bluuebunny/crossref_metadata_2025 huggingface dataset:
Downscaling Geomechanics Data for Thin Beds Using Petrophysical Techniques
Authors: Qiu K. , Marsden J. R. , Solovyov Y. , Safdar M. , Chardac O. , Shatwan M.
Published: December 2007

Thin-bed sequences, especially those made up of alternating weak and strong sand layers with thickness of less than 1-ft, present a particular challenge in the generation of mechanical earth models (MEMs) for geomechanics design and analyses. Because these beds are thinner than the tool resolution, their heterogeneity and the variations between adjacent layers are often undetected by logging tools normally used to acquire geomechanics data. In other words, these tools cannot resolve the existence of alternating strong and weak sequences; they provide only averaged mechanical properties across these sequences.

In one such case, an MEM and sanding study based on wireline sonic data indicated no tendency for sanding across a thick reservoir interval at the drawdowns required for economic oil production. The somewhat flat, log-derived curve of unconfined compressive strength (UCS) indicated that the entire reservoir was above the critical sand-free UCS state; however, laboratory data had revealed a large spread in UCS values, including rock strength values that are indicative of a significant sanding risk. In fact, the field had a history of solids production with depletion.

Using the high-resolution images (with vertical resolution of 0.2 in.) provided by a microresistivity imaging tool across the same thin-bed intervals, and using alpha processing and other petrophysical log enhancement to further improve data interpretation, it was possible to generate a high-resolution (around 0.2 in.) porosity log. These downscaling techniques were combined with an empirical UCS-porosity relationship obtained from the available laboratory data. The resulting downscaled UCS log exhibited the wide range of strength values that were known to exist across the thin-bed sequence and were consistent with the history of sand production in the field.

The remaining sanding evaluation for the well was completed using this integrated petrophysics and geomechanics approach. When the MEM and sanding analyses were extended to other wells in this field, the results matched well with the actual depletion curves and sanding history data.
A Miscible WAG Project Using Horizontal Wells in a Mature, Offshore, Carbonate Middle East Reservoir
Authors: Schneider C. , Shi W.
Published: December 2007

This paper summarizes the design, operation, results, and reservoir modeling of a miscible hydrocarbon gas injection pilot using horizontal wells in the Fateh Mishrif, a large carbonate reservoir in an offshore operating environment.The pilot included a single horizontal water-alternating-gas (WAG) injector flanked by two horizontal producers drilled near the base of the reservoir.The three-well pattern was surrounded by four water injectors which provided confinement and pressure control.Produced gas from the field was used for injection without supplemental enrichment.

The pilot began operations in 1997. Commencing in 1999, gas was injected in three cycles over a period of four years. A clear incremental oil rate response to the gas injection was first observed in early 2003, peaking with a 400% incremental oil rate increase from the two producers.

Pilot results have been history matched with a compositional reservoir model to reconcile reservoir characterization interpretations and to provide prediction of ultimate recovery. Incremental recovery over waterflood operations is predicted to be 6% of original oil-in-place for 0.15 hydrocarbon pore volumes of gas injection.
Production Optimization in ESP Completions with Intelligent Well Technology by Using Downhole Chokes to Optimize ESP Performance
Authors: Vachon G. , Furui K.
Published: December 2007

Accelerated production, increased ultimate recovery, and reduced interventions are goals of any operating company. It is now possible to attain all of these goals simultaneously by retrofitting intelligent well technology to an existing, conventional completion. This task is much more complex when the new technology must be installed in conjunction with artificial lift, such as an electric submersible pump (ESP). However, new technology and procedures have overcome this complexity and offer a viable option for optimizing production in existing completions that use artificial lift.

Commingled or selective production from two or more zones is an ideal method of accelerating production from a single well. Traditional designs require interventions into the well to select the intervals to be produced. In most ESP wells, commingling is achieved by using "Y" blocks which allow production tubing to be run from the tubing hanger to the zones of interest. The ESP must then be downsized to accommodate this side-string, which significantly reduces available pump horsepower. This paper focuses on single-ESP wells producing from multiple pay zones. Various application patterns for use of intelligent well technology beneath ESPs are presented, especially focusing on immediate and future benefits. Theoretical examples are presented to illustrate how intelligent completions can enhance the ESP performance, add flexibility, and extend the range of application for a given pump.
JD as a Performance Indicator for Hydraulically Fractured Wells
Authors: Dietrich J. K.
Published: December 2007

Hydraulic fracture treatments are designed with a goal of maximizing the dimensionless productivity index (JD). Single-well, pseudo steady-state models are commonly used in the treatment design process, notwithstanding the fact that the stimulated well is often in a pattern water flood, and therefore, more nearly in a steady-state flow regime. Using a combination of analytical and numerical methods, it is shown that application of the pseudo steady-state solution to a steady-state problem invariably leads to over-prediction of JD and the benefits of hydraulic fracturing. As a solution to this exaggeration, there is a need to consistently apply the model having boundary conditions most like those of the field. The first step is to understand the differences and formally distinguish between the pseudo steady-state and steady-state dimensionless productivity indices; thus two purportedly new terms are introduced for this purpose: JDpss and JDss. Results demonstrate that JDss << JDpss over the full range of fracture penetrations, the difference becoming greater with increasing fracture conductivity and penetration, reaching 50% at the theoretical limits and 30%, or more, at practical fracture conditions.

