bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methodology for Production History Matching of Petroleum Fields Utilizing Logging Saturation Data
Authors: Grecco C. B. , Schiozer D. J. 
Published: June 2014

Abstract
In the production history matching process, the reservoir simulation model is modified in a way that it becomes consistent with production data, keeping the observed restrictions of the geological characterization phase. This technique is limited, mainly in mature fields, when the production history is not reliable, or in the beginning of production, when there are only a few observed data and uncertainties are higher. The development of new saturation data acquisition tools, such as 4D seismic and TDT/TDM logging tools helped to overcome some difficulties in the geologic model construction phase but the great challenge is how to use this data in a way to improve the petroleum production.
History matching methodologies integrated with saturation data from 4D seismic are available in literature but no publications that utilize saturation data obtained from well logging were found. The advantage of the logging tools is the data accuracy but, on the other hand, it is limited to a few feet around the wells. The main objective of this project is to integrate the traditional history matching process with logging saturation data, developing more reliable simulation models and production forecasts. The saturation data is utilized as a new parameter to be matched as well as an auxiliary tool to help to determine critical regions which will be modified. An assisted history matching methodology, utilizing saturation data, streamlines and an optimization algorithm is proposed.
The proposed methodology is applied to a synthetic reservoir model. Parameters of the process are studied and detailed, finding the best way to use the data. The model is also history matched with no saturation information and predictions of the matched models are compared, showing the benefits and restrictions of the new methodology.
Production Strategy Optimization Using Genetic Algorithm and Quality Map
Authors: Maschio Célio , Nakajima Lincoln , Schiozer Denis J. 
Published: June 2014

Abstract
The definition of a production strategy is one of the most important tasks in reservoir management, since it influences projects attractiveness. However, the process to define variables such as well placement, number and type of wells and operational conditions is time-consuming and it demands high computational effort. The use of an optimization algorithm to achieve a good solution can be very valuable to the process but it can also lead to an exhaustive search, demanding a great number of simulations to test many possibilities.
In order to minimize the number of combinations (number of wells and positions), it is proposed the use of the quality map, that is a two dimensional representation of regions with production potential in a reservoir, as a criteria to allocate the wells.
The optimization algorithm used in this work is the genetic algorithm (GA) which is a method based on natural evolution process. The main characteristic of GA is the ability to work in a solution space with non-smooth and non-linear topology, where the traditional methods generally fail.
The methodology proposed in this work is used to optimize production strategies in a realistic reservoir model, defining the number and position of production and injection wells, and the production/injection flow rates. The number of individuals in a population and the number of generations were also varied to evaluate the efficiency of the algorithm.
Results showing the performance of several optimization processes are presented. The influence of the GA parameters control are analyzed and compared.
Minimizing Risk of Gas Escape in Gas Storage by In-Situ Measurement of Gas Threshold Pressure and Optimized Completion Solutions
Authors: Ostrowski L. , Ülker B. 
Published: June 2014

Abstract
Underground gas storage operations and CO2 sequestration in aquifers relay on both proper wellbore construction and sealing function of the cap rock. The potential leakage paths are the migration along the wellbore due to poor cementation and flow through the cap rock. Although 60% of the gas storage wells undergo a costly work-over process to remedy missing cement seal only few operators consider appropriate completion solutions to minimize the risk of losses due to leaky annulus space. The leakage through the cap rock can occur by diffusion and two-phase migration. Modeling of two-phase flow requires the determination of the functional relationship between capillary pressure, relative permeability and saturation. The injected gas moves to the top of the formation below the cap rock due to gravity and density differences. Therefore, the ability of a cap rock to seal fluids is another key parameter for the successful gas storage or long term disposal of CO2 in addition to a proper completion. Capillary pressure data, which are critical for exact prediction of gas leakage through the cap rock are seldom available and yet necessary. In-situ method of gas entry pressure was developed and successfully implemented to help reducing uncertainties in gas leakage predictions. Zonal isolation of cap rock is performed followed by exchange of wellbore liquid by gas. Constant rate injection of gas is then conducted to determine the gas entry pressure into a fully water saturated cap rock. Simulations were performed using this gas threshold entry pressure to investigate the gas leakage amount through the cap rock and along the wellbore for both natural gas and CO2 storage models. It was shown that the uncertainty of predictions could be significantly reduced by using data obtained from in-situ gas threshold determination. Recommended completion solutions for both types of storage operations are presented, which minimize a risk of uncontrolled gas escape.
Selecting an Optimal Field Development Strategy for the Vankor Oilfield Using an Integrated-Asset-Modeling Approach
Authors: Antonenko D. A. , Pavlov V. A. , Surtaev V. N. , Sevastyanova K. K. 
Published: June 2014

