bluuebunny/crossref_metadata_2025 huggingface dataset:
An International Perspective on Risk/Reward Contracting: Comparison of U.S., Middle East and U.K. Alliances
Authors: Farrell Susan , McDermott J. Ray
Published: December 2007

The purpose of (he paper is to compare the structure of six contracts considered by clients and contractors to be partnering or alliance arrangements. Two are in the U.K., three in the U.S. and one in the Middle East. Particular emphasis is placed on the management structure and risk/reward elements found in the contracts.

Basic project characteristics such as total value, work scope and length of agreement highlight the impossibility of applying a simple checklist to identify a likely partnering candidate. Each client determines if its project is best served through a partnering arrangement with a risk/reward structure.

The management of the agreements has more similarities than differences, with four of the six projects being managed via Integrated Teams. While only two contracts studied are termed alliances, there nevertheless appears to be a trend to alliances by companies with some partnering experience.

The risk/reward structure of the six contracts shows a great deal of variability. The sharing of upside potential is most frequently on a 50/50 basis between the client and the contractor. However, as multiple contractors are introduced into an alliance, the percentage sharing changes. One alliance treats all contractors equally for reward sharing, while another rewards in relation to relative value in the contract.

The sharing of downside risk is highly dependent on the amount of perceived risk in the contract. One contract shows zero downside for the client, several share 50/50 with the contractors, while another places most of the downside risk on the client.

The offshore industry is still at an early stage of implementing partnering, alliancing and risk/reward elements. One would expect an increasing number of alliances and more complex risk/reward structures as companies gain experience with the concepts.
E & P FORUM Health, Safety and Environmental Management System Guidelines
Authors: Downey I. L.
Published: December 2007

Introduction

During the last decade management of safety has progressively moved from reaction to an incident towards prevention of the incident occurring.

Safety management has moved from being a side-issue to being an integral part of the business to be managed in the same way as other critical issues. Incidents which in the past may have been viewed as unfortunate events are now recognised as costly and avoidable events.

The principles of the management of safety risks are similar to management of health and environmental risks. Indeed the considerations am often overlapping. A combined system for management of health, safety and the environment is both more efficient and more effective than tiying to manage the elements separately.
Methods and Tools for Cost Effective Subsea Inspection Planning
Authors: Descamps B. , Woolley K. , Baker M. J. , Corbett G. G.
Published: December 2007

International competition, and to some extent the CRINE initiative, have stimulated oil and gas operators to minimise production costs wherever possible. Underwater inspection, repair and maintenance (DRM) of the platform jacket consumes a major proportion of the overall maintenance budget and consequently any reduction in this area is likely to have a significant impact on overall costs.

All offshore jackets are inspected regularly to ensure structural integrity and satisfy the strict statutory requirements. Technical advances have been achieved in recent years, particularly in ROV capability, which have led to a general reduction in highly expensive diver time. However, it is widely recognised within the industry that inspection costs could be further reduced by combining such advances with a much more rigorous planning philosophy, the aim being to reduce the total amount of inspection activity whilst maintaining or improving the effectiveness of the work carried out.

Quest Consulting Ltd and Aberdeen University are working jointly on a Teaching Company Scheme, part funded by the Government, to develop methods and tools for targeting the inspection of offshore structures at areas of greatest criticality on a sound scientific basis. This paper presents the results of ongoing research and proposes that planned inspection should include a refined risk assessment to rank components and define the most appropriate inspection methods and optimum inspection intervals for a given structure. This will result in the most cost effective approach to underwater inspection being implemented.
Coiled Tubing Extended Reach Technology
Authors: Bhalla Kenneth
Published: December 2007

Coiled Tubing is used increasingly to service highly deviated and horizontal well. A limitation or horizontal displacement occurs because of the frictional forces between the coiled tubing string and borehole while running in coiled tubing. This causes helical buckling and can lead to lockup of the coiled tubing string, thereby limiting reach.

This paper will address the various techniques currently in use and propose new techniques to achieve additional reach. The topics that will be discussed are buoyancy reduction, friction reducers, optimal taper and pipe size of coiled tubing, straightening coiled tubing, downhole tractor simulation, flowing fluid, and pumpdown.

