bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of a Method to Oil Spill Risk Assessment From Pipeline Failures
Authors: Sharma M. P. , Kim B. , Harris H. G.
Published: December 2007

This paper presents a method for assessing the risk of oil spills during oil pipeline operations. The method has been developed and validated using field data from Western Europe on failure and performance of crude oil cross-country pipelines. The basis for the theoretical part of the analysis is application of an emerging method of "failure data analysis" - Weibull Analysis - which has been widely applied in automotive and aerospace industries in past, and more recently in the areas of electrical power, nuclear, and medical industries including the failure analysis of such components as compressors, bearings, cables, and wheels etc.

Oil spill size has a probabilistic nature and hence it should be predictable using relative statistical methods. Consequently, the purpose of this paper is to describe the development of models for forecasting the volume of oil spill during pipeline operations, with the ultimate aim of evaluating and assessing possible environmental impact.

In recent years a number of publications have presented data dealing with pipeline failures, de la Mare and Andersen developed a statistical model to estimate failure rates by analyzing data for onshore and offshore pipelines. A generalized probabilistic model for predicting cumulative number of pipeline leaks and time-to-first-leak was proposed by Sheikh, Boah and Hansen.
Establishing International Performance Standards
Authors: Hutson R. L.
Published: December 2007

This poster session delineates the process that Amoco Corporation used for assuring EH&S management consistency throughout its global operations and specifically addresses the challenges imposed by language and cultural differences in surrounding these barriers.

Early in 1990, Amoco assembled a special international task force of senior level operating managers and EH&S managers to begin the process of defining a set of minimum acceptable EH&S operating standards which will be employed by Amoco anywhere in its global operations.

The process known as Amoco's International Standard of Care (ISOC) management process, starts with a small task force of operating company representatives. Under the chairmanship of a member of the Corporate EH&S department, the group spends approximately one to two years in developing and approving a single standard. Some standards are incremental steps toward achieving the ultimate goal while other standards are specific operating measures. In this way, the process allows each facility flexibility to develop and manage their own EH&S programs while adhering the certain minimum operating requirements or key program elements.
Ergonomic Development of Propulsion Hand Tools for Underwater Technologies: System Approach
Authors: Dmochowski Jan , Pacholski Leszek
Published: December 2007

Divers working underwater are often using hand tools with hydraulic propulsion. These tools have strong impact on divers work conditions, which are entirely different than conditions of work of the people acting in workshops. For the submerged diver acting underwater, where foam suit and life support system provide him a chance to survive and execute his task - the modified diagram of "man-machine" ergonomic system must be applied. The proposed schematic diagram of the "diver-tool" ergonomic system for underwater conditions is shown on Figure 1.

The mechanized hand tool as element of this system is effected by different factors connected with the water as medium, and hydrostatic pressure. This consideration of the hand tool is mainly based on expirience with the developement of hydraulic drilers.

The hydraulic driller as element of ergonomic system is effected by the factors: cold water with high specific heat is acting as a cooling medium of drill;cold water is acting as cooling medium of the diller;water with high viscosity and density is lubricating drill movement;diver hands and fingers which are earring and operating the driller are effected by cold water.
The Sleipner Accident
Authors: Ynnesdal Harald , Berger Fredrik
Published: December 2007

The Sleipner A-platform is a combined drilling, production and living quarter platform intended for North Sea use. It consists of two main parts: The Steel Deck and the Gravity Base Structure (GBS) made of concrete.

The structure is designed with 24 cells, four of which are extended as shafts supporting the deck structure. The gravity base covers an area of 11.900 m2. The shafts are of a height of 110 m above the base.

The construction started in July 1989. The GBS was completed up to the upper edge of the cells in a dry dock. After tow-out to the fjord, the upper domes of the cells as well as the shafts were completed. In parallel, the mechanical equipment was installed.
Effluent Water Quality Improvement
Authors: Hamid Shahul , Yeo W. N.
Published: December 2007

The Labuan Crude Oil Terminal LCOT is the receiving plant for all crude production from 5 major oil fields offshore state of Sabah in Malaysia. Two pipelines, one in the north and another from the south deliver crude to the Terminal. The wet crude of water content of 5 to 40 percent arrives fully stabilized. The Terminal stores and prepares the crude for export via Single Buoy Mooring system line.

The primary facilities of the Terminal are: 4 Crude Oil Storage Tanks totaling 1.64 million barrels storage capacity,4 Free Water Knock-Out Vessels (FWKO)An Effluent Treatment Plant (ETP)An Emulsion and Wax Treatment Plant (EWTP) andExport Pumps and Custody Transfer Meters.

Figure 1 schematically represents the primary facilities in the Terminal.
HSE Management in Seismic Operation
Authors: Davidson D. S. , Ranke H. T. P.
Published: December 2007

1993 has shown a gradual change from the traditional manner of managing HSE in Shell's seismic operations which was based on a number of safety management principles and an HSE plan to the more structured approach of Safety Management Systems including the Hazard Management Process.

