bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of Rock Failure Characteristics on Sanding Behavior: Analysis of Reservoir Sandstones From the Norwegian Sea
Authors: Heiland J. C. , Flor M. E.
Published: December 2007

During production of hydrocarbons, the formation is subjected to increasing levels of effective stress, resulting from the reduction in pore pressure. In weak, but consolidated sandstones, this can lead to shear failure in the rock surrounding the perforations and the borehole. Sand production in weakly consolidated formations is generally assumed to be a two-step process, with the shear failure being the first step and the transport of the sand out of the perforations and up to the surface being the second step. Existing sand production prediction models have focused on predicting the onset of sanding by predicting the drawdown at which failure of the formation will start. A further development are models, which try to predict the total volume, which can be expected to be produced, by assessing the geometrical extend of the failed zone. These volumetric estimates of sand production are often based on rock mechanical models, which predict the extent of a yielded zone, using various constitutive material laws. This assumes that all material from a yielded zone will be produced as sand. Combining a model for a volumetric estimate of sand failure with a model for transport of solids in a fluid, might eventually lead to a realistic sanding rate prediction. Existing sand production prediction models tend to assume that the formation disintegrates into sand grains the moment yield or failure occurs and that these grains are taken up by the fluid flow at the time when failure occurs. However, in reality the failure-characteristics of sandstone and the pick-up of the failed material by fluid flow are a very complex process and very little research effort has been dedicated to the morphological description of rock failure.

Using an endoscope camera, it was possible to observe the failure behavior and sand transport during sanding experiments in different types of sandstones. Two different failure behaviors of perforation-sized cavities were identified in these experiments. These failure patterns resulted in very different shapes of the failed zones and during the experiments very different amounts of sand were produced and at different rates. It can be assumed that this behavior can also be found downhole and we concluded that the different failure behaviors of sandstone could be a geological reason for the different severity of sanding problems in various oilfields. Using image analysis of thin sections the different failure behavior could be linked to petrographical rock properties and a predictive model of sandstone failure characteristics was developed. This paper describes the development of the model and the application of this model to formations from an oilfield in the Norwegian Sea.
Effective Stimulation of High-Temperature Sandstone Formations in East Venezuela With a New Sandstone Acidizing System
Authors: Ali S. A. , Pardo C. W. , Xiao Z. , Tuedor F. E. , Boucher A. , Al-Harthy S. A. , Lecerf B. , Salamat G.
Published: December 2007

The wells in an oil field in East Venezuela have a bottomhole static temperature of approximately 230°F and varied mineralogical composition from interval to interval. Near-wellbore fines damage and carbonate scale damage have been reported in these wells. Currently, various formulations of mud acids, organics acids, and solvents are used to treat these wells with mixed results.

A novel chemical system has been developed for the stimulation of high-temperature sandstone reservoirs. By introduction of unique chemical mechanisms, the new sandstone acidizing system (1) reduces the multiple stages in traditional sandstone acidizing to one stage; (2) minimizes precipitations by delayed and stabilized reaction mechanisms; (3) provides homogeneous dissolution of formation; (4) has a much lower emulsion and sludge tendency than conventional fluids as well as lower corrosion rate; and (5) stimulates sandstone reservoirs at high-temperature by effective damage removal and further matrix dissolution.

Acid solubility, ion concentration, and mineralogical analyses indicate that the sandstone formation in this well has high content of iron-bearing minerals and a moderate content of sensitive clays. Results of core flooding tests conducted on the damaged field cores show that both mud acid and organic clay acid systems show secondary damage on the formation core sample during the acid preflush. Additionally, mud acid shows further damage after the treatment. In contrast, the new fluid system shows consistent damage removal during the treatment with the highest regained permeability. Geochemical simulations also show that more skin reduction is obtained with the new fluid than with the other conventional acid systems tested.
Optimization of a Viscoelastic Surfactant (VES) Fracturing Fluid for Application in High-Permeability Formations
Authors: Sullivan P. F. , Gadiyar B. , Morales R. H. , Holicek R. , Sorrells D. , Lee J. , Fischer D.
Published: December 2007

Visco-Elastic Surfactant (VES) fluids are polymer-free fluids that generate viscosities suitable for fracturing operations without the use of polymer additives. VES fluids do not form polymer filter-cake, and thus, viscous resistance of the fluid flowing through the rock matrix primarily governs fluid loss. This has historically limited the application to fracturing reservoirs with low permeabilities. A new VES fracturing fluid has been developed for use in high permeability reservoirs and successfully pumped in the Gulf of Mexico. The fluid exhibits enhanced fluid efficiency while still maintaining the high proppant pack conductivity associated with the lack of polymer damage.

