bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of Liner Drilling Technology as a Solution to Hole Instability and Loss Intervals: A Case Study Offshore Indonesia
Authors: Jianhua Liao , Chao Zhao , Jinxiang Li , Rosenberg Steve , Hillis Keith , Utama Budi , Gala Deepak M. 
Published: March 2010

Summary
The Banuwati field offshore southeast Sumatra, Indonesia, presents major challenges to both drilling and liner running operations because of the problematic lower Baturaja limestone formation, which is a carbonate reef structure known for severe lost-circulation conditions. The operator previously had experienced severe losses with wellbore-stability issues while drilling this formation with the inability to set the 7-in. drilling liner at the planned depth in Well A-3. The liner had to be pulled out of the hole, leading to the eventual abandonment of the existing openhole section and resulting in the sidetracking of the well. Liner-while-drilling technology was identified as the most suitable solution for setting the planned 7-in. drilling liner through the loss interval because of the following: Documented lost-circulation problems have been minimized or eliminated through the use of liner drilling technology possibly attributed to the "smear effect" (Fontenot et al. 2004) phenomenon.The liner system selected provided for high torsional capability as well as the requirement for both a mechanical and a pressure event to release the setting tool, thus minimizing the chances of premature release.A drill shoe with a displaceable polycrystalline-diamond-compact (PDC) cutting structure was used to drill the 8½-in. hole section and subsequently displaced before cementing so as to allow drill out with a conventional drill bit and bottomhole assembly (BHA).
This paper will discuss the implementation of liner drilling technology in the Banuwati field project. This technology was used to drill successfully through the known lost-circulation zone with the 7-in. liner cemented in place, allowing the operator to reach the completion objectives while realizing a savings of more than USD 1 million.
Embedding a Petroelastic Model in a Multipurpose Flow Simulator To Enhance the Value of 4D Seismic
Authors: Fanchi John R. 
Published: March 2010

Summary
Time-lapse (4D) seismic can be effectively integrated into the reservoir-management process by embedding the calculation of seismic attributes in a flow simulator. This paper describes a petroelastic model (PEM) embedded in a multipurpose flow simulator. The flow simulator may be used to model gas, black-oil, compositional, and thermal systems. The PEM can calculate reservoir geophysical attributes such as compressional-wave (P-wave) and shear-wave (S-wave) velocities and impedances, dynamic and static Young's moduli, and dynamic and static Poisson's ratios. Examples illustrate how to use the PEM to facilitate the integration of 4D seismic and reservoir flow modeling.
Investigation of Flow Behavior of Slickwater in Large Straight and Coiled Tubing
Authors: Shah S.N.. N. , Ahmed Kamel A.H. H 
Published: March 2010

Summary
Low-damage fracturing fluids are normally used for better fracture-dimension confinement and lower residue. This leads not only to longer fracture lengths, but also to higher fracture conductivity. Slickwater fracturing technology, developed in the 1980s, is less expensive than gel treatments. Fluid and proppant volumes can be reduced, and treatment flow rates can be increased significantly. When compared to conventional gel treatments, slickwater fracturing can generate similar or better production responses.
In frac treatments, slickwater is pumped through straight tubing (ST) and coiled tubing (CT). As a result of secondary flow, frictional pressure losses in CT are higher than in ST. Determining these losses is of the utmost importance for successful treatments. Customarily, laboratory-generated flow data are used to develop correlations to predict frictional pressure loss of fluids flowing in ST and CT. These correlations are then, without verification, applied to field applications, which employ much larger conduit sizes.
The present study is aimed to experimentally investigate the hydraulic properties of a commonly used drag reducer—Nalco ASP-820—in larger tubing sizes. This is a modified partially hydrolyzed polyacrylamide (PHPA). Previously, we reported flow data gathered employing ½-in. ST and CT (varying curvature ratio) and the correlations developed to predict frictional pressure losses of fluids in ST and CT. In this investigation, the large-scale flow data acquired from 200-ft ST and 1,000-, 2,000-, and 3,000-ft,1½-in. CT, and 1,000-ft 2⅜- and 2⅞-in. CT, are compared with the predictions from the correlations developed from ½-in.-pipe data. The effects of shear intensity, shear duration, and pipe roughness on flow properties of the ASP-820 fluid are also investigated.
Results show significantly lower drag reduction in CT than in ST because of secondary flow caused by the CT curvature. Polymer degradation because of shear (shear intensity and duration) and/or tubing roughness can reduce drag reduction significantly. The results are discussed in light of a recently developed "drag-reduction envelope" to evaluate the drag reduction characteristics of slickwater fluid in ST and CT.
Feedback Controllers for the Simulation of Field Processes
Authors: Güyagüler B.. , Papadopoulos A.T.. T. , Philpot J.A.. A. 
Published: March 2010