The paper describes the lessons learned during the preparation and early implementation phase of such a Management System. In particular it addresses the necessity of a close cooperation between the Client and the Contractor and the need of user friendly products to enable full acceptance and implementation at all levels in the Client and Contractor organisations.

Examples of such products, the enthusiastic way in which they are used and the improvements that have been created in the management of HSE are given in the paper.
Temperature Sensitivity of Formation Damage in Petroleum Reservoirs
Authors: Gupta Anuj , Civan Faruk
Published: December 2007

Temperature is an important yet often ignored variable in translating laboratory measurement of oil and gas recovery related operations to reservoir conditions. The present study addresses the variation of formation damage potential of a reservoir with temperature. A strategy for obtaining the temperature sensitivity of various model parameters determining the formation damage potential of a reservoir rock is presented.
The Performance of Scale Inhibitors in the Inhibition of Iron Carbonate Scale
Authors: Kriel B. G. , Lacey C. A. , Lane R. H.
Published: December 2007

A potential mechanism for part of the production decline observed in the Prudhoe Bay field is siderite (iron carbonate) scale deposition. This laboratory investigation focused on evaluating the effect of the existing downhole scale inhibitor program on the proposed siderite formation damage mechanism. A tube block test was employed to generate iron carbonate and evaluate commercial products for its inhibition. This study indicates that the current inhibition program for barium sulfate and calcium carbonate is not protecting against damage by iron carbonate deposition. The other products tested were also ineffective. Furthermore, precipitation of the scale inhibitors by iron(II) is suspected. There is no field evidence of damage from this precipitation with the current inhibition program.
3½-in. Coiled Tubing: A First Run
Authors: Prestridge M. L. , Mahoney A. J.
Published: December 2007

The world's first string of 3-½" coiled tubing was run as completion tubing in an exploration well on the North Slope of Alaska. The tubing was run as a single permanent completion on four different zones in the well. The tubing performance successfully met the goals of the test, including being used for a frac. Operational problems associated with handling coiled tubing of this size are discussed, along with the lessons learned from using it. Future applications are also discussed.
The Lateral Tie-Back System: The Ability to Drill and Case Multiple Laterals
Authors: Smith R. C. , Hayes L. A. , Wilkin J. F.
Published: December 2007

A system has been developed for new wells to achieve greater reservoir exposure by allowing multiple lateral wellbores to be drilled and cased from a single primary wellbore. The Lateral Tie-Back System (LTBS™) described in this paper allows all of the laterals to be cased, providing a complex interconnection of individual production liners, with total wellbore integrity. The system increases reservoir exposure even beyond the dramatic improvement offered by a single horizontal well. Multiple laterals may be drilled at virtually any predetermined depth in a new vertical, directional or horizontal wellbore and at any time during the productive life cycle of the well. The system also allows quick re-entry into all laterals for well servicing and workovers.

A prototype system was successfully field tested in cooperation with CS Resources Limited in a shallow, unconsolidated sand formation where a definite correlation has been established between horizontal reservoir exposure and increased production. This provided an excellent opportunity to test the advantages of the Lateral Tie-Back System.

The system provides a new opportunity to significantly reduce overall drilling and casing costs for the development of entire fields. Its application to date has been in horizontal wells that require slotted liner completions. This paper reviews the development and use of the first Lateral Tie-Back System. Additional developments and future advances of this technology are presented which will adapt to a broader range of applications.
Coiled-Tubing Drilling with Specialized PDC Bits
Authors: Mensa-Wilmot Graham , Coolidge R. B.
Published: December 2007

abstract

The ability to effectively use any technology depends on how well it is understood. This condition becomes even more important with emerging technologies, as is Coiled Tubing Drilling (CTD). This paper will define the components of CTD as a "system" (Coiled Tubing Unit-Downhole Motor-Bit), and show that the understanding of the system and the ability to match its capability and needs is very important. It will show that properly engineered and selected PDC bits are effective on CTD and provide information on how seemingly minor changes on PDC bits affect their performance more than they do other types of bits. PDC bit development methodology and effectiveness will be discussed. It will describe how specialized PDC bits performed competitively within the operational constraints established by the system, and how the bits responded as analytically predicted.

Finally, this paper will describe how a group effort which allowed the free flow of information between all the parties involved was successfully used on a PDC-CTD project.
The Scrap Sale of Six Long-Term Stacked MODU's
Authors: Colledge K. G.
Published: December 2007

Diamond Offshore Drilling Inc. had a number of MODU's which had been long term dead stacked, some since 1984, sitting on bottom at various locations in the Gulf of Mexico. Inspection of these rigs revealed that six (6) (two (2) jackups, one (1) submersible and three (3) semi submersibles) were not economically viable for reactivation to drilling status, nor conversion for alternate use. It was also determined that the longer the units remained idle in a dead stack mode the greater the potential for deterioration to a condition that would make them difficult to move. The company desired to eliminate liability exposure of these aging hulls, yet wanted to retain considerable amounts of equipment which still remained on some of the rigs because of their value as spares for the rest of the operating fleet.

