bluuebunny/crossref_metadata_2025_split huggingface dataset:
Isolating Water Production at the Source Utilizing Through-Tubing Inflatable Technology
Authors: Kelbie Graeme M. , Garfield Garry L. 
Published: December 2007

Abstract
With continual increase in water production from maturing reservoirs comes the expense of installation of surface handling equipment, disposal and environmental concerns and a reduction in production efficiency from hydrocarbon producing wells. These costs run into millions of dollars every year, dealing with this problem. The operators of these wells have utilized differing technologies and procedures in efforts to control production of these unwanted fluids. Water shut-off applications in one way or another are an everyday part of well servicing work. Some of the methods and practices currently used today to help combat this problem include, placement of cements, plugging back the zone with the aid of mechanical isolation devices, pulling the completion and performing work-overs, and the utilization of purposely designed cements or chemical water blocking agents. Initial efforts to utilize such fluids proved encouraging but methods were required by the operators in order to allow accurate placement of these chemicals. Some of the drivers are;
Economics, in terms of the relatively high cost of such fluids and; The reaction of such water blocking chemicals when placed incorrectly within producing formations and the inability to reverse engineer such misplacements.
Couple these problems with the well geometry to be worked in and the solution of placement can be seen to involve many diverse complications. For this reason the requirement for innovative through-tubing zonal isolation solutions has never been greater. Through-tubing inflatable technology has, for some time now, been providing high-expansion devices in order to provide our industry with an economical and reliable method of isolating and placing water blocking treatment fluids. In this paper we will focus on current inflatable tools that are available today and how they can be utilized to provide cost effective water shut-off solutions at the source of the problem.
Influence of Shrinkage and Swelling of Coal on Production of Coalbed Methane and Sequestration of Carbon Dioxide
Authors: Siriwardane H. J. , Smith D. H. , Gorucu F. , Ertekin T. 
Published: December 2007

Abstract
The potential for enhanced methane production and geologic sequestration of carbon dioxide in unmineable coal seams needs to be evaluated before large-scale sequestration projects are undertaken. Coal is known to competitively adsorb carbon dioxide and methane gases. Laboratory experiments indicate that coal will swell when a gas is adsorbed and shrink when a gas is desorbed. The swelling and shrinkage may change the cleat porosity and permeability of the coal. This paper deals with the influence of shrinkage and swelling of coal on the production of methane from, and injection of carbon dioxide into, a coalbed reservoir. A three-dimensional swelling and shrinkage model was developed. This model is based on constitutive equations that account for coupled fluid pressure-deformation behavior of a porous medium that undergoes swelling and shrinkage. The swelling and shrinkage strains are computed on the basis of the amounts of different gases adsorbed or desorbed. The permeability of the reservoir is modified by the shrinkage or swelling. The paper presents numerical results on the reservoir performance during injection of carbon dioxide in a previous field test that has been reported in the literature. The results indicate that coal swelling and shrinkage can influence the production rates and reservoir pressure distribution in the field.
A New Pulsed Neutron Sonde for Derivation of Formation Lithology and Mineralogy
Authors: Pemper R. , Sommer A. , Guo P. , Jacobi D. , Longo J. , Bliven S. , Rodriguez E. , Mendez F. , Han X. 
Published: December 2007

Abstract
A new openhole logging service, RockViewSM, has been developed which provides lithological and quantitative mineralogical information for accurate formation evaluation. The assessment begins with elemental formation weights and follows with an interpretation of lithology and mineralogy. Lithologies are divided into general categories including sand, shale, coal, carbonates, and evaporites. Potentially identifiable minerals are quartz, potassium-feldspar, albite, calcite, dolomite, siderite, anhydrite, illite/smectite, kaolinite, glauconite, chlorite, pyrite, and others.
The logging system utilizes an electronic pulsed source to send high energy neutrons into the surrounding formation1-8. These neutrons quickly lose energy as a result of scattering, after which they are absorbed by the various atoms within the ambient environment. The scattered as well as the absorbed neutrons cause the atoms of the various elements to emit gamma rays with characteristic energies. These are measured with a scintillation detector, resulting in both inelastic and capture gamma ray energy spectra. A matrix inversion spectral fit algorithm is used to analyze these spectra in order to separate the total response into its individual elemental components. The prominent measured elements associated with subsurface rock formations include calcium, silicon, magnesium, carbon, sulfur, aluminum, and iron. Potassium, thorium, and uranium are measured separately with a natural gamma ray spectroscopy instrument9-11. The tool response is characterized for each individual element by placing it into formations of known chemical composition.
Interpretation of the data begins with an assessment of the elemental formation weights, which then leads to a determination of lithology and mineralogy. Each step in the process is guided by the examination of ternary plots containing selected elements. Magnesium is an extremely important part of the interpretation process since it distinguishes dolomite from calcite and helps to identify various types of clay.
Data from field examples is presented in order to illustrate the effectiveness of this technology.
Borehole Deviation Surveys Are Necessary for Hydraulic Fracture Monitoring
Authors: Bulant P. , Eisner L. , Pšencík I. , Le Calvez J. 
Published: December 2007