While multiple well interference effects are shown to be capable of limiting the achievable level of JD, there are actions that can be taken to greatly increase it: optimizing flood pattern shape and aligning patterns parallel to the hydraulic fracture azimuth are two measures that are each shown to be capable of increasing JD by 50%, or more.
Pressurized LNG: A Paradigm Shift in Gas Transportation
Authors: Nelson E. D. , Papka S. D. , Bowen R. R. , Gentry M. C. , Leger A. T.
Published: December 2007

Proposal

With natural gas emerging as a critical energy source, industry is placing significant effort into reducing the cost of commercializing gas resources.Since many resources are located far from markets, one area of particular interest has been gas transportation. Advancements in both pipelines and LNG continue to improve the economics for these conventional methods of gas transportation.In addition, new concepts are being investigated to potentially improve the economics of commercializing remotely located gas resources. ExxonMobil has developed a new gas transportation technology called Pressurized Liquefied Natural Gas (PLNG) that has the potential to reduce the costs of delivering gas in some applications.

The PLNG concept utilizes specially designed containers integrated into a ship to store LNG under moderate pressures. Conventional LNG ships transport gas with no applied pressure at -160°C, whereas gas transported in a PLNG ship is under 17 bar of pressure at -115°C.A large portion of the investment for a LNG development is in the gas treating and liquefaction at the export plant. The increase in the liquefaction temperature for PLNG reduces the required refrigeration horsepower. In addition, the gas treating requirements are less stringent because higher concentrations of some components, such as CO2, can be tolerated at the higher PLNG temperatures. The result is approximately a 50% reduction in the facilities. A key PLNG advantage, along with the savings in facilities costs, is the smaller export plant footprint that facilitates offshore deployment on a ship or barge.The implications can be significant for offshore developments or in areas where onshore construction costs are prohibitive.

In order for this concept to be realized, ExxonMobil researchers developed a new high strength, low temperature (HSLT) steel and welding consumable for the containers. After the necessary properties were obtained from the steel plate and welds, a commercial fabricator constructed a prototype container in their facility using the new materials and welding procedures to further verify the manufacturing feasibility.

Shipyards and fabricators from around the world have evaluated the base ship design and provided cost estimates. Conceptual designs for both the import and export terminals leverage existing LNG technology with the necessary modifications to handle the pressure. The completion of the prototype fabrication and the development of the conceptual designs of the ship, terminals, and facilities established the technical viability of PLNG.

With a suite of gas transportation options, ExxonMobil can consider a broad range of development concepts and select the optimum for a specific application.
High-Accuracy Oriented Perforating Extends the Sand-Free Production Life of Andrew Field
Authors: Martin A. J. , Robertson D. , Wreford J. , Lindsay A.
Published: December 2007

BP started development of Andrew field in 1996 with a program for 13 producer wells and one gas injection well. Oriented perforating was used for the weaker Andrew sandstone intervals in some wells, as a means of reducing the risk of sand production. However, the accuracy of oriented perforating was unknown at the time and sanding has recently occurred on some of the wells. Subsequent work with the latest sanding-prediction software showed that perforations oriented away from the vertical direction could have collapsed and provided a source of sand production. Perforations oriented much closer to the vertical direction would, however, be stable and would extend the sand-free field life considerably. This paper describes the results and the evolution to high-accuracy orienting systems on three new Andrew wells and two workover wells.
ExxonMobil's Advanced Gas-to-Liquids Technology–AGC-21
Authors: Fiato R. A. , Sibal P. W.
Published: December 2007

Conversion of natural gas to liquids (GTL) utilizing Fischer-Tropsch hydrocarbon synthesis technology is a viable option to bring gas resources to market. Over the past two decades, ExxonMobil has invested in the development of proprietary technology, Advanced Gas Conversion for the 21st Century (AGC-21) [1].

