bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of 3-D Reservoir Simulator for Hydraulically Fractured Wells
Authors: Lolon E. P. , Shaoul J. R. , Mayerhofer M. J. 
Published: December 2007

Abstract
The evaluation of hydrocarbon reservoirs often requires a reservoir simulation model. Historically, there have been two basic approaches used for modeling a hydraulic fracture in a 3-D reservoir simulator. In the first method, the hydraulic fracture was approximated with a negative skin or an increase in the effective wellbore radius. This approach was generally adequate for moderate to high permeability wells; however, it does not capture all the important physics of flow into and through the fracture. This limitation becomes even more critical in cases of multiphase flow, multi-layer reservoir and non-Darcy effects in the fracture. In the second method, the fracture was explicitly simulated in the reservoir model. In simple cases, this approach was practical even when the gridding was performed manually. Its main limitation was the gridding schemes that represent both the fracture and reservoir becoming complicated–especially for horizontal wells with multiple hydraulic fractures and multi-layer reservoirs.
In the past few years, with advanced computer technology, it became feasible to routinely run 3-D simulations of multiphase production from multi-layer reservoirs while explicitly modeling the hydraulic fracture in a reservoir simulator. Although such a technique is not new, the latest capability reported in this paper completely automates the process of setting up the grid and initializing the grid block properties for the fracture and reservoir. It automatically transfers the fracture properties such as geometry, permeability, porosity, filtrate fluid distribution and initial pressure distribution from the fracture growth simulator into the reservoir simulator, thus making the optimization of hydraulic fracturing both easier and more realistic.
This paper reviews the advantages of 3-D numerical simulation for hydraulically fractured wells. Field examples are presented to illustrate the application of this technology for production modeling and history matching complicated reservoir cases involving fracture stimulation.
Analyzing Simultaneous Rate and Pressure Data from Permanent Downhole Gauges
Authors: Rai Himansu , Horne Roland N. 
Published: December 2007

Abstract
Permanent downhole gauge data provide us with reservoir information in space and time and aid in well and reservoir management. Interpretation of permanent downhole gauge data is a fairly new problem and several outstanding issues remain in this area.
This paper addresses some of the challenges in analyzing flow rate data and pressure data from permanent downhole gauges - development of improved algorithms for reliable and accurate identification of transient break points (to separate transients into relevant subsections), and investigating the impact of continuous downhole rate data in analyzing well tests.
We tested four different algorithms, one based on the stationary Harr wavelet transform method and others based on nonwavelet approaches such as Savitzky-Golay Smoothing Filters and a novel pattern recognition approach called the Segmentation Method. These four methods were developed for accurate and reliable identification of break points using both pressure and rate data.
The new methods developed in this paper were applied to real field data and the results were compared to the spline wavelet-based approach. All the nonwavelet approaches showed significant improvement over the wavelet-based method in identifying the true break points and avoiding false break points, thus reducing manual editing of break points. Also, significant difference in the estimates of permeability and skin was observed by using continuous rate information instead of average rate data for interpreting transient pressure data.
These new algorithms find their application in the interpretation of permanent downhole gauge data using conventional well test interpretation methods, to obtain dynamic information about changes in properties of the well and reservoir. The use of continuous downhole rate data can have significant advantage in well test interpretation.
Iteratively Coupled Reservoir Simulation for Multiphase Flow
Authors: Lu Bo , Alshaalan Tareq M. , Wheeler Mary F. 
Published: December 2007

Abstract
FIM (Fully Implicit Method) and IMPES (Implicit Pressure Explicit Saturation) are two of the most commonly used time-stepping schemes in present reservoir simulation. However, neither of them satisfies the requirements of accuracy and efficiency with increasing size and degree of complexity of highly heterogeneous reservoirs. In this paper, an iterative coupling scheme is developed and applied to multiphase reservoir problems, which aims to model and simulate realistic reservoirs accurately and efficiently.
Numerical examples reflecting major difficulties in treating heterogeneities and simulating complex reservoir phenomena such as coning and countercurrent flow problems are presented in comparison studies of iterative coupling, FIM and IMPES methods. Our results indicate that for the same accuracy the iterative approach can reduce computational time by 30%-40% or even more over the FIM. In comparing with the IMPES method, the iterative method shows better stability for taking larger time steps, and superior local mass balance. In this paper, the iterative approach is also shown to be scalable in parallel.
Another advantage of the iterative coupled approach over FIM is that different numerical schemes and even physical models can be incorporated into the algorithm thus allowing more flexibility in treating complicated problems, e.g. highly heterogeneous reservoirs with different subdomain stochastic properties.
CBM: Fracture Stimulation—An Australian Experience
Authors: McMillan D. W. , Palanyk V. S. 
Published: December 2007

