bluuebunny/crossref_metadata_2025 huggingface dataset:
A Risk-Based Screening Method for Evaluating Total Petroleum Hydrocarbons at Upstream Sites
Authors: McMillen S. J. , Magaw R. I. , Deeley G. , Kerr J. M. , Edwards D. A.
Published: December 2007

Regulators often require that Total Petroleum Hydrocarbons (TPH) be measured and set TPH clean-up criteria for soils impacted by crude oil. However, the lack of a standardized, scientifically defensible procedure for interpreting TPH has resulted in the establishment of arbitrary criteria ranging from 100 to 20,000 ppm (mg/kg) TPH in soil. In the past, TPH regulations and guidance have not considered a technical approach to addressing risk to human health. Recent efforts by the TPH Criteria Working Group (TPHCWG) have established human-health Risk-Based Screening Levels (RBSLs) for refined petroleum products. RBSLs for crude oils and exploration/ production wastes are being addressed by a joint industry effort through Petroleum Environmental Research Forum Project 97-08. The TPHCWG methodology was modified to include the high molecular weight compounds that are present in many crude oils. As part of the project, 48 crude oils were characterized for aliphatic and aromatic hydrocarbon content within equivalent carbon number ranges. Appropriate toxicity, fate, and transport values were determined for compounds greater than carbon number C35. Upon project completion, a risk-based screening method will be available for evaluating TPH at upstream sites. This method can be incorporated into an upstream version of a Risk-Based Corrective Action Plan (RBCA).
A Risk Evaluation of Metals in Crude Oils
Authors: Magaw R. I. , McMillen S. J. , Gala W. R. , Trefry J. H. , Trocine R. P.
Published: December 2007

All crude oils contain trace quantities of naturally occurring metals, however, few data have been published on the specific metal content of crude oils. In this study, the metals concentrations in 26 crude oils from North America, South America, the North Sea, the Middle East, and Far East Asia were determined. The crude oils represent both a range of geographical production areas and a range of crude oil types, with the oils having API gravity values ranging from 12° to 46°. The concentrations of 18 metals were determined, and the potential human health risks associated with the metals were evaluated, assuming standard exposure scenarios. The potential for ecological impact was also evaluated by comparing the metal concentrations to ecological soil screening level benchmarks. The results indicate that many metals are present at such low levels that there is no need to consider them as chemicals of concern for purposes of site characterizations and risk assessments at sites where accidental and/or historical crude oil releases have occurred.
Bioavailability of Hydrocarbons in Untreated and Bioremediated Field Soils
Authors: Loehr Raymond C. , Webster Matthew T.
Published: December 2007

Two soils were bioremediated in a field-scale land treatment unit and bioremediation process performance was assessed with respect to reductions in chemical concentration, relative toxicity and chemical mobility. In addition, a batch rate of release (ROR) procedure was used to determine the rate and extent of release of hydrocarbons from the untreated and bioremediated soils.

For one soil containing aged crude oil (Hilbig),no reductions in hydrocarbon concentrations occurred. However, no toxicity and little chemical mobility were measured in the soil. For a second soil containing a fresh diesel fuel spill (Gideon), land treatment reduced both chemical concentrations and toxicity, and the chemicals in the soil exhibited little potential mobility.

Results of ROR studies were used to verify that the chemicals in the Hilbig soil and those remaining in the treated Gideon soil were not available to be released from the soil. Thus, an environmentally acceptable endpoint had been achieved for the Hilbig soil before treatment and for the Gideon soil after land treatment.
Recent Advances in Surfactant Remediation of Contaminated Soils
Authors: Ooi K. C. , Dwarakanath V. , Holzmer F. J. , Jackson R. E. , Pope G. A. , Weerasooriya V.
Published: December 2007

Significant advances have occurred in the application of surfactants for the remediation of soils contaminated by a wide variety of oils and chlorinated solvents. Many new laboratory and field data have become available and provide a basis for a better understanding of the use of surfactants and how to design remediation projects. Surfactant selection must be tailored to the specific site conditions and contaminants and satisfy many stringent criteria including regulatory and cost considerations. We illustrate our approach to surfactant selection with an example that required the synthesis and testing of a completely new surfactant for a very viscous oil which was outside the range of experience with surfactants for either enhanced oil recovery or surfactant enhanced aquifer remediation.
Non-Invasive Imaging of Biofilms in Porous Media Using NMR Methods
Authors: Hoskins Brian C. , Majors Paul , Sharma Mukul M. , Georgiou George
Published: December 2007

The use of bacteria for the in situ remediation of contaminants is becoming a common practice. To effectively apply such bioremediation techniques we must have a better understanding of how bacteria, present mostly as biofilms, move through a porous medium. No experimental or field data presented to date provide information on the spatial distribution of the biofilm as growth and fluid convection occurs.

