bluuebunny/crossref_metadata_2025_split huggingface dataset:
More Rapid and Robust Multiple History Matching With Geological and Dynamic Uncertainties: Heavy-Oil Case Study
Authors: Poncet J. , Vincent G. , Inizan M. , Henriquel P. , Jannes P. 
Published: December 2007

Abstract
The generation of reservoir simulation models that match field production data has been and is still a long-time industry challenge, not only for the time spent on history matching studies but also because of the non-uniqueness of the solution. This paper presents a new approach called "Hybrid Models" to accelerate this process and get more realistic history match models. Hundreds of stochastic possible geological models are produced and tested in regard to the dynamic data. The Hybrid model is a composite geological model, not only constrained by the initial well data but also with selected parts of the first realizations matching around some wells. This technique allows a relatively quick history matching process and results in a series of matched geological models.
This process was applied in part of a heavy oil field (14 horizontal wells in fluvial reservoirs were considered), after 3 years of production. The objective was to explain and reproduce the high water-cut, oil rates, GOR and bottom-hole pressures in this part of the field. A complete uncertainty workflow was applied with sedimentological and petrophysical uncertainties as well as fluids and dynamic uncertainties. Results showed that static uncertainties were essential to get a coherent match and "Hybrid Model" technology was applied with success.
The Hybrid model technique gives several matched geological models. All models have been carried out through forecasting keeping the present development plan, evaluating the potential impact of remaining static uncertainties. Dynamic uncertainties were also considered on one geological matched model. Several combinations of dynamic parameters have been computed to keep a match. Corresponding models have been transferred through forecasting. Final conclusions were that at fixed development plan, dynamic uncertainties are more to be considered and combined for the forecast than static ones.
The use of the "Hybrid models" technique and the integration of static and dynamic properties as matching parameters have been shown to be efficient to produce accurate multiple production history matched models. From those models, it has been possible to quantify the remaining uncertainties in terms of future production and to propose new developments.
Utilizing Geosteering in Horizontal Wells to Maximize Value in Mature Fields, Central Sumatra, Indonesia
Authors: Moestopo Hendar S. , Jacobs Gary W. , Nur Hasyim M. , Reinhold Mark R. , Pramudyo Yuni B. , Purwanto Komar E. 
Published: December 2007

Abstract
Geosteering techniques are used to maximize exposure of well bore to pay zones. Accurate well bore placement is vital to the success of horizontal well drilling. The last 3 years has seen 50 horizontal wells drilled by PT Chevron Pacific Indonesia in the Central Sumatra Basin of Indonesia. We have found that geologic uncertainty is the largest risk to successfully drilling these wells. Small faults that cannot be accurately mapped with existing seismic and with displacements of 15 feet or less are commonly found and present a challenge to stay in the target. Obviously, the loss of objective section reduces the effective drilled lateral footage of a well and thereby affects productivity.
One key to achieving desired lateral footage drilled is understanding the response of resistivity and gamma ray while drilling. That, combined with cuttings analysis, rate of penetration (ROP), and other drilling parameters, permits the response and reaction to geologic uncertainty to be managed more effectively.
Monitoring these data as acquired in real time with reference to pre-job modeling, provides the key elements for intelligent decision making on trajectory decision.
This paper will share specific examples of the challenges we have faced and how we recognize and react to geologic uncertainty while drilling.
Formation Evaluation in Thin Sand/Shale Laminations
Authors: Minh Chanh Cao , Joao Isabel , Clavaud Jean-Baptiste , Sundararaman Padmanabhan 
Published: December 2007

Abstract
Formation evaluation in thin sand-shale lamination seeks first to determine sand resistivity, volume fraction, and porosity. Afterwards, saturation and volume are simple Archie applications. Resistivity anisotropy techniques can provide estimates of sand resistivity and volume fraction, but good results depend on the choice of the anisotropic shale point. The same shale point should be used in the determination of sand porosity. Difficulties will arise when anisotropy is not caused by sand-shale laminations, when no sand-shale point exists, or when the nearby thick sand-shale is not representative of the sand-shale in the laminations. In producing fields that have undergone several waterfloods, water resistivity is often unknown in the swept thick sands and might not be representative of the water in the unswept thin sands.
As discussed previously, NMR offers useful insights into the petrophysics of thin sand-shale laminations. Typically, 1D high-resolution data is acquired to estimate sand volume fraction, porosity, and permeability, and 3D fluids data is used to evaluate the hydrocarbon type and content in the thin sands. However, shallow depth of investigation, slow logging speed, and sometimes unfavorable signal-to-noise ratios limit the applicability of the NMR technique.
In this paper we first demonstrate the variability of sand resistivity, volume fraction, and porosity output depending on the input parameters. Next, we show the complementary aspects of the resistivity anisotropy and NMR techniques. Since several are the same or determined independently, using both datasets ensures more plausible results in thin beds than either stand-alone technique could provide. Field examples of a straightforward case with a well-defined anisotropic shale point, as well as a difficult case with multiple shale points, are used to demonstrate the new workflow. In general we see improvements in the estimation of the hydrocarbon in place; however, not all thin beds offer large hydrocarbon volumes.
A New Approach for Interpreting Pressure Data To Estimate Key Reservoir Parameters From Closed-Chamber Tests
Authors: Rahman N. M. A. , Santo M. S. , Mattar L. 
Published: December 2007

