bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of NMR T2 Relaxation to Drainage Capillary Pressure in Vuggy Carbonate Reservoirs
Authors: Ouzzane J. , Okuyiga M. , Gomaa N. , Ramamoorthy R. , Rose D. , Boyd A. , Allen D. F. 
Published: December 2007

Abstract
Capillary pressure curves are a fundamental input to reservoir simulators both from the standpoint of initializing fluid saturations and from the perspective of predicting dynamic reservoir behavior. Traditionally, this input has been obtained from special core analysis (SCAL) from a limited amount of cores due to time and cost. Rock typing is often used to help map the available capillary pressure data to the reservoir layers.
Borehole nuclear magnetic resonance (NMR) has been demonstrated to provide pore size distribution information and methods exist in the literature to derive primary drainage capillary pressure data from the NMR log. In carbonates, however, it has been pointed out that variations exist in the relationship between pore body size and pore throat size. NMR is believed to reflect the former, while the latter controls capillary pressure. Hence, the applicability of NMR derived capillary pressure curves in carbonates has been questioned.
In a well in a complex carbonate reservoir, extensive log and core data has been acquired. We explore the correlation between NMR and mercury injection porosimetry through laboratory experiments on core samples from a variety of carbonate rock types. We further investigate the feasibility of determining primary drainage capillary pressure information from borehole NMR data and comment on the effect of tar or heavy hydrocarbon on the validity of the technique. We also explore methods to improve the accuracy of the results.
Our study shows the following: Under favorable conditions, it is possible to derive primary drainage capillary pressure curves from borehole NMR data in carbonate reservoirsCaution should be exercised in zones containing tar or heavy oilLaboratory studies on core can be used to enhance the accuracy of the results from borehole NMR dataResults from borehole NMR can be more representative of actual reservoir properties in vuggy carbonates than those obtained from SCAL measurements on core plugs of limited dimensions
We discuss the impact of the results on input to reservoir simulation and management.
Real-Time Image Data for Successful Horizontal Drilling in Carbonate Reservoirs Onshore Abu Dhabi, UAE
Authors: Ribeiro Maria Teresa , Al Neaimi Mohamed , Hendrawan Irfan , Karrani Sultan , Saad Mohamed Ben , Ayoub Mohammed R. , Zubair Kamal , Al Marzouqui Khalid , Khoori Suaad 
Published: December 2007

Abstract
The objective of this paper is to present the use of real-time image interpretation during an intensive drilling campaign of horizontal wells in two major carbonate fields onshore Abu Dhabi.
Seismic faults are identified using sophisticated methods for interpretation that revealed major faults as well as smaller ones. These are then calibrated using image logs while drilling the horizontal wells targeting the field development.
Achieving the objective of drilling horizontal wells depends on an accurate well placement within the reservoir which is related with the presence of structural features like formation dips and presence of faults along the hole trajectory. Careful pre-job planning using offset well data and seismic maps and x-sections helps on reducing the uncertainty. However, the unpredictability of structural and stratigraphic reservoir features between planned and offset wells information is always present. Even the formation dips computed from seismic and offset wells are prone to some degree of error.
The advances in real-time data transmission and LWD technology, namely resistivity and density image tools can be used for accurate modelling of the formation dips and structural anomalies and remedial actions taken immediately.
This paper describes the use of real-time image data interpretation and the great value in making geosteering decisions while drilling into reservoirs with structural complex/ unknown geology or in areas with sparse geological/ structural information.
Using image data, trajectories can be adjusted during drilling yielding optional well placement, but also actions for future wells, leading to a better success in the drilling campaign of long horizontal wells with a short tolerance radius.
An integrated multidisciplinary workflow is presented from well planning, using all available data including previous well information and the continuous update of the reservoir understanding, to immediate decisions while drilling. Several examples illustrate the different phases leading to the well conclusion and the use of such valuable information in better reservoir knowledge.
Finally, a comparison (LWD and WL) and value of information is also presented to highlight the advantages/ drawbacks of different tools on a case dependent selection.
Successful Drilling of a High Step-Out Ratio Well With Water-Based Mud in Morecambe Bay
Authors: Hodder M. , Ross N. , Gibb S. , Redgrave S. 
Published: December 2007