Abstract
This paper reviews the fracture stimulation experience at the Dawson Valley CBM project situated in the Bowen Basin, Queensland, Australia. Multi stage water fracture stimulation was proven to be the most effective stimulation method. Stimulating multi-seam targets requires an aggressive fracture technique to ensure more than one seam is stimulated. Water volume, rather than sand volume, influences the Fracture Stimulation effectiveness.
Detecting Water Influx in Beam Pump Lifted Horizontal Wells in a South Oman Field Uing Temperature Measurements, Production Profiling, and Concentric Coiled Tubing
Authors: Mahrooqi Majid , Hinai Ghaliba , Kuchel Mike , Al Sakhbouri Harith 
Published: December 2007

Abstract
Strong bottom water drive, high matrix permeability and complex fracture and fault networks have resulted in a significant water influx problem in a South Oman field. The majority of wells produce with a water cut of at least 90% and some new wells are experiencing early water break-through. To combat this problem, swelling elastomers (SE) on wire-wrapped screen (WWS) completions have been used since early 2004 to provide reservoir segmentation behind the horizontal completion. Open hole logging and/or underbalanced drilling are used to determine where the elastomers should be placed. Reservoir segmentation allows mechanical water shut-off methods (i.e. scab liners, clads and bridge plugs) to be employed. Older wells that do not have elastomers will require chemical water shut-off treatments.
Water shut-off (WSO) will enable redirection of reservoir and artificial lift energy to oil producing zones and hence maximize oil production and ultimate oil recovery. However, before an effective WSO treatment can be applied, the location of water breakthrough, (due to coning or a conductive fracture or fault) has to be determined. Most of the wells are artificially lifted using beam pumps which represent a barrier and a great challenge to surveillance activities under dynamic conditions. Concentric coiled tubing (CCT) and a specialized jet pump or vacuum tool has been utilized to overcome this problem.
The technique combines concentric coiled tubing vacuum technology (CCTVT) with a pressure and temperature memory gauge. A procedure has been developed to utilize static and dynamic well conditions to determine water entry points: The static temperature indicates fluid migration behind the horizontal completion and gives the history of water movement from the reservoir to wellbore.The geothermal gradient is measured and compared to the static temperature – this indicates where warmer fluids are migrating from below (aquifer).The specially designed jet pump on CCT creates a localized drawdown and a steady state flowing condition.The temperature measured during the dynamic production period is compared to the static temperature to indicate the current flow of reservoir fluids.Surface sampling to measure water cut is correlated with depth to corroborate the temperature data.
This paper will present case histories of the profiling technique along with results and conclusions. It will also compare the response from this technique to normal production logging.
Simulation Studies on the Mechanisms and Performances of MEOR using Polymer Producing Microorganism Clostridium sp. TU-15A
Authors: Sugai Yuichi , Chengxie Hong , Chida Tadashi , Enomoto Heiji 
Published: December 2007

Abstract
Polymer-producing microorganism Clostridium sp. strain TU-15A was isolated from reservoir brine of Jilin Oilfield, China. TU-15A produces polymer in a molasses medium and increases the viscosity of the culture solution to 70cP by 10days cultivation. It's expected to be an effective microorganism for MEOR.
In this study, a simulator was developed in order to analyze the mechanisms of MEOR using polymer-producing microorganism. The numerical model in this simulator consists of 2-phases(oil and water) and 5-components(oil, water, microorganism, nutrient and polymer). This model includes almost all processes of MEOR such as growth and death of microorganism, nutrient consumption, polymer production, water viscosity increment, improvement of the flow profile in a reservoir and enhancement of oil recovery. The validity of this simulator was shown by a comparison of both results of the numerical simulation and a flooding experiment.
The quantitative change of microorganism, nutrient, polymer(water viscosity) and oil saturation were analyzed by a simulation of MEOR using polymer-producing microorganism on quarter of fivespot pattern flooding. Regarding the alteration of flow pattern in the reservoir, it was found that (1) the polymer produced by microorganism in reservoir flew into the main flow channel along the shortest way between the injection and production wells and water viscosity there increased, (2) subsequently more uniform flow profile of injected water as a postflash was established, and (3) the residual oil was mobilized to the production well. The additional oil recovery of 10% or higher was obtained at the early stage of the postflash.
Our simulator will be a first comprehensive simulator for MEOR using an existing strain that produces polymer strongly. By using this simulator, the phenomena occurred in a reservoir on MEOR using a polymer-producing microorganism have been clarified and the high performance of this MEOR process have been demonstrated.
An Update to Viscosity Correlations for Gas-Saturated Crude Oils
Authors: Bergman David F. , Sutton Robert P. 
Published: December 2007