A sorted relaxation-resolved NMRI technique is introduced for the non-destructive, quantitative spatial resolution of biofilm in an idealized porous medium. T1 and T2 relaxation NMR imaging data were used to resolve spatial maps of biofilm. Experiments with a transparent, open-flow and glass bead-packed parallel-plate bioreactor, yielded NMR biofilm images comparable to photographs of the bioreactor. Sorting of the relaxation data improves NMRI by using a threshold biofilm relaxation time value from relaxation time histograms. Ranges of relaxation times for biofilm were determined to be between 0.3 and 2.2 seconds for T1, and 0.07 and 0.11 seconds for T2. Our results clearly point to the feasibility of using NMR methods for the in-situ monitoring of bacterial populations in porous media. We also show that T1 and T2 resolved methods will work best for this application.
Large-Scale Injection of North Slope Drilling Cuttings
Authors: Schmidt J.H. , Friar W.L. , Bill M.L. , Cooper G.D.
Published: December 2007

This paper was prepared for presentation at the 1999 SPE/EPA Exploration and Production Environmental Conference held in Austin, Texas, 28 February-3 March 1999.
Modeling the Effects of a Deepwater Leak on Behavior of a Multiphase Production Flowline
Authors: Scott Stuart L. , Lei Liu , Jinghai Yi
Published: December 2007

Identification of a leaking flowline represents a special challenge for the many deepwater developments planned in the U.S. Gulf of Mexico (GOM) and around the world. While historically, the number of shallow water releases from pipelines is extremely small, deepwater flowlines operate under conditions rarely encountered in previous development schemes. The remoteness of the deepwater flowline, coupled with a number of complex interactions between the released fluids and the deepwater environment effectively eliminates most external detection methods. Commonly applied internal leak detection methods are also ineffective due to multiphase flow and their dependence on precise metering of both the inlet and outlet flowrates. While multiphase meter technology is emerging for the deepwater market, these devices have rarely been applied in the GOM and may have difficulty providing the required accuracy given the wide range of flow conditions encountered during the life of a well. This paper considers how the presence of a leak would be manifest in the flow behavior of a deepwater production flowline for the annular mist, stratified and slug flow regimes. The models developed require only routine production data, i.e. inlet and outlet pressure and outlet flowrates. Also, various leak locations along the pipe circumference are considered, i.e. top and bottom leaks. The results indicate that a leak can be detected in many instances if special testing and monitoring methods are utilized. In particular, detection is greatly enhanced when flow pattern changes occur downstream from the leak. The case of liquid leaking from the bottom of the pipe in stratified flow may be the most difficult to detect.
Single Step Enzyme Treatment Enhances Production Capacity on Horizontal Wells
Authors: Stanley Frederick O. , Rae Phil , Troncoso Juan C.
Published: December 2007

A new technology utilizing a Single Step Specific Enzyme Breaker (SSSEB) process has been applied for the removal of damage caused by drill-in fluid on horizontal wells. This technique has resulted in significant improvements in well performance. Previous SEB (Specific Enzyme Breaker) technology, as it applies to xanthan, starch and carbonate drill-in fluid, focused primarily on a two step process for removal of horizontal well drill-in fluid filter cake damage; an initial SEB treatment for starch or xanthan polymer removal followed by a second treatment of acid for calcium carbonate removal.1,2 This new SSSEB method provides an effective one step system for removing both the starch polymer and calcium carbonate components of drill-in mud filter cake formed during horizontal open hole operations.

Case history information and laboratory data are presented to validate the effectiveness of the SSSEB formulation on the degradation of the filter cake formed when a starch, xanthan and calcium carbonate drill-in fluid is utilized. Previous laboratory and field data have demonstrated the effectiveness of SEB technology for degrading starch polymer. The new SSSEB method utilizes the identical starch specific enzyme product used in previous SEB treatments; however, it also employs a buffered, organic acid fluid. The organic acid reacts with the calcium carbonate portion of the filter cake as the enzyme simultaneously acts on the starch polymer. Compared to conventional high strength mineral acid systems (such as hydrochloric acid) often used for calcium carbonate filter cake removal, the SSSEB acid solution reduces the risk of fluid emulsions, formation acid sensitivity issues, secondary precipitate problems as well as safety and environmental issues. The system is also relatively slow-reacting which is important for the effective placement of the breaker fluid across the entire horizontal interval and allows for uniform filter cake deterioration.

