Offshore Rigs Research Articles

Conversations: You Must Be the Change

President's column The aging of our industry’s workforce and the near-term disappearance of the related knowledge base and experience are apparent when examining the data on SPE members’ age distribution (excluding student members). Fig. 1 shows that the “big crew change” is well under way with the Baby Boomers* preparing to leave our industry. It is estimated that the potential outflux in the next decade will be as large as 50% of those who are currently employed in the industry. The chart also shows a developing second peak where Generation Y* enters the industry in recent years, with a low for the Generation X* segment of the workforce. Our industry lost a generation of workers in the 1980s, and now it is obvious that the rate of skills replacement is not adequate. Demographics in other sectors are similar to SPE’s. Charles Davidson, the CEO of Noble Energy, says, “There are about three per cent of the American Association of Petroleum Geologists members who are around 80 years old, and we may be needing them!” (Rhodes 2007). To sustain a planned expansion in investment estimated at USD 200 billion over the next 15 years, the industry is poised to recruit a large number of new talent. According to Lee Hunt, president of the International Association of Drilling Contractors, just the offshore rigs currently under construction will require an additional 17,000 new people not currently employed in our industry (Duey 2008). This talent squeeze can slow down the industry’s growth. The current economic downturn has only delayed the wave of retirements and has resulted in a slowdown in hiring that may have somewhat masked one of the most significant challenges facing our industry today—inspiring talented young people to join the industry and prepare to lead it into the future. *Baby Boomers are those born in the mid 20th Century, following World War II. Generation Y is the group born during the period 1976–95. Generation X is roughly defined as those born during 1965–80.

Failure is common on offshore rigs' blowout preventers

Failure is common on offshore rigs' blowout preventers

Kalman filtering for positioning and heading control of ships and offshore rigs

In this article, we have described the main components of a ship motion-control system and two particular motion-control problems that require wave filtering, namely, dynamic positioning and heading autopilot. Then, we discussed the models commonly used for vessel response and showed how these models are used for Kalman filter design. We also briefly discussed parameter and noise covariance estimation, which are used for filter tuning. To illustrate the performance, a case study based on numerical simulations for a ship autopilot was considered. The material discussed in this article conforms to modern commercially available ship motion-control systems. Most of the vessels operating in the offshore industry worldwide use Kalman filters for velocity estimation and wave filtering. Thus, the article provides an up-to-date tutorial and overview of Kalman-filter-based wave filtering.

River current a new source of renewable energy

Whirlpools created by river currents as they flow around obstacles are capable of tearing bridges and offshore rigs apart. Now they are being harnessed as a source of renewable power

Will there be enough offshore rigs available for Australia's needs?

Will there be enough offshore rigs available for Australia's needs?

Fifty Years of Change in the Petroleum Engineering Profession

Without a doubt, the petroleum engineers of today are very different from those of yesteryear. They are trained differently, think differently, operate differently, and use a different tool kit from that of their predecessors. Some of the changes in the profession are obvious, such as the availability of a more sophisticated tool kit and the presence of women in every facet of the business. Other changes have been more subtle, including engineers' attitude toward their profession, improved communications skills, and the rise of information overload. Women Join the Ranks One of the most profound changes in petroleum engineering since 1957 has been the participation of female engineers in a career field that had been overwhelmingly male. Exceedingly rare 50 years ago, female engineers and managers are now common. "Our industry is still underserved by the female half of society, but it is a far cry from the 1950s and before," said James Pappas, Global Technology Director for Devon Energy and SPE's Technical Director for Production and Operations. "Now more than ever, women are needed in the workforce because the industry has never been so short on engineers. To have excluded half of the population in the past from such an important career amounts to nothing less than a huge case of short-sightedness by the industry." Many of the first wave of women entering the profession were themselves daughters of oilmen, who encouraged them to pursue careers in petroleum while simultaneously cautioning the young women that the oil patch could indeed be a difficult place for them to work and succeed. Some of the obstacles included the difficulty of accommodating both men and women on offshore rigs, and sometimes women were not welcome by the wives of men working aboard a drilling and production platform offshore. "Equality legislation during the 1970s and early 1980s did much to open doors for women and other minorities in our profession," says C.O. (Doc) Stokley, vice president of R&D for TAM International and a 42-year veteran petroleum engineer. "The result has been a much smoother path for women and other minority engineers during the past several decades." The Move to Teamwork Depending on the culture of the company, some engineers during the 1950s and 1960s began to be exposed to multiple disciplines, such as drilling, completions, workover, fracturing, production, reservoir, and other areas in an effort to broaden their knowledge and experience. But other companies believed it was better for engineers to focus on a single discipline. By the end of the 1970s, the industry was a mix of specialists and multidiscipline generalists. This period also brought closer together the exploration and production sides of the business.