Abstract
The H9 well in Morecambe Bay was drilled in Block 110/2a to a total depth of 18,009 ft at true vertical depth of 3484 ft, giving a step-out ratio of 5.17. This represented a record step-out ratio for this area and was achieved using water-based drilling fluids. This achievement was made possible by careful planning, good drilling practices and the judicial use of lubricants.
Normally an oil-based mud (OBM) would be used for a well of this type; however the field is in shallow water, close to shore in an environmentally sensitive area, precluding the use of OBM.
Rotary steerable tools were employed to maintain the well path within a very thin (17-ft) reservoir. A total of 8,891 ft was drilled in the reservoir section and the well path only exited the reservoir once for a short length before being brought back.
Although the well was planned to TD at 18,000 ft, it was not realistically expected to achieve over 15,000 ft. When drilling ceased, it was for geological reasons-the well path was dipped just prior to TD to assess reservoir thickness, which increased the torque significantly. Without this planned deviation, further drilling would have been possible.
This paper describes the planning process, the drilling practices and the fluid characteristics that enabled the well to be successfully completed.
Improved and More-Rapid History Matching With a Nonlinear Proxy and Global Optimization
Authors: Cullick A. S. , Johnson D. , Shi G. 
Published: December 2007

Abstract
The generation of reservoir simulation models that match field production data has been a long-time industry challenge. This paper presents two workflows for assisted history match. One workflow minimizes the misfit between simulated versus history data with a global optimizer, by adjusting reservoir and well unknown parameters in the simulation model. An alternative workflow is used to reduce the number of numerical simulations. The workflow trains a comprehensive nonlinear proxy model with a small set of numerical simulations from experimental design. The nonlinear proxy neural network is used to characterize parameter sensitivities to reservoir parameters and to generate solution sets of the parameters that match history. The neural network solution sets can be validated with the simulator or used as initial solutions for a full optimization. The paper demonstrates that the neural network is an excellent proxy for the numerical simulator over the trained parameter space. A field example from a water injection project illustrates the approach with excellent matches for individual well fluid rates, using a number of reservoir and well parameters. The use of the proxy yields excellent matches for well production profiles.
Transaction Costs and Risk Preferences: Modeling Governance in Offshore Drilling
Authors: Jablonowski C. J. , Kleit A. N. 
Published: December 2007

SUMMARY
This research examines oil companies' decision to vertically integrate into the drilling function within a transaction cost economics framework. Risk preference is also investigated as an explanation for organizational choice. Econometric models are specified and estimated for organizational choice and for the underlying cost functions of competing organizational forms. Estimation of the cost functions permits isolation of the effects of transaction attributes to each form of organization, shedding light on the relative impacts of hazards of exchange and internal costs. Results provide support for both the transaction cost and risk preference hypotheses as determinants of organizational form. The cost functions also enable estimation of the incentive gains of outsourcing and the avoided transaction costs due to organizing activities internally.
Slimhole Drilling: An Economic and Effective Answer to the Development of Previously Known "Uneconomic Reserves"
Authors: Khan Hasnain Ahmad , Sajid Hafiz Lutf-ur-Rehman , Zahid Salman 
Published: December 2007

AbstractThe economics of exploration and production (E&P) continue to encourage use of new methods to reduce costs. Slimhole technology is one such method which offers effective cost reduction by reducing; equipment size, tubular costs and environmental impact.The technology is a proven alternative to conventional drilling operations. Since it is now technically feasible and economically viable to produce from smaller well bores. It has become a realistic alternative to the development of previously known uneconomic reserves. Also extensive application in exploration has validated the use of disposable slimhole wells to improve seismic data interpretation.Currently the E&P industry faces the challenge of increasing production to meet growing energy needs. Many proven reserves remain unexploited due to unfavorable economics (e.g. small size, remote location). A reduced cost slimhole drilling plan can put these reserves to production. This paper outlines the application of slimhole technology to the development of such reserves which cannot be developed using conventional drilling. Cost reduction, which is heavily influenced by hole size, is a major factor prompting the application of slimhole technology to development of small reserves.This paper provides economic comparison between slimhole technology and conventional methods of exploitation. It also outlines a strategy to identify and produce smaller reserves using slimhole as an effective technique for enhancing exploitation economics.
Use of Reservoir Simulation for Optimizing Recovery Performance of One of the Iranian Oil Fields
Authors: Taheri A. , Sajjadian V. A. 
Published: December 2007