A tubing forces model has been developed that models these techniques. Results showing additional reach attained will be presented in the form of the surface weight prediction for commercial and conceptual wells.
CAN SMEs Survive Crine
Authors: Gray Andrew , Hay James , Marsh Richard , Punt Alistair
Published: December 2007

Small companies have been the source of much of the innovation that has helped to develop the North Sea. They have relied on the support, both financial and risk taking, of the oil companies to bring their ideas to the market. Much has been spoken and written about the changes in the mode of working in the North Sea and the increasing contracting out by oil companies, which comes in the various guides of partnering, partnerships, alliances, risk sharing and performance related contracts, MMSC contracts etc. All have certain common features, such as being large contracts with large companies for lengthy periods, possibly for the life of a field, and require some acceptance of risk by the contractor. There is now a question as to who will supply that support, Will the new buyers adopt this role, or will they stay with the tried and tested to minimise their own risks? CRINE also suggests standardisation which by definition kills innovation. Will this mean that no new small companies emerge and many existing ones go to the wall? Will this secure the future? Apart from a few expressions of good intent, for example, at the 1994 CRINE Conference, little has been said about the issues that these changes bring for small companies. These issues exist across the whole spectrum of the oil industry, but this paper looks at one area of activity which has largely developed in the North Sea, and which is one that has offered real hopes of exports - underwater operations, The issues facing three different types of small company are examined - one product development, one services, and one consultant engineering, The conclusion is that SMEs can survive CRINE, but only if they and the market adjust to the new circumstances.
Studies on New Gas Hydrate Inhibitors
Authors: Kelland M. A. , Svartaas T. M. , Dybvik L.
Published: December 2007

Traditional hydrate inhibitors such as methanol and glycols have been in use for many years, but at today's oil pricesjhe demand for cheaper methods of inhibition will be required. The development of alternative, cost-effective and environmentally acceptable hydrate inhibitors is a technological challenge for the oil and gas production industry. These new hydrate inhibitors can lead to very substantial cost savings, not only for the reduced cost of the new inhibitor but also in the size of the injection, pumping and storage facilities. Thus it is possible to redesign production facilities on a smaller scale. A few chemicals have been tested in field trials already with mixed success. Certainly, there is room for more active and cheaper inhibitors. We will review the relative merits of the two main types of hydrate inhibitor, "kinetic inhibitors" and "anti-agglomerators" regarding their applicability, and discuss how test results obtained in the laboratory compare to real field trials. We will also describe new techniques for comparing the effectiveness and activity of new hydrate inhibitors and present laboratory results on various chemicals. Patented examples will also be mentioned. Finally, a comparison of model systems with real fluids with regards to hydrate formation and inhibition will be given.
Downhole Swab Valve Aids in Underbalanced Completion of North Sea Well
Authors: Walker Tim , Hopmann Mark
Published: December 2007

As operators around the world continue to explore coiled tubing drilling and completions, one of the main benefits this technology has demonstrated is the ability to drill through the formation in an underbalanced situation. The benefit is somewhat minimized, however, if the well has to be loaded with kill weight fluid prior to running the completion or perforating. This paper will discuss how this problem was solved for one North Sea operator and how that solution can be extended to other operators.
Some Powerful Reasons for Adopting Front Tracking Simulation
Authors: Tyrie J. J. , Gimse T.
Published: December 2007

The advantages of Front Tracking simulation are becoming well known. This paper is directed towards demonstrating some of the advantages of front tracking simulation by briefly describing a field example of an infill well in the large Magnus Field operated by BP. This was not a test case conducted to prove the simulator but a case with the specific objective of reducing the risk associated with the infill well.

The Frontline simulator was used to investigate the movement of water in a specific layer of the Magnus oil reservoir around the PN5 infill well location on the west flank of the field. Sensitivities were conducted which reflected the geological uncertainties of the area with a view to assessing the possibility of the infill area having already been swept as water had swept through nearby wells. The PN5 block remained unswept in all sensitivities although some cases did draw water closer to the area. The PN5 area was found to be in a drainage area between a northern producer, A5, and a southern injector, D5, and would not be swept for some time without PN5.

This was the first Frontline simulation study to be conducted by BP in Aberdeen. Overall Frontline has proven to be a quick, alternative approach to assessing a reservoir sweep problem and readily provided well communication information which is not available from standard simulations. Frontline significantly reduced the uncertainty and the well was drilled shortly after the study and although part of one layer was swept the target layer was unswept and the well brought on stream in excess of 20 mbd dry oil.
Cost Reduction and Safety Improvement through Integrated Drilling Operations
Authors: Stromsnes O. , Stakkeland H. , Pedersen S.
Published: December 2007

A new concept that makes it possible to integrate all equipment and services in the drilling industry has been developed. Utilised to its full extent, this opens up for improved process information and advanced automation, with the possibility of running the operations from a central control room.

The intention behind the work has been to reduce the operational cost and improve safety.
Advances in Extended Reach Drilling – An Eye to 10 km Stepout
Authors: Ryan G. , Reynolds J. , Raitt F.
Published: December 2007

This paper will present recent technological innovations which have been used to surpass previous extended reach records together with other technologies which are viewed as fundamental in overcoming current limitations for extended reach and designer wells. The paper will focus on three specific drilling applications which provide a range of options for operating companies with varying field development philosophies.
Drilling and Completing Wells for High Productivity in the Point Mclntyre Field: Strategy, Implementation and Verification
Authors: Bloys J. B. , Murphy J. , Weingarten J. S. , Wheatall M. W.
Published: December 2007