This state-of-the-art GTL technology provides an important option for commercialization of natural gas resources. ExxonMobil is continuing to pursue technology enhancements to further reduce the cost of producing fuels, lube basestocks and other specialty products from natural gas. This paper discusses advances in ExxonMobil's AGC-21 technology achieved over the years as a result of a comprehensive research, development and engineering program.
Impact Of Gas Flaring On Soil Fertility
Authors: Akpojivi R. E. , Akumagba P. E
Published: December 2007

Gas flaring is employed by oil production companies in Nigeria as a means of getting rid of associated gas. Low flare stacks are employed bringing the ‘flare’ into close proximity to nearby vegetation and soil. This study investigated the impact of oil sector gas flaring activity in Nigeria on some soil fertility parameters. Gas flaring impacts adversely on soil fertility; air/soil temperature becomes higher, soil becomes more acidic and total organic carbon, nitrate, and phosphate content of the soil decreases. No clear relationship was observed between soil potassium and gas flaring.
Applications of Underbalanced Drilling Reservoir Characterisation for Water Shut Off in a Fractured Carbonate Reservoir—A Project Overview
Authors: Murphy D. , Davidson I. , Kennedy Kennedy , Busaidi R. , Wind J. , Mykytiw C. , Arseneault L.
Published: December 2007

Following successful implementation of underbalanced drilling in Petroleum Development Oman (PDO) an evaluation of the value of underbalanced drilling (UBD) in a northern carbonate field was commissioned. The study showed that there was a production upside to developing the reservoir with UBD. A four-well trial campaign was conducted between June and October 2004 to assess the potential.

The trial campaign was implemented following a structured program built from PDO's previous experience. During this campaign a Reservoir Characterization (RC) system allowing identification of multiple high permeability features was developed. Water shut-off devices were installed in two wells based upon the results of the Reservoir Characterisation system. Production in the four wells was equivalent to or greater than field average and the campaign scope has been increased. The campaign was also a stepping stone towards the goal of integrating UBD, Reservoir Characterization and water shut off techniques.
The Role of Geographical Information System in Land Acquisition and Optimization of Well Location
Authors: Shamsan F. , Kumar K.
Published: December 2007

Bahrain field is located in the central part of the Bahrain Main Island. The peripheral areas of the field are in Townships and suburban villages. This causes industrial interference with Electricity, Water, Telephone, and Sewerage authorities.Field development planning of the peripheral areas commenced in late eighties. From this time onwards land acquisition in the peripheral areas has been undergoing negotiations with landowners and city planners. Also field facilities such as wells, pipelines, and separation equipment come more in contact with the inhabitants around. This can pose safety and security issues to both the people and the facilities. Therefore it is wiser to think of such issues during the field development planning itself.

Such cumbersome tasks, where innumerable land/property owners, municipalities, town ship planners, industrial institutions have to be contacted and negotiated becomes almost impossible with out utilizing GIS maps. Every peripheral potential area of Bahrain field has to be negotiated with the above agencies. Using conventional mapping would take large durations of time and result in inconsistencies, when dealing with a number of agencies for a single potential area.

The purpose of this poster is to show our experience in utilizing GIS for field development planning and to have a consistent approach in dealing with outside agencies for land acquisition. GIS has been used for number of purposes like optimization of the selection of surface locations for development wells, shifting of wells, safety & security management, planning and design of pipeline routes etc.
Competency-Based Program: An Effective Tool to Develop Graduate Engineers
Authors: Sammarrai W. A. , Saadawi H. , Olma S. A.
Published: December 2007

As a part of the United Arab Emirates Government policy to increase the percentage of nationals in the workforce of the oil sector, every year a number of UAE national graduates join Abu Dhabi Company for Onshore Oil Operations (ADCO) as developee engineers. They follow a development program to introduce them to the oil industry, company activities and develop operational competencies.

The traditional approach to develop graduate engineers is to prepare a "time and skill" program of rotation among the various departments. Over the past eight years, the Engineering and Major Projects (EMP) Division of Abu Dhabi Company for Onshore Oil Operations (ADCO) has successfully implemented a Graduate Development Program (GDP) complete with competence profile and development pathways for its new engineers.

The main features of this Graduate Development Program (GDP) are: Phased approachSkills aligned with the career ladderMentor support systemCompetency assurances measures

This paper discusses ADCO‘s experience in implementing this program.
Multicomponent Processing and Fracture Characterization Analysis of 3-D PS-Wave Onshore Seismic Surveys
Authors: Gaiser J. E. , Van Dok R. R.
Published: December 2007

Multicomponent 3-D surveys where downgoing compres-sional (P) waves convert to upgoing shear (S) waves at interfaces provide a practical means for analyzing fracture properties.This is particularly important for delineating naturally fractured reservoirs by exploiting the unique characteristics of S-wave azimuthal anisotropy induced by vertical fracturing. In the presence of fractured media, S-waves split into a fast wave that is polarized parallel to fractures and a slow wave that is polarized normal to fractures.The amount of splitting (time difference between the two S-waves) is proportional to fracture intensities.To investigate this phenomenon we utilize a wide range of source-receiver azimuths in the processing and analyze the fast and slow S-waves to extract fracture information.

