bluuebunny/crossref_metadata_2025_split huggingface dataset:
Screen Development to Withstand 4,000-psi Overbalance, Subhydrostatic Completion in Deepwater GOM Subsea Waterflood Injector Wells
Authors: Gillespie George , Hinnant Chuck , Davis Chris , Schober Jamie , Darring Mike 
Published: September 2008

Abstract
This paper describes challenges, test equipment, test program and results in the development of a screen product and contingency fluid-loss control (FLC) pill formulation to withstand 4,600-psi burst resistance pressure.
In maturing deepwater fields, such as Shell Ursa/Princess where depleted reservoir pressures are significantly below the hydrostatic pressure of a seawater column, a modified screen design was required since screen products currently available were limited to &lt;3,500 psi. FLC pill formulations also required modification because they were only validated to 1,000 psi in the current laboratory test apparatus.
A series of burst tests were conducted on a wire-wrap screen design direct wrapped to 4-in. base pipe. The objective was to determine if the screen could withstand at least 4,600 psi without damage. The wire-wrap design selected to improve the pressure rating was substantially heavier than what has been used in traditional sand-control completions. Initial burst tests with available 316L material averaged 4,600 psi. Two sets of additional burst tests were conducted with Alloy 625 screens on 25 Chrome base pipe to meet injector material requirements. The FLC formulation was modified from conventional design to enhance the pressure response. The last test results averaged over 5,100 psi.
Comprehensive before and after measurements and slot inspections were done; the data were used in Finite Element Analysis to finalize the detailed screen design. No traditional mechanical burst of the screen occurred. Most influential factors were slot size/geometry and pill formulation.
Analytical Upgridding Method to Preserve Dynamic Flow Behavior
Authors: Hosseini Seyyed Abolfazi , Kelkar Mohan 
Published: September 2008

Abstract
Geo-cellular model contains millions of grid blocks and needs to be up-scaled before the model can be used as an input for flow simulation. Available techniques for upgridding vary from simple methods such as proportional fractioning to more complicated methods such as maintaining heterogeneities through variance calculations. All these methods are independent of the flow process for which simulation is going to be used, and are independent of well configuration. We propose a new upgridding method which preserves the pressure profile at the upscaled level.
It is well established that more complex the flow process, more the detailed level of heterogeneity is needed in simulation model. In general, ideal upscaling is the process which preserves the "pressure profile" from the fine scale model under the applicable flow process. In our method we upgrid the geological model using simple flow equations in porous media. However, it should be remembered that to get a better match between fine scale and coarse scale, we also need to use appropriate upscaling of the reservoir properties.
The new methodology is currently developed for single phase flow; however, we used it for both single phase and two phase flows for 2D and 3D cases. The methodology fundamentally differs from the other methods which try to preserve heterogeneities. In those methods, grid blocks are combined which have similar velocities (or other properties) by assuming constant pressure drop across the blocks. Instead, we combine the grid blocks which have similar pressure profiles. The procedure is analytical and hence very efficient, but preserves the pressure profile in the reservoir. The grid blocks (or layers) are combined in a way so that the difference between fine scale and coarse scale pressure profiles is minimized. In addition, we also propose two new criteria that allow us to choose the optimum number of the layers more accurately so that critical level of heterogeneity is preserved. These criteria provide insight into the overall level of heterogeneity in the reservoir as well as effectiveness of the layering design.
We compare the results of our method with proportional layering and King et al.'s method (King 2005) and show that, for the same number of layers, the proposed method better captures the results of the fine scale model. We show that the layer merging not only depends on the variation in the permeability between the grid blocks, but also on relative magnitude of the permeability values. We also show that new method can account for additional variables such as grid block thicknesses and the size.
Development of Gas/Oil Miscibility in Water and Gas Injection
Authors: LaForce Tara , Orr Franklin M. 
Published: September 2008

AbstractIn this paper we use analytical solutions to study the development of multicontact miscibility in simultaneous water and gas (SWAG) injection into a reservoir containing a mixture of hydrocarbons. Application to CO2 storage and enhanced oil recovery is considered. We consider fully compositional one-dimensional (1D), four-component, three-phase flow through a porous medium.Solutions are constructed for a vaporizing gas drive at a pressure below and above the gas/oil minimum miscibility pressure (MMP). We demonstrate that miscibility does not develop when the fraction of water in the injection mixture is sufficiently high and define the minimum gas fraction (MGF) necessary to achieve miscibility.SWAG injection when a mobile water phase is present in the reservoir initially is also studied. We show that the MGF necessary to achieve miscibility depends on the fraction of water present in the reservoir at the start of SWAG injection. In all cases the relative permeability of the supercritical CO2 and water phases determine the MGF. These results indicate that, unlike in miscible gas injection, in SWAG injection the development of miscibility is dependent on the multiphase flow parameters, not just the phase behavior, and highlights the importance of improved relative permeability models.
Determination of Structural Dip and Azimuth from LWD Azimuthal Propagation Resistivity Measurements in Anisotropic Formations
Authors: Fang S. , Merchant A. , Hart E. , Kirkwood A. 
Published: September 2008