Abstract
A black oil reservoir simulator has been used to determine the reservoir management and production strategies to optimize the oil recovery from an offshore low porosity, low permeability carbonate reservoir with permeability of 1-3 md and porosity of 5-20%. This reservoir is a candidate for an EOR process, because the reservoir production rate has been declined rapidly to about half of the initial production rate within four years. The injection techniques that were used in this study include: (1) water injection, (2) gas injection, (3) water alternating gas injection (WAG), (4) simultaneous water alternating gas injection (SWAG), (5) gas injection in the top of the reservoir with water injection in the reservoir bottom and (6) gas injection in the bottom of the reservoir with water injection in the reservoir top. Specific strategy that was used includes the use of horizontal injectors and producers. This well configuration has been shown to yield the best oil recovery compared to other well configurations. Simulation results show that the most economical method to produce this reservoir is WAG. This production strategy has resulted in better efficiency and therefore higher oil recovery and good economics.
Beyond the Limits of Drilling and Completion—Expandables
Authors: Mawford Nick , Stephenson David , York Pat , Rosenberg Steve 
Published: December 2007

AbstractDrilling trouble zones has haunted drilling operations experts through the years. Conventional methods for mitigating formation problems encountered during the drilling phase of a well, such as unstable formations, overpressured formations, and loss zones, are often costly and ineffective. Age-old methods of simply setting a casing and drilling ahead with a different mud weight and a smaller hole size are becoming increasingly unacceptable as the industry strives to reach deeper reserves.The use of cement, chemical "cocktails," and loss-circulation materials can significantly increase well costs. Using conventional solid expandable drilling liners which are tied back to the previous casing can also be cost prohibitive and lead to non-standard equipment requirements for the following section of the well.This paper explains how a non-cemented, solid expandable open-hole clad can be installed remotely from a previous casing to isolate problem formations so that the target setting depth can be reached with conventional casing, without sacrificing hole size.Installation of a solid expandable open-hole clad will result in mitigation of problem sections and allow drilling to continue with the same hole size. The problem formation is straddled with a short length of expandable casing or clad with a resultant drift ID equal to the diameter of the original hole or drill bit. With this full bore ID, further clads can be run through, and deployed lower in, the same hole section.In addition to reducing operational risks associated with expanding long lengths of conventional tied-back solid expandable open-hole liners, the open-hole clad or "Steel Mudcake" significantly reduces well costs and results in higher and earlier production associated with the increased hole size in the reservoir section.Open-hole patch systems have been used extensively with excellent results in carbonate formations, in remote locations over the past 20 years. This type of system is expected to have a significant effect on the global drilling industry because it will allow downsizing of conventional casing designs by eliminating conventional and expandable contingency casing strings without sacrificing completion and production performance. This advantage allows the operator to drive down well costs by minimizing the well's "flat" time on the drilling curve and using conventional long, tied-back expandable drilling liners.
A Novel Model for Viscoelastic Fluid Flow in Porous Media
Authors: Garrocuh A. A. , Gharbi R. B. 
Published: December 2007

Abstract
Steady-state flow experimental data have been analyzed for two commonly used polymers representing two generic classes: polysaccharides (xanflood), and partially hydrolyzed polyacrylamides (pusher-700) flowing inside bead packs and Berea sandstone. Oscillatory flow measurements have been used to compute the polymer solution's longest relaxation time (θf1) which is referred to as the characteristic relaxation time in this paper. Steady-state flow experimental data for the two polymers combined with measured polymer viscous properties have been converted to average shear stress-shear rate data inside porous media. An average power-law exponent (n¯) is therefore obtained for the polymer flow inside porous media. Using and θf1, and n¯, rock permeability (k) and porosity (ϕ) and fluid flow velocity (u), a viscoelasticity number (NV) is calculated, and found to strongly correlate with the pressure gradient inside porous media. This correlation is the basis for defining a viscoelastic model for polymer flow, analogous to Darcy's law. The proposed model asserts a non-linear relationship between fluid velocity and pressure gradient. It accounts for polymer elasticity, and for pore geometry changes due to molecular adsorption and mechanical entrapment.
Independent Real-Time Quality Control of Directional Survey Data—Adding Value and Improving Safety on the Norwegian Continental Shelf
Authors: Nyberg Runar Kolseth , Håvardstein Stein Tjelta 
Published: December 2007

AbstractData quality is a number one priority when using data for real time decision making. Independent quality control is the key element for good reservoir and safety management. The concept of independent QC shows how gross errors and poor tool performance could easily be detected. Approximately 94%1 of the wells drilled showed some kind of gross errors and most of these were resolved without any loss of rig time.The in-house developed Survey QA/QC application connects to the service companies’ WISML servers, and retrieves standard parameters and detailed magnetic survey data information.Standard parameters are streamed directly into the Directional Drilling Database, preventing mistyped survey data being presented and used.The detailed magnetic survey data is processed in the Survey QA/QC application where lack of quality is highlighted.If the data quality requirements are not met, the asset's Directional Drilling Surveying Specialist will discuss with the service company representatives and decide if any further action is required. This close interaction between operator and Service Company increases the potential to learn from each other and overall achieves a better service and common understanding. This however does not alter lines of responsibility
Managing Sustainable Annulus Pressures (SAP) in Adco Field
Authors: Al Hosani Hasan 
Published: December 2007