Two 3-D 3-component (one vertical and two horizontal geophones) surveys from Wyoming are presented: one acquired over a portion of the Pinedale Field and the other in the Washakie Basin. The targets are naturally fractured gas sand reservoirs. From the analysis of fast and slow S-waves a regional direction of anisotropy was observed in both areas. Layer-based analyses confirmed that much of the anisotropy was in the overburden, which required compensation during the processing to isolate the variations at reservoir depths.Eight limited-azimuth volumes were created for the two horizontal geophone components. These volumes were analyzed to determine the time-variant anisotropy within the survey and indicated areas of increased S-wave splitting in the overburden as well as at target levels. Azimuthal anisotropy sweet spots observed in the datasets suggest more intense fracturing, and are typically associated with other structural features such as lineaments, faults and folds. At Pinedale this occurs over the crest and along the limbs of the anticline. Also, the strike of near vertical fractures observed on an FMI log is in agreement with the fast S-wave direction.
Waterflood Geocellular Model of a Giant Carbonate Reservoir in the Lower Cretaceous, Abu Dhabi, U. A. E
Authors: Rassas S. , Valle A. , Hassen M.
Published: December 2007

A 3D geo-cellular model of water-flood fluid saturation was constructed for a giant onshore Lower Cretaceous carbonate reservoir in Abu Dhabi, UAE.The water-flood saturation geo-cellular model was created using water saturation versus depth data from Open Hole log interpretations of wells drilled between 1997 and 2003 and from Pulsed Neutron Log (PNL) data acquired during the same time period. In addition, integration of engineering data such as well performance, well and field history and well completion anomalies, is a necessity in order to produce a model that represents the current water-flood status.

The new model has been checked and validated against actual well performance data and results of recently drilled wells. Integration of multidisciplinary data including geology, reservoir engineering to petrophysics and geophysics is imperative to understand the reservoir performance and for building an accurate 3D geo-cellular model of the water-flood. Such model is being used to select new well locations, plan well horizontalizations, and for daily reservoir management decisions related to field and well performance.
Novel Use of Seismic Volume Interpretation for Fracture Detection and Modeling: Examples from Fields in the Philippines and The Middle East
Authors: Stephenson B. , Cassidy P. , Warrlich G.
Published: December 2007

A fundamental problem with the characterization of fractured reservoirs is that there is a scale of structure that is difficult to identify – that between fractures detected in the well bore and faults/fractures interpreted from seismic. A new workflow for structural characterization is presented here based on the application of Shell's proprietary software:- "Van Gogh" filtering for the highlighting of structural discontinuities from 3D seismic, called Stopper-Voxels,"FaultWorld" for analyzing the Stopper-Voxels,"SVS" for characterisation and modelling of fractured reservoirs.

The result is several field-wide discrete fracture/fault scenarios, based on detection rather than prediction.
Incorporating Hydraulic Units Concepts in Saturation-Height Modeling in a Gas Field
Authors: Amabeoku M. O. , Kersey D. G. , BinNasser R. H. , Al-Waheed H. H. , Belowi A. R.
Published: December 2007

A comprehensive petrophysical study in a gas field has demonstrated the effective application of saturation-height functions for calculating water saturation. The results show that linking depositional and diagenetic rock fabric to hydraulic units, and then linking the hydraulic units to zones with similar core capillary pressure relationships, improved the accuracy of the models. In the study field, saturation-height functions provided accurate water saturation, and they can potentially overcome uncertainties associated with log interpretation, using Archie or shaly sand models. The saturation-height models were developed from core capillary pressure (Pc) data to calculate water saturation versus depth, which is independent of logs. Consequently, the core-based saturation height functions can be useful in the calibration of log-based petrophysical models.

Capillary pressure curves from special core analysis (SCAL) studies were distributed into corresponding hydraulic units (HUs), based on the calculated flow zone indicators. Saturation-height function was then developed for each HU and used to calculate water saturation in the study field. The most accurate saturation model that evolved is a function of only porosity and height above free water level. It is a modification of Cuddy's1 saturation function, which relates the bulk volume water (BVW) to height above free water level. Cuddy referred to the function as FOIL, but did not define the acronym. Like FOIL, the Modified FOIL function, that has been developed, does not require permeability in its application, and performed better than the Leverett J-function in this field.

Modified FOIL model that has evolved out of rigorous core-log integration will provide more accurate petrophysical interpretation in shaly sands and thin bed units.
Investigation of injectivity Loss Caused by Iron in Waterflood Water
Authors: Al-Bazzaz W. H. , Gupta A.
Published: December 2007

Injection of seawater through pipelines subject to corrosive conditions may lead to the introduction of dissolved and particulate iron which may cause formation damage and loss in injectivity. This study addresses the estimation of damage potential by a combination of modeling and laboratory testing. The specific goal of the proposed program is to create a database of acceptable iron contamination in injection water, and, injection rates for targeted reservoirs in Kuwait.

