bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Unified Mathematical Model for Unconventional Reservoir Simulation
Authors: Wu Yu-Shu , Fakcharoenphol Perapon 
Published: September 2011

Abstract
Unconventional hydrocarbon resources from low-permeability formation, i.e., tight sands and shales, are currently received great attention because of their potential to supply the entire world with sufficient energy for the decades to come. In the past few years, as a result of industry-wide R&D effort, progresses are being made towards commercial development of gas and oil from such unconventional resources. However, studies, understandings, and effective technologies needed for development of unconventional reservoirs are far behind the industry needs.
Unconventional reservoir dynamics is characterized by highly nonlinear behavior of multiphase flow in extremely low- permeability rock, coupled by many co-existing, processes, e.g., non-Darcy flow and rock-fluid interaction within tiny pores or micro-fractures. Quantitative characterization of unconventional reservoirs has been a significant scientific challenge currently. Because of complicated flow behavior, strong interaction between fluid and rock as well as multi-scaled heterogeneity, the traditional Darcy-law-and-REV-based model may not be applicable for describing flow phenomena in unconventional reservoirs. In this paper, we will discuss a general mathematical model proposed for unconventional reservoir simulation. We will present a unified framework model to incorporate various nonlinear flow and transport processes using a multi-domain, multi-continuum concept to handle multi-scaled heterogeneity of unconventional formation. Specifically, we will use extended or modified Darcy law to include the following processes: (1) non-Darcy flow with inertial effects; (2) non-Newtonian behavior (i.e., threshold pressure gradient for flow to occur); (3) adsorption and other reaction effect; and (4) rock deformation. The proposed modeling methodology has been implemented into a general reservoir simulator and will be demonstrated for its application in analyzing well tests in fractured vuggy reservoirs, non-Darcy flow, and non-Newtonian flow in porous and fractured reservoirs.
Integrated Asset Model in Camisea, Peru
Authors: Downie A. , Salazar A. , Monsalve M. , Cruells J. , Pomeraniec M. , Navarrete C. 
Published: September 2011

Abstract
An Integrated Asset Model (IAM) Project was carried out for the 56 & 88 Blocks of Camisea area. This area is located in the South Ucayali Basin, Peru, within the Sub-Andean fold and thrust belt. Camisea involves three anticlines with three independent world class reservoirs and is one of the most important natural gas and condensate reserves ever discovered in Latin America.
The targets of this study were to evaluate: the Field Development Plan, the Scenario Analysis, Conceptual Compression Plan, Monitoring and Surveillance plan.
The IAM was used to evaluate the potential development scenarios, and also to optimize production taking into account reservoir performance, surface facility and process plant constraints. The IAM also makes it easier for production and asset managers to diagnose potential problems at an early stage, and thus intervene before production is compromised, and provides an invaluable framework for performance analysis and decision making.
Camisea lies within an environmentally sensitive area, which has dictated an offshore-on-land strategy to minimize the number and footprint of the drilling facilities, and also places significant restrictions on the design of compression equipment which will be required to maintain production rates in the future.
The IAM was built incorporating the following models and software: a compositional reservoir model, nodal analysis, surface network modelling and process simulation. The individual models were linked together within integration software which enables dynamic linking and controlling of the various packages.
The IAM was validated against historical production data and also benchmarked against stand-alone reservoir model predictions. Several development scenarios were then investigated, including: facility debottlenecking, conversion of redundant cycling injector wells to production, compression optimization, and reservoir uncertainty. The IAM was also used to facilitate the economic evaluation of each case.
Incorporating 4D Seismic Attributes Into History Matching Process Through An Inversion Scheme
Authors: Davolio A. , Maschio C. , Schiozer D. J. 
Published: September 2011

Abstract
Time-Lapse seismic attributes has been showed as a promising tool to be used in the history matching process. The most common seismic attribute used to integrate these data is P-impedance. The procedure usually made is a minimization of the differences between the seismic P-impedance and the synthetic P-impedance computed from the flow simulation data through a forward modeling. On this paper, we propose a methodology that goes in the opposite way. We invert the seismic data to pressure and saturation and then incorporate these results in the history match procedure in order to integrate the inversion process with the flow simulator, using the results of the reservoir simulation to guide the process. Another feature is that instead of using only the P-impedance in our inversion procedure we are also taking into account a second seismic attribute the S-impedance, which is more sensitive to pressure than saturation variations. A discussion is presented regarding the results obtained using a model with characteristics similar to the Brazilian offshore fields and synthetic seismic data. The main contribution of this work is the integration of the seismic attributes inversion and reservoir simulation processes. We also show the advantages of the inversion procedure to obtain pressure and saturation considering prediction of petroleum production and the details used in the methodology to avoid multiple combinations of saturation and pressure in the inversion process.
Gas-Condensate Relative Permeability Curves Determined from Separator Test Data: Britannia Field Case Study
Authors: Göktas B. , Thrasher T. S. 
Published: September 2011