A proactive approach to economically improving well productivity was undertaken at the beginning of the development drilling program in the Point McIntyre field on the North Slope of Alaska. This paper describes the comprehensive approach, laboratory tests, field implementation, and well test verification of reduced skin damage. The approach was a combination of a minimally damaging KCl mud with limited leakoff, KCl in the cement and spacer, rapid drilling rates, and deep perforations. Laboratory tests of the rock and mud were performed before the onset of the drilling program, to identify potential damage mechanisms and to select the least expensive, least damaging, drilling mud. Field procedures were developed which ultimately led to open-hole displacement of freshwater mud to KCl mud just above the pay, which reduced the incremental cost by a factor of 2. The success of the drilling and completion strategy was demonstrated using pressure buildup tests to measure skin. Inexpensive pressure buildup tests were conducted prior to field startup, using in-house personnel and equipment, in addition to more conventional testing after field startup. Development well skins were compared with those of previous exploration wells and with water injectors which were drilled with a common low-solids non-dispersed freshwater mud. Although this reservoir would not normally be identified as particularly damage-prone, use of the KCl mud helped improve well productivity by almost 60% over wells drilled with the freshwater mud commonly used in the region. The well test and productivity data clearly justified the additional cost of using the more expensive drilling mud. Costly well stimulations were avoided, and infill drilling was deferred.
Experience With Drilling C-26A, A World Record Extended Reach Horizontal Well in the Oseberg Field, North Sea.
Authors: Andresen Svein , Hovda Sigve , Olsen Tor Lie
Published: December 2007

Well 30/6-C-26A was drilled to 9327 m measured depth in January 1995 from the Oseberg C platform in the North Sea. The well has a horizontal reach of 7853 m which is a new world record in Extended Reach Drilling, The last 2100 m were drilled horizontally in the reservoir 6 – 8 m vertically above the oil water contact. This paper will describe the planning phase as well as operational challenges experienced during drilling of this well.
An Integrated Approach to Evaluating and Managing Wellbore Instability in the Cusiana Field, Colombia, South America
Authors: Last N. , Plumb R. , Harkness R. , Charlez P. , Alsen J. , McLean M.
Published: December 2007

An integrated approach to evaluating the causes of severe wellbore instability in the Cusiana field is described. The field is located in a tectonically active region of Colombia. Deterioration of the hole during drilling operations has led to excessive nonproductive time and expensive wells. The scale of the problem is unprecedented in the world. In wells costing tens of millions of dollars, millions per well could be attributed to poor hole conditions.

This paper describes how the problem was addressed and what actions were taken to improve operational performance, resulting in reduced drilling costs. The improved understanding has contributed to better well planning, and improved drilling performance, and has underlined the need to consider all aspects of the drilling process to achieve improved hole conditions in a difficult geological setting.
New Concepts Lower Deep Water Drilling Costs
Authors: Jenkins Roger W.
Published: December 2007

Texaco Exploration and Production Inc. recently drilled a deep water location in Green Canyon 506 (Gulf of Mexico) with the Sonat Discoverer 534 drill ship. The well was drilled to below 21,000 ft measured depth in only 80 days. TEPI developed a simple well head system for containing shallow water flow zones. Underreaming and drilling was accomplished simultaneously which allowed the drilling time to be greatly reduced. A "thin is best" approach was used on the drilling fluid to promote solids removal efficiency. A unique incentive plan involving the contractor and key service providers was used to motivate rig employees.
Gulf Coast Section SPE Production Operations Study Group – Technical Highlights from a Series of Frac pack Treatment Symposiums
Authors: McLarty J. M.
Published: December 2007

One of the main functions of the SPE is to provide a means for collection, dissemination, and exchange of technical information and to provide technical forums that afford opportunities for members to maintain and upgrade their technical competence. The large chapters (such as Houston SPE) located near many oil company headquarters have the advantage of being able to bring together a cross section of service company and operator personnel representing operations and research from major and independent operators. This paper describes a series of 1-day symposiums on frac pack technology that were organized by the Houston-based Gulf Coast Section SPE Production Operations Study Group. These study sessions provided a means for the local members of the industry to further develop a new technology as a team. Publishing the major focus and contributions of the seminars will allow sharing of the technology with chapters outside of Houston.
Success Achieved in Lenticular Reservoirs Through Enhanced Viscosity, Increased Sand Volume, and Minimization of Echelon Fractures
Authors: Ely J. W. , Brown T. D. , Reed S. D.
Published: December 2007