The Safety and Reliability of Complex Energy Processing Systems

A common characteristic of large-scale, complex energy conversion, generation, and processing systems, such as fossil fuel/thermoelectric power plants, gas processing facilities, off-shore rigs, and high-capacity compressor and pumping stations, is that large amounts of potentially flammable, combustible, or pressurized materials are concentrated and processed in single sites under the centralized control of a few operators (working in a control-room environment). The effects of human error in these facilities are often neither observable nor reversible; therefore, error recovery is either too late or impossible. Catastrophic breakdowns of these systems, created by man-made and natural causes, pose serious threats and long-lasting health and environmental consequences for workers in the facility, for the local public, and possibly for the neighboring region and the whole country. For the foreseeable future, despite increasing levels of computerization and automation, human operators will remain in charge of the day-to-day controlling and monitoring of these systems. Thus, the safe and efficient operation of these technological systems is a function of the interactions among their human (i.e., personnel and organizational) and engineered subsystems. This article attempts to (a) review the causes of complex technological systems' failures, (b) demonstrate that Human-Organization-Technology interactions play a critical role in the safe and efficient performance of complex energy processing systems, (c) raise some additional related and critical issues for developing countries, and (d) make recommendations for improving the performance of human and organizational factors of energy processing installations during normal as well as emergency situations.

MODU Performance in Hurricane Ivan

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper OTC 18322, "MODU Performance in Hurricane Ivan," by B.P.M. Sharples, SPE, Offshore Risk & Technology Consulting Inc., and S. Buffington, U.S. Minerals Management Service, prepared for the 2006 Offshore Technology Conference, Houston, 1–4 May. Hurricane Ivan tracked through a high-density corridor of mobile offshore drilling units (MODUs) in the U.S. Gulf of Mexico (GOM), resulting in five semisubmersibles losing station and collapse of one jackup. In the aftermath of this hurricane, the industry is reflecting on lessons learned and re-examining industry standards. There was no loss of life and no major pollution from MODUs in Hurricane Ivan. A study commissioned by the U.S. Minerals Management Service (MMS) has chronicled the incidents of Hurricane Ivan to provide information that may lead to more-robust criteria for MODU safety. Introduction A study was commissioned by the MMS to gather information and examine MODU loss of station keeping during Hurricane Ivan. There were approximately 112 jackups and 32 semisubmersibles in the GOM at the time of Hurricane Ivan. Only three jackups were affected, and only one of those was a total loss. Five semisubmersibles were affected. Four left their general location and became adrift, and one moved approximately 3,000 ft. Most of the information came directly from drilling contractors, some came from oil companies, and some came from MMS files. Because the study was not complete at the time the full-length paper was written, the information is preliminary and subject to correction and change. Overview In September 2004, Hurricane Ivan, a Category 4 storm with waves exceeding the 100-year design criteria for offshore facilities, moved through the GOM. Of the more than 4,000 offshore oil and gas facilities and 33,000 miles of pipelines in federal waters, approximately 150 facilities and 10,000 miles of pipelines were in the direct path of Ivan. Damaged facilities included MODUs, offshore platforms, producing wells, topside systems, and pipeline systems that transport oil and gas ashore. MMS received industry reports indicating that seven platforms were destroyed, six platforms and five drilling rigs had major damage, and a substantial amount of oil and gas production remained shut-in because of pipeline damage. Semisubmersible MODUs Ocean Star and Ocean American. Diamond Offshore Drilling reported that drill platform Ocean Star drifted from its moored location. A visual inspection by fixed-wing aircraft confirmed that Ocean Star was afloat with no apparent damage. A visual inspection by aircraft of four other Diamond Offshore rigs operating in the path of Ivan also indicated no apparent dam-age or pollution. The Ocean Star was approximately 1.5 miles east of the storm track. Most of the wires were said to have broken below the rig fairlead near the highest loading point on the system. Hindcast weather data clearly show that conditions exceeded the American Petroleum Inst. (API) 10-year design criteria.