Abstract
With the use of both azimuthal propagation resistivity main and cross component data, the resistivity anisotropy and its dip and azimuth angles of a massive formation (anisotropic shale or laminated sand) can be determined. The accuracy of the determined parameters depends on the amount of available data. A minimum amount of data are two frequency main components and real and quadrature cross components. The boundary effects will distort the solution eventually; however, the anisotropy enhanced processing will minimize the effects to extend the algorithm to a certain distance away from a boundary.
Pore Pressure Coefficient Anisotropy Measurements for Intrinsic and Induced Anisotropy in Sandstone
Authors: Al-Tahini Ashraf , Abousleiman Younane 
Published: September 2008

Abstract
In this study, we determine experimentally the effect of inherent and stress-induced anisotropy on stiffness components, elastic moduli, and Biot's pore pressure coefficients (PPCs) for Lyons outcrop Colorado sandstone which exhibits a clear transverse isotropic rock structure. Both dynamic and quasi-static methods were used under a non-hydrostatic state of stress to perform the measurements on dry core samples. Our assumption of apparent transverse anisotropy was initially confirmed with acoustic velocity measurements and at a later stage in the loading with experimental transverse anisotropic failure analysis. The objective of this study is to identify and isolate the effect of stress-induced anisotropy from the inherent transverse anisotropy on the measured stiffness components, elastic moduli, and Biot's PPCs. The effect of stress-induced anisotropy appears to have significant control on measured stiffness components, elastic moduli, and Biot's PPCs as compared with the inherent transverse anisotropy effect. Our work shows that the stiffness components, Mij, thus computed elastic moduli, are highly influenced by the stress-induced anisotropy especially the off-diagonal stiffness components, M12 and M13, where the increase in their magnitudes from the dynamic measurements prior to failure is determined to be 100% and 81%, respectively. The difference in the magnitude between the axial and lateral Biot's PPCs, in line with bedding planes and perpendicular to them, is measured to be 24% and 16% from the quasi-static and dynamic methods, respectively; whereas, the effect of stress-induced anisotropy reduced the dynamic average magnitude of the Biot's PPCs along the bedding planes and transverse to these planes by 63% over a stress range of 145 MPa.
Semianalytical Representation of Wells and Near-Well Flow Convergence in Numerical Reservoir Simulation
Authors: Kurtoglu B. , Medeiros F. , Ozkan E. , Kazemi H. 
Published: September 2008

Abstract
This paper presents a new approach to compute wellbore pressures and near-well flow convergence in numerical reservoir simulation. In this semi-analytical approach, the solution of the flow problem in porous media is related to the boundary-element formulations. To account for reservoir heterogeneity, solution domain is subdivided into internally homogeneous reservoir blocks, which may include wells, and the solutions are coupled with the requirement of flux and pressure continuity at the block boundaries. Knowing the boundary values of the solution domain, this formulation solves for the flux at the block boundaries and flux and pressure on wells. Knowing the flux boundary condition, this formulation also enables the solution of pressure at any point within the reservoir blocks. This feature of the solution serves the purposes of multiscale simulation of flow and transport in porous media. Although the solution can be applied on field scale, this paper focuses on the applications to near-well flow convergence region. When the solution is used for the near-well flow-convergence region, the required boundary values of the solution domain can be obtained from any standard solution techniques, including finite-difference simulation, by accounting for wells as source terms.
Multilaterals Drilling and Sustainable Openhole Production From Theory to Field Case Studies
Authors: Hoang Son K. , Abousleiman Younane N. , Al-Tahini Ashraf 
Published: September 2008