A common trend in our industry is to minimize gel concentrations and utilize the lowest viscosity fluid available to place proppant. Barrett Resources Corporation has found, for lenticular microdarcy formations, that one of the keys for success is enhanced proppant transport. This is achieved incorporating stable gels which maintain greater than 1000 cps viscosity at bottomhole static temperature for the duration of the treatment. An extensive case study has been completed, involving over 500 fracture stimulation treatments in more than 175 wells, that illustrates the poor results achieved in the Williams Formation of the Mesaverde Group using low viscosity fluids. Low viscosity fluids invariably exhibit poor proppant transport. The statistical study shows that larger treatments utilizing "perfect proppant transport" fluids gain superior results. Based upon the case study, 100% economic success has been achieved upon incorporating stable fluids containing delayed breakers, reducing pad volumes to less than 5% of total job size, and minimizing echelon fractures while implementing a limited entry stimulation technique.
Hydraulic Fracture Reorientation in Primary and Secondary Recovery from Low-Permeability Reservoirs
Authors: Wright C. A. , Conant R. A.
Published: December 2007

Hydraulic fracture orientation is critical to both primary and secondary oil recovery in low-permeability reservoirs. Incomplete and often overlapping drainage patterns under primary recovery, as well as inefficient sweep and premature water (or steam) breakthrough under secondary recovery are some of the common production problems that often result from hydraulic fracture reorientation. Often, hydraulic fracture orientation is measured on a few wells, and then generalized across the entire field under development. This characterization of regional fracture (stress) orientation is then assumed constant over the development life of the field. A wealth of recent' observations have definitively shown that fracture (stress) orientation in low-permeability reservoirs can be profoundly affected by production activities.

Hydraulic fracture reorientation has been observed on dozens of staged fracture treatments (in several fields) under both primary and secondary recovery. A summary of collected field data from three extensive field studies is presented. The production impact of fracture reorientation on both primary and secondary recovery schemes is addressed; and strategies are presented which utilize the recent findings for both enhancing primary recovery and mitigating some common problems with secondary recovery.

The discussion of reorientation mechanisms is greatly enlightened by recent data which reveals a startling correlation between observed fracture reorientation and indirect measurements of reservoir compaction.
The Development of Laboratory Correlations Showing the Impact of Multiphase Flow, Fluid, and Proppant Selection Upon Gas Well Productivity
Authors: Penny Glenn S. , Jin Liang
Published: December 2007

This paper describes the development and use of laboratory data to show the impact of multiphase, non-Darcy flow upon gas production from hydraulic fractures. In the work, the impact of proppant type and fracturing fluid damage upon non-Darcy flow and effective conductivity vs. closure, temperature and gas/water/oil ratios is shown for sands, resin-coated sands and ceramics with various fracturing fluids. Laboratory derived correlations are then used to predict gas productivity and economics under various conditions of multiphase non-Darcy flow and the predictions are compared to field examples.

The results of the testing show that multiphase non-Darcy flow dramatically increases the difference between the effective conductivities of various proppants at high closures. The laboratory data and field observations show that when this is taken into account, a premium proppant can show twice the production rate of commonly used sand products at high closures in gas wells producing as little as 10 barrels of water or condensate per MMCF.
Uncertainty Analysis of Borehole Stability Problems
Authors: Morita Nobuo
Published: December 2007

An uncertainty analysis is conducted for borehole stability problems based on a statistical error analysis method. The uncertainty analysis shows that the parameters impacting on the safe mud weight to stabilize borehoie are rock strength followed by shale swelling, in-situ stress, pore pressure, well inclination, and so on. Several procedures to improve borehole stability analysis are proposed.
Overcoming Interpretation Problems of Gas-Contaminated Cement Using Ultrasonic Cement Logs
Authors: Butsch R. J.
Published: December 2007

The primary objective of cement sheath evaluation logs is to determine whether the production or injection zones, as well as other critical zones, are hydraulically isolated. Ultrasonic measurements have been used in cement evaluation since the early 1980s, Ultrasonic tools evaluate the cement sheath by measuring the acoustic impedance of the material outside the casing. Cement has a higher acoustic impedance than drilling fluids or water, and gas has an acoustic impedance near zero. Gas-contaminated cement poses the main problem in interpretation of ultrasonic cement tools,

To understand the problem, the acoustic impedance of what might be in the casing-to-formation annulus must be considered. The acoustic impedance of cement can range from slightly over 3.0 MRayl to about 7,0 MRayl. Drilling fluids can be 1,5 MRayl to 3.0 MRayl. Water has an acoustic impedance of 1.5, and gas has an acoustic impedance of less than 0.04 MRayl. As long as there is sufficient difference between the acoustic impedance of the cement and the acoustic impedance of the liquid phase, channels in the cement can quickly be identified. In the case of gas-cut cement the texture of the material tends to be that of a honeycomb. The result is that each segment of the casing radius examined by the ultrasonic transducer may contain a combination of cement and gas, The acoustic impedance measured could be anywhere from that of gas to that of cement, depending on the percentage of the different materials contained in that small area. As a result, the acoustic impedance image displayed by the ultrasonic tools looks like a random pattern of cement, liquid and gas, but usually indicates that a channel is present. Because of the interpretation problems in gas-contaminated cement, it is frequently recommended that an attenuation-type cement bond tool be run in combination with the ultrasonic tool. The only advantage the attenuation-type cement bond tools have over the ultrasonic tools is that they are less affected by gas-contaminated cement,