The most noticeable economic benefit resulting from the application of the Single Step Specific Enzyme Breaker system is increased production of hydrocarbons. The SSSEB technique also offers savings on rig and related charges, chemical costs and operational charges by allowing for wells to be placed on production more rapidly and not requiring follow up acid work.
Helical Buckling of Pipe With Connectors
Authors: Mitchell R. F.
Published: December 2007

The effect of connectors on pipe buckling is acknowledged, but has received little attention. Lubinski analysed the effect of connectors on pipe in tension in a curved borehole, while Paslay and Cernocky extended this analysis to pipe in compression. These papers indicate that bending stresses are greater due to connector stand-off. However, these papers do not consider a buckled pipe.

This paper presents an analytic solution of the beam-column equations in three-dimensions for a helically buckled pipe with connectors. For low axial compression, the solution approximates helically buckled pipe without connectors, however, at higher axial forces, the effects of connectors on contact forces and bending stress becomes significant. Sag between connectors is calculated so that pipe body contact between connectors can be determined.

Applications include the analysis of bottom hole assemblies, drill pipe, casing, and tubing. The solutions are simple formulas that are suitable for hand calculations.
SandPro - A New Application Program for Predicting Onset of Sand Production
Authors: Awal Mohamed R. , Osman El-Sayed A.
Published: December 2007

A costly problem encountered in sandstone reservoirs is the production of sand with the produced fluids. We have developed a user-friendly computer program to identify potential sanding locations in the payzone. Various poroelastic and elasto-plastic sand prediction models available in the literature included.

Using Visual Basic™, an interactive windows™ program has been developed. The package is readily usable by field engineers to determine critical flowrate and drawdown without a prior knowledge of the theories of rock failure. The simulator can also be used during planning stages to access the effect of depletion and improved recovery methods (such as water flooding) on sand production.
Rapid Assessment of Development Planning Options for Giant Oil Reservoirs in West Kuwait
Authors: Salam T. A. , Al-Maraghi E. , Jariwala H. , Thawer R.
Published: December 2007

The West Kuwait development consists of 4 fields, Umm Gudair, Minagish, Abduliyah and Dharif and 5 major producing horizons (Minagish Oolite, Najma, Sargelu, Marrat, Wara, Burgan). Total combined production is currently some 200 mbopd.

A production target of 500 mbopd from West Kuwait fields was established in 1994. This target was planned to be achieved by mid 1999 and sustained for minimum of 5 years. A major field development scheme was adopted requiring the drilling and completion of some 80 new wells, the commissioning of two new gathering centres, a powered water injection plant, an effluent gathering and transfer system, artificial lift and corresponding power systems.

While the conceptual scheme was rapidly adopted, it became apparent that a tool which described and integrated the whole of the West Kuwait production at a very high level from reservoirs through gathering centres to export was required to address the complex range of subsurface, drilling and facilities implementation outcomes.

This paper describes how a system dynamics model was developed to investigate the chokes in the West Kuwait system design and delivery programme. The model was constructed using a standard system dynamics software package. Simple methodologies were used to describe reservoir and well performance; to describe constraints in the surface facilities and export facilities; to develop remedial options to overcome these constraints; and to enable the cost benefit of options to be rapidly calculated.

The model has allowed the impact of subsurface uncertainty on the performance of the surface facilities and export routes to be readily visualised and options to manage this uncertainty to be identified. The model has helped identify bottlenecks in the system design so that these could be rectified. Additionally, the use of the model has allowed the impact of differential slip between the timing of drilling and facilities delivery to be identified and minimised.
Data Warehousing Within Well Engineering
Authors: Singh Raghubir , Albuquerque Harold , Al Hinai Abdul Karim
Published: December 2007

In view of the scale of operations within Petroleum Development Oman, there is an ever increasing business requirement for good quality information to support well design and management information. Numerous applications have developed from different sources with sharing of data through numerous interfaces. Access to data was difficult as it was distributed, and the quality unreliable. Frustrated users resorted to developing their own niche applications. The consequence was a portfolio which was expensive to maintain, increasingly difficult to effectively manage, supported by information that was largely inaccessible and of variable quality.

This paper describes the process of establishing a Well Engineering data warehouse, based on the Petrotechnical Open Software Corporation (POSC) industry standard. Applications have been modified to interface directly with this warehouse. Data has been separated from applications enabling easy access to one common source of reliable information. Sharing agreements enforce ownership and ensure information quality. Effective portfolio maintenance is achieved through reduced complexity and number of interfaces between applications.

