bluuebunny/crossref_metadata_2025_split huggingface dataset:
Meeting the Challenges in Design and Execution of Two High Rate Acid Gas Injection Wells
Authors: Benge Glen , Dew E. G. 
Published: December 2007

Abstract
Two high rate acid gas injection wells were drilled in the LaBarge area of Wyoming. These wells were designed for injection of up to 65 million scf/day of a mixture of 65% H2S and 35% CO2. The primary engineering challenges in well design, casing selection, and cementing of the injection strings, along with the related operational challenges for both wells are discussed. Key drivers influencing zonal isolation, salt zone loading, casing and centralizer selection are presented.
Casing selection was influenced by corrosive gas composition, high injection rates, and the potential for salt zone loading. The use of CRA tubulars, heavy wall casing for the salt loading, handling requirements, and centralizer selection are discussed.
The primary driver in cement design was resistance to CO2, as past work has shown little H2S interaction with cement under these well conditions. A discussion of the development of a high alumina cement system with low fluid loss to address CO2 resistance and long liner length is coupled with the quality control steps taken from time of manufacture of the specialty cement to final placement in the well.
Also described is the development of an alternate Portland cement system containing a reduced concentration of Portland cement by the use of sized particles to dilute the cement and reduce total system permeability.
The unique engineering solutions resulted in operational challenges with casing running, cementing materials and equipment. A description of the location problems and the steps taken to resolve the issues are included.
3-D Elastoplastic FEM Modelling in a Reservoir Simulator
Authors: Han G. , Stone T. , Liu Q. , Cook J. , Papanastasiou P. 
Published: December 2007

Abstract
With an increase of loading forces due to continuous reservoir depletion, irreversible rock displacements occur, leading to various problems such as reservoir compaction, surface subsidence, formation fracturing, etc. In the oil industry, numerous efforts have been made to incorporate rock elastoplastic analyses into widely available reservoir simulators. Based on current rock mechanics theories and experimental results, a 3-D elastoplastic approach solved with the Finite Element Method in Corner Point Geometry grid cells is proposed, and its application to a commercial reservoir simulator is demonstrated.
Both Mohr-Coulomb and Drucker-Prager yield criteria are used as definitions of yield surface, where rock behaves elastoplastically. The plasticity modulus is expressed as a function of both rock stresses and strains. Using a generalized plastic strain variable, two types of work-hardening rules including a hyperbolic law and a power law are applied to describe rock cohesion-hardening behaviour, correlated with mechanical behaviour of a medium to strong reservoir sandstone. Simulation results reveal their relative advantages and suggestions are provided for future simulator development.
This discussion can serve as a basis for development of more comprehensive and efficient geomechanical models for large-scale reservoir simulation.
Experimental Investigation and Numerical Simulation of Water Imbibition in Fractured Turbidite Systems
Authors: Cunha L. B. , Bonet E. J. , Cunha J. C. 
Published: December 2007

Abstract
The flow description applied for double porosity reservoirs is of paramount importance for evaluating the performance of fractured turbidite reservoirs. Many authors have measured in the lab and formulated formulas describing the transfer function between the fracture and the contiguous less permeable porous media. Other authors using these transfer functions described the flow behavior in a system of double porosity and double permeability.
In this work, laboratory tests were performed in long cores with different fluids, diverse wettability condition and various flow rates. At first experiments were conducted on unfractured cores. Then, for the same core, geometry, flow pattern and fluids, the transfer function that occurred in a subsequent flow test for a double porosity system was measured. The saturation history during the test was measured with an X-ray scanning system. The experiments were conducted quite differently from those commonly used in imbibition experiments and provided additional insight into oil recovery from fractured reservoirs.
In order to describe the lab flow tests it was used three mathematical approaches, namely: a finite difference commercial reservoir simulator, a semi-analytical solution, and an analytical solution for the hyperbolic system of equations governing the process. The experimental results obtained were matched satisfactorily by the three mathematical approaches investigated. At the end, the first two mathematical methods were applied to predict the production behavior for an equivalent injection pattern in a Brazilian fractured turbidite reservoir.
Improvements for Flow Correlations for Gas Wells Experiencing Liquid Loading
Authors: Kumar N. 
Published: December 2007