This paper proposes a technique for using high-resolution ultrasonic data to identify gas-contaminated cement, while maintaining nearly the same vertical and radial resolution, thus allowing the identification of liquid-and gas-filled channels. The proposed technique allows improved interpretation of the high-resolution ultrasonic data when gas-contaminated cement is encountered. Even when attenuation-type logs are run, this technique will aid the interpretation, The results to date indicate that this technique can be applied to eliminate unnecessary cement squeeze jobs caused by misinterpretation of the ultrasonic data. Examples are shown to compare the technique to other cement log data and cement squeeze results.
Slimhole Cementing - Analysis and Possible Solution of the Problem
Authors: van Vliet J. P. M. , Bour D. L , Griffith J. E.
Published: December 2007

Very little quantitative data are available on how to cement slimhole wells while still adhering to good cementing practices. Therefore, a combined theoretical and experimental study has been carried out, from which a number of slimhole cementing guidelines have been derived. The analysed example case considered the cementation of a 3−1/2" liner in a 4−1/8" hole, in a relatively deep, high pressure, high temperature well drilled in a formation with minimal difference between pore and fracture pressure gradients.

It was found that a conventional (solids laden) high pressure, high temperature (HPHT) water-based drilling fluid cannot be fully displaced by the cement slurry, without exceeding the pressure limits of the formation. On the other hand, a potassium formate brine based HPHT drilling fluid can be displaced with close to 100% efficiency, even with sub-optimum cementation practices (i.e. no pipe movement, low annular velocity of the mud in the initial stage of the cementation). The low, flat gels and thin, tough filtercake greatly facilitate mud removal during cementing.
A Progress Report of Polymer Flooding - Skull Creek South Unit, Weston County, Wyoming
Authors: Lane B.B.
Published: December 2007

This paper presents a case history of polymer flooding to date in the Skull Creek polymer flooding to date in the Skull Creek South Unit located in Weston County, Wyo. The polymer flood was initiated in Sept., 1967. As of the time of this report, performance indicates at least 61 bbl/acre-ft performance indicates at least 61 bbl/acre-ft additional oil will be recovered by the use of polymer in the pilot area over conventional polymer in the pilot area over conventional waterflooding. This exceeds the laboratory predictions of Dow Chemical Co. The cost of predictions of Dow Chemical Co. The cost of polymer and its application has been estimated polymer and its application has been estimated to be $0.70 per incremental additional gross barrel of oil.

Evidence of the increased recovery efficiency of the polymer flooding over conventional waterflooding has been (1) a downward reversal of the producing WOR, (2) the first appearance of polymer at the closest producer 1 year after the arrival of a radioactive producer 1 year after the arrival of a radioactive tracer injected immediately before the polymer slug and (3) the improvement in the injectivity profile observed when (prior) water injection was profile observed when (prior) water injection was converted to polymer injection.

Because of the performance of the pilot injector, the polymer flood was expanded to two additional injectors in Dec., 1969.

Introduction

The Skull Creek field, located approximately 7 miles southwest of the town of Newcastle in Weston County, Wyo., is divided into two unitized areas (Fig. 1). The northern two-thirds of the field is referred to as the Skull Creek North unit (SCNU). The southern one-third is referred to as the Skull Creek South Unit (SCSU). The Newcastle sand formation of the above mentioned units was unitized for the purpose of initiating waterflood operations. The purpose of this paper is to report the performance due to the use of a polymer in the SCSU and the economics of obtaining the increased incremental oil.
Optimizing the Productivity of Acid-Fracture Treatments in Horizontal Wells
Authors: Allen Elise
Published: December 2007

Existing prediction methods are inadequate for unstable radial displacement1, with prediction errors of up to 500%. This work provides a new theoretical basis for understanding unstable displacements in both Newtonian and non-Newtonian fluids, based on a detailed analysis of the fingering morphology and a new derivation using fractional flow theory for radial flow. Design guidelines are given to assist in optimizing the design of fingered acid-fracture treatments for horizontal wells in carbonate formations.

Unstable radial displacement creates power-law (fractal) displacement patterns, for a wide range of mobility ratios, and the displacement efficiency can be expressed as a function of the mobility ratio M. The finger wavelength is a function of the mobility ratio M. The finger aperture, and the detailed morphology can be understood in terms of the fluid rheology. The size of the fingering zone can be predicted from the mobility ratio and Peclet number. A productivity index factor PIF can be used to compare different treatment scenarios, and thus optimise the productivity of acid-fracture treatments.
Modeling of Capillary Pressure Behavior Using Standard Open Hole Wireline Log Data: Demonstrated on Carbonates from the Middle East
Authors: Ross C. M. , Callender C. A. , Turbeville J. B. , Funk J. J.
Published: December 2007

A new technique was developed to model capillary pressure behavior from wireline log data and applied to carbonate reservoir rock from a Saudi Aramco field. The method utilizes image analysis of petrographic thin sections, capillary pressure measurements, and neural network analysis of standard open hole wireline log data. Twenty capillary pressure curves and their associated pore type proportions (identified in thin section) arc the basis for the capillary pressure predictive model for the reservoir interval under study. Neural network analysis of the wireline log data was used to continuously predict pore type proportions downhole. The neural network-derived pore proportions were then applied in constructing wireline log-based capillary pressure curves using the capillary pressure predictive model.