AbstractFor live crude oils, dissolved gas acts to reduce viscosity from the value observed for dead oils. The reduction in viscosity can significantly impact pressure drop and flow rate and must be properly accounted for by any viscosity model. This article provides a detailed review of existing correlation methods and offers state-of-the-art solutions necessary for oil field operations in 2007 and beyond.A total of 21 methods for calculating saturated oil viscosity have been identified from the literature. A large database consisting of data from oil PVT reports and literature sources has been compiled in order to evaluate these methods. This data represents over 12,000 measurements from 1849 samples. The gases dissolved in the oils contain varying amounts of non-hydrocarbons and the oils provide a representative crossection of the expected range in API gravity and Watson characterization factor found in crude oils from producing regions located around the world. A detailed analysis of correlation performance has been conducted which reveals inaccuracies in many of the previously published methods. As a result, a new method is proposed which is consistent across a wide range of parameters and offers increased accuracy over existing methods.
Supporting Deployment of New Technology in Developing Oil and Gas Provinces From a Centralized Support Centre
Authors: Cannon Katherine , Kay Ian , Amadi Kingsley 
Published: December 2007

Abstract
Industry growth is currently characterized by the migration of cutting edge technologies from regions traditionally used as the proving grounds (eg North Sea, GoM) to emerging markets such as West Africa, Russia and the Caspian.
There are many challenges to successful deployment of complicated new technologies in these areas including logistics a lack of infrastructure and access to experienced work force.
This paper aims to describe the development and implementation of a centralized support center, work processes developed to enhance local maintenance procedures, enabling technologies developed, describe successes to date and outlines potential further developments.
Recent technology introduction/ migration in Nigeria necessitated the re-tooling of the workshop, competency development of local maintenance workforce and skill development of the offshore staff.
Building on over eight years of remote operations experience a centralized support center was established at a maintenance centre in Aberdeen to support new downhole technology introduction in West Africa.
The support centre was created to enable subject matter expert's access to all facets of the technology introduction and, for what is believed to be a first for a service company; work processes and technology were developed to provide focused second line support for the workshop maintenance personnel in Port Harcourt.
New roles and work processes were developed that give local repair and maintenance staff access to dedicated expert support during critical phases of tool turnaround including strip down, component inspection and tool programming. These processes are enabled by an underlying communications infrastructure that allows portable computing devices to be utilized on the shop floor, video conferencing and network access to workshop computers.
Expertise to support rigsite operational excellence and improved rig-site workflows is facilitated by installing dedicated satellite communication systems which allow for work processes developed in North Sea Integrated Operations settings to be adapted for Nigerian conditions
Successes to date include remote training sessions of local maintenance staff in tool programming, real time remote troubleshooting at rigsites to resolve issues quickly and efficiently and multi-team collaboration during advanced rig- site operations.
Enhancing Production From Thin Oil Column Reservoirs Using Intelligent Completions
Authors: Almutairi Fajhan H. , Davies David R. , Singh Shamrendra 
Published: December 2007

Abstract
Intelligent completion have been proven to be an efficient reservoir management tool, with rapid deployment in various reservoirs environments, value have been established for the use of inflow control valves (ICVs) and different downhole sensors. One of the difficult environments to manage is the thin oil column reservoirs, where issues of rapid and simultaneous gas and water breakthrough affect ultimate oil recovery.
This study investigates the opportunities that intelligent completions provide for efficient oil recovery from thin oil column reservoirs. Three wells located in an offshore field were studied to show the benefit of intelligent completions in different reservoir behavior.
The study shows that using intelligent well completion can increase the total oil production from a well by controlling the gas and water production. The value is clearer in wells where the gas or water constraint is reached early in the well life, causing cessation of production. The ICV control strategy chosen illustrates how emphasis should be placed on delaying the gas/water breakthrough rather than controlling the production of unwanted fluids if choking reduces the well's deliverability. It also highlights the importance of applying conventional well design and reservoir engineering prior to the consideration of using intelligent wells.
Applications of NMR Logs and Borehole Images to the Evaluation of Laminated Deepwater Reservoirs
Authors: Claverie Michel , Hansen Steve , Daungkaew Saifon , Prickett Zane , Akinsanmi Olumide , Pillai Paul 
Published: December 2007