Abstract
Drilling and production optimization are two interconnected operations for successful well construction and reservoir management, in particular for extended reach of multilateral wells. Formation damage, especially permeability reduction induced during drilling, greatly affect well completion and future potential reserve production. Reservoir pressure depletion and the consequent increase in effective stresses around the well branches are the main reasons behind solid production or total wellbore collapse. Unfortunately, to date, analytical study for the stability of multilaterals has been very limited due to the complex geometry and stress state involved. This work entails a recently derived analytical solution to estimate the safe mudweight window for wellbore stability during drilling, as well as to predict the maximum pressure drawdown for a stable junction during production. The presented solution is capable of handling the complexity of 3D anisotropic state of stress as well as any mother and lateral size, inclination, and azimuth. The study shows that the design of multilateral junction, especially inclination and azimuth of both wellbores with respect to regional in-situ stresses play a crucial role in the multilateral junction stability and the critical pressure drawdown estimation to prevent solid production and wellbore collapse. A field case study of a multilateral well drilled in the Khuff-C formation, Ghawar field, Saudi Arabia, is analyzed herein with drilling data, core-retrieved rock properties, and pressure drawdown and production estimates. The results showed alternate optimized completions that could have been applied early in the drilling and branching of the laterals. Practical guidelines concerning branching optimization have been established for junction planning and execution. The new analytical modeling has also been calibrated with a published peer-reviewed large-scale experimental program simulating both the anisotropy of far-field stresses and complex junction geometry with exceptional qualitative and quantitative results.
Wellbore Stability Performance of Water Base Mud Additives
Authors: Ewy Russell T. , Morton E. Keith 
Published: September 2008

Abstract
A critical property for many water-base muds is the ability to prevent near-wellbore pore pressure increase in shales. By slowing or preventing this pressure rise, a true overbalance pressure is maintained, which promotes wellbore stability. Using a device that simulates downhole rock stress and overbalance fluid pressure conditions, and using preserved shale samples, we tested four different muds containing different additives. Direct measurements of shale pore pressure vs. time were obtained, representing the pore pressure inside the wall of the wellbore. All muds slowed the loss of overbalance pressure compared to a base-case brine fluid, but two muds were very effective at slowing and/or preventing the loss of overbalance. One active mechanism appears to be an increase in the osmotic membrane efficiency, but permeability measurements conducted during these same tests show that physical plugging of the pore space is also an important mechanism for these two fluids. Measurements of fluid-induced swelling were also conducted in this same set of tests, and all four muds resulted in less swelling than the base-case brine. The most effective fluid was repeat-tested using a completely different shale, and it again was found to be very effective at preventing near-wellbore pore pressure increase.
Interpretation of Interwell Connectivity Tests in a Waterflood System
Authors: Dinh A. V. , Tiab D. 
Published: September 2008

Abstract
This study is an extension of a novel technique to determine interwell connectivity in a reservoir based on fluctuations of bottom hole pressure of both injectors and producers in a waterflood system. The technique uses a constrained multivariate linear regression analysis to obtain information about permeability trends, channel and barriers. Some of the advantages of this new technique are simplified one-step calculation of interwell connectivity coefficients, small number of data points and flexible testing plan. However, the previous study did not provide either in-depth understanding or any relationship between the interwell connectivity coefficients and other reservoir parameters.
This paper presents a mathematical model for bottom hole pressure responses of injectors and producers in a waterflood system. The model is based on available solution for fully penetrating vertical wells in a closed rectangular reservoir. It is then used to calculate interwell relative permeability, average reservoir pressure change and total reservoir pore volume using data from interwell connectivity test described in previous study. Reservoir compartmentalization can be inferred from the results. Cases of producers as signal wells, injectors as response wells and shut-in wells as response wells are also presented. Summary of results for these cases are provided. Reservoir behaviors and effect of skin factors are also discussed in this study.
Some of the conclusions drawn from this study are: (1) The mathematical model works well with interwell connectivity coefficients to quantify reservoir parameters; (2) The procedure provides in-depth understanding of the multi-well system with water injection in the presence of heterogeneity; (3) Injectors and producers have the same effect in terms of calculating interwell connectivity and thus, their roles can be interchanged. This study provides flexibility and understanding to the method of inferring interwell connectivity from bottom-hole pressure fluctuations. Interwell connectivity tests allow us to quantify accurately various reservoir properties in order to optimize reservoir performance.
Different synthetic reservoir models were analyzed including: homogeneous, anisotropic reservoirs, reservoirs with high permeability channel, partially sealing fault and sealing fault. The results are presented in details in the paper. A step-by-step procedure, charts, tables, and derivations are included in the paper.
Numerical Simulation and Sensitivity Analysis of In-Situ Fluid Flow in MRI Laboratory Waterfloods of Fractured Carbonate Rocks at Different Wettabilities
Authors: Haugen Åsmund , Fernø Martin A. , Graue Arne 
Published: September 2008