In this paper, laboratory test results for the new fluid are presented along with three high-permeability case histories. The estimated reservoir permeabilities were as high as 167 mD and reservoir heights ranged from 30-90 feet. In all cases the entire propped fracture design was successfully placed.
Challenges on Completion for Productivity for Deepwater Heavy Oil
Authors: Bianco L. C. , Gabrysch A. D. , Montagna J. N.
Published: December 2007

The incremental demand for oil and gas is driving the industry to search and produce hydrocarbons in more challenging environments. The evolution of Drilling Technologies in recent years has allowed operators to explore high viscous oil in turbidite reservoirs, at shallow burial depth and water depths greater than 1500 m. In such environment, the reservoirs are usually formed by unconsolidated sands with low fracture gradient, high porosity and permeability, and low water saturation at low temperatures.

Although great advances have been made for open-hole completion technologies, optimizing sandface completion for productivity is a big challenge. Issues for a sub-sea well construction can be: reduced drilling fluid weight window available; special well geometries to maximize reservoir drainage; non-invasive drilling and completion fluids for well productivity; mandatory sand control; effective control on water injection and production; completion reliability and intervention requirements, thermal effects due to cold waters like hydrate formation and thermal fractures for injectors.

This paper addresses the issues related to well construction in such environment and presents recent developments for well completion design such as: new approach for sand control system selection for heavy oil that excludes sand but allows fines to pass; minimization of the pressure drop through the sand control system; well segmentation to correct the oil influx profile, improving reservoir drainage, and giving selectivity and control of water production.
Engineered Application of a Weighted Fracturing Fluid in Deep Water
Authors: Bagal J. , Gurmen N. M. , Holicek R. A. , Gadiyar B. R. , Fredd C. N.
Published: December 2007

Over the past decade, operators in offshore fields such as the Gulf of Mexico and West Africa have increased their investment in deepwater projects. The trend is expected to continue in the future. For frac and pack operations in deep water, the industry is facing some particular challenges that limit completion options. A major challenge is the need to reduce the surface treating pressure to stay within current equipment operating limits. One solution is to increase the fluid density, thereby allowing for a reduction in the surface pressure while generating the same bottomhole pressure. However, higher fluid densities can also lead to higher friction pressures that may overcome the hydrostatic benefits. In addition, as the water depth increases, the travel time to the mudline increases, resulting in the need for extended crosslink delay times. Therefore, fluids that provide flexibility in density and extended crosslink delay times are required for effective treatment designs in deep water.

This paper describes a weighted, delayed crosslink polymer (WDC) fluid and engineering guidelines for its use in frac and pack applications. Sodium bromide is used as the weighting agent to provide higher densities (8.3 to 12.5 ppg) compared to conventional fluids. Additionally, the fluid has a delayed crosslink that can be controlled from 2 to 20 minutes, which helps in limiting the tubing friction.

Extensive laboratory testing was performed to ensure the technical feasibility and effectiveness of the WDC fluid. Tests included polymer hydration in brine, crosslink delay time measurements, rheology at bottom-hole static temperatures, shear sensitivity, fluid stability at mudline temperatures, breaker design, leakoff characteristics and matrix cleanup, proppant-pack conductivity, and friction pressure tests. Results demonstrate that the WDC fluid meets all performance requirements. It is stable at mudline temperatures down to 40 °F, and effective at bottom-hole temperatures of at least 250 °F.

An engineering simulator was developed based on completion characteristics to select the weighted fluid in cases where it can be beneficial. Example case histories are presented that demonstrate conditions under which weighted fluids provides a reduction in treating pressure. The WDC fluid has shown the ability to reduce the treating pressure by at least 20% depending on the wellbore configuration. The strong dependence of treating pressure on completion geometry, fluid density, and crosslink delay time necessitates evaluation of each treatment on a well-by-well basis to determine effective applications of weighted fluids.
Fracture Propagation, Filter-Cake Buildup and Formation Plugging During PWRI
Authors: Zaki K. S. , Sarfare M. D. , Abou-Sayed A. S. , Murray L. R.
Published: December 2007

Produced water reinjection (PWRI) offers an efficient and effective means of disposing of the PW waste stream and provides an opportunity for a water drive when applied during waterflooding. The required rate of produced water reinjection can be anticipated using the expected pore volume replacement ratio and water-cut estimated from the production forecast. Fracturing is likely to occur during produced water reinjection at voidage replacement rates. The extent (size) of the induced fracture(s) will significantly impact the waste disposal process. It is, therefore, necessary for well injectivity planning and fracture sizing to have an accurate estimate of pore pressure, the rock's mechanical properties and the minimum in-situ stress in the injection horizon. This collective information can be used to estimate the required injection pressure and the number of injectors throughout the production period. In addition, well planning and design will also benefit from predictions concerning the injector performance histories – and the length of the created fracture. Overall, the waterflood planning-cycle efficiency will be increased.