The potential for sale of the rigs on the open scrap market was investigated and revealed that the company could retain desired equipment, scrap the unusable hull and break even monetarily. All potential salvage companies required the rigs to be safely afloat at the time of delivery, and some offers were contingent on the rigs being delivered to the salvage company's facility.

The prices paid for scrap vary significantly throughout the world market, however, when the cost of

delivery was considered the resulting offer for a vessel offshore in the Gulf of Mexico became similar and domestic salvage companies were competitive.

This paper discusses the development of the bid procedures and sales contract for the scrapping of the six (6) aforementioned dead stacked rigs, the operational aspects of carrying out the latter, economic evaluation, government regulation requirements and environmental compliance.
Cost-Effective Spud Can Modification to Achieve Increased Bearing Capacity
Authors: Leland Anders , Mommaas C. J. , Baerheim M.
Published: December 2007

Spud can/soil interaction is a critical parameter in determining the safety of jack-up operations under complex soil conditions. This paper presents a cost effective modification to a standard spud can design, based on the requirement for a 5 m long skirt and an increase of the spud can area from 250 m2 to 350 m2. This is achieved through addition of a dough-nut shaped extension which can be installed and removed with the rig afloat in sheltered water.

The primary reason for the modification is to increase the soil bearing capacity.

Since the extension increases the seabed fixity of the footing; moment loading and dynamic effects on the jack-up are also reduced, increasing the operating envelope of the jack-up.
Universal Fluid: A Drilling Fluid to Reduce Lost Circulation and Improve Cementing
Authors: Nahm J. J. , Romero R. N. , Wyant R. E. , Hale A. A. , Briggs B. R. , Smith T. R. , Lombardi M. A. , Keedy C. R.
Published: December 2007

A universal fluid (UF) is typically a water-base fluid that has been treated with finely ground blast furnace slag and that still maintains the appropriate characteristics of a good drilling fluid. The slag becomes concentrated in the filter cake formed while drilling permeable formations and slowly sets to form a hard layer intimately bonded to the formation. True zonal isolation can be obtained by using a UF and subsequently cementing with slag-based mud solidification technology. Complete mud displacement and efforts to remove filter cake are not necessary prior to cementing since the solidified UF filter cake bonds strongly both to the formation and to the cement and since undisplaced portions of the UF set up as well.

The universal fluid (UF) has been developed primarily out of the need to improve cementing in horizontal and extended-reach wells. To date UFs have been used to improve zonal isolation and to reduce or prevent lost circulation or cement fallback during drilling and cementing. Two Diatomite wells in the Belridge Field, California and the vertical portion of one horizontal well in the Midway Sunset Field, California were successfully drilled with a UF and cemented with slag mix cement slurries. Also, a well in the Midway Sunset Field, where losses are routinely experienced, was drilled with a UF specifically to control lost circulation, and no losses were experienced. Five wells in the Peace River area in Canada were successfully drilled with aUF to prevent cement fallback upon cementing.
Physicochemical Properties of Synthetic Drilling Fluids
Authors: Growcock F. B. , Andrews S. L. , Frederick T. P.
Published: December 2007

Synthetic-based muds (SBM's) were developed as environmentally friendly alternatives to conventional petroleum-derived oil-based muds (OBM's). Although each synthetic fluid is chemically unique, the physicochemical properties of the SBM's exhibit some common trends. SBM's are safer to work with, more biodegradable and more dispersible in seawater than conventional OBM's. On the other hand, SBM's are more viscous at low temperatures, thin more with increasing temperature, have lower thermal stability and do not dehydrate shales as readily as conventional OBM's. By adjusting the emulsifier package in each mud, these properties may be brought more in line with those of conventional OBM's.
Strategic Alliances in the Wireline Services Industry
Authors: Phillips C. J. , Stewart C. G. , Barnette J. C. , Copoulos A. E. , Henderson Bruce
Published: December 2007

A strategic alliance formed between the two organizations represented by the authors has fundamentally changed the operating practices of the wireline services industry in Alaska. Through a combined team effort, operating practices have been altered to emphasize efficiency, improved quality control, enhanced teamwork, constant communications, simplistic and flexible pricing, safety and environmental protection, and continuous improvement in every respect. The net result is added value and profitability for both the operating and service company.

One year after implementation, the alliance in Alaska has proven to be a success for both the operator and the wireline services company. Its success is based largely on the mutual trust, constant communication, and teamwork present between the two companies. Results will be demonstrated through an active case history.