Abstract
Dynamic 3D MRI in-situ fluid saturation images during laboratory waterfloods of fractured carbonate rocks provided useful insights to the oil recovery mechanisms at water-wet and oil-wet conditions. The high spatial resolution imaging data formed the basis for a numerical representation of the experiment, and the numerical model was validated by history matching the experimentally observed results. Experimentally measured multiphase functions were used to match the in-situ fluid flow propagation during waterfloods of fractured rock, improving the confidence in the simulations beyond simply relying on material balance. A numerical sensitivity analysis of the effects from variations in fracture properties identified the impacts on sweep efficiency and oil recovery in waterfloods of fractured rock.
Multi-frequency LWD Acoustic Tool for Shear Slowness Measurement.
Authors: Andonof Luis J. , Buster Derek , Eiane Tor , Petpisit Kiattisak 
Published: September 2008

Abstract
This paper presents some case histories involving multi-frequency quadrupole acoustic measurement to obtain the formation shear slowness under varying conditions. Quadrupole modes in high frequencies for fast formations acquired in parallel with low frequencies for slow formations are processed such that the final result is that the combination of both responses yield the shear slowness across the range encountered. These conditions range from large shallow boreholes with unconsolidated formations to consolidated formations where the shear velocity is faster or close to mud compressional velocity.
As is well known in the industry, the monopole mode allows the measurement of shear slowness in fast formations. However, for slow formations this refracted shear does not exist which requires other means to be employed. The application of the dipole measurement which is used in wireline encounters problems in the Logging While Drilling (LWD) environment. These problems are due to the presence of the collar which greatly influences the flexural mode in the formation along with the additional signal caused by the collar flexural wave1.
Cases when the shear slowness lies in the range of the fluid slowness, a special treatment needs to be considered. The fact that one frequency (high or low) is unable to accurately respond above and below this threshold emphasizes the advantage and need for having multi-frequency LWD acoustic data to accomodate the demands of the environment. Also the challenging case where the shear slowness is in the same range as the mud compressional slowness will be discussed. All these results point to the importance of the use of a multi-frequency LWD acoustic tool for shear measurements. Some quality control considerations such as the rate of penetration (ROP) need to be taken into account in order to have a successful job.
Successful Field Application in Continuous DTS Monitoring Under Harsh Environment of SAGD Wells Using New Optical-Fiber Technology: Case Study From Canada
Authors: Kaura Jiten , Sierra Jose 
Published: September 2008

Abstract
The use of optical fibers in the oil and gas industry is becoming more viable for several applications, particularly in permanent reservoir monitoring, such as distributed temperature sensing (DTS) and optical pressure transducers. However, poor long-term performance of fibers, especially at elevated temperatures, is still an issue yet to be fully resolved. This problem is critically important in steam assisted gravity drainage (SAGD) applications, where wells operate in extreme conditions of high temperatures, often exceeding 250°C, as well as in high pressures within a hydrogen-rich environment.
Optical fiber performance is seriously affected by many factors, including: Hydrogen ingressionThermal resistance of the materialsMechanical resistance of the fiber
Exposure of optical fibers to hydrogen changes the performance of the fibers through what is referred to in the industry as "hydrogen aging" or "hydrogen darkening." Hydrogen darkening is increased absorption or light loss due to various chemical species in the glass fiber resulting from the presence of hydrogen.
Dehy 20 Water Filtration Plant—A Closed Loop Water Treating Facility
Authors: Grishaber E. L. 
Published: September 2008

Abstract
A Southern California oil producer needed to expand its light oil waterflood. An existing oil treating plant was expanded to include a new state-of-the-art water plant to recycle all produced water associated with light oil production for use in the existing waterflood. The new 350,000–barrel-per-day water plant was designed to treat the produced water to remove suspended solids and oil to a specification that equaled or exceeded the existing waterflood aquifer source. In addition, the plant had to minimize waste while maximizing treated water output and be built for a 40-year life. The plant addition was designed and constructed using a unique combination of water de-oiling, desanding, and filtration equipment together with centrifuges and gas flotation equipment similar to equipment used in municipal wastewater treatment plants. All wastes such as filter backwash are processed and reused.
The water plant is now operational, performing at or above expectations. It treats and recycles more than 340,000 barrels of water per day for use in the field's waterflood project. This recycling has largely displaced the existing waterflood source supply system (saving power and well maintenance and replacement costs) and reduced produced water disposal well injection costs resulting from much improved water quality. The new plant has met its goal of providing a high-quality water source for waterflood with typically less than 2 milligrams per liter of solids, oil, and grease.