Abstract
Improvements to pressure traverse (predictions) using simple modifications to a two phase flow program (Gray1,2 correlation) for gas wells producing some liquids have been discussed in this paper. The Gray correlation was found to be the best of several initially tested. Improvements in pressure traverse predictions with modifications are shown compared to a set of high quality data. The absolute average error between the measured data and calculated data for fifteen wells was reduced from about 28 % to about 22% using suggested modifications or improvements. Modifications tested included modeling downhole condensation or vaporization of water, a correction for water density, use of a regression technique to minimize error in a program that was written to allow input constants to help adjust predications to measurements, and adding multiphase flow regimes in the two phase flow program. Also, some suggestions for future work to improve correlations for liquid loaded gas well pressure profile predications are discussed.
Integrated Characterization of Low Permeability, Submarine Fan Reservoirs for Waterflood Implementation, Chicontepec Fan System, Mexico
Authors: Tyler Noel , Gachuz-Muro Heron , Rivera-R. Jesus , Rodriguez Dominguez Juan Manual , Rivas-Gomez Santiago , Tyler Roger , Nunez-Vegas Victor 
Published: December 2007

Abstract
Through integrated characterization of highly heterogeneous submarine fan reservoirs of the Chicontepec fan system optimum location for a waterflood pilot was identified and tested. Positioned in a high quality, comparatively low heterogeneity part of the complex, results of the pilot indicate that water flooding the Chicontepec is feasible and that the reservoirs tested would benefit from a several pattern, long-term water injection program.
Methodology to Implement the Optimum Fracture Design in an Oil-Bearing Reservoir
Authors: Stegent N. A. , Sorenson F. , Brake S. C. , Fontana C. J. 
Published: December 2007

Abstract
Preparing a completion design can require time and effort to optimize economic returns. Often, actual production results do not reflect the predicted outcome. Many reasons can account for this discrepancy, ranging from incorrect interpretation of petrophysical analysis to unintentional deviation of design during job execution at the wellsite. Completion analysis is essential for determining why actual and predicted outcomes vary; it also helps determine where inaccurate values entered into the design process.
This paper discusses the methodology used to execute an optimized production design. Wellsite analysis and post-production analysis are essential to this process. The paper describes processes used to obtain data for these analyses and for several other methods used to verify prejob parameters. Onsite fluid tests must be comparable to prejob tests to ensure that fracturing fluids perform in the reservoir as in the laboratory. Well selection, petrophysical and rock mechanics analysis, and design considerations are detailed. Most importantly, the onsite mini-frac analysis intrepetation is the iterative link to verify design parameters and is used to incorporate changes that will achieve the optimum stimulation treatment.
Reservoir Performance Under Solution Gas - Drive and Gravity Drainage
Authors: Padilla-S. Roberto , Camacho-V. Rodolfo 
Published: December 2007

Abstract
This work examines the well and reservoir performance under both solution gas-drive and gravity drainage in homogeneous systems. Based on synthetic information obtained with a fully implicit black-oil simulator, the influence of different parameters like oil rate, position of the producing interval, wellbore pressure level, skin factor, and vertical permeability, for both constant oil rate and constant pressure production modes are documented. Analytical results for the reservoir performance during the boundary dominated flow period are derived. An approximate expression that describes the variation of oil saturation with average pressure is presented. For constant oil rate production, the influence of gravity drainage on the inflow performance relationships curves is studied, and a new correlation is presented. For constant pressure production, the decline curve behavior is analyzed and it is found that under favourable gravitational effects, the production behavior shows two decline stages such as double porosity systems; however, it does not follows the typical decline type curves for naturally fractured reservoirs. At certain backpressure values during the first stage an exponential decline behavior could be observed, while during the second stage values of the decline exponent less than zero are observed.
Experimental Study of Effective Diffusion in Porous Media
Authors: Islas-Juárez R. , Samaniego V. F. , Luna E. , Perez-Rosales C. , Cruz J. 
Published: December 2007