Different types of alliances, partnerships, and other working relationships have been developed in the oil and gas industry. In comparison, the alliance structure developed in Alaska offers significantly more benefits than many other alliances.
Designer Directional Drilling to Increase Total Recovery and Production Rates
Authors: Eck-Olsen Johan , Drevdal Kjell Erik , Samuell John , Reynolds Jim
Published: December 2007

The implementation of a new type of well profile, the designer profile, has resulted in increased recovery and production rates. The geologically complex Gullfaks Field (See fig. 1), located in the Norwegian sector of the North Sea, has seen significant change in the initial field development plan (FDP) as a result of the design technology. A new type of well profile was necessary to increase both total recovery and production rates from Gullfaks platforms A, B and C. Advances in steerable technology and directional drilling performance enabled a three dimensional horizontal / extended reach well profile, now designated as a designer well, to be utilized to penetrate multiple targets. This paper presents the concept, motivation, performance, results and conclusions from four designer wells used in the revised FDP.
Hole Cleaning in Large, High-Angle Wellbores
Authors: Rasi Marco
Published: December 2007

Beds of cuttings are usually formed on the bottom of large, high-angle wellbores during drilling. When the drill string is moved axially along the wellbore, large bottom-hole assembly elements such as drill bit and stabilizers tend to plow the cuttings bed, thereby causing the formation of plugs of cuttings which give rise to high overpulls, loss of circulation, continuous need for operations such as backreaming, and stuck pipe. To reduce the likelihood of these costly hole problems occurring, it is necessary to minimize the height of the cuttings bed which forms while drilling, and to minimize the tendency of the bottom-hole assembly to form plugs of cuttings. This can be done with a new hole cleaning tool described in this paper. This tool was developed using a combination of analytical modeling based on fluid mechanics first principles, experimental data, and field data. The tool enables establishment of pump flow rates, drilling fluid rheological properties, drill string configurations, and well profiles for minimal risk of experiencing problems associated with the existence of a cuttings bed.
New Nozzle To Increase Drilling Rate by Pulsating Jet Flow
Authors: Liao Rongqing , Wu Jiang , Juvkam-Wold H. C.
Published: December 2007

A new type of jet nozzle for drill bits used in the oil industry is presented in this paper. This new nozzle utilizes Helmholz oscillation theory and generates a pulsating jet flow under common drilling hydraulics conditions and pump horsepower. This pulsating jet flow produces much higher instantaneous jet velocity and impact pressure than those from currently used jet nozzles, resulting in significant improvements in hole cleaning and drilling rate.

The new nozzle can be used in conventional jet bits without modification. No auxiliary equipment is needed downhole or at the surface to generate the pulsating jet flow. Field tests of this new nozzle in six oil fields in P.R. China have shown that the nozzle can increase drilling rate 36 - 77 %, and increase bit footage 6-44 %.

The theory and the laboratory test results with the new nozzle are presented in this paper. The field test results with the new nozzle are also presented and compared with the results from conventional nozzles. The field test results indicate a satisfactory economical benefit for this new nozzle in drilling both shallow wells and deep wells up to 15,000 ft.
An Expert System for Drill Bit Selection
Authors: Fear M. J. , Meany N. C. , Evans J. M.
Published: December 2007

An expert system has been developed to assist with the selection of poly-crystalline diamond compact (PDC) drill bits. The system uses a knowledge base of bit selection rules to produce a generic description of the most suitable bit for a particular set of drilling and geologic conditions. The rules are derived from rigorous study of foot-based drilling, geology and rock property data from past bit runs. Compared to conventional bit selection methods this approach makes more effective use of past experience, leading to a higher and more uniform level of bit selection expertise in drilling operations.
The Successful Use of Anti-Whirl Technology in Conventional Coring
Authors: Armagost W. K. , Sinor L. A.
Published: December 2007

Anti-Whirl PDC bit technology, proven in full-hole bit designs, has been successfully applied to conventional coring operations. Coring operations were conducted during Amoco's Deep Water Drilling Program in water depths ranging from 3250 to 6521 ft. This paper reviews the coring operations on three wells and compares the results to those achieved in other Deep Water applications. Also included are the results of laboratory testing to establish hydraulic levels required to core Gulf Coast shales.
Lean Drilling – Introducing the Application of Automotive Lean Manufacturing Techniques to Well Construction
Authors: de Wardt John P.
Published: December 2007

In the automotive industry, Henry Ford and Alfred Sloan moved manufacturing from craft production (highly skilled workers using simple but flexible tools to make what the customer asked for – one at a time) to mass production (narrowly skilled professionals who design products made by unskilled or semi skilled workers tending expensive, single purpose machines). Later Eiji Toyoda and Taiichi Ohno pioneered the concept of lean production which combines the advantages of craft production and mass production whilst avoiding the high cost of the former and the rigidity of the latter.