This method provides an accurate means of determining capillary pressure behavior from wireline log data and extends the applicability of the limited number of available capillary pressure curves. Once trained, the neural network may be applied to other wells in the field as long as the training set (both rock samples and wireline log types) is representative within the study area. The capillary pressure curves predicted from wireline log data can be used for the same purposes as capillary pressure curves measured on core samples, such as determining water saturation in intervals above and within the transition zone.
Investigation of the Effect of Temperature and Pressure on Wettability Using Modified Pendant Drop Method
Authors: Wang W. , Gupta A.
Published: December 2007

Wettability is a key parameter that affects the petrophysical properties of reservoir rocks. The objective of the present work is to investigate the influence of temperature and pressure on the wettability of reservoir rocks. An experimental method for the measurements of contact angle at elevated temperature and pressure has been developed, in which a Pendant Drop Interfacial Tension Cell was modified. Experimental results of contact angle and interfacial tension for two different crude oil-brine-quartz/calcite and mineral oil-distilled water systems over a range of temperatures and pressures are reported. Contact angle for the systems studied increased with pressure, increased with temperature for sandstone system and decreased with temperature for carbonate system.
Horizontal Well Placement and Petrophysical Evaluation Using LWD
Authors: Prilliman J. D. , Allen D. F. , Lehtonen L. R.
Published: December 2007

A well recently drilled in the Gulf of Mexico utilized new developments in logging while drilling (LWD) technology to allow a horizontal wellbore to be accurately placed in difficult targets. Simultaneously, high-quality petrophysical log measurements were taken, allowing very detailed formation evaluation. An instrumented motor provided resistivity, gamma ray, and inclination measurements at or very close to the bit. A new porosity and lithology tool provided azimuthal data from four quadrants of the borehole. All data were used for bed boundary detection at high relative dip angles, geosteering accuracy, and for better estimates of net pay.
Formation Evaluation and Geological Interpretation from the Resistivity-at-the-Bit Tool
Authors: Rosthal R. A. , Young R. A. , Lovell J. R. , Buffington L. , Arceneaux C. L.
Published: December 2007

The RAB* (Resistivity-at-the-Bit) tool is a logging-while-drilling device designed to accurately measure resistivity in salty muds and high resistivity formations such as carbonates. Included among the RAB’s measurements are three azimuthally oriented buttons that provide focused resistivity images with shallow, medium and deep depths of investigation. Combinations of these measurements with a focused ring electrode can be used to determine Rt in the presence of invasion. RAB data can also be combined with other LWD measurements to obtain high quality formation evaluation.

The RAB tool is unique among LWD tools in its ability to acquire fullbore formation images. Such images not only provide quantitative resistivity, but also give information on the structural geology and depositional environment. Bedding dips computed from the RAB tool compare well with those from wireline image logs. Large scale structural features (bedding, faults, etc.) are readily interpreted from RAB images and dips. As with dip interpretation from other image logs, best results are obtained when images are used to evaluate structural interpretation from batch-processed RAB dips.

To help operators more fully utilize RAB data in time-critical drilling situations, a technique is proposed to compute high-angle apparent dips in real-time. Such a capability will be particularly useful for geosteering near-horizontal wells.
Well Testing in Coalbed Methane (CBM) Wells: An Environmental Remediation Case History
Authors: Cox D. O. , Young G. B. C. , Bell M. J.
Published: December 2007

In 1993, methane seepage was observed near coalbed methane wells in southwestern Colorado. Well tests were conducted to identify the source of the seeps. The well tests were complicated by two-phase flow, groundwater flow, and gas readsorption. Using the test results, production from the area was simulated. The cause of the seeps was found to be depressuring in shallow coal near the surface, and a remediation plan using water injection near the seep area was formulated.
Simulation of Geological Models Using Multipoint Histogram
Authors: Qiu W. Y. , Kelkar M. G.
Published: December 2007

Simulated annealing optimization technique was used to simulate geological models. After comparing one-point perturbation scheme with two-point swapping scheme, and the Metropolis algorithm with the greedy algorithm, an optimized combination of simulated annealing schedule is presented. The two-dimensional correlation coefficient matrix is introduced to determine a unit configuration which can represent essential features of a geological model. The proposed simulated annealing technique can be used to reproduce the characteristics of a geological model based on multipoint histogram which can be obtained by using a unit configuration.