Technology Update: Pemex Uses Data Management as a Vital Part of Decision Making in the Oil Patch

The E&P arm of Mexican state oil company Pemex faced the same challenge as many upstream oil and gas companies—large amounts of valuable data, tedious methods for managing it, and employees across the company struggling to access, share, and analyze historical and current data to make timely, well-informed decisions. Pemex E&P also shared the goal most similar companies have to optimize production and reserves from its oil and gas fields. Its objective was to find a solution that included a scalable, secure way to manage and track valuable data; man-age systems connected to the data and to each other; and develop effective work processes so that people could use data as needed in their daily work. Experts at the E&P subsidiary, which manages approximately 70 onshore and offshore rigs in southern Mexico, questioned whether spreadsheets were the most effective way to manage rig activities. Spreadsheets are commonly used to estimate production, track assets, and perform other important oil and gas functions. The spreadsheet is a great tool in many situations—and much more effective than its predecessor, the map. But in situations involving large volumes of data, oil and gas companies are seeking ways to analyze and modify their processes to ensure optimum performance with minimal production and operations interruptions. As the firm continued to add activities, the spreadsheet also greatly expanded in size and complexity. The company's planning group, business units, and drilling-services organization jointly maintained a complex 50- to 60-column spreadsheet containing drilling, financial, and technical information and the various geological, engineering, and other information needed to plan and coordinate activities for each rig. Each business unit (asset) used the spreadsheet to add its prospects and compete for scarce and valuable resources. The drilling-services organization used the spreadsheet to schedule, deploy, and organize rig activities, and it was the planning group's source for allocating funds to create the right balance between internal supply and demand. A group of engineers and planners from the three groups recreated the spreadsheet approximately every 6 weeks to reflect ongoing activities, maintenance, new requirements, changing budgets and schedules, and various other fluctuations. Recreating each spreadsheet took up to 6 days and required tedious attention to detail to capture the cascading effect each change had on other activities. Printed reports were so large that they filled an entire wall. For a single moment, people had a snapshot of the current view from which to make critical decisions. By the next day it might be obsolete. Real-Time View of Rig Activities In late 2005, Pemex implemented a new Web-based software application to schedule and manage all of its drilling-rig activities. Teams used the old spreadsheet in parallel with the new system for 6 months to catch any problems and then retired the spreadsheet. The company has completed a full year of drilling activity using this system, including quarterly and annual programs, and has planned the 2007 program using the new system.

Immersive Safety Handling and Training

tion of efficiency development for the entire oil and gas industry. The result of the full implementation of IO is a business transformation that will influence the oil and gas companies at all levels: advanced technology applications, organizational structures and work processes, and the interaction between all parties involved both inside and outside the oil companies. The oil companies and the service companies will work in a much closer relationship in the future. One important change is the new Onshore Support Centers (OSC) that supplements, and in some cases take over, the traditional control structures at the offshore oil and gas installations. This transformation of control from the offshore rigs to onshore control centers requires a strong focus on safety handling and training. The use of Virtual Reality centers to train control room personnel to handle simulated offshore operations is an appealing way to maintain the strict safety regulations demanded in the oil and gas industry. Existing studies on training of control room operators have concentrated on team development and training on such diverse teams as aircraft cockpit crews, military combat center groups and nuclear power plants operators [1], in which the former resembles the subjects in our case. The international aviation industry has been using a special form of human factors training with their flight deck crews and other teams, called crew resource manage