Abstract
A new technique for analyzing and modeling the pressure data from both flow and buildup periods in closed chamber tests (CCT) has been developed. It can be used for estimating the key reservoir parameters such as reservoir pressure, permeability and skin.
There are two aspects of the proposed approach - straightline analysis and modeling. A novel approach is taken to develop the analytical solutions and procedures for both liquid and gas wells. Approximate solutions for the early-time and late-time pressure behavior are derived from the rigorous solution and are used for developing the basis for the straightline analysis. A derivative function is utilized to ascertain if the data contains any portion of reservoir-dominated flow. Two synthetic data examples are presented to illustrate the process.
Important contributions made in this study are as follows:
The analysis procedure is simple enough to implement in a spreadsheet, but is more accurate than the currently available methods. Calculating influx rates during the drawdown period is not an essential part of the analysis or modeling. Thus, any noise in the data would not aggravate the accuracy of calculations. The complete analytical solution for modeling the entire CCT data will allow one to investigate possible test durations for CCTs, and also to refine the parameters determined from approximate analyses.
The presented technique is also applicable for analyzing drillstem test (DST) data, as long as the flowing fluid does not reach the surface.
Experimental Investigation of Emulsion Stability in GOSPs, Part II: Emulsion Behavior
Authors: Al-Ghamdi A. M. , Noïk C. , Dalmazzone C. , Kokal S. 
Published: December 2007

Abstract
This paper presents an experimental study performed jointly by IFP and Saudi Aramco to characterize the stability of emulsion samples collected from different Saudi Aramco Gas Oil Separation Plants (GOSPs). The first part of the study1 (SPE 106128) focused on the analyses of separated phases. Many techniques (differential scanning calorimeter, Karl Fisher coulometer, rheology, optical microscopy, cryo-scanning electron microscope) were applied to analyze and characterize the separated phases: crude oil, emulsion and free water. In the second part of this study, the stability of residual emulsions was investigated against several chemical demulsifiers by using classical bottle tests and an automated, vertical-scan, macroscopic analyzer (Turbiscan). This instrument is used to obtain kinetics of separation of concentrated and opaque dispersed systems such as emulsions, suspensions and foams. Interfacial tension measurements were also made to obtain information about the interfacial behavior of samples including viscoelasticity properties of the film. The results of transient emulsion separation experiments provide some useful insights into their behavior, stability and tightness. The study highlights the main physicochemical parameters responsible for the varying tightness of these emulsions, and provides recommendations to optimize their treatment costs and resolve emulsion issues in the GOSPs.
Seismic-While-Drilling Operation and Applications
Authors: Dethloff Morten H. , Petersen Steen Agerlin 
Published: December 2007

Abstract
Even though the seismic while drilling (SWD) tool is coupled to the Bottom Hole Assembly like a standard tool its operation and setup is far from standard. It requires proper planning ahead of the acquisition and a proper understanding of the full potential of the data to make this service a powerful drilling decision tool.
The SWD full value can only be attained through a holistic approach. This paper will discuss the necessity of effective communication and planning for the successful outcome of a complex SWD operation. A proper time line, project management and focus on all parties involved are essential for the SWD operation to be successful without disturbance of the drilling operation.
SWD has the potential of producing a real time update to the geological model. It offers improved resolution and more accurate depth conversion. Due to the flexibility of source/receiver positioning several other geophysical applications will be possible. Salt flank and fault plane imaging are two examples of these applications. The challenges encountered for alternative source/receiver positions will be analyzed.
The SWD service has the potential of becoming a key drilling decision tool. The necessity of applications, resources, cooperation and decisions will be analysed. The need for developing a team effort and common set of tools is described. Uncertainties in data quality coupled with surface seismic limitations lead to a risk management process. This requires a proper understanding of the workflow of seismic processing and reservoir properties to minimize time for data preparations prior to evaluation and decisions.
Developing a Holistic Global Approach to Asset Management
Authors: Cabrera Benito , Musri Daniel , Selva Carlos , Lardone Carlos 
Published: December 2007