Abstract
In this work the effective molecular diffusion in homogeneous porous media was studied. An experimental setup was constructed to measure the effective molecular diffusion coefficient in packed unconsolidated sands, which allowed to take samples of fluids at different positions and times. The fluid samples were analyzed by gas chromatography to determine fluid concentration; these data were analyzed using the Fick’s second law to calculate the molecular diffusion coefficient. These results were compared with those obtained using a different methodology based in pressure changes developed by Luna et al. A good agreement between both methodologies was obtained.
Application of Interval Pressure Transient Testing with Downhole Fluid Analysis for Characterising Permeability Distributions, In-Situ Flow Fractions and Water Cut
Authors: Jackson R. R. , Xian C. , Carnegie A. , Gauthier P. , Brooks A. D. 
Published: December 2007

Abstract
In this paper we describe the application of interval pressure transient testing (IPTT) combined with downhole fluid identification and analysis (DFA) for characterising horizontal and vertical permeability, and determining in-situ effective oil mobility and downhole water cut in a complex and heterogeneous carbonate reservoir. We provide three well examples where interval transient testing and fluid sampling was applied at multiple depths, and resulted in an improved understanding of a complex reservoir.
Use of Advanced Completion Solutions to Maximise Reservoir Potential – Experiences in The Snorre Field
Authors: Skarsholt Line T. , Mitchell Anthony F. , Bjørnsgaard Are H. 
Published: December 2007

Abstract
The Snorre licence operating in blocks 34/4 and 34/7 of the Norwegian North Sea was the first to install surface operated zonal control to allow selective production from different sections of the reservoir. The concept of Downhole Instrumentation and Control Systems (DIACS) has, subsequently, been further developed and refined and is used today, by many operators. The Snorre field remains at the forefront of this development and the technology has been employed in a further 17 wells (both injectors and producers) across the field.
The Snorre reservoir is highly heterogeneous and faulted and consists of layers with differential pressures of up to 150 bar. This has lead to many instances of rapid water and gas breakthrough in individual zones, whilst other layers have remained largely un-drained. The use of DIACS has lead to improved reservoir exploitation and has formed the basis for implementation of the concept as the preferred completion solution for the northern area of the field, via the Snorre B platform.
This paper will focus on the use and advantages of advanced completions from both a reservoir and production engineering viewpoint; it will summarise experience gained with regard to mechanical aspects of the completion hardware; data collection and management and will discuss future plans and expected benefits of this type of completion system.
Pressured Mud Cap Drilling from A Semi-Submersible Drilling Rig
Authors: Terwogt J. H. , Mäkiaho L. B. , van Beelen N. , Gedge B. J. , Jenkins J. 
Published: December 2007

Abstract
Pressured Mud Cap Drilling (PMCD) is an advanced technique to control wells which encounter heavy mud losses and has been applied on onshore and offshore wells with surface wellheads. The key to successfully apply the technique is the use of a Rotating Control Device (RCD), which is a technology taken from Under Balanced Drilling (UBD). PMCD has not been applied to date on subsea wells as rigging up the RCD on the drilling riser brings additional challenges compared to surface wells.
Three subsea wells were drilled Offshore Sarawak, utilizing the PMCD technique. A detailed review was made to rig up an RCD on the drilling riser of a Semi-Submersible drilling rig. The riser between the subsea BOP and the RCD at surface formed a low-pressure system to control the well.
The first 2 wells did not see any losses but on the 3rd well, total losses occurred and the system was activated. The final result gave reason to look back on a successful operation but also good learnings were made for future operations.
High-Temperature Plug Formation with Silicates
Authors: Bauer S. , Gronewald P. , Hamilton J. , LaPlant D. , Mansure A. 
Published: December 2007