Summary
Control systems with feedback controllers are useful in reservoir simulation because they enable the maintenance of desired operating conditions of a field. This, in turn, helps to establish the value of implementing automated mechanisms in the field, and also in determining long-term field operating strategies. A generic controller framework is constructed within a reservoir simulator that enables the usage of different kinds of controller algorithms for managing a variety of field processes. In this study, three field processes are considered. First, average pressure within a reservoir region is maintained by adjusting the voidage-replacement ratio between a group of injectors and producers. Second, control systems are used for the prevention of gas/water coning for single and multiple wells. Finally, the average temperature within a reservoir region is maintained at a critical value by controlling flow into the formation, so as to operate with the desired mobility of heavy oil. Traditional proportional, integral, derivative (PID) controllers, as well as linear and nonlinear fuzzy controllers, are considered. The advantages and disadvantages of the approaches are discussed. Tuning control systems is a difficult process in practice. Several methods for tuning the parameters of these controllers are investigated, and rule-of-thumb values are suggested in this study. Synthetic and real reservoir models are used.
Tie-Simplex Parameterization for EOS-Based Thermal Compositional Simulation
Authors: Iranshahr A.. , Voskov D.V.. V. , Tchelepi H.A.. A. 
Published: March 2010

Summary
Thermodynamic equilibrium computations are usually the most time-consuming component in compositional reservoir flow simulation. A compositional space adaptive tabulation (CSAT) approach was developed as a preconditioner for equation of state (EOS) computations in isothermal compositional simulation. The compositional space is decomposed into sub- and supercritical regions. In the subcritical region, we adaptively parameterize the compositional space using a small number of tie-lines, which are assembled into a table. The critical surface is parameterized and used to identify supercritical compositions. The phase-equilibrium information for a composition is interpolated as a function of pressure using the tie-line table. We extend the CSAT approach to thermal problems. Given an overall composition at a fixed temperature, the boundary between sub- and supercritical pressures is represented by the critical tie-line and the corresponding minimal critical pressure (MCP). A small set of subcritical tie-lines is computed and stored for a given temperature. This process is repeated for the pressure and temperature ranges of interest, and a coarse (regular) tie-line table is constructed. Close to the critical boundary, a refined tie-line table is used. A combination of regular and refined interpolation improves the robustness of the tie-line search procedure and the overall efficiency of the computations. Several challenging problems, including an unstructured heterogeneous discrete fracture field model with 26 components, are used to demonstrate the robustness and efficiency of this general tie-line-based parameterization method. Our results indicate that CSAT provides accurate treatment of the near-critical region. Moreover, the computational efficiency of the method is at least an order of magnitude better than that of standard EOS-based reservoir simulation approaches. We also show the efficiency gains relative to standard techniques as a function of the number of gridblocks in the simulation model.
Fractional-Flow Theory of Foam Displacements With Oil
Authors: Ashoori E.. , van der Heijden T.L.M.. L.M. , Rossen W.R.. R. 
Published: March 2010