Summary
Significant errors in the calculated azimuth and other parameters of a monitored fracture can be caused by not performing accurate borehole deviation surveys for hydraulic fracture monitoring (HFM) and neglecting the effects of the deviating borehole trajectory. For common HFM geometries, a 2° deviation uncertainty of the positions of monitoring or treatment well surveys can cause more than a 40° uncertainty of the inverted fracture azimuths. Furthermore, if the positions of the injection point and the receiver array are not known accurately and the velocity model is artificially adjusted to locate perforations on assumed positions, several milliseconds discrepancies between measured and modelled SH-P-wave traveltime differences may appear along the receiver array. These traveltime discrepancies may then be misinterpreted as an effect of TI anisotropy, and use of such an anisotropic model may lead to the mislocation of the detected fracture(s). The uncertainty of the relative positions between the monitoring and treatment wells can have a cumulative, non-linear effect on inverted fracture parameters.
Interfacial Instability in Reactive Miscible Flow Displacements
Authors: Ghesmat K. , Azaiez J. 
Published: December 2007

Abstract
Flow processes that involve the displacement of a viscous fluid by a less viscous one often lead to a hydrodynamic instability known as viscous fingering. In this study the viscous fingering instability for reactive flows will be addressed. In order to understand the physics of this reactive flow displacement, the basic equations of conservation of mass, energy and momentum are solved for a two-dimensional porous medium. The flow is modeled numerically using a spectral method based on the Hartley transformation. The streamfunction and concentration fields are determined for the two dimensional flow in every time-step to track the development of the flow. In this study, two different kinds of auto-catalytic reactions are considered and the effects of stoichiometry on finger patterns are examined. Finger patterns are analyzed for different values of the viscosity ratio, reaction rate and order. We will discuss how the interplay between chemical reaction and hydrodynamics could result in interesting instability schemes. Physical discussions of how the reactions may affect the viscous fingering patterns are also presented.
Field and Laboratory Observations of Post-Failure Stabilizations During Sand Production
Authors: Morita N. , Fuh G. -F. , Burton B. 
Published: December 2007

Abstract
Sand flow models have been successfully applied to heavy oil reservoirs1,2,3. However, when these models are applied to light oil and gas reservoirs, the equations controlling generation of eroded solid mass or sand release rate are vastly simplified4–11 necessitating further field observations controlling sand flow rate in order to improve accuracy. Sand flow is catastrophic when formation is soft. However, if certain conditions are satisfied, the sand rate is reasonably stable. This paper clarifies nine forms of post-failure stabilization. Subsequently, field methods to deal with sand problems with uncertain sand rate predictions are proposed.
Focused Risk-Management Brings a Step-Change Improvement in Drilling Performance at Sakhalin's Odoptu ERD Development
Authors: Mohammed N. , Chernov M. , Mañalac-Trøan E. , Kaydalov Y. 
Published: December 2007

Abstract
Since 1998 Rosneft SMNG (Sakhalinmorneftegas) has been developing the northern part of the Odoptu structure, near-shore to eastern Sakhalin Island, using ERD (extended reach drilling). Discovered in 1977, North Odoptu is alone among Sakhalin ERD projects in that it is entirely Russian operated and utilizes a unique hybrid of both Russian and international capabilities to address the considerable challenges of ERD well construction. To date 21 wells, with horizontal displacement/TVD aspect ratios up to 4.1, have been drilled and completed from two land-based drilling locations.
The use of rotary steerable (RSS) technology has more than doubled net drilling performance compared with early wells drilled using positive displacement motors (PDM's). A hole-cleaning challenge remains however, due to a practical necessity for back-reaming while tripping out of the hole. This has led to serious delays as localized unstable sections of the well-bore collapse due to mechanical disturbance, forming cavities that complicate hole-cleaning operations with pack-offs and stuck-pipe.
Low-resolution 2-D seismic has been a limitation on understanding the detailed nature of the over-burden stratigraphy and thus the ability to characterize the cavities. Geo-mechanical models, while clarifying the impact of the regional stress regime, have indicated that the origin of this instability phenomenon may not be due to compressive shear-failure.
The primary focus has therefore been on the development of cost-effective and innovative drilling optimization techniques to predict and identify cavity zones early in the drilling operation, and application of a fit-for-purpose, rig-based, risk-management approach to well-bore instability events. The progressive application of these techniques and the adopted risk-mitigation strategies is documented. This approach, in conjunction with the use of a regularly updated geo-mechanical model, has resulted in a successful outcome for well construction in a previously severely problematic region of the field.
The ability to recover well from instability-related setbacks has helped to foster a co-operative, continuous-improvement culture among the extended drilling team - Russian operator and international contractors alike. Recommendations are made for follow-on technologies and strategies that will have the greatest impact on the next phase of field development.
A Semianalytical, Pressure-Transient Model for Horizontal and Multilateral Wells in Composite, Layered, and Compartmentalized Reservoirs
Authors: Medeiros F. , Ozkan E. , Kazemi H. 
Published: December 2007