Abstract
Two fundamental advances in field development planning took place recently in the last decades. First advance is of an evolutionary type, which allows building large and detail reservoir models and is directly conditioned by the computation capacity growth. Another advance arises from a new revolutionary concept in the field development system design, called the integrated approach. Such approach means that the field development optimization should combine reservoir, well and surface facilities modeling to allow the field development managing based on maximizing technical and economic performance.
The presented study describes an approach to selection of optimal strategy for the Vankor field development. Vankor is a new oil field located in poorly explored area remote from the infrastructure and services. At the time this article was prepared, there were no production wells and surface facilities. Since there are numerous alternatives to optimize field development, the special interest is paid to the field development planning.
Based on the integrated digital model of the Vankor field, the commingled development of two productive zones was studied for the purpose of selecting lifting method, gathering and injection system.
Updating Fault Transmissibilies in Simulations by Successively Adding Data to an Automated Seismic History Matching Processes: A Case Study
Authors: Edris N. R. , Stephen K. D. , Shams A. , Macbeth C. 
Published: June 2014

Abstract
Reservoir management may be improved if the present state of the field is known and if changes may be predicted. The former requires information about current fluid sweep and pressure changes while the latter requires accurate reservoir description and a predictive tool such as a simulation model. With this information, important decisions can then be made including facility maintenance and well optimisation. In some fields, faults control the flow patterns and the update of the transmissiblities has great impact on matching of fluid saturations and pressure to time-lapse seismic (4D) or production history observations. We present an automated history matching method that updates fault transmissibilities by matching 4D seismic predictions from the simulations to observed data. We investigate the impact of successively updating faults by adding new data to our observed dataset and compare this to a single history match where all data is used. We demonstrate the method by applying it to the UK Continental Shelf (UKCS) Schiehallion reservoir. Using an upscaled version of the operator's model, we consider fault transmissibilities as uncertain parameters. Our results show a good match to the observed seismic attributes and dynamic well data with significant improvement to the base case. The best results occur when early data is used in short simulations first as we learn about optimum parameter values and identify the most important parameters. Later data may be added for fine tuning or to explore new parameters.
Interpretation of an Unusual Bubblepoint Pressure Variation in an Offshore Field
Authors: Nasrabadi Hadi , Firoozabadi Abbas , Esposito Rogerio Oliveira , Vieira Alexandre Jaime Mello 
Published: June 2014

Abstract
Bottomhole samples were obtained from eight different wells in an undersaturated offshore oil field. A total of 25 samples were obtained from these wells at various depths. The well temperature data show considerable gradient in both the horizontal and vertical directions. Bubblepoint pressure measurements reveal unusual variations. Some of the wells have a gradual increase in bubblepoint pressure with depth. Some other wells show a decrease after increase and some wells a decrease with depth. The decrease in bubblepoint pressure with depth is the common behavior. There are also vast variations in measured composition, oil density, and the molecular weight of last fraction in different wells.
These variations can be due to compartmentalization and barriers or could be due to gravity, molecular diffusion, thermal diffusion, natural convection or reservoir filling history. Identifying the cause of the variations is important especially in offshore fields. Reservoir compartmentalization can significantly affect the field development plan and the reservoir management.
We have made an analysis of the variations in composition and bubblepoint pressure due to all the above mechanisms in the reservoir with no barriers. The results are different than the observed variations. The reservoir filling effect cannot also explain the large measured variations since calculated mixing time for the fluid is much less than the age of the reservoir. Based on our analysis we conclude existence of barriers in certain parts of the reservoir which explains significant changes in composition and bubblepoint pressure. We also show that thermal diffusion and natural convection can result in an unusual increase in bubblepoint pressure with depth.
To the best of our knowledge this is the first report of this unusual trend in bubblepoint pressure and its interpretation based on the effects of gravity, molecular diffusion, thermal diffusion, natural convection, and reservoir filling history.
Modification of Temperature Prediction Model to Accommodate I-Well Complexities
Authors: Almutairi Fajhan H. , Davies David R. 
Published: June 2014