It is generally accepted that PWRI leads to plugging of fractures and damage of injection zone permeability1-2. The engineering issue faced by the operator is reduced to establishing the balance between two (2) competing mechanisms. The first mechanism is related to the well-injectivity improvement that may result from any fracturing associated with produced water reinjection. The competing mechanism results from plugging of the near crack-tip region and the impairment of reservoir performance (permeability) around the fracture caused by water contaminant invasion of the injection horizon.

The interplay between the reservoir rock properties and water quality parameters3-4 has been qualitatively discussed in some detail in the past. However, this paper will confine discussions to fracture propagation and its impact on well injectivity, under conditions of produced water reinjection in permeable reservoirs. Results of such analyses can provide estimates of filter-cake permeability and thickness, as well as the magnitude of permeability impairment around the fracture and the extent of the impairment zone.
Taking Nondamaging Fluids to New Extremes: Formate-Based Drilling Fluids for High-Temperature Reservoirs in Pakistan
Authors: Oswald R. J. , Knox D. A. , Monem M. R.
Published: December 2007

The use of low-solids, water-based reservoir drilling fluids has generally been restricted to fields with temperatures of less than 300°F, primarily due to the limitations of fluids in more aggressive environments. The Miano and Sawan fields in Pakistan are both classified as high temperature (up to 340°F BHST), and some wells have been recognised as requiring sand control for optimal production.The operator of this field is dedicated to the application of water-based muds in all activities to reduce the environmental impact of operations.

Based on these criteria and extensive laboratory testing for thermal stability and expandable screen (filter cake quality) compatibility, a formate-based, low-solids, reservoir drilling fluid was selected. The laboratory performance of the fluid will be confirmed by the performance in the world's first field application of high-temperature formate drilling fluid run with expandable screens.
A New Technical Standard for Testing of Heavy Brines
Authors: Javora P. H. , Berry S. L. , Stevens R. F. , Carpenter J. F. , Isaac D. D. , Dalton F. G. , Augsburger J. , Guy-Caffey J. K. , Tomlin M. , Jones T. A. , Malachosky E. , Prasek B. A. , Foxenberg W. E. , Freeman M. A. , Howard S. K. , Benton W. J. , Son A. , Eichelberger P. , Stark C. L.
Published: December 2007

A new technical standard has been developed for assessing the performance and physical characteristics of heavy brines used in completion, packer, and drill-in operations. This technical standard includes procedures for evaluating the density, specific gravity, clarity, amount of suspended particulate matter, crystallization point, pH, and iron contamination. It also contains a discussion of gas hydrate formation and mitigation, brine viscosity,brine crystallization at high pressures,corrosion testing, buffering capacity,and a standardized reporting form.
Openhole Gravel Packing in the Roaring Forties
Authors: Puyo P. , Bourgeois A. , Penno A. D. , Oliveira A. C.
Published: December 2007

TOTAL AUSTRAL operates the Carina and Aries fields, which are located in offshore Tierra del Fuego in the most southern region of Argentina. These fields are prolific gas producers and are being developed with a reduced number of wells with departures of up to 3.5 km at approximately 1000 m TVD.

This paper discusses the issues surrounding the TOTAL AUSTRAL Carina field development project and the innovative processes that were used to address these situations. Through careful planning,the processes selected to facilitate the completions were successful in achieving the project goals of the operator. These goals included not only the production of gas at relatively high rates from the shallow unconsolidated sand-stone reservoir at approximately 1000 m TVD but also minimization of impact to the environment.

To minimize cost and still accomplish the project goals, the wells were drilled from a single platform.
Unique Experience in Roncador Asset: A New Approach to Hard Drilling Conditions
Authors: de Meira D. C. Alves , de Barros L. P. Franco
Published: December 2007

During the last three years, Petrobras has experienced a sharp increase in the amount of ultra deep water operations. Moreover, most of its production comes from that challenging environment. Doing it well is a matter of company survival.

Petrobras' UN-RIO business unit Roncador asset, due to reservoir characteristics and production strategy, has implemented a unique configuration for its oil production and injection network. In summary, the Roncador asset decided to use pilot wells to tag the best positions within the reservoir.

By trying to re-use most of the pilot wells, the Roncador asset drills long horizontal sections, which are more than 1000m long. Drilling those particular wells has provided Petrobras with many lessons and approaches. It is a continuos improvement process. Nevertheless, big challenges are still on!