Abstract
A grouting system is being developed that is applicable to water shutoff, steam flooding, and high-temperature grouting/plugging for lost circulation. This grouting system uses silicate hydrates as the plugging material. We describe a means to introduce sodium silicate and an activator through a single tubular by encapsulating the activator in a material that is temperature sensitive, thus delaying the initiation of the reaction. The formation of silicate hydrate plugs has been studied over the range of 80°C to 300°C as well as the chemical stability of silicate hydrate for 10-12 weeks.
Deployment of Swelling Elastomer Packers in Shell E&P
Authors: Kleverlaan Martijn , van Noort Roger. H. , Jones Ian 
Published: December 2007

Abstract
In Shell Exploration & Production, swelling elastomers have been deployed in a variety of applications: as a means to establish zonal isolation in liner completions, as a production separation packer, and as an integral part of an expandable open hole clad. In these applications, the elastomers have been run in various open hole, casing, and tubing sizes. A total of around 60 deployments in Shell have been recorded, all of which were technically successful.
Case examples of each of the three mentioned applications will be presented from Shell operations in the North Sea, the Middle East, and the Far East.
Asphaltene Deposition During Drilling with Emulsified Drilling Fluids
Authors: Fjelde I. 
Published: December 2007

Abstract
If the reservoir oil and drilling mud filtrate of drilling fluids are not compatible, mixing of these fluids in the oil reservoir can cause formation damages. For environmental reasons base oils with low aromatic content are preferred in emulsified drilling fluids. The potential for asphaltene deposition by mixing of emulsified drilling fluids and reservoir oils has been studied using stock tank oils with low and high asphaltene content. Two low aromatic emulsified drilling fluids were used, one with mineral base oil and one with synthetic base oil. Asphaltene deposition was studied both in bulk experiments and in floods using core-plugs of sandstone outcrop of low-to-medium permeability.
When crude oils and mud filtrates were mixed in bulk, asphaltene deposition was detected in all cases. The formation damage was largest when the mud filtrates were mixed with the crude oil with the highest asphaltene content. During backflooding with the same crude oil, the formation damages caused by asphaltene deposition were removed. It is concluded that the potential for formation damage by asphaltene deposition is highest for reservoir oils with high concentrations of asphaltene close to the onset of asphaltene deposition. The potential will increase with decreasing aromatic content in the emulsified drilling fluids. If the reservoir oil is not saturated with asphaltenes and the damage area can be swept by the reservoir oil, formation damages caused by asphaltene deposition can be nonpermanent. If white oil is used in laboratory experiments, the potential for asphaltene deposition and removal of this damage can come out wrong.
Cased-Hole Reservoir Saturation Monitoring in Mixed-Salinity Environments – A New Integrated Approach
Authors: Ma S. M. , Al-Hajari A. A. , Berberian G. , Ramamoorthy R. 
Published: December 2007

Abstract
For mature-reservoir description, accurately monitoring oil saturation is a major challenge. Traditional methods for cased-hole saturation monitoring use either pulse-neutron capture or spectroscopic nuclear logging tools. This paper presents a new approach to cased-hole resistivity measurements. This approach has an advantage over nuclear logs because its depth of investigation is more than 10 times that of any nuclear logging measurement.
Calculation of saturation from resistivity logs is difficult if formation-water salinity is mixed. In this paper, we overcome this difficulty by combining pseudo formation-water salinity from carbon-oxygen (C-O) logs with bottomhole samples. Using this calibrated formation-water salinity and variable Archie saturation exponents of drainage and imbibition, calculation of reservoir saturation from cased-hole resistivity measurements becomes more accurate.
Reservoir saturation is also calculated from C-O logs run at the same time as cased-hole resistivity logs. Wellbore fluid reinvasion is identified from C-O derived saturation across perforation intervals. In unperforated intervals, saturation derived from C-O compares favorably with the original openhole log analysis, well history, and fluid-flow profiles from production logs. Reservoir saturation is finalized by integrating saturations from cased-hole resistivity and C-O measurements. This paper illustrates the importance of integrating all data to obtain accurate saturation calculation of producing reservoirs in mixed-salinity environments.
Operational Experience with Use of a Hex Pump on a Land Rig
Authors: Kverneland Hege , Kyllingstad Åge , Moe Magne M. 
Published: December 2007