Various geological vertical cross sections and horizontal slices based on field data are used to validate this new technique. Simulated results confirm that one-point perturbation scheme with the Metropolis algorithm provides the best combination to capture the essential features of a geological model. Further, the two-dimensional correlation coefficient matrix provides a technique to choose a priori unit configuration for multipoint histogram, which captures the geological characteristics adequately.
Measurement of Formation Resistivity Through Steel Casing
Authors: Singer B. Sh. , Fanini O. , Strack K.-M. , Tabarovsky L. A. , Zhang X.
Published: December 2007

Through casing resistivity measurements confirmed the original concept proposed by Alpin (Ref. 1) and recently revived and improved by Kaufman (Ref. 2) and Vail (Ref. 3). A commercial tool can be used for monitoring producing wells, waterflooding control, and searching for bypassed hydrocarbons in abandoned and active wells.

The information on the resistivity of the formation is represented by the second spacial derivative of the casing voltage that is generally small. This makes the evaluation of possible distortions arising from different kinds of casing imperfections important. These imperfections include casing collars, corrosion, perforations, etc. The fact that only low frequencies can be used for the measurement allows us to propose fast and accurate modeling algorithms. Numerical evaluation shows that the distorting effect of casing imperfections is quite moderate. Typically, it does not exceed 10 – 20% of the measured apparent resistivity.

The vertical resolution of the measurements is limited by the spacing between the voltage sensing electrodes. It can be deteriorate due to the cement sheath that always exists around the casing. A significant distortion of the measurement occurs near the bottom of the casing. This distortion can reach 50% of the signal. To improve the readings, a simplified inversion algorithm has been developed. The most direct application of the algorithm is the monitoring of the pay zone resistivity.
Extending Minimal Structures into Deeper Waters: A Case History
Authors: Kallaby Joseph , Billings C. M. Josh , Doing Mark H.
Published: December 2007

This paper presents a case history of the successful use of a minimal concept platform extended into water depths greater than 400 ft. The structure consists of an integrated deck supported on a tripod jacket and fastened to the seabed with three piles. The deck is capable of supporting a self contained workover rig, or a tender assisted drilling rig. The platform was successfully installed in 428 ft. of water depth in April of 1995.

The design is based on a rational development of the environmental criteria developed in cooperation with the Minerals Management Service, including the effects of wave dynamics and fatigue. The paper describes the innovative use of recently developed installation aids, and presents the relative economics of the concept used as compared to other concepts.
An Integrated System for Improving Design Team Performance and for Measuring Operability Results
Authors: McCuish J. D. , Wilson J. L. , Hallam J. L. , McClure J. F. , Ramsay S. F. , Denton M. A.
Published: December 2007

Operability is defined as the effectiveness of the facility in performing as designed upon commissioning and is measured principally in the first 6-12 months of new operation. Generally in the construction and installation of production facilities, teams have had few tools or generally accepted practices for impacting the effective Operability of the facility, measuring that Operability, and linking the two. This paper describes a recent study of a significant number of projects incorporating operability results and other information gathered from world-wide subject-matter experts and the subsequent development of new tools to improve Operability performance. Presented are the data analyses methodology, results and new tools for predicting the likelihood of project operability success several years ahead of commissionin. This paper describes the Operability Toolbox method to measure and improve Operability effectiveness.
Simultaneous Water and Gas Injection Pilot at the Kuparuk River Field, Surface Line Impact
Authors: Stoisits R. F. , Krist G. J. , Ma T. D. , Rugen J. A. , Kolpak M. M. , Payne R. L.
Published: December 2007

Immiscible water alternating gas (IWAG) injection has effectively managed produced gas at the Kuparuk River Field: increasing field oil rate and recovery. Although IWAG economics are very favorable, this pilot study was undertaken to ascertain whether separate water and gas injection lines to the drill sites and on-pad distribution systems can be eliminated by simultaneously injecting water and gas in waterflood lines.

A significant problem in simultaneous water and gas injection is the phase separation which occurs at branches in the injection pipe network. The higher density phase, because of its greater momentum, will tend to flow in the straight or least deviated pipe branch, while the lower density phase will tend to flow into the most deviated branch of pipe. Studies conducted at ARCO’s Exploration and Production Technology Research Center in Plano, Texas; indicated that static mixers positioned at the pipe branches could achieve equal distribution of the phases to both runs of the pipe branch.