Past studies show that iron concentration in injection water fluctuates due to seasonal temperature variations which control the corrosion rate inside pipelines. Conventional methods for quantifying formation damage due to seawater injection do not accurately reflect the processes occurring in the field, such as the variation of iron concentration with temperature.

Traditional "rules-of-thumb" for predicting the lifespan and performance of injection wells ignore the contribution of temperature fluctuations on iron concentration in the injection water. This study proposes a procedure to estimate the potential and tolerance for formation damage in injection well systems due to uncontrolled introduction of iron and other particulate in the injection water. The proposed experiments include: study of the dry rock samples; study of reservoir brine and injected water; and, study of the fluid-rock interactions.

Study of reservoir-rock utilizes routine core analyses to obtain the petrophysical parameters. SEM/ EDS are proposed as tools to characterize mineralogy and pore-morphology. Porosimitery is proposed for obtaining the pore size distributions and the mean hydraulic radius, MHR. Fluid Characterization involves the analysis and interaction of formation brine and the injection fluids. Knowledge of rock mineralogy and pore throat size distribution is expected to help in estimating the acceptable solid and iron concentration in the injected water. Characterization of rock-fluid interactions involves the injection of water with a range of solids and iron concentration in the reservoir cores to identify potential formation damage.
The Application of an Analytical Model for the Controlled Makeup of Rotary Shouldered Connections in the Field
Authors: Teodoriu C. , Kinzel H.
Published: December 2007

Accurate makeup of Rotary Shouldered Connections (RSC) is of most importance in achieving the best torque and axial force transmission through the connection which optimizes its lifetime under downhole conditions. The makeup torque value of RSC depends on the friction coefficient between the threads and the parts of the shoulder that are connected during the makeup procedure. This friction coefficient cannot normally be individually measured or determined, so that the API Recommended Practice 7G gives an average recommended makeup torque based upon an assumed friction coefficient, adding a certain safety margin. Therefore, the majority of the RSC are being made-up with a torque value that differs from the connection optimum torque. This has two consequences: the lifetime of each connection is not maximized and the torque and axial force values that can be transferred through the connection is different from the technical maximum that the connection is able to transfer if it was made-up with the optimum makeup torque

This paper describes a computer model that can be used to determine the optimum torque at rig site. The model was developed at the Institute of Petroleum Engineering of the University of Technology Clausthal and is based on more than 300 tests on full scale specimens. Throughout the research project the authors found a new method of determining the overall coefficient. A dynamic friction coefficient to achieve a much better applicability of this method was introduced and the way to determine is presented. This dynamic coefficient is the key to compute the optimum makeup torque.

Systems to makeup rotary shouldered connections are much more accurate than the traditional makeup with chains and rig tongs, thus reducing the damage of connections. State-of-theart devices do not only allow the precise mechanized makeup of connections, but they also provide sufficient data to analyze the quality of the connection make-up. The motivation behind the research performed is the desire to make use of the data that are already provided for the benefit of increased lifetime of the connections and the reduction of drill string failures.

A comparative evaluation of the proposed and the existing (API and Baryshnikov) methods was studied. The new method out performed the existing ones. The new method can be implemented in the new generation of computer controlled power tongs to improve the makeup quality at rig site.
The Role of Unconventional Natural Gases in the Next 30 Years in Asia
Authors: Terasaki D. , Fujita K.
Published: December 2007

Genetic algorithm method was utilized to study on the optimum supply rates of various types of natural gases for the importing countries such as China, India and Japan. Genetic algorithm procedure was able to compute annual time series of economically optimum supply rates combination consisting individual natural gases so that net present value of total supply costs could be minimized to result in economic optimization.

First of all, several computations for USA case history data matching were carried out to establish appropriate parameters of genetic algorithm, because USA has long term historical data provided by DOE/EIA and USGS about natural gas production activities and has the infrastructures of gas pipelines fully furnished.

Next, computations for the whole region of Asia, Oceania and the Middle East based on the forecast of total demand by OECD/IEA were carried out, and then individual computation for China, India and Japan was carried out in the same way. It was concluded that unbalance between the demand and the supply of natural gases would occur in Asia, and unconventional natural gases especially coal-bed methane would play an important role both to satisfy stable natural gas demand, and to keep national security on energy in the next 30 years in Asia, especially China and India countries.
Managing Risks and Uncertainties in Drill Cuttings Re-Injection in Challenging Environments – Field Experience from Sakhalin Island
Authors: Guo Q. , Geehan T. , Pincock M.
Published: December 2007

Drilling waste disposal using hydraulic fracturing is often the preferred waste management option because it can achieve true zero discharge without being limited by the drilling location. This is particularly true for drilling operations in remote and challenging areas such as offshore Sakhalin Island as there is no established infrastructure for drilling waste management.