Abstract
This paper presents a semianalytical model for the pressure-transient analysis of horizontal wells in composite, layered, and compartmentalized reservoirs. The model divides the reservoir into blocks that represent locally homogeneous substructures of the reservoir and couples the analytical, pressure-transient solutions at the block boundaries. This approach is consistent with the averaging effect of pressure transients and provides an alternative to full numerical modeling of horizontal-well pressure-transient responses in heterogeneous formations. The model can also be generalized for multiple wells of different geometry including multiple laterals.
Integrating People and Technology: Successful Implementation of Six Key Elements Towards Project Excellence in Angsi Field Development, Malaysia
Authors: Karim Rahimah Abd. , Dahlan M. Shaufi , Noordin Khairul Annuar , Noor Harun M. 
Published: December 2007

Abstract
Angsi is an integrated oil and gas development project in offshore east coast of Peninsular Malaysia. It is one of the biggest oil producers in Malaysia, contributing one-sixth of the total national daily oil production. During its planning and execution stages, the project has had many successes and positive outcomes. It has been recognized as the model of success for all domestic and international operations in PETRONAS Carigali Sdn. Bhd. (PCSB).
The uniqueness of achievements in Angsi project relies on the successfulness of integrating its people and technology. With the recent skyrocketing oil price, the trend has been to chase for additional reserves and maximize crude production, and make it happen by whatever means possible (new technologies, joint ventures, aggressive recruitments etc). However, many projects failed to achieve these targets, despite being equipped with niche and advanced technologies.
Angsi project has successfully overcome these obstacles. The secret relies in the six key elements that have been nurtured in the working culture of every team member, which are; people, focus, integrated approach, planning, communication and feedback loop. With this unique culture, it has allowed the team to achieve major successes over the past 5 years.
Among those is the successful implementation of the largest platform-based hydraulic fracturing program worldwide, and first in Malaysia. This allows the development 0.5 TCF gas from the otherwise uneconomic tight gas reservoir. The team also managed to increase its reserves level 2.5 times from its initial size. Consequently, it increases Angsi's daily production rate from 65 to 115 kbpd. Finally, Angsi project successfully reduces its unit development cost (UDC) by 67%, lowering it from 5.1 USD/boe to 1.7 USD/boe.
This paper discusses how the six key elements have contributed to the successes of Angsi Field Development Project.
Reaction of Calcite With Surfactant-Based Acids
Authors: Al-Mohammad A. M. , Nasr-El-Din H. A. , Al-Aamri A. M. , Al-Fuwaires O. 
Published: December 2007

AbstractSurfactant-based acids have been extensively used in matrix and acid fracturing treatments in carbonate formations. As the acid spends and the pH rises, the surfactant molecules aggregate and form long entangled micelles, which enhance the apparent viscosity of the solution. The high viscosity is required for proper acid diversion, which is needed in horizontal and vertical wells with long target zones. Successful field data were obtained with surfactant-based acid, however the impact of the viscoelastic surfactant used on the reaction of the acid with the rock was not systematically examined before. Therefore the objective of the present work is to examine in detail the effect of a viscoelastic surfactant (amphoteric) on the reaction of HCl acid with calcite.The reaction between calcite and surfactant-based acids was thoroughly investigated using the rotating disk apparatus. The effects of disk rotational speed, surfactant concentration and temperature on the dissolution rate were determined. All experiments were conducted using 20 wt% HCl and various combinations of corrosion inhibitor and surfactant concentrations. The system pressure was maintained at 1,000 psi and the reaction was allowed to proceed for 20 minutes only. Samples from the reaction vessel were collected at various times and were analyzed for calcium using ICP. The apparent viscosity of surfactant-based acids was measured as a function of shear rate, temperature, and surfactant concentration using a HTHP Brookfield viscometer.The results obtained indicated that the viscoelastic surfactant significantly reduced the dissolution rate of calcite with HCl. This trend continued as the concentration of the surfactant was increased to 4 wt%. The effect of temperature on the dissolution rate was similar to that of temperature on the apparent viscosity of surfactant solutions where there was a maximum in viscosity at 50-60°C. The dissolution rate was controlled by mass transfer of H+ to the surface of calcite.
Buckling of Tubulars in Actual Field Conditions
Authors: Menand S. , Sellami H. , Tijani M. , Akowanou J. 
Published: December 2007

