bluuebunny/crossref_metadata_2025_split huggingface dataset:
Permeability Upscaling for Near-Wellbore Heterogeneities
Authors: Soeriawinata Tono , Kasap Ekrem , Kelkar Mohan 
Published: December 2007

Summary
Reservoir simulations are limited to large-scale gridblocks because of prohibitive computational costs of fine-grid simulations. Rock properties, such as permeability, are measured on a scale smaller than coarse-scale simulation gridblocks. Therefore, the properties defined on a smaller scale are upscaled to a coarser scale. Few prior studies on permeability upscaling paid special attention to the problem of radial flow in the vicinity of a wellbore. This study presents an analytical method to calculate effective permeability of a coarse-grid wellblock from its constituent fine gridblocks. The method uses the incomplete-layer upscaling procedure, which is modified for radial flow around wellbore but applied to permeability heterogeneity defined in a Cartesian grid scheme. The method is validated by numerical simulations of primary and secondary recovery processes involving two-dimensional (2D) and three-dimensional (3D) systems. The simulation results with permeabilities from radial flow upscaling for wellblocks agreed better with the simulation results with the original permeabilities than results from linear-flow upscaling.
Popeye Project: Subsea System
Authors: Ritter P. B. , Langner C. G. , Sgouros G. E. , Saucier B. J. , Voss R. K. 
Published: December 2007

Summary
The subsea system installed for the Shell Offshore Inc. (SOI) Popeye project represents an advance in deepwater subsea technology. It is a diverless, guidelineless, 10,000-psi cluster-manifold concept, the first of its kind. The cluster concept was selected in large part based on SOI's deepwater experience and anticipated future subsea-development needs. This paper describes how the innovative Popeye subsea system was selected, designed, tested, and successfully installed.
Control-Volume Discretization Methods for 3D Quadrilateral Grids in Inhomogeneous, Anisotropic Reservoirs
Authors: Aavatsmark Ivar , Barkve Tor , Mannseth Trond 
Published: December 2007

Summary
The paper presents a class of control-volume discretization methods for general quadrilateral grids in three space dimensions. The methods allow full permeability tensor and arbitrary orientation of the grid. The paper discusses handling of inactive cells and flow barriers. Numerical examples are used to compare the new methods with conventional corner-point geometry methods.
Multilateral Horizontal Well Increases Liquids Recovery in the Gulf of Thailand
Authors: Horn M. J. , Plathey D. P. , Ibrahim Ouahiba 
Published: December 2007

Summary
This paper describes the objectives, the completion, and the first results of the dual-horizontal Well BK-4-M, which was drilled in May 1996 in the Bongkot field. The main objective of Well BK-4-M was to maximize the recovery from a shallow and thin oil rim by delaying the water breakthrough by 2 years and by maintaining a flow rate of 4,000 B/D. Compared with a conventional deviated well, the final recovery will increase by three times. The completion of Well BK-4-M was a challenge in terms of technical and economic planning. Well BK-4-M was put on stream successfully in July 1996 with a potential flow rate of 4,000 B/D. The duration of operations was 21 days, including completion. Each of the two horizontal branches has a length of approximately 1000 m and is located in the upper third of the 10-m-thick oil rim. The cost of Well BK-4-M was 1.70 times higher than a conventional single-drain deviated well, and the well is expected to triple recovery by using only one platform slot. It is the first dual-horizontal well ever completed in Southeast Asia.
Increasing Coal Absolute Permeability in the San Juan Basin Fruitland Formation
Authors: Mavor M. J. , Vaughn J. E. 
Published: December 2007

Summary
Recently measured data show that the absolute permeability of coal natural fracture is increasing significantly with continued gas production in the San Juan basin Fruitland formation. This phenomenon caused gas-production rates to be many times greater than expected from early production history. The phenomenon also caused producing bottomhole pressures to increase when gas rates were constant, opposite from that expected from conventional applications of Darcy's law.
The increase in absolute permeability caused by gas desorption has been measured on cores,1–3 but, until recently,4 there was no verification that this phenomenon occurs in situ. Palmer and Mansoori4 (P&M) presented a new theory and showed how this theory matched gas- and water-production rates and estimated bottom-hole-pressure data for a high-deliverability San Juan basin Fruitland formation coal-gas well. However, Palmer and Mansoori4 had no transient pressure data to support in-situ permeability changes. This paper documents data from drillstem tests (DST's) and shut-in tests with analyses thereof and additional production-rate and pressure behaviors that support the P&M theory.
The well-test data were measured in three wells completed in the San Juan basin Fruitland formation coal seams located under the Valencia Canyon (VC) area. These wells, VC 29-4, VC 32-1, and VC 32-4, are located in Sections 29 and 32, T33N, R11W, La Plata County, Colorado, and operated by EnerVest San Juan Operating LLC. In addition to the well-test data, EnerVest and the Gas Research Inst. (GRI) collected extensive formation-evaluation data and performed detailed analyses that allowed a thorough description of the area. Although there are other wells operated by EnerVest in the area, well-test data were not available from the other wells to determine the absolute permeability estimates; therefore, these wells are not discussed in this paper.
The P&M theory was calibrated with well-test-derived absolute permeability estimates and published coal-shrinkage data.5 Reservoir simulation models, based on the calibrated theory, matched the unusual producing, bottomhole-pressure behavior. Without the P&M theory it was not possible to match pressure behavior or permeability estimates with reasonable variations of reservoirproperties input into the reservoir-simulation models.
The remainder of this paper summarizes the well-test analysis results from the three wells and, for brevity, one set of well-test data and one simulation study. The well-test data and simulation studies for the other wells were similar to the examples.
Optimization of Pipeline Networks With a Hybrid MCST-CD Networking Model
Authors: Sung Wonmo , Huh Daegee , Lee Junghwan , Kwon Oukwang 
Published: December 2007