Abstract
This paper presents a methodology for determination of gas-oil relative permeability curves using well performance data from retrograde condensate wells. Computations are based on PVT, producing gas-oil ratio, flowing bottom-hole pressure and material balance. The methodology presented was successfully applied to Britannia wells across the field, and findings were verified with numerical simulation to show proper modeling of condensate banking.
Production performance of Britannia wells is monitored through back-pressure curves, constructed by plotting single-phase pseudo-pressure difference versus flow rate on log-log scale, using individual well separator test data. As condensate accumulates near the wellbore, reducing productivity, well performance deteriorates (points move left) from the established pseudo steady state (pss) deliverability line. Once productivity deterioration becomes negligible, the well performance response shows a linear trend. The empirical deliverability equation, delta pseudo-pressure versus flow rate log-log, yields a linear relationship with a slope of (1/n). Using this relationship, n is determined from the observed well deliverability line, shifted left due to condensate blockage. The coefficient C is then calculated at the pss deliverability line by assuming that the coefficient n remained unchanged.
With accurate gas-oil relative permeability data included in the two-phase pseudo-pressure integral, plotting delta two-phase pseudo-pressure versus flow rate for separator test points should develop an alignment with the pss deliverability line. An objective function is defined as the difference between the delta pseudo-pressure, determined using the empirical deliverability equation, and the measured delta two-phase pseudo-pressure for separator test flow rates. The process outlined in this paper aims to find a gas-oil relative permeability curve that produces the best alignment, that is, the minimum objective function.
In complex fields, e.g. Britannia, multiple gas-oil relative permeability curves might be needed to model condensate banking. In the absence of relative permeability data, the presented approach could provide valuable information on relative permeabilities.
Grid-Based Inversion Methods for Spatial Feature Identification and Parameter Estimation from Pressure Transient Tests
Authors: Morton K. L. , Booth R. J. , Kuchuk F. J. , Onur M. 
Published: September 2011

Abstract
We present and compare three different grid-based inversion methods for estimation of formation parameters and spatial geological feature identification based on pressure transient test (PTT) data from multiple-well locations. The first and second methods employ efficient adjoint schemes to determine the gradient of the objective functions resulting in the most likely set of reservoir parameters and an ensemble of updated realizations of the parameters, respectively. The second method is based on the Langevin equation. The third method uses ensemble Kalman filtering (EnKF) for data assimilation, in which the outcome is an ensemble of updated parameter realizations. These three methods use a grid-independent prior model (in view of the limited prior knowledge of the system expected to be available), described by as few parameters as possible, and consider a non-uniform grid with the highest resolution near the wells. With these methods, the existence of and location of many sub- seismic features such as strong spatial permeability variations, faults, fractures and pinch outs may be determined using exploration and production data. Such features may not be known a priori, particularly in the exploration of heterogeneous carbonate reservoirs.
We examine each method considering the degree of prior information required, the computational overhead and the applicability to the reservoir characterization workflow. Our results indicate that the first method provides a good history match to the observed PTT data and is suited for the early exploration phase of the reservoir. However, the parameters must be convolved with the smaller scale data to produce multiple realizations away from the implausibly smooth most-likely solution. The observed PTT data lies within the ensemble of predicted pressures in the EnKF and Langevin-based methods which are both applicable to probabilistic workflows where uncertainty is treated rigorously. However, EnKF seems to be computationally more efficient than the Langevin approach.
Quantitative Integration of Time-Lapse Seismic Derived Information in a History Matching Procedure
Authors: Souza R. M. , Munerato F. P. , Schiozer D. J. 
Published: September 2011