Abstract
Buckling of tubulars inside wellbore has been the subject of many researches and articles in the past. However, these theories have always followed the same assumptions: the wellbore has a perfect and unrealistic geometry (vertical, horizontal, deviated, curved) and the friction is ignored, conditions relatively far from actual field conditions. How do tubulars buckle in actual field conditions, that is, in a naturally tortuous wellbore with friction and rotation ? Can we apply conservatively theories developped for perfect well conditions (no tortuosity, no friction) to actual well conditions ? This paper gives answers to these questions in comparing results obtained from existant models with results obtained from an advanced model dedicated to drillstring mechanics.
Firslty, this paper presents the new developements integrated in a recently advanced model for drillstring mechanics and enabling to take into account the buckling phenomenom in any actual well trajectory. Secondly, this paper shows the influence of tortuosity and friction on the buckling phenomenom for some practical and critical case met in the drilling industry. These tortuosity and friction effects are demonstrated with an experimental set up that enables to confirm theoretical features. Lastly, we compare results obtained from existant models with results obtained from our new model to evaluate the tortuosity and friction effects on the critical buckling load found in the litterature.
North Sea Completions: Trends, Reliability, Services, and Resources
Authors: Elliot G. 
Published: December 2007

Summary
BP's North Sea Strategic Performance Unit, headquartered in Aberdeen, is a large, geographically and technically diverse business. It encompasses some 45 fields in the UK and Norwegian North Sea, mainland UK and the Netherlands, with wells drilled from all rigs; subsea, platform, and land. There is a wide range of completion requirements in these wells, from open-hole to sand-control to horizontal perforation across the reservoir, and all forms of artificial lift, together with intelligent completion components. From 2001–2005, approximately 150 operated wells have been completed with the number per year ranging from 9 to 37 planned for 2006. BP will invest ca. $640MM in Drilling and Completions in the region during 2006, with completion spend a significant percentage of this figure ( &gt; 30%).
With this high activity and spend, ensuring completion reliability is key to maximizing reserves, and hence the return from each well. Reliability starts at the completion design phase and goes through to installation and on-going well management activity. The purpose of this paper is to articulate key directions taken in an attempt to maintain (and improve) overall completion effectiveness, against a backdrop of high oil price, increasing activity and competition for services and resources. I have discussed ‘where we were, where we are now and where we intend to go’ in various important areas, all ultimately linked to optimizing completion performance.
Areas of focus include; People (resource planning, training, organization structure and the impact of market pressure), Completion Equipment and Services (equipment standardization and inventory management), evolution of Completion Design (type and size of well, material, lifetime). Reliability and performance data will be presented. An internal study in 2004 showed that approximately 20% of wells less than 3 years old were having completions integrity problems. The causes will be highlighted and discussed, together with the key reasons for completion Non-Productive Time.
An Investigative Study of Potential Emulsion Problems Before Field Development
Authors: Kokal S. , Al-Ghamdi A. , Meeranpillai N. S. 
Published: December 2007

Abstract
Before the development of a field it is worthwhile to determine the characteristics of crude oil emulsions. This may be even more important if the wells are to be equipped with electrical submersible pumps (ESPs) which can create a shearing environment resulting in tight emulsions. One such study was conducted to determine the characteristics of emulsions from a cluster of oil fields planned for development. The proposed development is to produce from three fields and several different reservoirs. The central crude processing facility will process ~500 MBD of crude and 50 MBD of water. A study was conducted to determine the impact of ESP on emulsions and hence on the ESP design (horsepower) and the possibility of demulsifier injection downhole. The emulsion properties are also needed for the design of central wet crude handling facilities. A series of emulsion tests were conducted with crudes from different reservoirs at bottomhole and surface temperatures, range of watercuts and shearing conditions. The results are provided in terms of ‘relative’ tightness of emulsions from different reservoirs. The viscosities of various emulsions were also determined. The results indicate that demulsifier injection facilities will be needed at the wet crude handling facilities and possibly in wells from one reservoir that has a high asphaltenic and viscous crude. The paper provides a framework of laboratory emulsions studies that can provide valuable information for the design of processing facilities before they are built. The paper also discusses some practical aspects of demulsifier treatment program including demulsifier selection and optimization and methods to prevent emulsion problems.