Abstract
Inflow profiling has proved to be a major application of Distributed Temperature Sensor (DTS) systems. The real-time, downhole temperature data is analyzed by matching the measurements with values predicted by a well thermal model; reducing the uncertainty in the well's production parameters (e.g. permeability, water cut). The accuracy of the resulting inflow profile depends heavily on the accuracy of the temperature prediction model.
Existing wellbore fluid temperature models were developed for conventional wells. This paper focuses on the modification of these temperature models for application to intelligent completions equipped with DTS & Inflow Control Valves. A published temperature prediction model was modified to analyze an intelligent well's geometry i.e. distributed inflow into an annulus, fluid mixing at multiple points etc. The new model was used to demonstrate the effect of water production in an oil and water production environment on the valve's mixing temperature and the tubing's temperature profile.
Our results show that the temperature profile and the mixing valve temperature are over-estimated by current models that represent the inflow of each zone of a multizone I-Wells by a single inflow point. As expected, increasing the number of inflow points within each zone reduces this discrepancy.
This over-estimation reduces the accuracy of inflow profile analysis calculated from the DTS data. Changes in valve temperature in single phase production in a multi-zone intelligent well can be used to indicate the fraction of the zone that is main contributor to zonal inflow e.g. a higher temperature indicates the lower portion on the pay zone is the main contributor and vice versa. A sensitivity study showed that the valve temperatures experience a unique profile depending on which zone is producing water.
The Zatchi B Heavy Oil Reservoir Development: The Unique Challenges of the TAML6 Multilateral Well ZAM-408ML
Authors: Tealdi L. , Baldini D. , Baioni A. , Isella D. , Riccobon L. , Okassa F. , Obondoko G. , Itoua-Konga F. , Malonga H. , Rampoldi M. 
Published: June 2014

Abstract
The Zatchi field, located in the Lower Congo Basin offshore, is a multi-layer reservoir of Cenomanian/Albian age operated by Eni Congo in partnership with Total Congo.
The "Zatchi B" reservoir is a 30 m thick sand characterized by a large accumulation of heavy and highly viscous oil (15° API, 1000 cP) trapped in the marine-transgressive sands of the "Gres de Tchala" formation.
Three aspects make the successful development of such reservoir an extreme challenge: the presence of both bottom water and a gas cap, the very low reservoir pressure, the very high viscosity of the oil. As a matter of fact, over the 19-year life of the field, only three wells were put in production from the "B" layer, with not satisfying results due to the heaviness and viscosity of the oil and the severe problem of gas coning and cresting.
The multilateral technology generally allows increasing the reservoir exposure with fewer wellbores, reducing and spreading the drawdown along the drains reducing the potential for coning. For this reason, in order to improve the reservoir drainage reducing times and costs, the layer B was selected as the optimal candidate for the first multilateral well in the Congo basin: well ZAM 408 ML.
This paper will review the Zatchi B reservoir history and development challenges with a focus on the multilateral well reservoir modeling, the TAML6 completion and ESP artificial lift design. An innovative system for the ZAM-408ML ESP PCP efficiency improvement will be also presented. Furthermore, the challenges encountered during the operations in terms of reservoir properties sampling, operations geology, drilling, completions and production will be discussed in detail.
Enhanced Reservoir Contact using new LWD Technology in Thin Channel Sands
Authors: Hashem Mohamed , Miller Randy , Dossari Saleh M. , Butt Parvez , Hassan Raza , Hussain Sadiq 
Published: June 2014

Abstract
The drilling of development wells in sand stringers involves very thin and sinuous targets. These targets are the channel sand stringers and contain a substantial amount of hydrocarbons. Optimal well placement is a requirement for these very thin reservoirs in order to drain them in a cost effective manner.
Conventional well placement has met with limited success in stringers and the production can be expected to be low from these stringers. A technology driven approach of detecting the formation changes early during drilling was needed. These changes, when addressed, can be translated into maximizing reservoir contact, limiting well-bore tortuosity thus enhancing optimal production.
Due to the uncertainty that is inherently present in the distribution of the channel sands, the prediction of the azimuth of channel meander can now be confidently solidified with new deep and directional electromagnetic measurements (EM) tool. This is a technology which uses directional EM through the use of tilted and transverse current-loop antennas. By detecting the upper and lower conductive shale boundaries the wells have been steered in this very challenging environment of channel sands.
This technology has proven to be a major success in the development of the sand stringers by improving the Net to Gross ratio by more than 50% and hence the longevity and producabilty of the stringer wells as compared to conventional well placement LWD techniques.
The Benefits of Integrated Asset Modeling: Lesson Learned from Field Cases
Authors: Rotondi M. , Cominelli A. , Di Giorgio C. , Rossi R. , Vignati E. , Carati B. 
Published: June 2014