This paper presents a case history of managing uncertainties and risks related to a drill cuttings re-injection (CRI) project offshore Sakhalin Island. Although there are uncertainties and risks with the CRI project in this case, regulatory requirements and the operator’s commitment to zero discharge made it the preferred option for drilling waste management. Complicating the decision was a previous injection well where cuttings settling made it inoperative. Thus, the only option was to inject the oily cuttings into a deviated well intended for future use as a development well, which posed a number of risks related to the proposed CRI operation.

Since this is the only option for drilling waste management and loss of this well would have delayed the drilling program and field development for at least a year, managing the risks and uncertainties related to this CRI project and assurance of a trouble-free CRI operation were critical.

This paper presents monitoring and diagnostic analyses that were used for slurry design and optimization, pumping procedure design and optimization considerations, as well as solids transport modeling and planning length of shut-in intervals between batches. These quality assurance and optimization measures were proven to be effective in managing the risks and uncertainties associated with this critical cuttings injection well off Sakhalin Island. At the time of this writing, more than 100,000 bbl of slurry and fluid had been injected into this well without incident.
SSC Resistance of QT-900 Coiled Tubing
Authors: McCoy T.
Published: December 2007

Laboratory sulfide stress cracking (SSC) tests were performed on specimens taken from a QT-900 coiled-tubing test string in an attempt to define zones of acceptable sour service. SSC tests were performed at room temperature in brine fluid environments with H2S partial pressures (PH2S) ranging from 0.01 to 10 bars and pH levels from 2.8 to 4.5. In addition, the effectiveness of a new inhibitor for crack prevention was tested. SSC testing, which included NACE Method A tensile, four-point bent beam and slow strain rate test specimens, were performed on as-milled as well as fatigue-cycled tubing. Fatigue cycling of the QT-900 test string was performed on a pressure bending fatigue machine with tubing samples cycled from 33% to 75% of average tested fatigue life. Test specimens were taken from parent metal, bias weld, seam weld (ERW), and butt weld locations. As a result of this test program, acceptable zones of service in sour environments have been proposed although further testing may alter boundary locations.
The Malaan Area of Northern Oman: PDO Opens up an Unconventional Play
Authors: Hiebert S. , Mazrui M. , Al-Harthy M. , Harris K. , Shuster M. , Hadhrami M. A. , Blonk B.
Published: December 2007

In the northwest area of Petroleum Development Oman's (referred to later in this paper as ‘PDO’) concession, substantial oil volumes have been discovered in conventional structures trapping low permeability carbonates of both the Upper and Lower units of the Cretaceous Shuaiba Formation. However, since full-scale development of the area began, only a fraction of production has come from the Upper Shuaiba. Previous drilling campaigns targeting Upper Shuaiba have met with limited commercial success, because oil-charged reservoir occurs in thin pay (1-5m), and production test rates from the mostly vertical wells are generally less than 100 bbl/d. In late 2000, an exploration well was drilled on the crest of the Malaan structure, and similar to many previous tests in the area, encountered oil in several thin units of very low permeability (2-10 mD), but failed to flow at a sustainable rate. Subsequent reprocessing and inversion of the seismic, combined with a revised geological model which was partly based on experience of neighbouring operators, indicated the possibility of a higher porosity and permeability trend considerably down the flank of the Malaan structure. The trend is coincident with a top-lap truncation imaged on seismic, forming elements of a stratigraphic trap with the overlying Nahr Umr Shale.

In July 2003, the Malaan-2 well was spudded approximately 3 km northwest and 29m down flank of Malaan-1, and found significantly better reservoir quality. New logging while drilling technology (LWD) from Schlumberger, used for the first time in the world in an exploration well, was critical to maintain the horizontal well path in the best quality reservoir rock. The well has been tested and hooked up, and appears to have a stable production rate of over 1400 bbl/d net oil.

Seismic imaging shows that the best reservoir is coincident with an amplitude anomaly which extends more than 20km in a south-westerly arc, and which is independent of current structure. Forward modeling, incorporating all well data, has now allowed a match between synthetic and real seismic, and giving more confidence in the geologic model.

The trapping mechanism, and the factors controlling oil saturation, are not fully understood; the area has recently undergone regional structural tilting, and it is possible that the hydrocarbons are not yet in equilibrium. Several appraisal wells planned for 2004 will further delineate the extent of the accumulation and provide a better understanding of the trap. In a success case, the elements of this exploration play will be applied to other similar seismic trends already identified across northwest Oman.
Global Environmental Perfomance Indicators in an E&P Service Company
Authors: Sealy I.
Published: December 2007

Proposal

The paper describes the development, implementation and application of a program of environmental performance measurement in a global service company working the in exploration & production industry.

A set of environmental performance indicators has been defined in order to provide data on internal compliance, environmental incidents, resource consumption, and waste generation (and management). Information is captured in an on-line database from over 500 sites in approximately 100 countries, on a monthly basis, and is immediately available for analysis and management review. The paper discusses the selection of the indicators that are used, and the intended value of each indicator, or group of indicators.