Summary
Fractional-flow theory provides key insights into complex foam enhanced-oil-recovery (EOR) displacements and acts as a benchmark for foam simulators. In some cases with mobile oil present, the process can be represented as a two-phase displacement. We examine three such cases.
A first-contact-miscible (FCM) gasflood with foam injection includes a chemical shock defining the surfactant front and a miscible shock defining the gas front. The optimal water fraction for the foam, that which gives the fastest oil recovery in 1D, maintains the gas front slightly ahead of the foam (surfactant) front.
The success of a foam process with FCM CO2 and surfactant dissolved in the (supercritical) CO2 depends on the strength of foam at very low water fractional flow, such as for a surfactant- alternating-gas (SAG) process with surfactant dissolved in water. The speed of propagation of the foam front depends on surfactant adsorption on rock and on the partitioning of surfactant between water and CO2 but is always less than the velocity of the foam front in a SAG flood with surfactant ahead of the gas. A foam with surfactant that partitions preferentially into water rather than into CO2 would propagate slowly, regardless of the surfactant's absolute solubility or the level of adsorption on rock. An aqueous surfactant preflush can speed the advance of foam, however.
An idealized model of a surfactant flood pushed by foam suggests that it is best to inject a relatively high water content into the foam to ensure that the gas front remains behind the surfactant front as the flood proceeds. Any gas that passes ahead of the surfactant front would finger through the oil and be wasted.
We present simulations to verify the solutions obtained with fractional-flow methods and illustrate the challenges of accurate simulation of these processes.
Design and Development of a Novel Process To Treat Drilling-Fluid Slops: A Positive Environmental and Economic Impact
Authors: Dixit Rahul , Patel Arvind 
Published: March 2010

Summary
Slop mud, created by water contamination of invert drilling fluids during displacement and cleaning activities, has been successfully treated at source to recover the drilling-fluid phase and water phase. This method included treating the slop mud with a biodegradable demulsifier. The recovered drilling fluid can be reconditioned to acceptable properties for reuse or can be sent for disposal. The recovered/separated slop water phase is contaminated with hydrocarbons and cannot be discharged in an offshore environment unless it meets the discharge criteria of &lt; 30 mg/L of oil in water. Thus, it becomes imperative for the operator to treat the water at source, reduce the enormous expenses associated with transportation/disposal, and embark upon a potentially significant environmental issue. This was achieved by development of an on-site treatment process including filtration, ozonation, and phase separation.
A synthetic-based drilling fluid contaminated with water was separated with a biodegradable demulsifier. The addition of the surfactant resulted in phase separation (i.e., separated drilling-fluid and water phases). As tested by the approved International Organization for Standardization (ISO) method, the separated water phase was found to have oil-in-water content of 4,000 mg/L, which is unacceptable for discharge. The separated water then was treated with ozone. The ozone-treated water was allowed to separate in two phases (i.e., clarified water phase and organic rich phase). The oil-in-water content of the clarified ozone-treated water phase was found to be 30 mg/L, thus reducing the oil-in-water content by 99%.
This paper will present the demulsification methodology, the chemistry of ozonolysis, and the results obtained to meet or exceed the oil-in-water discharge limits of 30 mg/L. The environmental and economic impact of the process will be discussed.
Water Quality and Well Injectivity: Do Residual Oil-in-Water Emulsions Matter?
Authors: Buret S.. , Nabzar L.. , Jada A.. 
Published: March 2010