The application of lean production created the most developed form of customer – supplier relationships (being developed elsewhere under the guise of alliances and partnerships) and achieved the highest productivity and quality in the industry. Studies have shown that productivity exceeds mass production by as much as fifty percent and the associated high level of quality is free. This outstanding result was not achieved through automation but through development and adoption of new organizational concepts. The drilling industry today resembles most closely the automotive craft production of the past; mass production has not been adopted due mainly to the non repetitive nature of drilling activities. Studies have concluded that lean manufacturing can replace both mass production and craft production in all areas of industrial activity. Lean manufacturing consequently has the potential to be applied to drilling or, more appropriately, well construction.

This paper describes the key elements of lean manufacturing and presents an analogy with the well construction industry which provides the necessary insight for the well construction industry to adopt them. The results achieved in the automotive industry show that major cost savings and improvements in quality can be achieved in the well construction industry through this application.
A New Generation of Instrumented Steerable Motors Improves Geosteering in North Sea Horizontal Wells
Authors: Peach S. R. , Kloss P. J. C.
Published: December 2007

Formation evaluation measurements in conventional steerable assemblies are lagging 30 ft – 100 ft behind the bit. This paper describes a fully instrumented steerable downhole motor recently introduced and proven in several North Sea horizontal wells.

The tool makes real time measurements of inclination, gamma ray and resistivity acquired at, or close to, the bit. These measurements, integrated into the steerable motor, have enabled complex horizontal wells to be drilled successfully.

Provision of inclination at the bit measurements enabled the wellsite engineers to continually determine the directional behavior of the bottom hole assembly. The reservoir entry point was determined immediately the bit penetrated the formation, gamma ray and resistivity measurements were used to correlate the position of the bit relative to offset wells. The use of the new instrumented motor enabled a specific horizon within the reservoir to be accurately followed.

The paper discusses operational aspects of the new instrumented motor. A case history is presented along with data from other field trials which include comparisons between data acquired by the instrumented motor and that acquired by conventional Logging While Drilling (LWD) tools run in the same hole section.
Simple Charts to Determine Hole Cleaning Requirements in Deviated Wells
Authors: Luo Yuejin , Bern P. A. , Chambers B. D. , Kellingray D. S.
Published: December 2007

Optimization of hole cleaning remains one of the major challenges when planning and drilling high angle and extended reach wells. In this paper, a simple rig-site graphical technique is presented for determining hole cleaning requirements for a range of hole sizes. The method uses a set of charts which have been derived from a computer model based on both laboratory and field measurements.

Access to the technology at the rig-site has been greatly improved by the development of the simplified charts. Examples are presented which illustrate how the charts can be applied to determine the influence of the major drilling variables on hole cleaning requirements. Mud rheology is shown to be a key variable for optimising hole cleaning in deviated wells. The charts can also be used to quantify the effect of hole enlargement which adversely affects hole cleaning.

In addition, the paper discusses the detailed methodology behind the development of the charts from the original physically-based model. The charts presented in the paper are valid for the typical North Sea drilling conditions.
Pore Pressures, Fracture Gradients, and Drilling Economics
Authors: Proehl T. S.
Published: December 2007

Introduction

Risk sharing and alliance formation are central themes in the E&P business environment of the 1990s. A common manifestation of these themes is the recruitment and use of partners and contractors to perform drilling operations on specific projects which formerly would have been 100% managed and operated by large integrated oil companies. One consequence of risk-sharing activity is that integrated companies have had the opportunity to closely observe and assess the drilling practices of other operators and incentive-oriented drilling contractors on wells in real time, with funds at risk.

The debate over which kind of business organization and risk-sharing philosophy produces the most cost-effective drilling result often neglects the fact that for any given well, the in-situ conditions would be identical for anyone undertaking the work. There is no inherent logic in the notion that turnkey contractors have an edge on oil companies in addressing subsurface conditions. The economic outcome of a given well is more dependent on objective subsurface factors and the way they are approached than on the kind of risk-sharing philosophy selected for drilling. Similarly, there is no inherent logic in the notion that hiring a turnkey contractor absolves an oil company from risk on a well. At a minimum, the risk of possible production delays caused by acts of a turnkey contractor is always present.

Three wells (A, B, and C) drilled recently illustrate the point. One well was drilled by an oil company and two were drilled by turnkey contractors. All three wells penetrated geopressured sections. The resulting geopressure-related problems with fracture gradients and wellbore integrity caused large economic impacts on turnkey drillers and operators alike. The wells were selected to highlight the common-sense idea that the key to risk management and achieving profit goals is good planning and proper execution, not the form of risk-sharing selected for any particular venture.
Recent Advances in Subsea Completion/Workover Blowout Preventers
Authors: Womble L. M.
Published: December 2007