The present work pinpoints drilling experience and problems in some noteworthy wells and the solutions found for the Roncador field. The onsite experience is mandatory for successful applications, because modeling can not reproduce the large amount of variables.
New Findings in Fracture Cleanup Change Common Industry Perceptions
Authors: Ayoub J. A. , Hutchins R. D. , van der Bas F. , Cobianco S. , Emiliani C. N. , Glover M. D. , Kohler M. , Marino S. , Nitters G. , Norman W. D. , Turk G. A.
Published: December 2007

This paper summarizes part of the results of an investigation of fracture clean-up mechanisms undertaken under a Joint Industry Project active since the year 2002. It is well documented in the literature that hydraulic fractures, although successful, often underperform: Frac and Pack completions exhibit positive skin values, and traditional hydraulic fracture completions show discrepancies between the placed propped length and the effective production fracture length. Ineffective fracture clean-up is often cited as a likely culprit.

The main results presented in this paper were obtained using a modified conductivity cell to allow polymer concentration via leakoff, and measurements of flow initiation gradients. The paper will discuss the experimental set-up and some of the artifacts that had to be removed prior to ensuring more reliable data. The results highlight the crucial role played by the filter cake and present new data that would significantly change the common industry practice of relying simply on an average polymer concentration factor.1-3

It is shown that contrary to the current method that calculates an average polymer concentration,the polymer,in practice, concentrates only in the filter cake. It is also shown that the filter cake thickness compared to the fracture thickness plays a critical role in creating significant yield stress effects,which could be either avoided through adequate design or used to estimate the resulting productivity loss.
What Would Be the Impact of Temporarily Fracturing Production Wells During Squeeze Treatments?
Authors: Al-Rabaani A. S. , Mackay E. J.
Published: December 2007

It is generally assumed that scale inhibitor squeeze treatments in production wells are displaced radially into the formation, since it is normal to pump these treatments below the fracture pressure. However, it is known that thermal stresses as a result of injecting cold fluids can result in thermally induced fractures (TIF). The first question that this paper addresses is the evidence of thermal fracturing during low volume (<10,000 bbl) treatments, and then, secondly, what would be the impact on squeeze life of treating a well that was fractured during treatment vs a non-fractured well.

The process involves modelling of fractured and unfractured treatments to identify what are the advantages and disadvantages of temporarily fracturing a well during a squeeze treatment in terms of inhibitor placement. While inhibitor may be placed at a greater distance from the wellbore if the formation is fractured during the treatment, the surface area of rock contacted during the treatment may be less than is the case in radial displacements. Issues such as consolidated vs unconsolidated formations, initial reservoir temperature, fluid temperature at the sandface during injection, injection rate and fracture dimensions should be considered.

In general, this work demonstrates that there are clear advantages to temporarily fracturing a well during a squeeze treatment, depending on the inhibitor return concentrations required to prevent mineral scale formation.
Meeting Global Natural Gas Demand: The Emergence of Nigeria's LNG Industry
Authors: Igbatayo Samuel A.
Published: December 2007

A naturally occurring fossil fuel of light hydrocarbons, natural gas has become an important industrial input, propelling economic growth and development in both industrialized and developing countries. The global demand for natural gas has been accompanied by a booming business in the marketing of Liquefied Natural Gas (LNG), particularly in the last decade. Driven by the need to commercialize the nation's huge gas reserves, as well as the imperative to reduce its dependence on crude oil, the Federal Government decided in 1995 to revive the Nigeria LNG project, as a vehicle to facilitate the nation's entry into the global LNG market Nigeria LNG accomplished its first shipment of LNG cargoes to the world market in October 1999, ushering in a new era in the country's long-standing drive to diversify its export revenue.

. However, the actualization of LNG projects in Nigeria is not without challenges. Constraints include funding difficulties, particularly on the part of the Federal Government. Among other challenges, there is need for an enabling environment necessary to inspire investors’ confidence, a precondition for the attraction of crucial foreign investment into the industry. Therefore this paper provides a strategic policy framework promoting liberalization of the nation's gas industry. It also prescribes economic and administrative incentives needed to propel Nigeria's nascent LNG Industry towards a dynamic performance and to becoming a regional force in the global LNG market
Economics of Conditioning Nigerian Natural Gas for Market
Authors: Enyi Chimagwu G. , Appah D.
Published: December 2007

In a non-monopoly gas distribution system, each pipeline company has its own set of natural gas quality specifications to meet market requirement. The processing required and facilities employed depend on the nature of the field and composition of the natural gas.

The cost of conditioning a typical Nigerian natural gas for contaminations, in preparation for delivery to sales line was studies. This may vary in complexity from the simplest removal of water vapour to the most extensive removal of sulphur compound, non-combustible gases and many of the heavier hydrocarbons. The conditioning process consists of separation unit, carbon dioxide removal, and dehydration and dew point control units. The capital cost of procuring, installing, and operating these units were obtained using Nelson Farrar cost index.

