalance in parallel compositional simulation. It overdecomposes the reservoir model to assign each processor a bundle of subdomains. Processors treat these bundles of subdomains as virtual processes or user-level migratable threads that can be dynamically migrated across processors in the run-time system. This technique is shown to be capable of achieving better overlap between computation and communication for cache efficiency. We use this approach in a legacy reservoir simulator and demonstrate a reduction in the execution time of parallel compositional simulations while requiring minimal changes to the source code. Finally, it is shown that domain overdecomposition, together with a load balancer, can improve speedup from 29.27 to 62.38 on 64 physical processors for a realistic simulation problem.

Dynamic Steam-Trap-Control Simulation Technique: Formulation, Implementation, and Performance Analysis

SPE Journal ◽  
2018 ◽  
Vol 23 (06) ◽  
pp. 2015-2025 ◽  
Author(s):  
M.. Heidari ◽  
Long X. Nghiem
Keyword(s):  
Mathematical Formulation ◽  
Saturation Temperature ◽  
Control Technique ◽  
Thermodynamic Approach ◽  
Real Field ◽  
Total Production ◽  
Production Well ◽  
New Approach ◽  
Steam Trap ◽  
Run Time

Summary Steam-trap subcool is a technique that is used to maintain the energy efficiency of the steam-assisted-gravity-drainage (SAGD) process by most heavy-oil producers in Canada. The concept is rather simple (i.e., create a liquid pool around the production well to prevent steam from escaping from the steam chamber into the production well). A numerical steam trap based on a thermodynamic approach was implemented by Edmunds (2000), and it has been used in simulations with different types of wellbore models in commercial codes. In this approach, a thermodynamic relationship is solved as a well-residual equation to guarantee that the bottomhole temperature (BHT) is less than the saturation temperature of water at the hottest location along the wellbore. The location of the hottest spot along the wellbore is static in time. Steam trap is a dynamic process, and inflow temperatures can vary significantly along the wellbore according to the local fluid and rock properties along the well. It is highly possible that the location of the hottest spot along the well changes frequently with time during the SAGD operation. In this study, the simulation of a dynamic steam-trap-control technique is provided. The location of the hottest spot along the wellbore is scanned at every timestep. Severe numerical instabilities are observed when the thermodynamic approach is used. A new constraint based on the total production rate at reservoir condition is introduced. Details of the mathematical formulation and the numerical behavior of the new method are discussed in this paper. Several real field models with different wellbore designs (multiple tubing strings) are simulated, and the results of the new approach are compared with the thermodynamic approach. Simulation results show that the numerical performance of this new approach is significantly more stable. We also compared the run time of simulation between cases with new well constraint and thermodynamic steam-trap control, and results show a significant improvement in simulation run time.

scholarly journals A thermal resistances-based approach for thermal-elastohydrodynamic calculations in point contacts

2017 ◽  
Vol 232 (11) ◽  
pp. 2088-2102 ◽  
Author(s):  
Eduardo de la Guerra Ochoa ◽  
Javier Echávarri Otero ◽  
Enrique Chacón Tanarro ◽  
Benito del Río López
Keyword(s):  
Friction Coefficient ◽  
Film Thickness ◽  
Thermal Effects ◽  
Good Accuracy ◽  
Computational Cost ◽  
Point Contact ◽  
Elastohydrodynamic Lubrication ◽  
Point Contacts ◽  
New Approach ◽  
Ball On Disc

This article presents a thermal resistances-based approach for solving the thermal-elastohydrodynamic lubrication problem in point contact, taking the lubricant rheology into account. The friction coefficient in the contact is estimated, along with the distribution of both film thickness and temperature. A commercial tribometer is used in order to measure the friction coefficient at a ball-on-disc point contact lubricated with a polyalphaolefin base. These data and other experimental results available in the bibliography are compared to those obtained by using the proposed methodology, and thermal effects are analysed. The new approach shows good accuracy for predicting the friction coefficient and requires less computational cost than full thermal-elastohydrodynamic simulations.