It has resulted in reduced repetitive checking and modification of the same information in multiple applications, resulting in significant efficiency gains. This has been enabled by a consistent single source of good quality information which is easily accessible. Data has been separated from applications. It further reduces the dependency on a single supplier for Well Engineering tools, as applications and data normally tend to be closely tied together. POSC further enhances possibilities for openly sharing the information between vendor application suites, within organizations, and even beyond.
Fracture Modelling as Part of Integrated Reservoir Characterization
Authors: Heffer K. J. , King P. R. , Jones A. D. W.
Published: December 2007

Natural fractures play an obvious role in many reservoir performances; in others their influence is more subtle, but yet still significant, especially in secondary or enhanced recovery schemes. It is more often than not the case that incorporation of fractures and small scale faults in a reservoir heterogeneity model will improve the validity and value of that model, and enable reservoir flow simulation and prediction to be on a surer basis. Numerical geomechanical models provide a means of predicting realistic strain fields associated with fracturing, and can incorporate general heterogeneities in mechanical properties, but have degrees of freedom in lateral boundary conditions that cannot be resolved by matching surface contours alone. They are also cumbersome to condition to data available from well. This paper introduces a geostatistical methodology for modelling strains that makes use of spatial covariances in the components of deformation: it provides a simpler, more flexible tool for conditioning strain to well data, in addition to surface data. It can be looked upon as an improved type of curvature analysis, but additionally capturing the 2 shear modes of strain that are neglected by that technique. This paper describes a set of stages for modelling strain that makes use of all the available structural information and taking the results forward to incorporate permeability due to fractures into the overall integrated reservoir characterisation and dynamic fluid flow prediction.
A New Development in Oil Recovery Polymers
Authors: Fratt W.J. , Bernot R.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the Rocky Mountain Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., April 7–9, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A recent development has made it possible to use high molecular weight polymers in a liquid, rather than solid form. A comparison of the particles of a solid and a liquid polyacrylamide is made with micrographs of polyacrylamide is made with micrographs of each presented. The effect of these particles on handling and solubility is then discussed. Also presented are viscosity comparisons between liquid and solid polymers, as well as comparative core flood data and a discussion of the results. Reference is made to recently issued patents relating to oil recovery utilizing liquid polymers. Also, brief reference is made to field injectivity projects in various parts of the country. projects in various parts of the country

Introduction

High molecular weight polymers have evoked considerable interest in recent years for oil recovery operations, both secondary and tertiary. Polysaccharides and partially hydrolyzed polyacrylamides have been tested, both in the lab and in field trials to aid in recovering oil left in the reservoir.

While many questions still remain to be answered about what occurs in the reservoir, many operators have enhanced their oil recovery through the use of polymers in secondary and tertiary recovery projects.

Some oil companies are licensing their technology in tertiary recovery methods, making use of polymers to serve as the dive fluid to more efficiently push the surfactant or micellar flood through the reservoir.

USE OF SOLID POLYMERS

Oil recovery polymers are generally very high molecular weight; at least 1 million and greater. Until recently, only dry polymers were available for oil recovery projects. polymers were available for oil recovery projects. To use the dry product effectively, particular care and attention must be given to the handling and make up procedures required to put them into solution. Solid polymers have a justifiable reputation of being difficult to dissolve.
Increasing Oil Recovery by Chemical Control of Producing Water-Oil Ratios
Authors: Sloat Ben
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

This paper was prepared for the Rocky Mountain Regional Meeting of the Society of Petroleum Engineers of AIME, to be held in Denver, Colo., April 7–9, 1975. Permission to copy is restricted to an abstract of not more than 300 words. Illustrations may not be copied. The abstract should contain conspicuous acknowledgment of where and by whom the paper is presented. Publication elsewhere after publication in the JOURNAL paper is presented. Publication elsewhere after publication in the JOURNAL OF PETROLEUM TECHNOLOGY or the SOCIETY OF PETROLEUM ENGINEERS JOURNAL is usually granted upon request to the Editor of the appropriate journal provided agreement to give proper credit is made. provided agreement to give proper credit is made. Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Natural water drive reservoirs, normally considered quite efficient, have not been subjected to extensive oil recovery improvement studies or field tests. Lately, however, special treatments to control the producing water to oil ratios in Tensleep sand and Arbuckle Dolomite have shown good payouts. These results are presented payouts. These results are presented in the form of time-rate production graphs and cost performance tables.

Conclusions are:Ultimate oil recovery from natural water drive reservoirs can be improved by chemical treatments to reduce water-oil ratios.New in situ polyacrylamide gelling techniques provide an effective degree of control over subsurface water movement.Chemical oil recovery costs under $.95/bbl can be expected for natural water drive limestone reservoirs.

Introduction

Three factors — higher crude oil prices, better technology and lower prices, better technology and lower treatment costs — have been combined to assure excellent payouts from producing wells treatments designed to producing wells treatments designed to lower water-oil ratios in natural water drive reservoirs. This paper studies the effect of each factor on a group of Arbuckle "control" wells in the Graham-Rooks County area of northwest Kansas (Fig. No. 1). Treatment of a Tensleep sand producer in Hot Springs County, Wyoming, is also summarized to show that good economics can be expected under a variety of reservoir rock and fluid conditions.