It was observed that for a total capital investment of $12,382,590 for processing 10MMscf of the gas per day, and the cash flow of $39,417,300 for selling the processed gas at $1.55 per MMscf, an internal rate of return on investment (ROI) of 34.80% and a payback period (PBP) of 1.90 years were achieved. It is recommended that Government should encourage entrepreneurs in gas processing business, by providing good gas distribution pipeline networks to reduce operating cost.
New Opportunity Identification in a Mature Basin: The Oguta North Prospect in OML 20, Niger Delta
Authors: Esedo Ralf , Ozumba Berti
Published: December 2007

Prospectivity review of the northern part of OML 20 located in the oldest depobelt of the Niger Delta (Northern Delta depobelt) was carried out following the acquisition of 3D seismic data in this predominantly 2D covered area. The only giant field in the Northern Delta Depobelt is the Oguta field and was drilled based on 2D seismic data in 1965. Acquisition of 3D seismic data and its interpretation has changed the structural understanding in this part of the delta and has resulted in the identification of the Oguta North prospect, which is a large fault bounded hanging wall closure against a northwest to southeast trending fault block north of the Akri-Oguta field. The culmination of this prospect is against an oblique fault that could not be defined on the previously sub-optimally acquired old 2D.

The prospect is a material opportunity of about 15 km2, with a vertical closure of about 2000 ft. The objective interval ranges in age from Late Eocene to Early Oligocene when the delta was essentially lobate and presumably river dominated. At Oguta-Akri field to the south the objective interval is about 2000-3000ft with deposition in deltaic shoreface to shelf environments. These sediments vary northwards to more proximal environments at the Oguta North prospect. Reservoir thicknesses from the correlating intervals range from 30 –250 ft. The main risks associated with this prospect include lack of amplitude support in the main reservoirs, possible fault seal failure and the lateral extent of some of the reservoirs.
Establishing Actual Quantity of Sand Using an Ultrasonic Sand Detector; The Niger Delta Experience
Authors: Musa Lazarus A. , Temisanren Tuoyo , Appah Dulu
Published: December 2007

The quantity of sand produced has been determined using a Digital Signal Processing Ultrasonic sand detector. Conventional sampling methods alone do not give the true picture of sand produced in individual wells. On the other hand, operators have not been able to account for frequent de-sanding programs due to unnoticed sand being produced.

The major advantage of using the ultrasonic sand detector to detect sand is that sand monitoring has moved forward from a level of production trend to actual quantification in real time. The detector quantifies sand beyond its initial limit of profiling. The principle adopted uses an iterative method to locate a considerable threshold in the sand signature logged. Raw signals, in energy/sec, were simulated to reflect true sand production by marking up the background noise value, with about 10% to achieve the true sand free level of the signals for sand rate calculation.

This principle was applied to two fields in Western Niger Delta, comparing the sand results, in Ib/1000bbls, between conventional well head sampling results and ultrasonic detector results. Mostly 35 to 65, 37 to 63, 38 to 62, 43 to 57, 45 to 55 and 46 to 54 percentage distributions were obtained, and ultrasonic results proved to be even more reliable. A detailed comparison of both showed a considerable harmony in quality and quantity.

In this work, the unit of sand transportation, in gram per second measurement, was converted to pound per thousand-barrel (Ib/1000bbls) for oil and pound per million standard cubic feet (Ib/mmscf) for gas. These units simplified sand measurement using an ultrasonic device, when a conversion factor was introduced.
Permeability Prediction Using Genetic Unit Averages of Flow Zone Indicators (FZIs) and Neural Networks
Authors: Uguru C. I. , Onyeagoro U. O. , Lin J. , Okkerman J. , Sikiru I. O.
Published: December 2007

A significant improvement in the prediction of permeability from wireline logs has been achieved for the Niger Delta reservoirs using the concept of Flow Zone Indicators (developed by Amaefule et al) based on genetic unit classification as well as the application of neural networks. This concept is building on earlier reservoir description work whereby reservoirs in the Niger Delta have been classified according to the environment of deposition and by the lithofacies associations (i.e. genetic units) in these depositional environments. Using core data, averages of the FZIs have been computed for each genetic unit. FZI values have then been assigned to reservoir intervals without core data whose respective genetic units have been identified from log data using for example neural networks. The permeability values in the uncored reservoir intervals have thus been estimated using the permeability-FZI-porosity relationship for identified genetic unit in those wells or through multiple nonlinear regression using neural networks. Clear benefits of this improved estimation of permeability have been achieved in the process of history matching well behaviour in full field reservoir simulation models.
Simple Models for Some Fluid Thermodynamic Properties: Part I- Low Pressure Systems
Authors: Lawal Kazeem A. , Osunleke Ajiboye S.
Published: December 2007

Most mathematical models for estimating thermodynamic properties of fluids are complex, with their applications generally dependent on the operating range. This notwithstanding, the accuracy is rarely proportionate. Additionally, engineering needs often demand a simpler approach though with varying compromise of accuracy. This paper presents simple models for estimating some thermodynamic properties- compressibility factor, fugacity coefficient, molar volume, residual enthalpy and residual entropy, over well-defined and narrow range of pressure and temperature.