Abstract
The oil and gas industry has made great strides in the individual applications of the intelligent oil field technologies. However, the "big prize"—the integration of the individual pieces into a comprehensive solution that transforms work processes to achieve step-change efficiencies in development and operations—has been more elusive.
This paper chronicles the work and resulting methodologies of the international unit of an oil company as it implements an open platform asset management solution in a newly producing field, and adapts and transforms related processes to develop a template for re-use in assets anywhere in the world to anticipate and pre-empt problems—essentially realizing the promise of the intelligent oil field.
This holistic approach begins at the static model and includes reservoir simulation, surface facilities, processing plants, through economics, thereby making available the comprehensive technical picture to all geoscience and engineering professionals, and providing the basis for sounder economic decisions.
The development of this methodology is possible because of the ability to exploit these factors:
A relatively new field coming online, with limited production problems, provides a solid starting ground on which to develop the methodology. Implementation of the most current asset management solution, based on an open platform that will allow the integration of other technology for the full spectrum of upstream applications, from static model through economics, provides the right technology. A commitment from the operator to not simply implement the solution, but to dedicate the resources to assess and analyze the workflow and processes, and combine the expertise of the operator, service company and consultants to develop methodologies that can be applied globally, to any operations.
Experiences with Streamline-Based Three-phase History Matching
Authors: Oyerinde Adedayo , Datta-Gupta Akhil , Milliken William 
Published: December 2007

Abstract
Streamline-based assisted and automatic history matching techniques have shown great potential in reconciling high resolution geologic models to production data. However, a major drawback of these approaches has been incompressibility or slight compressibility assumptions that have limited applications to two-phase water-oil displacements only. Recent generalization of streamline models to compressible flow has greatly expanded the scope and applicability of streamline-based history matching, in particular for three phase flow. In our previous work, we calibrated geologic models to production data by matching the water-cut and gas/oil ratio using the generalized travel time inversion (GTTI) technique. For field applications, however, the highly non-monotonic profile of the gas/oil ratio data often presents a challenge to this technique. In this work we present a transformation of the field production data that makes it more amenable to GTTI. Further, we generalize the approach to incorporate bottom-hole flowing pressure during three-phase history matching. We examine the practical feasibility of the method using a field-scale synthetic example (SPE-9 comparative study) and a field application. The field case is a highly faulted, west-African reservoir with an underlying aquifer. The reservoir is produced under depletion with three producers, and over thirty years of production history. The simulation model has several PVT and SCAL regions and over a hundred thousand cells. The GTTI is shown to be robust because of its quasi-linear properties as demonstrated by the water-cut and GOR match for a period of 30 years of production history.
Determination of Connected Volume and Connectivity From Extended Tests in Compartmentalized and Layered Reservoirs
Authors: Larsen Leif , Straub Richard Benjamin 
Published: December 2007

Abstract
Tests from compartmentalized and layered reservoirs can be difficult to interpret for connected volume and connectivity. The problem comes from the timing of the response from "primary" and "secondary" drainage volumes, either as well-compartment and distant compartments or as dominating and dominated layers, with reduced communication between volumes posing more challenges. Although simple material balance considerations can be used to estimate the total volume, the difficulty lies in determining individual volumes and connectivity. The term "connectivity" is used here in a broad sense to cover effects of differential depletion, a critical element of recovery from compartmentalized reservoirs.
Results from the paper are applied to both pressure transient tests and to production data (rate data) analyses based on decline curves and type curve methods. For pressure transient tests the distinction between extended buildup behavior and single-rate extended drawdown behavior, e.g., based on deconvolution data, is of particular importance, with different boundary characteristics picked up from the two data types. For production data analyses the main challenges are associated with effects of differential depletion and the concept of boundary dominated flow both for closed systems and for systems with pressure support or influx. Similar challenges apply to compartmentalized systems produced under simple depletion and pseudosteady state conditions.
In order to separate facts from fiction, all examples are based on analytical and numerical models. This is important since critical parameters such as pressure communication and flow between compartments and between layers must be known in order to determine how these effects can be properly investigated and understood based on pressure transient and well performance data. The basic analytical model used in this paper is fully transient with flow based on local gradients rather than on differences in average pressures between compartments which tend to yield data with delayed and exaggerated response.
A Compendium of Directional Calculations Based on the Minimum Curvature Method: Part 2
Authors: Sawaryn S. J. , Tulceanu M. A. 
Published: December 2007