Abstract
Managing Sustainable Annulus Pressures (SAP) is one of major well's integrity challenges in the oil & gas industry as they pose an HSE concern.
As the wells ages, more wells do exhibit SAP of a varying degrees, some could be managed, and others should be dealt with on fast track basis & send to work over (if required).
The objective of this paper is to provide an overview of ADCO's initiatives in managing casing sustainable annuli pressure in ADCO field.
Since the introduction of ADCO SAP guidelines in June 2002, to manage casing annuli pressures and ensure the integrity of all wells during their life cycle, ADCO field embarked on an aggressive campaign to implement the guidelines and manage SAP wells effectively.
The paper sheds light on how the SAP wells are being managed, base line data collection, integration with PIES (Production Injection Export System), SAP current status (compared with that recorded in early 2003) and associated KPI's.
And finally touch on recommendations & way forward based on ADCO massive experience gained during the last 3 years to ensure the integrity of all ADCO wells.
Faster, Longer, and More-Reliable Bit Runs With New-Generation PDC Cutter
Authors: Clegg J. 
Published: December 2007

Abstract
A new process for manufacture of Polycrystalline Diamond Compact (PDC) cutters creates a wrapped thermostable region across the face and around the periphery of the diamond compact. This differs significantly from existing first-generation thermostable product as the treated region has complex geometry in three dimensions. This paper describes the new geometry of the cutters and shows how the thermostable region supports the cutter as it slowly wears. It also shows how the onset of wear into the tungsten carbide substrate behind the diamond layer is delayed significantly.
Laboratory test results show a 270% improvement in abrasion resistance over premium PDC material and field case studies show how the new cutter type has saved money while drilling and allowed PDC bits to drill sections that previously required multiple bit runs.
Case studies are presented from a variety of applications around the world including hard and interbedded formations and abrasive sands. They compare direct offset runs with existing, first-generation thermostable data.
The new-generation thermostable cutter stays sharper, for longer, than either the first-generation thermostable cutter or previous non-thermostable PDC material. It will allow development of lighter set and more aggressive bit designs able to set new standards in speed, steerability and stability without having to sacrifice durability in the design.
New cutting material developments are at the forefront of the ongoing improvement of PDC bits. This is a significant development that shows a step change in cutter and bit performance. It allows for the realization of a new generation, not just of cutters, but also of bit designs.
Cost-Effective Life-Cycle Profile Control Completion System for Horizontal and Multilateral Wells
Authors: Ogoke V. , Aihevba C. , Marketz F. 
Published: December 2007

Abstract
A new cost effective life-cycle profile control completion system has been developed to solve major problems associated with surveillance and interventions in horizontal and TAML level 2 multilateral wells completed with ESP.
As fields age and produced water oil ratio increase, surveillance and profile control in the multilateral wells drilled in PDO have become a major challenge. These wells are TAML level 2 multilaterals. Production from two to nine barefoot lateral legs is commingled and artificially lifted by electrical submersible pumps (ESP). ESPs prevent through tubing access to the laterals. Installation of a Y-tool allows for wireline (WL) or coiled tubing (CT) deployed logging and some remedial CT intervention. Well and reservoir management challenges arise from completion design limitations such as barefoot completion, commingled production, the presence of ESPs, access to the TD of the backbone and inability to selectively re-enter the laterals.
New minimum-cost zonal isolation and downhole control technologies provide an opportunity to retrofit TAML level 2 multilateral wells for well and reservoir management purposes. Swelling elastomers in the form of the expandable zonal inflow profiler (EZIP) tool allows segmentation of wellbore section into a discrete number of management intervals. Interval control valves provide the capability to shut-off water or gas.
This paper describes the design and application of remotely operated selective EZIP completion technology (SECTOR) in TAML Level 2 multilateral wells in the carbonate reservoirs of Qarn Alam Asset of PDO. With SECTOR, existing TAML Level 2 multilateral oil producers are converted to TAML-5 multilateral wells. The lateral legs are isolated from each other and can be selectively produced, shut-off or stimulated. The need for CT interventions for production logging and water shut-offs is removed. The water shut-off process offered by this technology is reversible.