Several recent advances have been made in subsea completion/ workover blowout preventers (BOPs) which reduce the cost, weight, size, and time required for subsea workover and completion applications while maintaining safety. Newly released ram designs have made broad steps in the areas of shearing, suspending, and sealing. In addition to new rams, new approaches to bonnet design have increased the features while decreasing the size of subsea workover BOPs. The primary focus of these designs is the increased use of coiled tubing for drilling, completion, and workover operations. In most cases these new advances will cut the required number of ram cavities for a dual string system in half and eliminate at least one trip down hole. These designs have been proposed for use in subsea tree running tools, lower riser packages, subsea BOP blocks, cutting packages, and traditional workover BOP stacks.
Data Gathering for a Comprehensive Hydraulic Fracturing Diagnostic Project: A Case Study
Authors: Truby L. S. , Keck R. G. , Withers R. J.
Published: December 2007

ARCO is currently engaged in a comprehensive field project to demonstrate the use of hydraulic fracturing for solid waste disposal. Implementation of this research program includes drilling of three 5000' test wells: an injection well and two offsetting monitor wells that each contain twenty-five 3-component geophone pods for passive seismic fracture detection. This paper focuses on the data gathering during drilling operations and the unique drilling challenges required for this disposal demonstration project. Specialized data was required for assessment of fracture geometry and containment, measurement of fracture azimuth to site the monitor wells and verification of formation seismicity for fracture diagnostics. This information was obtained with extensive coring operations, open- and cased-hole micro-fracs, and an injection test to directly measure the formation seismicity. Drilling challenges included the placement and cementing of the 750' of geophone pods and 4250' of armored transmission cable in each monitor well, plus redesign of well plans due to wellbore stability problems.
Ravenspurn North Development Drilling: Key Techniques to Outstanding Success
Authors: Bird T. M. , Sears R. W. , Ollis Michael , Dickson Robert , Ferguson R. A.
Published: December 2007

This paper presents an overview of how the drilling performance on Ravenspurn North Development (RND) constantly improved resulting in significant savings in well costs. Performance statistics showing the learning curve effect and comparison of RND drilling performance with other Southern North Sea developments(1) are presented. Several key techniques contribute to this success including optimisation of well design, use of leading edge technology and performance monitoring. These topics are discussed along with specific examples of how they were applied.
Analysis of Interruption and Lost Rig Time Due to Equipment Failure in Offshore Drilling Operations
Authors: Andersen L. B. , Lembourn P. R.
Published: December 2007

Database records and maintenance reports were used to analyse lost rigtime during drilling operations on the Norwegian Continental Shelf (NCS). The equipment failure database contains detailed and unique information from more than 13,700 incidents of equipment failures that caused lost rigtime from 1985 to 1991. In addition to maintenance reports, the database records were used to survey to what degree equipment failure causes lost rigtime, what kind of equipment fails most often, and in which operation the equipment failure occurs. Emphasis was put on analysing the causes for "Top Drive" failure. The results presented in this paper represent an average in lost rigtime on the NCS and can therefore be used as a measure in the Continuos Improvement Process. The analysis of "Top Drive" failure is an example of how a causal analyses can be conducted, and of how the results can be utilised in improvement efforts.
Smooth Block Control: Automation of Traveling Block Postioning Using Existing Drilling Equipment
Authors: Zinkgraf H. L. , Porche M. N. , O'Brien D. M.
Published: December 2007

Automation of drilling rig functions can improve efficiency by reducing personnel and operating costs while providing an additional benefit of increased safety. Methods which use existing drilling equipment provide the most economic means to implement this automation. One function which can be implemented in this way is automatic positioning of the traveling block.

This paper examines general design requirements for achieving automatic positioning of the traveling block. It also presents details of a control system developed to provide controlled braking of the traveling block using previously installed eddy current brake systems. The system provides closed-loop braking control while monitoring the traveling block position, velocity and acceleration through its entire range of travel. Various parameters are constantly monitored to assure that the eddy current brake capacity limits are not exceeded at any time. The system smoothly stops the traveling block at positions selected by the operator, even with wide variations in load. Sensors may be added to prevent moving the traveling block to collide with pipe handling equipment. The advantages of closed-loop control utilizing eddy current brakes over kinetic energy monitoring and friction brake application will be detailed. The technical requirements for future extension of this system into a full automatic positioning controller are discussed.

Field performance data will be presented to illustrate the benefits obtained from closed-loop control of the eddy current brake to position the traveling block.
Tracking Stuck Pipe Probability While Drilling
Authors: Howard J. A. , Glover S. B.
Published: December 2007

Two stuck pipe databases have been developed with data from more than 1000 wells drilled in the Gulf of Mexico and the North Sea. Statistical techniques were used to develop stuck pipe predictive models. When classifying in three categories - differentially, mechanically or not stuck - an accuracy of 75 % is achieved, rising to 80% for two-class (stuck/not stuck) prediction. Using these models, graphical tracking of the probability of stuck pipe occurring may be undertaken, to monitor drilling operations for stuck pipe avoidance. A similar statistical model was developed to predict the probability of freeing pipe once stuck. Comparisons are also made with two published pipe-freeing models. The data were further analysed to identify any trends which may provide operational guidelines for stuck pipe avoidance or freeing operations.
Advances in Prediction of Stuck Pipe Using Multivariate Statistical Analysis
Authors: Biegler M. W. , Kuhn G. R.
Published: December 2007