ARBUCKLE DOLOMITE — GEOLOGY AND PRODUCING CHARACTERISTICS PRODUCING CHARACTERISTICSAn important subsurface feature in central Kansas is the Barton Arch — a buried ridge of Precambrian granite running northwest-southeast. Above this basal granite lies the Cambro-Ordovician Arbuckle Dolomite, the principal oil producing zone in central Kansas.
Development of a Portable Downhole Camera System for Mechanical Inspection of Wellbores
Authors: Whittaker J. L. , Schultz P. K. , Baker D. L.
Published: December 2007

A second generation, highly portable, downhole video camera system for mechanical inspection of wellbores has been successfully tested and field deployed in several global locations. The technology employed is unique from previous camera inspection systems in that it can be deployed on conventional wireline and has a fast data rate providing images every 3.5 seconds independent of cable length. This technology provides operators in remote locations a 舠fly away舡 diagnostic tool providing visual information of downhole problems and conditions. Visual inspection of downhole problems provides clear, definitive information, giving operators the highest possible confidence in remediation of problem wells. Because any conventional cable can be used, this camera system will provide video inspection when: 1) the well depth is too deep for full motion video systems, 2) corrosive fluids are present, 3) temperatures above 300°F are present, 4) the well is horizontal and the tools can only be deployed by coiled tubing or well tractor, and 5) rapid deployment is necessary including remote locations where other camera systems could not be mobilized on short notice.
Geological History of the Northwest Passage
Authors: Daae H.D. , Rutgers A.T.C.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

The broad structural geology and stratigraphy of the Northwest Passage is controlled by the Boothia Arch and structural depressions on each side, namely, Viscount Melville Sound and McClure Strait to the west (graben) and Lancaster Sound to the east (half-graben). Negative rift movements began during Mesozoic time and continued into the Tertiary.

Outcrop and well information from the islands are related to marine seismic data in the Northwest Passage. Paleozoic strata appear to continue offshore in facies predictable from data on the islands. Mesozoic and Tertiary strata, however, are represented by sparse remnants on land, but are well developed under Lancaster Sound, if low velocity beds present there are of these ages. M'Clure Strait also seems to have thicker Tertiary and Mesozoic sediments than do the adjacent islands.

Introduction

The study area is large (Fig. 1). it occupies a region 900 miles long by 300 miles wide. An effort has been made to incorporate all literature on outcrop data as published by the Geological Survey of Canada and indus together with well information released to the public. These sources of data were combined public. These sources of data were combined with 14,000 miles of marine seismic information obtained throughout the Northwest Passage. At the time of writing no offshore wells have yet been drilled in the Northwest Passage.

Fig. 2 shows the main geographic divisions. From east to west they are: Lancaster Sound, Barrow Strait, Viscount Melville Sound, and McClure Strait. The width of these sounds is approximately 50 miles, locally widening to 130 miles in Viscount Melville Sound, and narrowing to some 30 miles in Barrow Strait.

PALEOZOIC STRATIGRAPHY PALEOZOIC STRATIGRAPHY

Cambrian

The Cambrian lithofacies and isopach map, Fig. 3, shows the Minto Arch, the Boothia Arch, and a third area named the Stable Shelf. The Stable Shelf is that area which was not greatly affected by post-Precambrian orogenic movements. It underlies the eastern part of Devon Island, northern Baffin Island and Bylot Island. Late Proterozoic sediments outcrop along the Minto Proterozoic sediments outcrop along the Minto Arch, whereas crystalline rocks of Archean age are predominant on the Boothia Arch and Stable Shelf, with local outcrops of late Proterozoic sediments.
ICoTA's CT Drilling Training and Competence Guidelines - How to Use Them
Authors: Bijleveld A. F.
Published: December 2007

This paper describes the development and use of the International Coiled Tubing Association (ICoTA) guidelines for training and competence for CT drilling operations.

The lack of training standards within the coiled tubing industry is well recognised. In order to redress this and develop standard training requirements for CT operations ICoTA set up a workgroup in 1997. The aim of this workgroup was to identify the minimum required skills and knowledge for safe and efficient CT operations, to aid the training of personnel and enhance operational safety and efficiency. Initially CT Drilling operations are addressed as this is the area where the lack of a structured approach to training and competence is most apparent.

The paper discusses the results from this workgroup, and presents the suggested outcome. The approach to wellsite competence is based on competence presence, and is not related to people or job functions. Three levels of competence are recognised; ability to execute, ability to supervise execution and ability to assist. The guidelines take into account; applicability worldwide for all CT drilling operations, on all types of CT units, and different organisational structures.