Summary
The present work is a part of a thorough and systematic laboratory study of oil-in-water emulsion flow in porous media that we have undertaken recently to investigate the mechanisms of oil-droplet retention and its consecutive effect on permeability. One of our main objectives was to see how the in-depth propagation of produced- water (PW) residual dilute emulsion could impair the permeability during PW reinjection (PWRI). During this casework, we used granular packs of sharp-edged silicon carbide grains and stable and dilute dodecane-in-water emulsions. The flow experiments were performed under well-controlled conditions, and we studied the effect of most of the relevant parameters, including flow rate, salinity, droplet size, and permeability of the porous medium.
A careful monitoring of the salinity and the jamming ratio (JR) allowed us to consider and work separately on the two main mechanisms of droplet capture (i.e., surface capture and straining capture). In a previous paper (Buret et al. 2008), we reported on the effect of salinity and flow rate on emulsion flow through porous media where the pore-size/droplet-size ratio (JR) was very high, ensuring that only droplet capture on pore surface is operative. This paper reports on the effect of salinity and JR on both mechanisms, with the main focus being on the induced permeability impairment.
We demonstrated that surface capture could induce significant in-depth permeability losses even at a high JR. The maximum reached permeability loss is very sensitive to salinity and flow rate (shear-thinning effect). This maximum is always lower than a limiting value dictated by the surface-coverage jamming limit of random sequential adsorption (RSA) theory. This limiting value increases while decreasing the JR, according to a simple formula extracted from Poiseuille's law with a mean hydrodynamic thickness of the deposited layer close to the droplet diameter (monolayer deposition). Regarding the straining capture, we determined a critical JR of 7 for this mechanism to occur. Preliminary results using only two JR values and one flow rate are presented. Compared to surface capture, the results show that straining capture induces more severe plugging with a lower rate of propagation. The lower the JR is, the more severe the plugging is and the lower the propagation rate is. However, more investigations are still required, notably using various JRs and flow rates to characterize this important mechanism better.
Plunger-Lift Modeling Toward Efficient Liquid Unloading in Gas Wells
Authors: Chava G.. , Falcone G.. , Teodoriu C.. 
Published: March 2010

SummaryThis paper is a follow-up to Chava et al. (2008), which introduced a preliminary plunger-lift model built around the availability of smart-plunger (PCS 2005) data. The latter devices are equipped with internal gauges to record pressure and temperature with time, which can be downloaded whenever the plunger is at surface.We present an updated model that accounts for pressure drop caused only by gravitation but satisfactorily reproduces the dynamics of a field installation in east Texas.We also present a comparison of the predictions from the new model with the corresponding results from some earlier plunger-lift models available in the public domain.
Real-Time Diagnostics of Gas Lift Systems Using Intelligent Agents: A Case Study
Authors: Stephenson G. , Molotkov R. , De Guzman N. , Lafferty L. 
Published: March 2010

Summary
This paper describes a new method to continuously monitor and diagnose the condition of wells producing through continuous gas lift. The paper describes the application of this system in a mature onshore gas lift field in the western United States and the results obtained. A central problem related to the operation of gas lift wells is the ability to identify underperforming wells and to address the underlying issues appropriately and in a timely manner. This problem is compounded by the trend toward leaner operations and relative scarcity of application-specific domain knowledge. The purpose of this method is to address these issues by leveraging real-time data, gas lift domain expertise, and proven steady-state analysis techniques in a desktop software application.
This system performs four key functions: Monitoring the wells' condition by collecting data, assessing the meaning of these data, recommending actions for correcting problems and responding to threats, and explaining recommendations.
The performance of the system has met initial expectations and has provided additional unforeseen benefits. This paper cites specific cases that compare agent predictions to expert diagnoses and quantify the benefits of taking the recommended actions. What was found was that while the correct diagnoses of well performance issues was beneficial, the real benefit was in allowing production engineers to analyze a greater number of wells in far less time. To that end, the paper will discuss the role of this system as it relates to the overall production management workflow.
The success of this project has demonstrated that intelligent agents can effectively perform functions historically performed by a handful of experts. The paper will discuss key system-design features that enable this level of functionality as well as other potential areas in which the technology can be extended in the future.
Improved Geosteering by Integrating in Real Time Images From Multiple Depths of Investigation and Inversion of Azimuthal Resistivity Signals
Authors: Chemali Roland , Bittar Michael , Hveding Frode , Wu Min , Dautel Mike 
Published: March 2010