Employing the virial equation of state, a generalized but data-specific (local) model has been constructed for the compressibility factor of low-pressure systems. This model was then coupled with standard property equations to obtain data-based and boundary-respecting models for efficient computation of the other properties. Utilizing experimental data, with the objectives of computational efficiency, accuracy and local robustness, proposed models were constructed and compared with three existing, more rigorous models. The results were excellent. This notwithstanding, based on degrading performances observed, it is recommended that the

proposed models should be extrapolated with caution, if at all. This work is relevant to hydrocarbon production, processing and handling, facilities engineering and other field applications. These are in addition to unfolding new areas of research.
Framework for Sustainable Indigenous Technology Development and Capacity Building in Nigerian Petroleum Industry
Authors: Isehunwa Sunday O. , Falade Gabriel K.
Published: December 2007

A historical review of the evolution and development of engineering and technology generally in Nigeria is first presented. Major efforts at indigenous capacity building in the Nigerian oil industry did not commence until about 60 years after the first exploration efforts and ten years after oil discovery at Oloibiri. It was observed that in the last three decades, significant efforts have been made at establishing some institutions and infrastructure necessary for technology transfer and indigenous capacity building. Unfortunately, important requirements like favourable economic and political climate and essential linkages have been largely missing. A reliable survey and database of indigenous technology that can be applied in the oil industry is also missing. A general appraisal of the oil industry shows that while there is significant local expertise in Engineering services in such areas as drilling fluids engineering, PVT analysis, pipeline pigging and light facilities engineering, indigenous technological capacity is still very low and there is high dependence on foreign technology. We reiterate the well-known fact that ownership of production cannot be separated from the technology of production hence the need for a state-backed institutional framework for sustainable indigenous technology development and promotion of local content in the Nigerian oil industry as has been done in other counties and in the Nigerian defense industry.
A Local Content Knowledge Management System as a Strategy for Achieving Sustainable Local Content Development in the Nigerian Oil & Gas Industry
Authors: Emielu Emmanuel
Published: December 2007

The accepted industry definition of the concept of local content development in Nigeria refers to "the quantum of composite value added or created in the Nigerian economy through the utilization of indigenous human capabilities and material resources for the provision of goods and services to the petroleum industry, within acceptable quality, health, safety and environment standards" The operating factors here are the in-country ability to add value, and the international competitiveness of such added value.

By the nature of its challenges, virtually all human activities in the oil and gas industry emphasize knowledge work as it relates to solving problems, accomplishing given tasks, etc. Organizing, analyzing, creating, and synthesizing information and expertise have today become a core activity of knowledge workers. What with an ageing global workforce, exponentially exploding data volumes, extremely challenging work environment, and an unforgiving competitive landscape?

To address these challenges, oil and gas companies around the world are leveraging advances in the field of knowledge management to craft strategies for sustainable growth and competitiveness. Given that the local content players are faced with similar challenges – and perhaps more, given their weak technological financial, and managerial bases – it is argued that a Local Content Knowledge Management System presents a sustainable platform for the creation of a Nigerian value-added that is "within acceptable quality, health, safety and environment standards". In other words, the ability of the local content organizations to survive in the long run depends on their ability to deliver internationally recognizable superior performance which in turn will depend on their collective ability to gain access to, and harness the available institutional knowledge at each given point in time.

Knowledge Management (KM) as a discipline borrows extensively from other fields such as social psychology and information technology to provide frameworks for knowledge creation and sharing within social groups known as Communities of Practice (CoP). The paper explores emerging Knowledge Management perspectives and reviews a case study of the application of KM in a leading oil and gas service company's Logging and Perforating business unit. A model "Local Content Knowledge Management System" is presented and suggestions for implementation given.
Effects of Long-Term Exposure to Ultrahigh Temperature on the Mechanical Parameters of Cement
Authors: Stiles D.
Published: December 2007

Long-term mechanical durability of a cement sheath exposed to stresses in a wellbore environment is critical to maintaining zonal isolation for the life of a well. The ability of a cement sheath to remain intact when exposed to changing wellbore stresses is highly dependent upon the parameters of Young's Modulus, Poisson's Ratio and tensile strength of the cement and the surrounding rock. Wellbore stresses sufficient to cause failure of a cement sheath may result from changes in temperature, casing pressure, formation pressure, or near-wellbore tectonic stresses.