Stuck pipe is known to occur as a result of several major mechanisms including wellbore instability, improper hole cleaning, and differential sticking forces. Using an evolution of the discriminant analysis methodology first published by Chevron1,2, a second generation engineering statistical model has been developed that incorporates the use of physical stuck pipe parameters in combination with a large body of drilling data to quantify the probability of stuck drill pipe for a given day of a well. Further, the tool predicts which stuck pipe mechanism is driving sticking risk and can thus be used to modify drilling variables to minimize the likelihood of sticking. An example application of the model in a recent Gulf of Mexico well is given.
Recent Advances in Casing Wear Technology
Authors: Hall R. W. , Garkasi Ali , Deskins Greg , Vozniak John
Published: December 2007

Casing wear is often a problem in deep wells where doglegs and large tension loads on the drill string combine to produce high lateral loads where the drill string contacts the casing. Casing wear can result in blowouts, lost production, and other hazardous and expensive problems.

A mathematical model which describes casing wear in terms of hole geometry, casing/tool-joint material, mud system, and drilling program, has been developed and verified. Over 300 laboratory wear tests have provided wear factors which allow the model to be applied to a wide range of drilling situations. The model has been incorporated into a computer program, CWEAR.

The prediction of dogleg severity and casing wear is seriously compromised by directional surveys in which the station spacing is 100 ft or greater.

Through the laboratory test program, means to reduce casing wear rate have been demonstrated and applied in the field.

Mud lubricants, tool-joint materials, pipe protectors, and casing materials and internal coatings have all been examined as possible means to reduce casing wear.

Some mud lubricants significantly reduce frictional drag; others do not. Because a mud lubricant significantly reduces frictional drag does not imply that it will also reduce the casing wear rate.

Newer, proprietary tool-joint coating materials have proven effective in reducing casing wear, while continuing to protect the tool joints in open hole.

Pipe protectors have proven to be one of the better means of reducing casing wear. Laboratory experiments have demonstrated severe operational difficulties of these protectors. Several of the protector manufacturers are now engaged in development programs to improve their products.

Inadequacies in the available methods of measuring casing wear in the field have been demonstrated. As a result of this work, at least two new casing wear measurement tools are under development.
Geothermal Gradient Anomalies of Hydrocarbon Entrapment, UKCS Quadrants 35 to 54
Authors: Ibrahim M. W. I.
Published: December 2007

Geothermal Gradient anomalies have long since been recognised to accompany hydrocarbon traps. The anomalies are most probably byproducts of heat transporting processes of hydrocarbon migration and entrapment. Therefore, couldn't identical anomalies be used to locate undiscovered or bypassed traps?

This study used BHT data of exploration and development wells in UKCS guadrants 35 to 54 of the North Sea to: produce contour maps of the geothermal gradients, identify geothermal gradient anomalies associated with proven hydrocarbon traps then use the models identified to delineate potentia, probable and possible anomalies indicative of undiscovered hydrocarbon traps or migration paths in the same quadrants.

A computer programme (CGG-ESTI) was used to correct and test for reliability the BHT records of 238 wells in order to identify boreholes with statistically significant BHT data. Discriminative computer contouring technique was used to produce noninteractive, un-biased contours similar to the manual after-the-fact contours. This technique utilised statistically significant as well as undifferentiated control points to generate compensated geothermal gradient contours (CGG), extrapolated surface temperature intercept contours (ESTI) and map geothermal gradient anomalies of hydrocarbon entrapment.

The study delineated 50 PROVEN and 46 POTENTIAL, PROBABLE and POSSIBLE geothermal gradient (CGG-ESTI) anomalies of hydrocarbon entrapment.
The Geopseudo Atlas: Geologically Based Upscaling of Multiphase Flow
Authors: Pickup G. E. , Ringrose P. S. , Forrester M. M. , Jensen J. L. , Sorbie K. S.
Published: December 2007

Recent work has shown that rock heterogeneity at the sub-metre scale may have a significant effect on hydrocarbon recovery. These effects need to be upscaled to obtain accurate effective parameters (pseudo properties) to input into full field simulations. Modelling the wide range of scales inherent in hydrocarbon reservoirs is a demanding task which can be greatly assisted by a purpose-built software package. We are therefore developing the Geopseudo Atlas package to address this need. The package integrates reservoir simulation with recent advances in geological modelling, allowing the engineer to create permeability models which are geologically realistic, and to calculate the effective flow properties of such models. It is designed to complement the many existing large-scale reservoir modelling packages. The Geopseudo Atlas is intended to be an important tool linking geological models, data, and reservoir simulators.