Several examples of training requirements will be given for various CT drilling operations in order to illustrate how this document may best be used in practice.

Definition:

This paper is about training, competency and experience.

To achieve a common understanding of the definition of competency it is taken as meaning:

Competency – " Ability to perform the activity in the workplace consistently to the required standard ". In this context, competency consists of proven knowledge, skills and experience.
The All Electric BHA: Recent Developments toward an Intelligent Coiled-Tubing Drilling System
Authors: Turner Daniel R. , Head Philip F. , Yuratich Michael A. , Cameron Gerald
Published: December 2007

This paper considers the ongoing development of an electrically powered bottom hole assembly that has been designed for use in closed-loop, coiled tubing drilling (CTD) applications.

The electric BHA has been conceived and designed through a European Drilling Engineers Association [DEA(E)1] joint industry project. This paper introduces the project and reviews its progress to date.

Electric coiled tubing drilling, or E-CTD, was delineated as a three phase project to stage progress and reduce technical risk. Phase I of the project, completed in late 1997 was designed to prove the feasibility and concept using standard motor technology.

Phase II, currently in a bench testing programme, intends to deliver a fit-for-purpose electric downhole motor (EDM) suitable for drilling a 3.75″ hole. The motor is being incorporated into an electric bottom hole assembly (BHA) which incorporates pressure, temperature and vibration sensors. This is shortly to be field tested in Aberdeen.

Phase III of the project, scheduled to start mid-1999, integrates geo-steering and variable-bend directional technology to provide what has been termed the ‘all electric’ BHA. The ultimate goal of the project is to integrate the electric motor into a closed-loop drilling system. It is envisaged that, based upon feedback from near-bit sensors, such a system would be able to automatically adjust drilling parameters to optimise drilling performance.

Upon successful completion of basic closed loop functions, the intention is to incorporate the controlability of the BHA into what they describe as an ‘intelligent’ drilling system. This paper outlines a definition of this ‘intelligence’ and the authors also provide an insight into how far they believe that this technology may be taken, in terms of the autonomous decision making ability of a surface computer.
Coiled Tubing Failure Statistics Used to Develop Tubing Performance Indicators
Authors: Adrichem Willem P. van
Published: December 2007

Unpredicted CT string failures have not completely disappeared despite the industry having a greater understanding of cycle fatigue. A comprehensive process to systematically analyze CT string failures (field-based) has been in place since 1995. This system is described and details of a CT string failure database discussed. The database includes over 120 entries from the period 1995 through 1998 derived from worldwide CT operations of Schlumberger Dowell. The process delivers two principal data sets: the mode of failure (failure mechanism) and the cause (failure cause).

The four-year study period enables failure trends to be identified. Such trends are evident in both in failure mechanism and cause and are discussed.

Evaluating the "expired life" of the CT strings under study has led to the conclusion that traditional and current string management procedures (that are based on low cycle fatigue accumulation) are inadequate. This has implications in both the prediction of CT string failure and the optimization of string use.

The CT string failure data is derived from CT operations conducted by over 150 CT units that completed in excess of 35,000 operations during the study period. The volume of tubing used during these operations, in combination with the accumulated failures, allows for the introduction and discussion of "Tubing Performance Indicators", which the author believes can be considered representative for the industry.
Oil-Based Reservoir Drilling Fluid for Critical Field Cases: Integrated Formation-Damage Evaluation and System Development
Authors: Hanssen Jan Erik , Ping Jiang , Haga Marton , Berge Hans Ivar , Boassen Tony , van der Zwaag Claas
Published: December 2007

An increasing number of field developments in Norwegian waters are marginal, with the economics limited by reservoir deliverability and requiring optimum well productivity unaffected by formation damage. This paper presents a case history from an ongoing development in low-permeable, highly challenging reservoirs. The 150 °C downhole temperatures, well geometry restrictions imposed by the subsea development, and the use of non-perforated completions place additional constraints on fluid design. The focus of the paper is on formation damage studies and the identification of performance-critical drilling fluid parameters. The development of representative laboratory methods is discussed and uncertainties evaluated. The joint study highlights the importance of using a range of field and lab mud preparations and working in an open interactive manner for fluid development, evaluation and testing. Combining field and laboratory test results was a critical part of the effort.