Abstract
Nowadays oilfield development has become more technically and economically challenging and a high degree of interdisciplinary interaction is needed to have an effective and efficient management of the field. The achievement of this goal is made possible only if all the different resources of an organisation work together sharing the same reservoir model. Indeed, the main breakthrough behind Integrated Asset Modeling (IAM) is to combine reservoir, production and surface engineering modeling into an asset management tool that allows the simulation of the whole oilfield system. Though the need and the benefits of IAM were already recognised during the seventies, it is only in the last decade that software tools required to perform integrated production simulation have become available. Coupling dynamic reservoir and surface facility models into a single integrated model may address the following issues: pressure interaction between the surface and the subsurface; mixing of different fluids and flow assurance; accounting for facilities constraints; and identification of system bottlenecks and backpressures. In this way, unnecessary drilling can be avoided, new opportunities can be discovered, optimal artificial lift programs can be implemented to meet production targets.
In this paper the state of the art of IAM tools is reviewed, with emphasis on the solution implemented in our company. Benefits and criticalities are then discussed on the basis of three cases, including integrated models for regional gas production systems, deep water mixed oil-gas assets and gas lifted reservoir. Indeed, it has been noted that integrated surface-subsurface modeling will have a critical impact on field management by offering increased accuracy in forecasting reservoir behaviour and maximising the recovery factor at minimum cost.
Influence of Geological Features on Well Test Behavior
Authors: Mijinyawa A. , Gringarten A. C. 
Published: June 2014

Abstract
Well test analysis is used routinely to determine average reservoir properties with the help of relatively simple interpretation models. Identification and quantification of geologically complex reservoirs is also possible, but requires complex interpretation models often not available in the literature.
This paper investigates four common complex reservoir geometries using numerical simulation, namely: a semi-infinite channel with non-parallel boundaries; a T-shaped channel; a meandering channel with different well locations and meander angles; and a pinch-out boundary. It is shown that all these configurations yield characteristic behaviors in a well test, which can be analyzed as combinations of simpler, known behaviors. A semi-infinite channel with non-parallel sides appears as two sequential wedges; a T-shaped channel (which can be used as a simplified representation of a distributary or meandering channel system) is equivalent to two linear channels, either perpendicular to each other or positioned one after the other. The location of a well in a meandering channel affects the early-late and middle-late time behavior of the pressure and pressure derivative responses in a well test but not the late time behavior. Finally, the well test response of a pinch-out boundary is similar to that of a single sealing fault, but with a longer transition after the derivative main radial flow stabilization.
The overall conclusion is that complex geometries are revealed on the well test pressure derivative by a non-standard transition between the main radial flow derivative stabilization and the late time boundary behavior. This transition gives access to quantitative information related to the complex geometry that is usually ignored in routine well test interpretation.
Simulation of Transient Cuttings Transportation and ECD in Wellbore Drilling
Authors: Costa Suzana Santos , Stuckenbruck Sidney , da Fontoura Sergio A.B. , Martins André Leibsohn 
Published: June 2014

Abstract
Among the costs considered on an oil field exploration, the drilling process related ones constitute a significant share. Consequently, the focus on the removal of cuttings generated by the drilling process, or the hole cleaning operation, is essential.
This operation remains a critical issue in the drilling of high inclination-wells, since the cuttings tend to deposit themselves due to gravity's action, forming a bed in the annular space formed between the drill string and the casing. When this bed takes a sizable fraction of the annular space, it becomes responsible for many problems that appear on the drilling stage, such as premature bit's exhaustion, low rates of penetration, formation fracture, stuck pipe, fluid flow interruption, etc. If this situation is not treated properly, it may cause the loss of the well.
Once the phenomena affecting cuttings transportation, bottom hole pressures and ECD prediction are time dependents, a transient model for the whole trajectory of the wellbore was build. This model can predict the pressures developed in the annular due to the phenomenon that occurs in the drilling process, like bed height increase/decrease, drillpipe movement (surge and swab), increase in the amount of solids caused by rock instability problems and operational parameters changes (increase/decrease in ROP and fluid flow rates).
This paper objective is to present a new transient methodology to simulate the cutting's carrying and annular pressure evaluation on a transient approach and to present some examples of this model. These examples will showcase bed height, cuttings concentration, pressure and ECD curves along time and over the whole trajectory, due to changes in the parameters mentioned above.