Wells subjected to Cyclic Steam Stimulation (CSS) for heavy oil recovery undergo extreme temperature changes that impart substantial stresses on the cement sheath. During CSS, wellbore temperatures can fluctuate between 77°F and 645°F, potentially leading to cement sheath failure. Various Finite Element Analysis models exist that are useful in predicting the failure potential of a cement sheath. These models require input of cement mechanical parameters. Mechanical parameters of numerous cement formulations have been measured in recent years but none of those measurements was made after long-term exposure of the cement to the ultra-high temperatures encountered in CSS wells. Development of such data was required to model the risk of cement sheath failure in wells subjected to CSS.

This paper presents a test methodology for measuring the mechanical parameters of five cement formulations after exposure to a temperature of 645°F. Parameters of Young's Modulus, Poisson's Ratio and tensile strength were measured. Evolution of these parameters over a two-year period is presented. The temperature conditions to which the cement was exposed was found to have a significant impact on the mechanical parameters. The Young's Modulus, Poisson's Ratio and tensile strength of systems exposed to 645°F varied significantly from systems exposed to an ambient temperature of 77°F. The mechanical parameters of each individual cement formulation were also markedly different. Specialized cement systems, such as foamed cement or blends containing flexible particles, did not necessarily have mechanical parameters that were better suited for use in CSS wells than some of the more conventional formulations.
Acoustic Telemetry Can Deliver More Real-Time Downhole Data in Underbalanced Drilling Operations
Authors: Gao L. , Finley D. , Gardner W. , Robbins C. , Linyaev E. , Moore J. , Memarzadeh M. , Johnson D.
Published: December 2007

Underbalanced drilling (UBD) is known to be beneficial in hydrocarbon exploration and production: less formation damage, faster drilling, better control of lost circulation and stuck pipe situations, plus an enhanced ability to further develop depleted and marginal reservoirs and fields. However, UDB is inherently more complex than conventional drilling. Therefore it is essential that downhole tool and formation information be collected and delivered in real time to the driller during UBD. Achieving reasonable telemetry data rates for logging-while-drilling during UBD can be problematic with current telemetry techniques. Mud pulse telemetry may become ineffective when highly compressible UBD drilling fluid is used. Electromagnetic telemetry fails when the formation becomes too conductive. Acoustic telemetry, based on the propagation of stress waves through the drill string, is however particularly suited for operation in underbalanced drilling operations. It is relatively unaffected by the properties of the formation and operates even more efficiently in UBD with compressible low weight drilling fluids compared with conventional overbalanced drilling with heavy drilling fluids. This paper will discuss the drill string acoustic channel characteristics, with particular reference to signal attenuation and transmissibility. It will be shown that acoustic telemetry is potentially capable of transmitting 50 – 100 bits per second through the drill string channel while drilling. Finally, preliminary field test results will be presented as part of the goal of demonstrating the advantages of the acoustic telemetry over both mud pulse and EM telemetry.
A New Method of Producing Laterally Stable PDC Drill Bits
Authors: Johnson S.
Published: December 2007

Bit Whirl is well documented as a major cause of damage to PDC drill bits, resulting in short runs, low ROP, high cost per foot, poor hole quality and downhole tool damage. Hence, consistent lateral stability is highly desirable in PDC bits.

The paper presents a new method of producing PDC drill bits that reduce or eliminate bit whirl. Traditionally, attempts to design laterally stable PDC bits have assumed that the forces generated by the bit during stable drilling cause it to begin whirling. The new approach assumes that it is the response of the bit to forced motion off its centre that causes whirl.

The new approach has been validated theoretically, in the lab and the field. Test results from a full-scale drilling rig indicate that this method is superior to existing methods at minimizing bit whirl.

This new method was successfully validated through an extensive field test program undertaken in Northwest USA, involving high-speed downhole measurements from both conventional 7 7/8″ diameter PDC drill bits and bits designed using this new method. These results demonstrated that the conventional PDC drill bits exhibited bit whirl throughout the run. The bits designed using the new method completely eliminated bit whirl.

The performance benefits of this new method were demonstrated in a 16″ section in the Middle East, where lateral vibrations are a significant problem. Prior to testing the new method PDC bit, bit optimization led to the use of high imbalance force designs to minimize lateral vibration. The first test of the new method laterally stable PDC bit set field records for ROP, footage and cost per foot compared to over 50 runs of these "Anti-Whirl"1 designs, resulting in savings of over $50,000 per run.

This paper demonstrates how the use of this new method can eliminate whirl in both laboratory and field environments, and deliver significant performance improvements over existing stability techniques.

This new method represents a major step forward in the design of PDC bits to mitigate bit whirl, and has been proven to reduce bit damage, increase run lengths, increase ROP and deliver sizeable savings for operators.
Intrinsic Safety Analysis—Driving Safety Performance to a New Level
Authors: Orlean R. , Patterson R.
Published: December 2007

Safety performance in the drilling industry continues to pose a major challenge to both Contractors and Operators. Historical accident rates, while lower than they were a decade ago, remain at unacceptably high levels despite intense focus by all stakeholders, and the use of a wide range of safety systems.