Having described the basis for the EPI program, examples from the data capture and management review process are presented. These examples are used to illustrate the evolution of the EPI process over the past three years. There is particular emphasis on discussion of the challenges that are presented by a highly devolved and decentralized data capture process.

The third section of the paper concerns the trends and themes that are evident from the database, and their application and value to the management process. There is a discussion of indicators that have been removed from, or added to the program and the reasons for those changes.

The paper concludes with a discussion of the possible areas for future development of the program.
Restoring Integrity to Aged Petroleum-Production Facilities
Authors: Ciaraldi S. W. , Hedges B.
Published: December 2007

BP and its local predecessor Amoco have produced oil and gas off the east coast of Trinidad for over 30 years. This production originates from eight offshore fields and is transported to onshore terminals through an extensive pipeline network. Gas is further shipped for domestic use or LNG production. Oil is temporarily stored onshore and then tanker loaded for export. Despite excellent business success for the operator and nation, maturing production, long service time and constrained resources have taken a toll on the technical integrity of facilities.

In late 2000, a major program to restore integrity was developed, resourced and implementation begun. The restoration strategy was based on a four-step process involving assess, restore, upgrade and sustain. The program addresses the technical integrity of all assets including offshore topsides, subsea structures/pipelines, onshore terminals, tankage and oil/gas exports systems. It also includes enhancements to process safety protective systems and development of a comprehensive major accident hazards management system.

This paper outlines the many problems, solutions, challenges and successes of the integrity restoration program. It describes the required organizational commitment to a multi-year improvement campaign and a shared vision of sustained, world-class integrity management. Lessons learned from the program are now being applied to BP Indonesia operations offshore Java and elsewhere; specific areas of corporate sharing are described.
Sand Production Prediction and the Selection of Completion Methods for Horizontal Wells in Intercampo Oil Field, Venezuela
Authors: Hong'en D. , Dandan H. , Wenxin C.
Published: December 2007

Intercampo oilfield is unconsolidated sand reservoirs that are characterized by heavy crude oil and mid-high permeability and high saturation. This paper analyses sand production mechanism and applies five prediction models to predict sand production. Sand production condition of wells in Intercampo oilfield indicates that prediction results are to meet with oilfield actual status that sand production to occur seriously and the method of the combination modulus is more accurate than other models according to wells of acoustic logging data.

This paper considers the effect of formation damage and well completion parameters of different well completion methods on productivity forecast of horizontal wells with four series of well completion, including open hole, slotted liner with openhole, open hole gravel packing with wire wrapped/pre-packed screen and cased perforated completion. And, the productivity forecast equations were corrected by authors, the corrected equation is accuracy compared with the former equations by calculation, and one well completion method that open hole with gravel packing and pre-packed screen was selected. Sine 1999, the selected well completion method have been applied in Intercampo oilfield of CNPC in Lake of Maracaibo and obtained higher productivity than other completion methods of other companies. The sand production was effectively controlled and the oilfield was continuously kept sand free for 5 years in the area. Finally, a good economic benefit was gained because the workover and well re-completion in the oilfield for sand control was down.
Thermochemical Solution for Removal of Organic Solids Deposit in and Around Wellbore and Production Tubing
Authors: Ibrahim J. M. , Ali K.
Published: December 2007

During production of crude oil, temperature and pressure of the produced fluid decreases along its production pathway. The reduction in pressure and temperature disturbs the equilibrium of the composition of the oil particularly the heavier components leading to their separation, precipitation and deposition at in-and-around well bore (skin effect) and production tubing. Such a deposition can choke the flow passage from reservoir to well bore and reduce the production of oil appreciably (Diagram 1).

A unique two pack chemical system had been developed as an effective tool for:

Removal of organic deposits, such as in-and around well bore (skin) and production tubing Enhancement of production rate

The two pack chemical system when injected into the well bore through production tubing, reacts to produce in-situ heat with a reaction product. The heat generated in the system can dislodge and melt the deposits and the reaction product formed acts as dispersant and an effective surfactant.

The paper presents the results on two wells which were pilot implemented in Malaysian Offshore field, Temana (TE). Among the two treated wells, one well was a closed-in well while the other was gas lift producing well. Both wells had shown appreciable decrease in skin factor, reduction in water production and sustained an additional average incremental production of 190 to 320 bpd for the past one year. Pay back period of the treatment cost was between 11 to 19 days. The wells are still producing after one year of treatment.