Initial mud exposure tests on reservoir core samples indicated that an otherwise qualified HTHP oil-based drilling fluid could cause severe formation damage in this particular reservoir. This was quite unexpected, as the fluid in question has been used to drill highly productive wells in other fields. Similar damage was observed on field and laboratory mud samples. Parallel work showed selected water-based fluids to also be damaging with no other decisive advantages. A systematic program of reformulating the HPHT OBM was undertaken. First, each auxiliary system component was replaced, and the effect on formation damage measured. These changes were insufficient to remove the damage potential of the original fluid. Therefore, an alternative emulsifier pack-age was selected and used as the basis for designing a novel system. Core tests on lab formulations of the novel system indicated greatly reduced formation damage potential.

A field trial was immediately carried out to validate the novel system and showed good production potential with low skin damage. A repeat test in another well confirmed this observation. The field trials were designed to capture any changes in field fluid behavior that could be detrimental to well productivity. Drilling-fluid samples were collected at regular intervals and characterised for standard properties, filtration, particle sizing and formation damage. Supporting research, using powerful experimental tools such as ESEM, and pore-size analysis of reservoir cores gave added value. Surprising core-test results led to the identification of flaws in the lab test protocols affecting the saturations before and after mud exposure. By redefining the core-test procedures and correlating all the lab results, conclusions were obtained that were in agreement with the good field performance of the novel fluid and new knowledge was gained about the mechanisms of formation damage.
Ball Sealer Diversion When Fracturing Long and Multiple Triassic Sand Intervals on Alwyn Field, North Sea
Authors: Baylocq Pascal , Fery Jean Jacques , Parra Laurent , Derbez Emmanuel
Published: December 2007

This paper presents results related to the use of the ball sealer diversion technique to fracture long and multiple Triassic sand intervals in the Alwyn Field. It also focuses on the methodology adopted to design and prepare the treatment.

This technique was applied on a well producing from a gross pay zone thickness of 350 m with a perforated length of 98 meters. The production decreased drastically after condensate deposition in all reservoir intervals induced high skin levels. Due to low permeability, matrix treatments were discarded as a solution. Instead, a proppant fracture treatment was planned to by-pass the skin, using ball sealer diversion to treat the entire perforated interval.

The treatment was performed successfully in several stages including gel pad, proppant and ball sealers. Good indications of diversion showed that most of the intervals were fractured. However, performing such a treatment requires sophisticated engineering to determine the optimum number of stages, number of ball sealers per stage, gel and proppant volumes per stage and pumping rate.

The success of this operation will allow the technique to be considered for wider application such as fracturing long intervals in deviated or horizontal perforated wells at moderate cost.
Return Permeability: A Detailed Comparative Study
Authors: Marshall David S. , Gray Russell , Byrne Michael T.
Published: December 2007

This paper was prepared for presentation at the 1999 SPE European Formation Damage Conference held in The Hague, The Netherlands, 31 May–1 June 1999.
Direct Digital Laserlogging
Authors: Burgen Jack G.
Published: December 2007

This paper describes a newly developed, direct-digital system for monitored data acquisition, automatic computation and calibration of well log data with presentation on an entirely new Laser Beam graphic recorder. The new direct-digital system avoids the errors that are sometimes made by field engineers when faced with the multitide of switches, connectors, adjusting knobs and meter dials of conventional analog panels, as well as errors due to analog drift and nonlinearity. Many older systems have utilized a computer to "process" the data provided by the conventional analog panels, but processing by these hybrid systems does not avoid the errors that are inherent in the analog panels and in the adjustment of the analog knobs and dials during calibration and operation. The new system described in this paper, is digital from the start, avoids the knobs and dials and provides automatic calibration and quality control, resulting in precisely repeatable records. The Laser Beam photographic record is completely ready for use within a few seconds after the recorder receives the input data.

The steps involved in reaching this degree of refinement are generally analogous to those experienced in seismic exploration operations during conversion to digital methods; digital processing of data from standard analog truck equipment only prefaced the present direct-digital field equipment, which has made vastly improved data processing possible.
Clastic Formation Evaluation Program In Cased Holes For Both Fresh And Saline Formation Waters To Determine Hydrocarbon Content
Authors: Vercellino W.C. , Skaggs L.L. , Bishop W.D. , DeVries M.R. , McWhirter V.C. , Wichmann P.A.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

Formation evaluation of clastic formations in Cased Hole uses the principals and logics of Sandstone II and Complex Reservoir Formation Analysis. Included in the Program are analysis from Open Hole Surveys, when available, along with analysis of the Carbon Oxygen Ratios, Silicon Calcium Ratios, Gamma Ray, Silicon, Calcium, Compensated Neutron, Neutron Lifetime Sigmas, near detector curve from the Lifetime Log, and for detector curve from the Lifetime Log measurements. The Cased Hole Clastic Evaluation will allow analysis of possible hydrocarbon bearing zones regardless of water salinities through casing.