Abstract
The use of production data to increase the reliability of production forecasts of a field is limited, especially in early development, when there are fewer observed data and then a significant uncertainties raise. An alternative to improve the quality of the model is the use of saturation and pressure maps obtained from time-lapse seismic. The incorporation of this information has not been explored in reservoir engineering studies and has great potential for reducing uncertainties caused by lack of information and complexity of oil fields. Recent work indicates that the best way to use this information to calibrate reservoir numerical models is to convert it into saturation and pressure. Thus, this study aims to derive, from time-lapse seismic attributes, distributions of saturation and pressure in oil reservoirs.
This paper presents a methodology to estimate saturation and pressure maps simultaneously through an inversion process constrained by engineering data. These maps information are then combined with production data in a global objective function aiming at improving an integrated history matching procedure. This methodology is applied in a modified model of the "Namorado Field" (Campos Basin, Brazil), that has geological faults and high permeability channels. It was also necessary to apply an empirical modeling of the rock bulk modules regarding pressure variations, which improved the reservoir acoustic sensitivity and allowed, together with the engineering data constraints, to derive these maps. It was possible to identify the main structures that can influence fluid flow trends in the reservoir and significantly reduce time consuming and increase the reservoir behavior predictions reliability.
As major contributions of this study are the development of a methodology able to provide saturation and pressure trends regarding time-lapse information and engineering data constraints to the overall process and its quantitative application in an integrated history matching procedure.
Merging Coiled Tubing and Swellable Packer Technologies
Authors: Brooks Robert T. 
Published: September 2011

Abstract
For a number of years one of the main areas being developed has been multilateral wells to better access the reservoir. One of the greatest challenges in operating an efficient multilateral well is having control of where any water production is coming from. Effectively managing produced water can bring obvious benefits to the economics of a well. One tool that has not been fully exploited for this type of application is swellable packers. Coiled Tubing and Swellable Packer technologies were recently combined on a land-based operation in Holland to successfully isolate a water-producing leg of a well lateral. The operator asked for a proposed completion solution after a previous attempt to isolate the lateral had proved unsuccessful.
The proposed solution was designed to straddle the lateral entry/exit with a scab liner, isolated and anchored at either end by water-swellable packers. The straddle was required to seal inside the main bore casing and withstand a differential pressure at well operating temperatures. Swellable packers were selected from the various proven openhole isolation devices available to the industry to provide the zonal isolation required in the multi-zone intervals. This was the first swellable straddle completion in Holland in a watered out, commingled gas environment in which isolation would be contained solely by swellable packers.
The water producing lateral was successfully straddled using two water swellable packers run with base pipe between the two packers. In this application the Swellable Straddle was deployed in conjunction with an additional mechanical packer to anchor the straddle whilst the swelling process in the aqueous environment took place. A subsequent intervention with coiled tubing and a resettable Inflatable Test Packer confirmed the straddle had successfully sealed and had isolated the water producing lateral.
This paper presents a solution to the challenges of isolating laterals using swellable packers and coiled tubing, and how to verify that the junction has been successfully isolated.
Wettability Alteration at Optimum Fluorinated Polymer Concentration for Improvement in Gas Mobility
Authors: Fernandez R. , Fahes M. , Zoghbi B. , El Cheikh Ali N. 
Published: September 2011

Abstract
In gas condensate reservoirs, deliverability starts to decrease when retrograde condensation occurs. As the bottom-hole pressure drops below the dew-point, gas condensate and water build-up impede flow of gas to the wellbore. In order to stop the reduction in productivity, many publications suggest wettability alteration to gas-wetting as a permanent solution to the problem. Previous simulation work suggests an "optimum wetting state" to exist where maximum gas condensate well productivity is reached. This work has direct application in gas-condensate reservoirs, especially in identifying the most effective stimulation treatment which can be designed to provide the optimum wetting conditions in the near-wellbore region.
In this work, we aim to show the existence of such an optimum state of wettability that result in maximum gas mobility and in an increase of the relative permeability curves. We present an experimental study on Berea sandstone rocks treated with a fluorinated polymer and investigate the optimum fluorinated polymer concentration that would alter the wettability to intermediate gas-wet. Different experimental techniquesincluding flow tests and spontaneous imbibition are conducted to examine the effect of treatments on wettability. Interaction between rocks and the fluids is studied using a MicroCT scanner.
The studies in this area are important to improve the productivity of gas condensate reservoirs where liquid accumulates, decreasing production of the well. Efficiency in the extraction of natural gas is important for the economic and environmental considerations of the oil and gas industry. Wettability alteration is one of the newest stimulation methods proposed by researchers, and shows great potential for future field applications and further research studies.
Incorporation of 4D Seismic in the Re-Construction and History Matching of Marlim Sul Deep Water Field Flow Simulation Model
Authors: de Brito Daniel Ullmann , Caletti Luciano , de Moraes Rafael Jesus 
Published: September 2011