In the pilot study gas was injected into an 8″ waterflood line which supplied two drill sites. A static mixer was placed at the junction for the two drill sites. Static mixers were also placed in the 4″ injection manifold of one of the drill sites, the other drill site had no mixers in the injection manifold. Gas was distributed to both drill sites. At the drill site with static mixers in the injection manifold, gas was distributed to the wells on the injection manifold: while at the drill site without static mixers, phase separation occurred and only one well on the injection manifold received gas.
The Management and Optimization of a Major Wellwork Program at Prudhoe Bay
Authors: Martins J. P. , MacDonald J. M. , Stewart C. G. , Phillips C. J.
Published: December 2007

Over 800 remedial wellwork operations are performed each year at Prudhoe Bay. A hierarchy of performance measures and targets has been developed to facilitate the management and optimization of such a large and costly program of work. The paper discusses the Wellwork Evaluation Tracking System (WETS) which has been used over the past 7 years to assess the benefits achieved by a given wellwork operation, taking into account the appropriate facility constraints. The paper describes the process employed for using the performance measures to ensure the timely identification of both problems and opportunities across the field and it provides numerous examples of how the success of the wellwork program has been improved, despite more complex candidates, with the use of the performance measures.
The Application of Multi-phase Metering on Oil & Gas Gathering Platforms
Authors: Smith T. L.
Published: December 2007

Multi-phase Metering can provide lease operators an economical alternative for field development by eliminating multiple support structures. Although other development concepts have been proposed, such as Deep Star 1, which describes a concept of gathering platforms, this concept introduces the application of Multi-phase Metering using conventional processing techniques. This paper describes a single gathering platform designed to process production from multiple blocks, utilizing Multi-phase Metering techniques, to eliminate multiple support structures.
Simple, Effective Models for Evaluating Portfolios of Exploration and Production Projects
Authors: Davidson L. B. , Davis J. E.
Published: December 2007

This paper describes an approach for evaluating the risk and reward of exploration and production project portfolios. These models allow rapid, reasonably accurate assessment of the risk and reward of different exploration and development project mixes. They facilitate testing sensitivity to price, risk, and data assumptions. The methods described are also useful for evaluation of reserve acquisitions. The methods described in the paper are being used at Equitable Resources Energy Company.
Achievements of Biocatalytic Desulfurization
Authors: Johnson S. W.
Published: December 2007

Regulations reducing the sulfur content in transportation fuels and the increasing sulfur content of crude oil worldwide have put refiners under pressure to add desulfurization capacity. The conventional technology — hydrodesulfurization (HDS) — is expensive and non-selective in many cases. A new technology — biocatalytic desulfurization (BDS) — has the promise to complement HDS in some instances or to provide a unique solution in other cases, such as desulfurization of gasoline or crude oil. Biocatalyst development and process development are now at the pilot stage. Preliminary information from the pilot plant validated the extensive laboratory-generated database, and a commercial diesel desulfurization unit should be running in 1997.
Development of a Coiled Tubing Cable Installation System
Authors: Newman K. R. , Haver N. A. , Stone L. R. , Tong D.
Published: December 2007

A system has been developed which installs and de-installs an electric wireline cable in coiled tubing (CT) while the CT is still on the reel. This cable installation system reduces the cost of a cable installation significantly compared with previous installation methods.

This paper discusses the need for such a system, the theory used to develop this system, the various concepts considered, the system that was developed and test installation cases.
Coiled Tubing Stimulations Eliminate Hole Failures & Condensate Losses In Arun Field
Authors: Bunnell F. D. , Daud M. M.
Published: December 2007

Stimulation practices have evolved considerably over the life of the Arun Field. From the original HCl matrix treatments in the late 70's to the organic matrix and acid fracture treatments through the early 90's these techniques have proven effective. Beginning in recent years however, some problems have been observed. Problems include collapsing shales plugging one well and sharp drops in the condensate/gas ratio following stimulation in others. Open hole completions with a limited casing/cement barrier between the over pressured shale and the depleting Arun reservoir are subject to shale collapse and plugging when directly exposed to acid during conventional stimulations. Most Arun completions are subject to post stimulation condensate losses due to increasingly difficult conditions for effective diversion of acid treatment fluids.

Acid stimulation using coiled tubing techniques effectively addresses these problems. In seven stimulations performed to date shale failures and condensate losses have been eliminated. Direct acid washing across deeper intervals helps protect the acid sensitive barrier in open hole completions and effectively treats the lower, condensate rich zones.
Downhole Corrosion Inspection of 2 7/8 and 3 1/2 Inch Production Tubing Using Magnetic Flux Leakage
Authors: Sperling E. J. , Sharp C. Q. , MacLean A. R. , Spencer D. W.
Published: December 2007

A magnetic flux leakage (MFL) inspection system has been developed for in-place corrosion inspection of 2 7/8 and 3 1/2 inch downhole production tubing. The system consists of a downhole MFL inspection logging tool which communicates data via an electric wireline to a surface data acquisition system for storage and analysis. Data from field testing has demonstrated the system's ability to define the extent and severity of internal and external corrosion, mill defects, and tubing features such as perforations. The system has also demonstrated the ability to identify and quantify internal pitting and mill defects at tubing upsets and collar areas. The system was designed to be universally compatible with standard single conductor wireline units, and the downhole components have an operating upper limit to 300 degrees F and 12,000 psi.