Summary
In this paper, we present a hybrid network model (HY-PIPENET) that uses a minimum cost spanning tree (MCST) network algorithm to determine the optimum path and constrained derivative (CD) method, to select an optimum pipe diameter. The HY-PIPENET has been validated with the published data of a six-node/seven-pipe networking system, and, moreover, this system has been optimized with the MCST-CD method. As a result, it was determined that the gas can be sufficiently supplied at a lower pressure with smaller diameters of pipe, compared to the original system in a six-node/seven-pipe network. Hence, the construction cost was reduced about 40% in the optimized system. The hybrid networking model has also been applied to a complicated domestic gas pipeline network in a metropolitan area of Korea. In this simulation, a parametric study was performed to understand the role of each individual parameter such as the source pressure, flow rate, and pipe diameter on the optimized network. From the results of these simulations, we have proposed that the optimized network is a tree-type structure with an optimum pipe diameter and source pressure, which was used in a Korean metropolitan area. This proposed system however, does not consider potential environmental problems as well as safety concerns.
Laboratory Studies for Light-Oil Air Injection Projects: Potential Application in Handil Field
Authors: Clara Cédric , Durandeau Marc , Quenault Gérard , Nguyen Tuyêt-Hang 
Published: December 2007

SummaryAir injection into light-oil reservoirs is now a proven field technique. Because of the unlimited availability and the nil access cost of the injectant, the application potential of this improved recovery process is promising when associated with the lack of available hydrocarbon gas sources for injection. One of the keys of a successful air injection project is the evaluation of the process by carrying out representative laboratory studies. Therefore, an original laboratory strategy was proposed to assess the recovery potential by air injection into light-oil reservoirs, and to help the determination and the quantification of optimal operating conditions.In this paper, the air injection technique applied to light-oil reservoirs is explained. Then, the laboratory strategy proposed for the evaluation of an air injection project is described, and the experimental objectives, devices, and procedures are explained. In order to provide reliable experimental data, high-pressure and high-temperature experiments (up to 40 MPa and 500°C) are performed with consolidated reservoir cores and reservoir oils, at representative conditions of the air injection process in light-oil reservoirs.Finally, a laboratory evaluation regarding a potential application for an air injection pilot in the Handil field (Mahakam delta, Indonesia) is presented and discussed.
Identification of Unknown Permeability Trends From History Matching of Production Data
Authors: Grimstad Alv-Arne , Mannseth Trond , Aanonsen Sigurd Ivar , Aavatsmark Ivar , Cominelli Alberto , Mantica Stefano 
Published: December 2007

Summary
We investigate how a priori unknown large-scale permeability structures such as channels or barriers can be identified from history matching of production data, using Adaptive Multiscale Estimation (AME).
With Multiscale Estimation (ME) of the permeability, we solve a sequence of parameter estimation problems with increasing resolution for the permeability until a match is obtained. With AME—and contrary to Ordinary Multiscale Estimation (OME)—the parameterization refinement is not the same all over the reservoir. We aim at introducing new degrees of freedom in the permeability parameterization only where it is warranted by the production data.
The paper describes the principles of AME and extends AME to corner-point grids on nonrectangular 2D reservoirs. On 2D synthetic examples with simplistic geometry, we demonstrate how AME is able to completely identify simply shaped large-scale permeability trends and how it avoids overparameterization.
On 2D synthetic examples with more complex geometry (field-scale synthetic examples), AME is found to identify large-scale trends. When the large-scale trend has a more complex shape, AME identifies a similar trend of less complex shape at approximately the same location. The identification of the permeability trends for the field-scale synthetic examples can, however, be improved upon, and, for example, use of coarsening (as well as refinement) in the parameterization selection will be further considered in future work.
A New Technique to Solve Gas Hydrate Problems in Subsea Christmas Trees
Authors: Marques L. C. C. , Pedroso C. A. , Neumann L. F. 
Published: December 2007