The two pack chemicals system and related chemicals, and their reaction product are compatible with crude oil, rock formation, tubular steels and oil field rubber parts.
Foam Characterization Using Image Processing Techniques
Authors: Ozbayoglu E. M. , Akin S. , Eren T.
Published: December 2007

Foam has been used in petroleum industry as a fracturing fluid and a drilling circulation fluid for many years. Proper determination of volumetric requirements for gas and liquid phase of foam during drilling and fracturing applications is directly related with an accurate foam characterization. It has been observed that, bubble size and texture of foam has an influence on foam rheology, however, no mathematical description has been introduced for their effect. The idea behind conducting this study is to get a more comprehensive method of foam rheology definition in which the bubble size and texture effects of the foam are considered. Three different analysis methodologies are introduced; i) Generalized Volume Equalized approach, ii) Generalized Volume Equalized Approach + Image Processing data, and iii) Image Processing data only. The necessary information including the rheological information and image data is acquired from the developed set-up for this study. It has been observed that, the pressure losses could be predicted as a function of bubble size, circularity, and general rheological parameters, in ±20% certainty limit. It is also observed that using only the image information could also be used for characterizing the foam in an accurate and fast manner.
Cyclic Steam Well Design—A New Approach to Solve an Old Problem of Cement Sheath Failure in Cyclic Steam Wells
Authors: Bour D.
Published: December 2007

Proposal

Steam injection is often used to increase oil production in heavy-oil fields. While the concept of thinning heavy oil by raising the temperature though steam injection is a fairly simple one, the associated challenges of designing and constructing a well for this environment can be complicated. One specific challenge is to construct a well where the cement sheath(s) will not fail and allow interzonal communication. The temperature fluctuations and the associated mechanical stresses transmitted to the cement sheath can cause the cement to crack. This cement failure can lead to steam injection migrating to zones other than the injection target zone, loss of production, communication of corrosive fluids in the annulus, casing movement, and other associated problems.

Another factor that can affect the durability of the cement is the mechanical properties of the formations in which these wells are drilled. Excessively soft or low Young's Modulus formations exacerbate the problem by providing minimal confining stress on the cement sheath. In addition, wells drilled in a steam-flood field can often be plagued by lost-circulation problems, requiring use of low-density cements to address problems in cement placement.

This paper provides details on how to help construct a well under these difficult conditions with minimal or no cement-sheath failure in critical production zones. Finite elemental analysis (FEA) shows that conventional and even specialized cement blends alone may not stand up to stresses encountered under these conditions. A unique technique is provided and verified with FEA to show how a well might be constructed without cement-sheath failure or at least minimal failure in critical zones. In addition, FEA analysis is provided to show how to help (1) optimize casing sizes and weights and (2) minimize costs of construction.
Problem of Monitoring of Arbitrary Oriented Trajectories of Boreholes with Small Diameters by Means of Strapdown Gyroscopic Inclinometers and its Solution Methods
Authors: Binder Y. I. , Okon I. M. , Paderina T. V. , Rozentsvein V. G.
Published: December 2007

The possibility to use two-axis gyro rate sensor (GRS) in principle for measurement of trajectory parameters is shown., in the present report. The angular momentum vector of this sensor is oriented along the longitudinal axis of the borehole device. The errors and limits of this scheme utilization are defined, when operating in gyrocompassing mode. A method of utilization of the scheme with a longitudial gyro is original for two operation modes (gyrocompassing and analytical directional gyro) near the line West-East. The errors intrinsic to such a combined operation mode are analyzed.

In order to eliminate the restrictions typical for inclinometer with a longitudinal gyro, it was proposed to arrange GRS with angular momentum in the cross-section plane of the borehole. And with this, a method of inclinometer utilization was develop, which permits not only to solve the "accuracy loss zone" problem but also to eliminate effect of the gyro drift changeability caused both by its utilization period and the gyro start-up errors.

For the first time calibration of the gyro during operation is proposed by slewing the gyro housing about two multually perpendicular axes: the main sensor axis and the boring column axis. Algorithms on multiposition gyrocompassing of such a single-gyro system are proposed and analyzed.

Experimental results confirming the main conclusions of the teoretical investigations are presented.
Verification of Decline Curve Analysis Models for Production Prediction
Authors: Li K. , Horne R. N.
Published: December 2007

Reserves and production in petroleum reservoirs can be estimated using empirical and analytical decline curve analysis models. There have been many such models. In this study, three representative models (exponential, harmonic, and the mechanistic Li-Horne models) were chosen to predict and match oil and gas production from both core samples and reservoirs with different permeability. The recovery and reserves were estimated using the three models and the results were compared. The comparison demonstrated that the recovery at an assumed economic limit predicted using the Li-Horne model was greater than the exponential model but was less than the harmonic model. Note that the exponential model tends to underestimate reserves and production rates while the harmonic model has a tendency to overpredict the reservoir performance. It was also found that the reserves predicted using the harmonic model were greater than one pore volume in some cases, which is physically impossible. The model predictions using the experimental data of recovery in the core samples were also compared to the true values. The results demonstrated that the Li-Horne model had the best estimation of the recoverable recovery compared to the exponential and the harmonic models in the cases studied.