Abstract
Seismic data incorporation in reservoir simulation models history matching (HM) studies has been continuously growing. 4D seismic data, in contrast with well production data, can provide a very good scenario of fluids arrangement along reservoir. In this work we describe how 3D and 4D seismic data gathered in acquisitions performed in Campos Basin was incorporated in Marlim Sul deep water field geological model reconstruction and in assisted HM (AHM).
It is taken advantage of both 3D and 4D seismic data in several stages of the study, for instance, in the construction of a new porosity – most influential in impedance – model by using a methodology based on the inversion of synthetic seismic (calculated by petro-elastic model) in porosity through an optimization process that aims to reduce the difference between observed and synthetic impedance, and when defining influential parameters based on fluids displacement registered by seismic signal, by using a technique based on the creation of transmissibility multipliers parameters regions that considers the fluids displacement shown in 4D signal. Another relevant point is the use of information from reservoir and 3D seismic data when weighting the 4D data in the objective function.
Combining the above mentioned techniques with the knowledge of the field – supported by the 3D seismic data – which allowed, for instance, identification of faults – where fault transmissibility multipliers were used as parameters in the HM process – a fairly good agreement on the observed well and seismic production data was achieved.
HM studies using AHM tools have been shown a much more time-efficient technique when compared to manual HM. The incorporation of 4D seismic data can considerably improve the HM quality by improving the reservoir description, once it increases the ability of describing fluids arrangement and pressure distribution. The techniques successfully applied in the Marlim Sul field HM support these conclusions.
Effective Well Placement and Trajectory Planning Approach through Collaboration Environment Tools
Authors: Al-Baqawi Ahmed M. , Al-Naim Hamad A. , Araque Arcides J. , Habbtar Ali H. , Ismail Menhal A. , Al-Kanan Adnan A. , Al-Utaibi Abdullah A. 
Published: September 2011

Abstract
Well placement and trajectory planning is a critical and challenging task in any Oil & gas field development plan. This has always been a task that requires a strong team effort to ensure the best predictions and estimations are performed to penetrate the desired reservoir development zones and achieve the expected production rates. Numerous iterations with a high level of interaction between Reservoir Management, Reservoir Simulation, Reservoir characterization, Geology and Geophysics are expected when planning a new well or a difficult sidetrack.
Each member of the well planning team has his/her own environment along with dedicated standalone software tools. Today, with the introduction of the Intelligent Field center to provide the collaboration environment for the involved expertise along with the proper tool to offer a strong integration of different data sources in a single software environment that allows a team of field geologist, geophysicist, reservoir and simulation engineers to evaluate the best prospects available in planning any new drilling opportunity, furthermore the team is able to choose the best well azimuth and inclination based on reservoir properties and performance.
This paper discusses a newly integrated well planning process utilizing a collaboration environment to review seismic, well log cross sections, historical production and simulation predictions enabling the well planning team to place their gas wells using a reservoir 3D viewer, incorporating the reservoir simulation model, and run various cases and sensitivities. In This paper, full examples illustrate how effective software integration can optimize the time required to plan a new well without overlooking any important aspect. In addition, the paper discusses the lessons learned from this experience and how this approach changes the mechanism of an integrated well planning team working together.
Construction Project for the First Dendritic Well Offshore in Brazil
Authors: Guimaraes Zacarias , Duque Luis , Almeida Victor , Barros Robledo , Teles Carlos A. , Paixao Luiz , Pedroso Carlos 
Published: September 2011

Abstract
The application of the recent technique of creating lateral tunnels by acid jetting into the formation has been a topic of discussion in Petrobras because it is a reliable, fast an economic way to increase the well productivity index in complex geology carbonate reservoirs.
In order to evaluate this technology, a pioneer intervention was carried out in the Garoupa field on a typical offshore well in Brazil. The objective was to simultaneously increase oil production and decrease water cut, by creating lateral tunnels at specific points in the well open hole section. The number of tunnels created as well as their positions were defined as a function of both, oil and water saturation profiles. Also mineralogical and geomechanical analysis were conducted as well as rock dissolution on different hydrochloric acid concentrations, in order to determine tunnel perforation rate and hole stability,
The application of this technology has generated important incomes to the oil operator and the same technique could be also applied on other different scenarios.
This paper illustrates the process from selecting the well candidate, premilary laboratory tests, treatment designs and field operation to after treatment well production results.