Defining the Thermodynamic Efficiency in a Wave Rotor

2016 ◽  
Vol 138 (11) ◽  
Author(s):  
Shining Chan ◽  
Huoxing Liu ◽  
Fei Xing
Keyword(s):  
Gas Turbine ◽  
Control Volume ◽  
Thermodynamic Efficiency ◽  
Wave Rotor ◽  
Wave Rotors ◽  
Compression And Expansion ◽  
Efficiency Estimation ◽  
Parametric Analyses ◽  
Control Volumes ◽  
Thermodynamic Processes

A wave rotor enhances the performance of a gas turbine with its internal compression and expansion, yet the thermodynamic efficiency estimation has been troubling because the efficiency definition is unclear. This paper put forward three new thermodynamic efficiency definitions to overcome the trouble: the adiabatic efficiency, the weighted-pressure mixed efficiency, and the pressure pre-equilibrated efficiency. They were all derived from multistream control volumes. As a consequence, they could correct the efficiency values and make the values for compression and expansion independent. Moreover, the latter two incorporated new models of pre-equilibration inside a control volume, and modified the hypothetical “ideal” thermodynamic processes. Parametric analyses based on practical wave rotor data demonstrated that the trends of those efficiency values reflected the energy losses in wave rotors. Essentially, different thermodynamic efficiency definitions indicated different ideal thermal cycle that an optimal wave rotor can provide for a gas turbine, and they were recommended to application based on that essence.

Numerical prediction of the performance of gas-lubricated spiral groove thrust bearings

1997 ◽  
Vol 211 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Y Yue ◽  
T. A. Stolarski
Keyword(s):  
Control Volume ◽  
Numerical Procedure ◽  
Operating Conditions ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Flow Balance ◽  
Control Volumes ◽  
Volume Method ◽  
Spiral Angle ◽  
Spiral Grooves

The objective of this paper is to develop an accurate numerical procedure for the analysis of nominally flat contacts with spiral grooves lubricated by gases. The numerical procedure, which is based on the control-volume method, enables the solutions of the non-linear Reynolds equation to be obtained without limitation in geometry and operating conditions. Satisfactory flow balance was achieved on the control volumes as well as on the whole boundary and the method was proved to be very accurate. Convergence of the method was quick for any compressibility number. Three types of contact with spiral grooves were analysed. They were hydrodynamic bearings without interior chambers, hydrodynamic bearings with interior chambers and hybrid bearings. The effects of spiral angle, groove geometry (length, depth and width) and compressibility on performances were investigated for all possible designs.

Development of efficiency increase methods for water injection

2020 ◽  
pp. 57-60
Author(s):  
K.I. Mustafaev ◽  
◽  
◽  
Keyword(s):  
Water Injection ◽  
Cost Effective ◽  
Current Interest ◽  
Residual Oil ◽  
Production Well ◽  
Field Development ◽  
Oil Reserves ◽  
Production Wells ◽  
Efficiency Increase

The production of residual oil reserves in the fields being in a long-term exploitation is of current interest. The extraction of residual oil in such fields was cost-effective and simple technological process and is always hot topic for researchers. Oil wells become flooded in the course of time. The appearance of water shows in production wells in the field development and operation is basically negative occurrence and requires severe control. Namely for this reason, the studies were oriented, foremost, to the prevention of water shows in production well and the elimination of its complications as well. The paper discusses the ways of reflux efficiency increase during long-term exploitation and at the final stages of development to prevent the irrigation and water use in production wells.

Comparison of Various Discretization Schemes for Simulation of Large Field Case Reservoirs Using Unstructured Grids

2021 ◽  
Author(s):  
Samier Pierre ◽  
Raguenel Margaux ◽  
Darche Gilles
Keyword(s):  
Large Scale ◽  
Unstructured Grids ◽  
Computational Cost ◽  
Large Field ◽  
Real Field ◽  
Test Case ◽  
Generation Task ◽  
Field Case ◽  
Flux Approximation ◽  
Discretization Schemes

Abstract Solving the equations governing multiphase flow in geological formations involves the generation of a mesh that faithfully represents the structure of the porous medium. This challenging mesh generation task can be greatly simplified by the use of unstructured (tetrahedral) grids that conform to the complex geometric features present in the subsurface. However, running a million-cell simulation problem using an unstructured grid on a real, faulted field case remains a challenge for two main reasons. First, the workflow typically used to construct and run the simulation problems has been developed for structured grids and needs to be adapted to the unstructured case. Second, the use of unstructured grids that do not satisfy the K-orthogonality property may require advanced numerical schemes that preserve the accuracy of the results and reduce potential grid orientation effects. These two challenges are at the center of the present paper. We describe in detail the steps of our workflow to prepare and run a large-scale unstructured simulation of a real field case with faults. We perform the simulation using four different discretization schemes, including the cell-centered Two-Point and Multi-Point Flux Approximation (respectively, TPFA and MPFA) schemes, the cell- and vertex-centered Vertex Approximate Gradient (VAG) scheme, and the cell- and face-centered hybrid Mimetic Finite Difference (MFD) scheme. We compare the results in terms of accuracy, robustness, and computational cost to determine which scheme offers the best compromise for the test case considered here.