Summary
The paper is aimed at describing the series of actions taken to re-enter a well, the (wet) Christmas-tree cap of which was clogged by solid hydrate and therefore could not be released by means of a regular releasing tool. A deepwater well located in Campos Basin, offshore Rio de Janeiro, Brazil, was the location for this unique job. To our best understanding, the kind of approach used to solve this hydrate problem had never been used in the industry before.
A patented thermochemical method—the so-called self-generated nitrogen (SGN) method—was applied to heat and dissociate the crystallized hydrate, which was clogging the piston chamber of the tree-cap locking pin. Heat application around the body of the Christmas tree enabled us to dissociate the hydrate and release the tree cap by means of its regular retrieving tool.
This paper describes all the steps taken to perform this pioneer workover job. As a matter of fact, it was a multidisciplinary task that encompassed the following points:
- Development of a "tailor-made" environmentally friendly SGN formulation.
- Heat exchange simulations to design the optimum volume for the SGN treatment batch.
- A review of the theoretical aspects of hydrate formation/dissociation.
- Mechanical modifications of the (regular) tree cap releasing tool.
- A meticulous review of the job and safety procedures.
Imaging Unstable Wellbores While Drilling
Authors: Edwards S. , Matsutsuyu B. , Willson S. 
Published: December 2007

Summary
This paper presents a case study of borehole instability from four wellbores on the Gulf of Mexico (GOM) shelf, offshore Louisiana. Logging-while-drilling (LWD) borehole images are combined with observations of cavings and modeling of borehole shear failure to diagnose the mechanisms of instability and, thus, select the appropriate remedial action.
It is observed that instability caused by shear failure of intact rock (borehole breakout) can be suppressed by increasing the MW. However, where pre-existing planes of weakness (such as bedding planes and fractures) dominate the mechanism of instability, mudweight increases do not necessarily lead to a more stable hole and can, in fact, further destabilize the wellbore.
Removal of Water-Soluble Organics From Produced Brine Without Scale Formation
Authors: Hart Paul R. 
Published: December 2007

Summary
Water-soluble organics (WSOs) are included in the measurement of oil and grease (O&G), a conventional pollutant controlled by the Clean Water Act. WSOs partition to the produced brine at the production pH, but to the extraction solvent used to measure the O&G at the test pH of &lt;2. The predominant chemical species comprising WSOs in Gulf of Mexico crude oil brines are medium-chain carboxylic acids. Chemicals can be added to desolubilize these species in conjunction with treatments to remove the resultant emulsion. For a variety of reasons, the most reliable and cost-effective desolubilization agents have proven to be the nonvolatile, multiprotic oxo acids (e.g., HxSOx and HxPOx). However, in the presence of many common divalent cations in the brine, these form insoluble scale deposits. Moreover, in the presence of WSOs in mixed production, this scale becomes oil-wet and uninhibitable. A new treatment comprising a new class of desolubilizer in conjunction with certain polymers has now been shown to be equally reliable and cost-effective without the formation of scale, even at extreme concentrations of divalent cations. The chemistry is explained and case histories chronicled to illustrate its effectiveness in the field.
A Method for Isolating Pressure-Depleted Zones With Solid-Expandable Tubulars
Authors: Moore Melvin J. , Wright Jon C. , Winters Warren J. , Daigle Chan 
Published: December 2007

SummaryA method for installing solid-expandable-tubular (SET) drilling liners across pressure-depleted zones has been developed and demonstrated. High overbalance pressures are known to interfere with conventional SET expansion. "Scoping" allows an expandable liner to expand and move downward while the inner work string and expansion cone remain still. This expansion method keeps the expandable liner in continuous motion, thus reducing the risk of stuck pipe and SET failures related to differential sticking.The most common expansion method involves deployment of an SET liner on an expansion cone assembly connected to a work string. The SET is run to within 5 to 10 ft of the well bottom, then expanded hydraulically from the bottom upward. Initially, the expansion cone remains stationary when the liner is hydraulically pushed downward while expanding. The expanded liner stops advancing when it reaches bottom, and then the cone is hydraulically pushed upward as it continues to expand the liner.Scoping differs from standard expansion in that the expansion cone is initially positioned far off-bottom in the open hole between the previous casing shoe and the depleted zone. The liner is then extruded off the expansion-cone face, literally pumping the expanded liner to the bottom. The continuous movement of the expanded casing across the depleted zone reduces the risk of differential sticking. A purpose-built scoping shoe permits cementing after the pipe expansion on the same trip.This paper describes how scoping is performed and how it worked in a test well. Advantages (including time savings) and practical limitations are discussed. Additionally, the scoping shoe introduces new efficiencies to SET deployment, even if scoping is not used.
Organic Acids in Carbonate Acidizing
Authors: Buijse Marten , de Boer Peter , Breukel Bert , Burgos Gerardo 
Published: December 2007