Abstract
Deepwater turbidite reservoirs are composed of interbedded porous and permeable sands with variable proportions of thin silt and clay beds. These reservoir sands vary in thickness from millimeter to meters in thickness. The reservoirs are highly permeable, but the silt and clay laminations affect the reservoir permeability in each layer, resulting in changes in the well productivity and sweep properties.
We illustrate the applications of NMR, borehole images and wireline formation testing technology in oil-base mud to evaluating the lithology, the geometry, and the net producible fraction of these reservoirs: We demonstrate that the partitioning of NMR T2 distribution is a robust method for calculating independent volumes of clay, silt and sand.We present the experimental set-up and the application of a novel method to calculate the thin sand fraction of a laminated reservoir from NMR free fluid volume. The results of this method are compared to the sand counts from a high resolution borehole image and from core images. This comparison reveals the effect of the lamination geometry on the formation evaluation.We illustrate the effects of thin silt and clay laminations on wireline formation tests, and on the productivity and flow profile of a production test. The dynamic reservoir information obtained from these measurements enables to understand the fluid flow behaviour and potential productivity in such a reservoir.
These techniques reduce the uncertainty of hydrocarbon volume and productivity computations in a highly laminated deepwater reservoir. The field example used in this paper is a turbidite sand from North West Borneo. The techniques demonstrated here are also applicable to the analysis of other categories of thinly bedded, shaly sand reservoirs.
Integration of Production Data Analysis Results into Geostatistical Models by Downscaling
Authors: Archer Rosalind 
Published: December 2007

Abstract
Production data analysis offers mechanisms to estimate permeability values (for well drainage areas) from production data. These data are valuable and readily obtained from routinely measured data. For use in geostatistical modeling however a downscaling process is required because of the volume of support production data derived permeability values have. A workflow is proposed for the integration of production data into geostatistical modeling which creates a kriged 2D map of reservoir permeability by treating production data derived permeability values as point data. The permeability values in this map are in turn used as collocated secondary data in a cokriging process used in a sequential Gaussian simulation. Numerical experiments demonstrate that the use of this workflow can substantially improve the quality of realizations from the resulting 3D permeability model.
Pore-Scale Simulation of Dispersion in Porous Media
Authors: Garmeh G. , Johns R. T. , Lake L. W. 
Published: December 2007

Abstract
Mixing of miscible gas with oil in a reservoir decreases the effective strength of the gas, which can adversely affect miscibility and recovery efficiency. The level of true mixing that occurs in a reservoir, however, is widely debated and often ignored in reservoir simulation where very large grid blocks are used. Large grid blocks create artificially large mixing that can cause errors in predicted oil recovery.
This paper examines the mixing that occurs in porous media by solving for single-phase flow in a connected network of pores. This work differs from network models in that we directly solve the Navier-Stokes equation and the convection- diffusion equation to determine the velocities and concentrations at any location within the pores. Flow in series and layered heterogeneous porous media are modeled by using many grains in different arrangements. We consider both slug, continuous, and partial injection as well as echo tests (single-well tracer tests) and transmission tests (interwell tracer tests). We match the concentrations from the pore-scale simulations to the analytical convection dispersion solution that includes both transverse and longitudinal dispersion coefficients.
The results show that for flow in series and in layers, echo and transmission longitudinal dispersivities become equal and reach an asymptotic value if complete mixing over a cross section perpendicular to flow has occurred. In practice, the asymptotic value of dispersivity may never be reached depending on pattern-scale heterogeneity and well spacing. Transverse dispersion coefficients also are scale dependent, but they decrease with traveled distance. We further demonstrate that the classical Perkins-Johnston relationship between longitudinal dispersion coefficient and fluid velocity is obtained. We conclude that echo dispersivities are reliable indicators of true mixing in porous media.
Technology for Confecting Polymer Solution With Desalted Produced Water
Authors: Liu Shumeng , Dong Xigui , Ban Hui , Wang Tao , Pan Wenlong , Yu Haijun , Guo Cuiling , Suo Chunlei 
Published: December 2007

Abstract
Polymer flooding technology has been widely used in Daqing oilfield of China in recent years. To maintain the viscosity of polymer solution, fresh water was used to confect polymer solution instead of produced water. Then, a problem was generated that the produced water could not be injected into the stratum totally. The superfluous produced water must be treated to meet the requirement of discharge, which increased the cost of production. In this paper, we try to desalt the produced water using electrodialysis principle. A set of experimental equipments that could generate desalted produced water 300 m3/d, was operated at a produced water treatment station of Daqing Oilfield. The experimental results indicated that the total salinity of desalted produced water less than 1000 mg/L. Comparing with fresh water, the polymer solution confected with desalted produced water has a sound character, its viscosity increases 63.5%, and the recovery ratio increases 4.5 percentage points. This experimental study has an important significance for the balance of oily water of production and injection in Daqing Oilfield. This produced water desalination technology would have a better application prospect in polymer flooding production.