Abstract
The point to target calculations contained in part one of the compendium1 were restricted to those cases in which the 3D target coordinates were stated explicitly. However, another class of problems exists where the target's structural position is determined indirectly from other constraints defining the arc's orientation. This new paper builds on the earlier work and contains complete details of twelve explicit algorithms, including the calculation of a target based on the toolface at the start or end of an arc and for the landing of a well path parallel to a formation bedding plane.
These cases find practical application in computing trajectories of motor runs and in whip-stocking operations. The curvature of the trajectory landing on a bedding plane varies with direction and has a distinct minimum and maximum. These values may be used to either minimise the distance to the target or limit the dog leg severity to avoid drill-pipe fatigue, a concern in short radius drilling applications.
The algorithms add to the compendium and are useful extensions to the engineer's computational toolkit. The paper shows that the trajectories, computed using the minimum curvature calculation are contained on the geometric surfaces defined by a torus or cyclide. These geometries explain why the explicit solutions exist, opening up possibilities for obtaining solutions to the more complex cases.
Development of Deep Thin Reservoirs Through Meandering Morphologies Imaged in Seismic Data—A Case Study in San Jorge Basin, Argentina
Authors: Foster Martín , Iovine Gastón 
Published: December 2007

Abstract
This study was focused in the North of Los Perales Field, in San Jorge Basin, Argentina where very good results were obtained identifying extremely heterogeneous fluvial channel reservoirs by using strata slice seismic amplitude data combined with Spectral Decomposition. This last method is a relatively new technology and proved to be useful for mapping thin layers below the seismic resolution. The fluvial channels are well mapped in Castillo Formation, a multilayer reservoir characterised by sandstone bodies deposited by fluvial river systems with high pyroclastic content.
Although more than 3000 wells have been drilled in the field, few ones have reached the deep reservoirs in Castillo Formation.
We showed how the wells LP-2339 and LP-2355 have been drilled in order to evaluate the morphologies visualised with seismic data and how their productions are highly up the average well production in the field.
Seismic cubes at different frequencies were generated, and by blending some of them, it was possible to visualise different channels facies. The thin layers thickness of the reservoir in time produce tuning effect enhancing the frequency data allowing to understand the meandering morphologies representing fluvial channels, its possible depositional environment, and the paleocurrent in the main productive Formations. Because of the sand layer thickness and petrophysical properties of the reservoir, it was not possible to determine the reservoir fluid content by using seismic data alone, but now we know that all of the meandering morphologies showed in strata slices correlates perfectly well with high acoustic impedance sandstones.
These results, give us an extremely useful tool to improve well location in San Jorge Basin, especially in the western zone where the contrasts of impedance between sandstone and tuff are important.
Finally based on this study, new reserves will be incorporated in the area and a new development front is now open in this mature field.
Surface Tiltmeter Mapping Shows Hydraulic Fracture Reorientation in the Codell Formation, Wattenberg Field, Colorado
Authors: Wolhart Steve , Zoll Mike , McIntosh Greg , Weijers Leen 
Published: December 2007

Abstract
This paper reports on a study conducted to measure the orientation of fractures created during initial fracture and refracture treatments in the Codell formation of the Wattenberg Field, Colorado. The Codell is a thin, low permeability sandstone that is laterally continuous across the field area. Due to the low permeability, stimulation is required for economic development of the Codell. Refracturing of Codell wells in Wattenberg Field has been successfully performed for the last decade and several reasons have been suggested for the success of Codell refracs including reorientation of fractures.
Surface tiltmeter mapping was performed during this study on several initial fracture and refracture treatments in the field to determine fracture orientation. The average azimuth of initial fracture treatments was N66°E. Significant reorientation occurred on some refrac wells and the average azimuth of refracture treatments was N29°E although highly variable.
It has been observed that fracture orientation can vary due to changes in pore pressure as the result of asymmetrical depletion and/or injection or due to structural features. In this case we believe that asymmetrical depletion is affecting the in-situ stress orientation and thus the fracture orientation. There were also indications of fracture complexity with some treatments showing a change in fracture orientation during the treatment and several showing higher than normal horizontal components.
The results from this study help explain the success of refracture treatments in the Codell. Refracture reorientation allows existing wells to contact new reservoir increasing gas recovery per well. There may be the potential to fracture wells for a third time (re-refracs) for additional fracture reorientation and improved gas recovery. Mapping and production results are discussed in this paper.