Summary
This paper discusses the use of organic acid as a stimulation fluid in carbonate formations. Organic acids, such as acetic or formic acid, have been used for many years as alternatives to HCl because of the retarded reaction rate, low corrosivity, and reduced tendency to form acid/oil sludge in asphaltene-rich crudes. In Venezuela, organic acids were pumped in acid-fracturing treatments in deep, hot limestone formations. Although these treatments were very successful, optimization of the design was hampered by the fact that models for organic acid/carbonate spending did not exist. Case histories are discussed later.
A new model for acid spending is proposed in this paper that can be used for strong (HCl) and weak (organic) acids as well as acid mixtures. Compared to existing (HCl) models, the only new element is the acid dissociation constant that describes the differences between strong and weak acids. The model was verified by comparing simulated reaction rates with rates actually measured in the laboratory with a rotating disk. The results of acid-fracture simulations, comparing the etched length and width of organic acid with HCl acid, are also discussed.
Experimental Study of Gas Injection in a Surfactant-Alternating-Gas Foam Process
Authors: Xu Q. , Rossen W. R. 
Published: December 2007

SummaryFractional-flow methods have been shown to be accurate and successful in modeling surfactant-alternating-gas (SAG) foam processes. Fractional-flow theory indicates that the success of gas diversion in a SAG process depends on steady-state foam behavior at very low water fractional flow fw (very high foam quality). Previous simulation studies of these processes have relied on extrapolating steady-state data taken at much higher values of fw. Radically different results are predicted depending on how these extrapolations are made. Data are needed at very low fw to predict SAG performance in the field.Laboratory coreflood experiments were conducted to obtain the needed fractional-flow curves. For each value of fw, constant water- and gas-injection rates were imposed and maintained until the system reached steady state. The corresponding average water saturation in the core was determined by weighing the core continuously during the experiment. Experimental fractional-flow curves are presented for two surfactant formulations in Berea sandstone core, with no oil present, at extremely high foam quality.Results are then scaled up using fractional-flow theory to a hypothetical field-scale application. In both cases, the data scale up to successful mobility control on the field scale. In one case, foam suffered an abrupt decline from stronger foam to coarser foam with increasing foam quality, with a multivalued fractional-flow function, in agreement with some earlier experimental and theoretical results.
Specific Fluid Requirements for Successful Coiled-Tubing Fracturing Applications
Authors: Cawiezel Kay E. , Wheeler Richard S. , Vaughn David R. 
Published: December 2007

Summary
The recent success of coiled-tubing fracturing in shallow wells has increased interest in using coiled tubing for fracturing deeper and hotter wells. Industry efforts now need to focus on understanding what properties a fracturing fluid must possess to carry proppant successfully at high rates through coiled tubing, frac ports, and perforations and into these deeper formations. The key performance requirements of a coiled-tubing fracturing fluid for deeper wells are low frictional pressure loss and adequate proppant-carrying capability after exposure to high-shear zones and high temperatures.
This paper summarizes the results of pilot- and field-scale testing that led to the development of an optimized coiled-tubing fracturing fluid. Results show that polymer-based fracturing fluids can be controllably delayed to have low frictional pressure loss through the curved coiled-tubing unit and straight tubing. However, results also show that fluid stability can be reduced significantly when the fluid is pumped through small-diameter tubing followed by high-shear zones such as frac ports and then by perforations. Results demonstrate that correct fluid choice and fluid optimization are required to meet proppant-transport requirements. For coiled-tubing fracturing to be successful, the fluid and treatment-design recommendations should balance frictional-pressure-loss limitations with fluid-stability limitations.
Experimental and Theoretical Simulation of Gravel-Pack Displacement in Extended Horizontal-Offshore Wells
Authors: Martins A. L. , de Magalhães J. V. M. , Calderon A. , Mathis S. P. , Trujillo C. , Nguyen H. T. 
Published: December 2007

SummaryThis article presents the development of a computational tool to guide horizontal gravel-pack design for long horizontal offshore wells. Mechanistic model hypotheses, experimentation at a large-scale flow loop, and software development are detailed. The computer simulation results are then compared with field data collected in the Campos basin operations, offshore Brazil. A discussion on design alternatives for a long horizontal well at low fracture-gradient formations is presented. This discussion includes a sensibility analysis on screen eccentricity, open and closed blowout-preventer(BOP) configurations, and alpha (alone) vs. alpha plus beta wave displacement options.