Summary
Optimal field development often entails placing the wells in prescribed locations within the reservoir. An error of a few meters in height above the oil/water contact or with respect to the roof may result in leaving behind a significant portion of the producible reserves. Driven by this key requirement, new technologies continue to emerge to help geologists, drillers, and reservoir engineers geosteer the wells. In recent years, two types of logging-whiledrilling (LWD) information have been used. On one hand, wellbore imaging can determine when a well path has left the reservoir and the angle of exit. On the other hand, traditional axisymmetrical resistivity logs help to quantify the distance to an approaching boundary through inversion, but fail to tell its azimuth.
A newly deployed azimuthal deep resistivity instrument recognizes an approaching geological event before it intersects the well while continually imaging it at multiple depths of investigation. Of particular interest is the azimuth of approach with respect to the well path, advising in real time the most favorable change of direction. In addition, a series of transverse electromagnetic measurements specific to azimuthal resistivity, called geosignals, are presented. Geosignals help to quantify the distance and the rate of approach with great accuracy, before the actual intersection could occur. With this real-time information, geosteering engineers can remain at prescribed distances from important boundaries, including oil/water contacts and overlying shale roofs. Modeling and actual logs demonstrate that the new LWD instrument performs at its best when the reservoir is overlaid by shale. Modeling suggests, however, that suboptimal performance occurs in reservoirs with very resistive caprock, such as anhydrite.
Fully Coupled Numerical Modelling of Ground Surface Uplift in Steam Injection
Authors: Yin Shunde , Dusseault Maurice B. , Rothenburg Leo 
Published: March 2010

Abstract
In enhanced oil recovery, steam injection involves high stresses, pressures, temperatures and volume changes. Traditional reservoir simulation fails to predict associated transient ground surface movements because it does not consider coupled geomechanical effects. We present a fully-coupled, thermal half-space model using a hybrid DDFEM method, in which a simultaneous finite element method (FEM) solution is adopted for the reservoir and the surrounding thermally affected zone, and a displacement discontinuity (DD) method used for the elastic, non-thermal zone. This approach provides transient ground surface movements in a natural manner.
Introduction
Enhanced oil recovery (EOR) methods involving high pressures and steam injection (steamflooding, cyclic steam stimulation, steam-assisted gravity drainage) are accompanied by large volume changes in the reservoir horizon. Ground movements in excess of 300 mm heave or subsidence are registered during injection and production cycles. Reservoir simulation cannot address this phenomena without due consideration of geomechanical effects.
The earliest theory to account for coupled pore fluid behaviour and soil deformation was the Terzaghi one-dimensional consolidation theory, still used in soil mechanics. Since Biot's theory of consolidation(1) was introduced to petroleum engineering by Geertsma(2) with the coined term "poroelasticity,?? coupled analysis of petroleum geomechanics effects has been widely advocated(3-5). Coupled reservoir simulation can be carried out in a loosely coupled fashion(6, 7) or with a tightly coupled scheme(8-10), and comparisons of different coupling techniques can be found (11, 12).
In reservoir simulation, a coupled analysis demands simultaneous solution of changes in (p,T) and fluid flow as well as stress and strain. Computing challenges persist in large-scale 3D applications to real cases where there are a huge number of equations to solve iteratively; e.g. thermo-poro-elasto-plastic analyses involving several simultaneous diffusion processes (Darcy, Fourier, Fick). In regions of large pressure, temperature, concentration or stress gradients, accurate solution requires small-scale discretization. If the problem has strong non-linearity, such as changes in permeability, compressibility, or other properties arising from changes in pressure and effective stress, the computational effort increases by several orders of magnitude because multiple iteration loops are needed. These issues mean that accurate analysis of realistic complex 3D problems is challenging, and will so remain as we seek to solve larger and larger coupled problems involving non-linear responses.