A potentially novel approach to improving safety performance has been piloted by Shell Oil Company. This approach -Intrinsic Safety Analysis - uses a measurement system based on first-principles to examine the inherent safety of each operation on three parameters - the energy in the operation, the containment of that energy, and the exposure of personnel to the energy. The resulting Intrinsic Safety Exposure (ISE) gives a direct measure of the potential for an accident in each step of an operation, regardless of the novelty of the operation, or the historical experience with it.

Having this measure of the ISE enables several potent approaches that yield increasingly significant long-term improvements by: ■Allowing Contractors and Operators to identify which operations are intrinsically less safe and to put in place remedial measures for those with high exposure■Pointing the way for engineers to re-design operations and equipment such that they are intrinsically safer, using such powerful tools as Value Engineering to create designs with lower ISE■Integrating ISE thinking across the lifecycle of equipment and entire assets■Enabling a rigorous value-ranking of alternative investments to improve safety performance■Benchmarking and comparing ISE across assets and between competing operations■Establishing long term corporate goals for ISE

Moreover, analysis of ISE fits well with other value-improving activities and decision making tools commonly used in our industry. The long term benefits of this approach may be to drive the safety performance to new levels, while reducing costs and time.

This paper intends to expose the industry to this new approach and invite a maturing of the method as a potential new avenue for making a step change in safety performance
Experiences and Lessons Learned From Utilizing Automated Reliability-Centered Maintenance on Drill-Floor Equipment To Optimize Operation and Maintenance Planning
Authors: Holme A.
Published: December 2007

Over the last several years, automated systems for continuous collection of operational and environmental data from drilling equipment have been utilized. The goal has been to optimize operations, reduce downtime and improve maintenance planning by employing condition analysis techniques. This paper seeks to describe the benefits and challenges in introducing such an on-line monitoring system.
Utilizing Permanent Magnet Motor Technology on Larger Drilling Equipment for Improved Safety and Better Control
Authors: Kverneland H. , Kyllingstad Å. , Austefjord A. , Moe M.
Published: December 2007

Permanent magnet motor technology has been used for many years in small applications such as common hand held power tools. However, the technology has not been widely implemented on larger sized motors due to the relatively high cost of producing the permanent magnets. Over the past 4 years however this cost has been reduced and the benefits of PM motor technology is now economically feasible for larger drilling equipment such as utility winches, drawworks and top drives. Another important reason why the PM motor technology now is feasible in larger machines is the recent development of improved control systems for these motors.

When using PM-motors in winch applications, operational safety is improved due to the inherent failsafe electrical braking characteristics in PM-motor technology. Another benefit is that the power-to-weight/size ratio can be improved up to 30% compared with a standard induction motor. Permanent magnet motors additionally lend themselves to greater flexibility for high torque and low speed applications thus reducing the need for gear transmissions and in some cases eliminating the transmission all together. This simplifies the overall mechanical design and improves the ability to accurately control the machines.

This paper focuses on the opportunities to introduce larger drilling equipment with better performance characteristics related to increased capacities, improved control, enhanced safety, and reduced maintenance as a result of simplified mechanical design. The paper also discusses the challenges related to current regulations and standards that do not recognize with new and improved technology. Manufactures of drilling equipment should work closer together with the authorities and certification organizations to update standards and regulations so that this does not hinder introduction of new and better technology.
Expandable Technology Improves Reliability of Conventional Liner Hanger Systems
Authors: Walvekar S. , Jackson T.
Published: December 2007

Liner hangers and liner-top packers traditionally have been used in liner completions. However, in the conventional systems that employ "cone and slip" technology, the failure rate of the liner top packers as well as the failure of system installation has been an ongoing problem. In conventional systems, mechanical equipment with multiple slips are run and set. The disadvantages of these systems include multiple leak paths, reduced radial clearance, and exposed hydraulic ports, all of which increase the potential for failure. When these failures occur, the cost of the well completion is significantly impacted, and well completion efficiency is decreased.

Reasons for unsuccessful liner installations can be attributed to a number of conditions, such as:

the liner cannot be run to depth the liner hanger/packer pre-sets the setting tool fails the liner top cement job is poor.

This paper will discuss an expandable liner system that was developed to address the shortcomings of the traditional systems. The new liner system combines expandable solid liner technology with proven cementing products and service capabilities.

The following discussion will include details concerning development of the design, operating procedures, and benefits of the expandable liner hanger as well as how the versatility and adaptability of the system improves its reliability. Several case histories will be discussed to verify the efficiency of the new system.