Application and Research of Rotate-Lookup-Summation in Robot Motion

2011 ◽  
Vol 467-469 ◽  
pp. 186-191
Author(s):  
Hao Bin Shi ◽  
Wen Jie Dong
Keyword(s):  
Control Volume ◽  
Dimensional Space ◽  
Control Variable ◽  
Control Process ◽  
Controlling Factors ◽  
Dimensional Control ◽  
Control Factors ◽  
Look Up Table ◽  
New Research ◽  
Control Volumes

How to exercise reasonable motion control on robot becomes a new research focus in robot technology research. This paper proposes the Rotate-Lookup-Summation according to the deficiency of traditional look-up table. This method first confirm the controlling factors P1，P2….Pn that would affect the control volume Z, and then the multi-dimensional control volumes and multi-dimensional control factors would be projected to sub-dimensional space. Finally, the same controlling factors of different sub-dimensional space would be rotated to a single sub-dimensional space and establish a corresponding table. According to the single sub-dimensional space value of the controlling factors, the corresponding control variable could be found in table and eventually complete the control process. Experiments show that the method could ensure the integrity and accuracy of table, reduce the table memory capacitance and lookup time, so as to realize the control of look-up table in micro-device.

Multifrequency full-waveform sonic logging in the screened interval of a large-diameter production well

Geophysics ◽  
2013 ◽  
Vol 78 (5) ◽  
pp. B243-B257 ◽  
Author(s):  
Majed Almalki ◽  
Brett Harris ◽  
J. Christian Dupuis
Keyword(s):  
Phase Velocity ◽  
Velocity Dispersion ◽  
Large Diameter ◽  
Low Frequency ◽  
Production Well ◽  
Frequency Wave ◽  
Full Waveform ◽  
Phase Velocity Dispersion ◽  
Production Wells ◽  
Sonic Logging

A set of field experiments using multiple transmitter center frequencies was completed to test the application potential of low-frequency full-waveform sonic logging in large-diameter production wells. Wireline logs were acquired in a simple open drillhole and a high-yield large diameter production well completed with wire-wound sand screens at an aquifer storage and recovery site in Perth, Western Australia. Phase-shift transform methods were applied to obtain phase-velocity dispersion images for frequencies of up to 4 kHz. A 3D representation of phase-velocity dispersion was developed to assist in the analysis of possible connections between low-frequency wave propagation modes and the distribution of hydraulic properties. For sandstone intervals in the test well, the highest hydraulic conductivity intervals were typically correlated with the lowest phase velocities. The main characteristics of dispersion images obtained from the sand-screened well were highly comparable with those obtained at the same depth level in a nearby simple drillhole open to the formation. The sand-screened well and the open-hole displayed an expected and substantial difference between dispersion in sand- and clay-dominated intervals. It appears that for clay-dominated formations, the rate of change of phase velocity can be associated to clay content. We demonstrated that with appropriate acquisition and processing, multifrequency full-waveform sonic logging applied in existing large-diameter sand-screened wells can produce valuable results. There are few wireline logging technologies that can be applied in this setting. The techniques that we used would be highly suitable for time-lapse applications in high-volume production wells or for reassessing formation properties behind existing historical production wells.

scholarly journals Dependences Of Reservoir Oil Properties On Surface Oil

2020 ◽  
Author(s):  
Sudad H Al-Obaidi ◽  
Galkin AP
Keyword(s):  
Hydrodynamic Models ◽  
Reservoir Properties ◽  
High Quality ◽  
Data Dependencies ◽  
Models Of Development ◽  
Production Wells ◽  
Exploration And Production ◽  
High Degree ◽  
Selection Of

Knowledge of the properties of reservoir oil is necessary when calculating reserves, creating projects development, creating hydrodynamic models of development objects. Reservoir oil properties are determined by downhole samples taken, as usual, from exploration and production wells. In some cases, it is impossible to create conditions for the selection of high-quality downhole samples at exploration and production wells. In such cases, we must use samples of surface oil to obtain information about the reservoir properties of this oil. In this work and as a result of the analysis of the accumulated data, dependencies with a high degree of correlation were obtained, which make it possible to quickly assess the expected parameters of reservoir oil, having only the density of surface oil.

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