The package comprises four sections: the Atlas which contains a selection of ready-worked examples; Data Analysis which performs simple statistical analysis on available data; Field Generation which creates deterministic and stochastic permeability models; and Scale-up which performs single and two phase flow simulation. The Geopseudo Atlas is menu driven and runs on Unix-based machines with Motif. It is intended to interface with commercially available packages, such as the ECLIPSE™ reservoir simulation package, and STRATAMODEL™ and IREX™ for 3D visualisation.
A System for Estimating Uncertainties in Hydrocarbon Pore Volume
Authors: Siring Erling
Published: December 2007

This paper describes a Monte Carlo simulation system based on SAS (Statistical Analysis System), called MCS. The system has been designed to handle dependencies between variables and to integrate results from geostatistical programs with ordinary Monte Carlo simulations.

MCS has been developed in Statoil to estimate the uncertainties in Hydrocarbon Pore Volume in gas and oil fields. Special care has been taken to handle dependencies between petrophysical variables and rock volumes in different reservoir zones and fault block segments.
A Log-Inject-Log Application to Resolve Porosity in Tight, Fractured Formations
Authors: Bigelow E. L.
Published: December 2007

Petrophysical evaluations offractured reservoirs are always adifficult task. Recognizing fractures, determining their orientation, and identifying whether they are healed, partially healed, or open is itself difficult. In fractured reservoirs, conventionallog analysis methods rarely provide accurate porosity and saturation solutions with respect to productivity or reserve calculations. This article proposes a pulsed neutron log-inject-log technique as a method to provide more accurat porosity calculations in reservoirs that have extremely low matrix porosity, but produce from fracture systems.
Proposal for an Integrated Study of the Grayburg/San Andres Reservoir, Foster and South Cowden Fields, Ector County, Texas
Authors: Rowland D. A. , Reeves J. J. , Trentham R. C. , Smith W. H.
Published: December 2007

A cooperative study of the Grayburg/San Andres reservoir is planned for the Foster and South Cowden Fields, Ector County, Texas under the U.S. Department of Energy's Class II Program for ShallowShelf Carbonate. The project will utilize existing technology to increase oil production through infi11dri11ing, workovers, and water flood development. Productivity problems associated with a mature shall owshelf carbonate reservoir will be addressed by a multidisciplinary tech­ ni cal team which integrates high resolution 3-D seismic data, reservoir characterization techniques, and 3-D reservoir simulation.

A 3-D seismic survey designed specifically for i magi ng the Grayburg/ San Andres interval of the Foster and South Cowden fields will be acquired. A high performance computer work­ station will then be used to integrate existi ng subsurface geological and engineering data with the 3-D seismic data for a detailed evaluation of sequence strati graphy and facies relationships. Subsequentl y, a 3- D reservoir simulation model will use the results to hel pdefine flow units wi thin the reservoir. A field demonstrati on of in fill dri11ing and water flood deve1 opment wi11 follow.

The high resolution 3-D sei smic survey is expected to resol ve changes in the subsurface on the megascopic scal e, al l owi ng for carre­ lation of pet rophysical properties and stratigraphic information between boreholes. This informati on will be helpful in mapping porosity zones, permeability barriers, and "thief" zones within the reservoir.
DOE Class II Oil Program: Application of Reservoir Characterization and Advanced Technology Improves Recovery and Economics in Lower Quality San Andres
Authors: Taylor A. R. , Doty R. L. , Behm E. J. , Ulmschneider Rene , Watts George , Hickman T. S. , Underwood George , Justice J. H.
Published: December 2007

This proposal is aimed at proving lower quality San Andres Reservoirs can be economically flooded by applying reservoir characterization and a combination of EOR methods that are not widely utilized. This site is representative of DOE Class II reservoirs and is uniquely suited for the successful application of advanced technology. The reservoir characterization methods will apply new technologies which include cross wellbore tomography, hydraulic fracture orientation detection, and 3D seismic. The intent of this proposal is to show that, using commercial resources available to all producers, oil remaining after waterflooding can be economically recovered using C02 flooding and Cyclic C02 stimulation in reservoirs more heterogeneous and of lower quality than current C02 projects.

Work proposed will begin with reservoir characterization using conventional geological and petrophysical methods incorporating 3D seismic and cross wellbore tomography. This characterization will be used in a compositional simulation study to provide production schedules for economic evaluation. The improved simulation model will be able to provide production forecasts for conventional miscible C02 flooding and provide the added benefits of forecasting recoveries from the Cyclic C02 stimulation and increased injection from fractured injection wells. The Cyclic C02 stimulation process provides an almost immediate production increase, and thus the quicker payouts needed to economically justify the large capital outlay required to bring C02 to the field. The ability to accurately provide forecast production during this early phase is essential to performing a realistic economic evaluation of the project. Another factor influencing C02 floods is unfavorable mobility ratios which cause poor sweep efficiency, thus processing only a small portion of the reservoir. Improving the sweep efficiency would increase recoveries by an estimated 1015% in the flood area.