Abstract
This paper focuses on the operational experience that was gained during field test of the Hex Pump on a land rig in Jasper, Texas in October 2003. This field test showed that the pulsation frequency in the flow from the Hex Pump did not interfere with the MWD-measurements, providing a much cleaner signal to the directional driller. Also, the overall power consumption on the rig was reduced due to use of AC-motors.
Drilling Time Reduction Through an Integrated Rock Mechanics Analysis
Authors: Nes O.-M. , Fjær E. , Tronvoll J. , Kristiansen T. G. , Horsrud P. 
Published: December 2007

Abstract
A working methodology to minimize wellbore stability problems has been established through the use of unique laboratory tests, an experimental database for fluid-rock interaction and physical properties of shales, and an integrated modeling approach utilizing different types of experimental and field data. The model simulations provide output accounting for a wide range of input parameters such as well inclination, mud chemistry, rock mechanical properties, field stresses and pressures, formation anisotropy and shale mineralogy. The model output can subsequently be used to diagnose field drilling problems or to design drilling operations. As an example, data from an HP/HT field offshore Mid-Norway as well as a field in the overpressured shales in the southern part of the Norwegian North Sea have been analyzed and compared.
Use of Drilled-in Casing in Slim Deepwater Exploration Wells
Authors: Leach Colin , Bamford Tony 
Published: December 2007

Abstract
A new type of seabed support system is being developed that incorporates a subsea shut-off system and surface BOP. This enables slim, "finder wells" to be established in deepwater with drilled-in casing. By minimising the loads that must be supported by the vessel, the operator has a much greater choice of vessels for a given water depth. The system as described is aimed at "simple" deepwater wells, such as those found in West Africa – the impact of the approach described in this paper is to reduce exploration well costs by more than 50% when compared to the cost of deploying a "conventional" approach.
With this system, a 7 5/8" casing string is drilled into place (becoming the first pressure containing barrier) and converted into a riser. This is all done on a single trip to speed up the operation and reduce the risk. The casing string is captured and sealed within the subsea shut-off system, only after installing and spacing out a surface BOP. This approach has many advantages.
A surface BOP is used for primary well control, but in the event an emergency disconnection is required, dual shear rams cut the 7-5/8" casing and seal in the well. The system then allows a conventional subsea reconnection of the riser (casing).
This paper describes:
the basis for the design of the system, the engineering work carried out to validate the design, particularly with respect to the soil stability, bending loads and riser analysis. extending the water depth capability of the control system. Improving the reliability of the pipe shearing system A description of other key components of this new drilling system is included. It is intended to utilize composite coil tubing to perform the drilling below the 7 5/8" casing, though conventional slim jointed pipe could be used.
Drilling Fluids Planning and Execution for a World Record Water Depth Well
Authors: Dieffenbaugher J. , Dupre R. , Authement G. , Mullen G. , Gonzalez Y. , Tanche-Larsen P. B. 
Published: December 2007

Abstract
Proper drilling fluids planning and execution play a major role in minimizing the likelihood of drilling difficulties such as those encountered in ultra-deep waters.
Deepwater drilling is inherently expensive. Because of this, the proper selection of drilling fluids and other support technologies requires careful evaluation to diminish commonly observed deepwater challenges. These challenges include hydrate suppression, shallow water flows, logistics, lost circulation mitigation, viscosity profiles. Another critical deepwater challenge is properly managing ECD to maintain optimal well site safety and environmental compliance.
This paper discusses the planning and execution of a drilling fluids program for a world record ultra-deepwater well. The well was located at a water depth of 10,011 ft. (3,051 m) in the Gulf of Mexico's Alaminos Canyon (Block 951). The well was drilled to TD (22,695 ft. [6,917 m]) using an advanced synthetic-based mud that met all Gulf of Mexico compliance requirements and advanced engineering software and tools.