Matrix constants, formation salinities, clay volumes, formation fluid parameters, i.e., water, gas, and oil, are determined from comparison of a series of checks and balances of the survey responses and their material balance equations. The analysis is presented in analog form along with a printed report and commentary. Examples are shown from the Gulf Coast, California, Red Desert, and East Texas of the analysis along with tested results.

Introduction

Evaluation of clastic formations in cased holes uses pattern recognition in (addition to the principals and logic of Dresser Atlas' evaluation programs for Sandstone and Complex Reservoir formations. The evaluation technique allows analysis through casing on possible hydrocarbon bearing zones regardless possible hydrocarbon bearing zones regardless of water salinities. Data are utilized from Gamma Ray Logs, Silicon/Calicum (Si/Ca) ratios, Silicon/Calcium (Si/Ca) continuous curves, Carbon/Oxygen (C/O) ratios, Inelastic Neutron Logs, Compensated Neutron Logs, Dual Detector Neutron Lifetime Logs and open hole surveys.

Matrix constants and formation salinities are determined from crossplots. Shale volume parameters are calculated. Then the data is parameters are calculated. Then the data is compared in a series of checks and balances using crossplots of porosities that are shale volume corrected.

Data output is in analog and tabulated form. The analog plot is the Cased Hole Exploration Service Epilog, (Figure 8C). Displayed on a four track grid, the curves are recorded as follows:

Track I Lithologic characteristics - Shale% of Bulk Volume, Permeability Index, and C/O Ratio measurements.
A Quantitative Technique for Determining Injectivity Profiles Using Radioactive Tracers
Authors: Wiley Ralph , Cocanower R.D.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

A new technique is presented that will quantify the losses to the formations in the well bore utilizing tracer profiles. The method is supported analytically and provides a sound basis for tracer profiles not available with other surveys in the field today.

This quantitative technique utilizes the intensity of the radioactive tracer material as a function of depth. As the material is lost through the casing performations and open hole sections into the formation, the intensity of the tracer material remaining in the borehole is related to the intensity before any losses occur. The gamma ray count rate is related to the intensity by correcting the observed count rate for system resolving time and integrating the corrected count rate as the tool moves through the radioactive material. The integral of the corrected count rate of each drag run through the material is normalized to the intensity before any losses to the formation take place. place. The accuracy of this system over an existing manual geometric approximation technique is demonstrated by several field examples.

Introduction

Current methods to determine the vertical water injection distribution include radioactive velocity measurements and radioactive tracer logging. Velocity determination is performed by measuring the time elapsed for a slug of radioactive material to travel a known distance between two detectors. The velocity measurement and the well bore diameter are then used to obtain quantitative injection distribution. The tracer profile technique utilizes a single detector to determine the injection profile by determining the intensity of the radioactive material in the well bore as a function of depth.

A geometrical measurement is made of the recorded response in the surface unit and is related to the response of the tool as it passes through the radioactive slug as moving in the well bore. Comparison of the geometrical plots provide a profile of losses in the well bore. provide a profile of losses in the well bore. On occasions the velocity profile and the tracer profile have presented a difference in loss profile have presented a difference in loss percentage plots. percentage plots.
Reduction Of Grid Orientation Effects In Reservoir Simulation
Authors: Holloway Carl C. , Thomas L. Kent , Pierson Ray G.
Published: December 2007

American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc.

Discussion of this paper is invited. Three copies of any discussion should be sent to the Society of Petroleum Engineers office. Such discussion may be presented at the above meeting and, with the paper, may be considered for publication in one of the two SPE magazines.

This paper presents a method for reducing the effect of grid orientation on computed numerical results in finite difference reservoir simulation. The method involves modification to the interblock phase transmissibilities normally calculated and the use of a two-point weighting scheme in calculating mobilities. These are minor changes to an IMPES type simulator.

Example problems of unit mobility ratio and high mobility ratio with both long and short transition zones are included. The results indicate that neither the transmissibility modification nor the two-point weighting scheme are sufficient by themselves to correct the error although the two-point. weighting of mobility has the greatest effect.

Introduction

Many reservoir simulation problems involve the study of displacement patterns of injected fluids. Results of such studies using finite difference models are affected by grid orientation errors in which fluid tends to flow in the direction of the grid axes rather than diagonal to them. This paper presents a method for reducing grid orientation effects, inherent in finite difference simulators, by modification of the interblock phase transmissibilities to account for diagonal flow. Incorporation of the modified transmissibility is a minor change to an IMPES type simulator and when used with two-point upstream mobility weighting gives excellent results.

The grid orientation problem is illustrated by a quarter of a five spot overlain by two different finite difference grids. A diagonal grid has its coordinate axes parallel to the sides of the quadrant of the five spot, with the injection and production wells on diagonally opposite corners of the grid.