Seismic-While-Drilling Using a Swept-Impulse Source

This article, written by Technology Editor Dennis Denney, contains highlights of paper SPE 92114, "Seismic-While-Drilling Using a Swept-Impulse Source," by J.J. Kolle, SPE, and K. Theimer, Tempress, prepared for the 2005 SPE/IADC Drilling Conference, Amsterdam, 23-25 February. This paper describes a prototype swept-impulse hydraulic tool capable of generating a broadband seismic signal at the bit while drilling. The source was designed to overcome the limitations of drill-bit seismic services by allowing operations with polycrystalline-diamond-compact (PDC) bits in inclined wells and in soft formations. The swept-impulse seismic source generated a broadband, high-intensity compressional-wave (P-wave) signal that can be used for high-resolution seismic profiling and look-ahead imaging while drilling. Introduction Seismic-while-drilling (SWD) services provide operators with real-time depth correction of seismic records to improve drilling accuracy and placement of liners. Pore-pressure prediction ahead of the bit would provide substantial benefits as a result of the reduced risk of blowouts. Between 1960 and 1996, there were more than 30 blowouts per year in Texas, Louisiana, and the U.S. Gulf of Mexico. Seismic services offer the best approach to characterize formation pressures because of the substantial effect of pore pressure on seismic velocity. When integrated with other information (such as surface seismic, offset-well velocity profiles, and drilling parameters), it may be possible to predict pore-pressure levels at the bit and ahead of the bit. Through the Deepstar consortium, operators have developed the following criteria for pore-pressure-prediction services. - No delay of conventional drilling operations. - Prediction range of 1,000 ft ahead of the bit. - Accuracy better than 50 ft. - Provide formation velocities within 5% of a conventional wireline vertical-seismic profile (VSP) service. - Real-time prediction—defined as less than 10 hours. The service industry has developed a range of seismic techniques for seismic profiling and pore-pressure prediction. Existing practices include predrill seismic interpretation, wireline VSP, drillstring VSP, and drill-bit SWD. Predrill seismic surveys can provide an indication of velocity anomalies. The value of seismic surveys is limited by the large depth uncertainty, particularly in exploration areas. Wireline VSPs have been used to provide check-shot surveys using air-gun sources. On deepwater offshore rigs, the rig-time costs are high, and failure of the wireline may disable the blowout preventer, causing a loss of well control. Drillstring VSP is a relatively new service that is similar to wireline VSP except that the receivers are on the bottomhole assembly. An air-gun array is deployed from the rig and fired multiple times while a connection is being made. Data from receivers are stored in a memory tool downhole for processing after the bit run.

Determination of Stress Characteristics at Connections of Welded Members Using Finite Element Method

Tubular members are used in various structural members. They have a pleasant effect and good aesthetic values. They can be used in large roof structures, offshore rigs, pressure vessels, etc. The connection between tubular members normally involves cutting one of the members to obtain an exact fit, followed by welding of the two. This intersection becomes a point of high stress concentration, because of the different weld material present as well as the angle of intersection between the different elements. It can be a point of weakness especially in relation to fracture and fatigue. The state of stress here has to be obtained very accurately in order to design the joint accordingly. Finite element analysis provides one such tool. This paper attempts to provide an insight into how to obtain the three dimensional state of stress existing in the welded connection between two tubular members in an offshore structure. It is shown that results from finite element submodelling analysis are in good agreement with those from conventional parametric equations for the determination of stress concentration factor in tubular joints. Journal of Civil Engineering Research and Practice Vol.1(1) 2004: 21-31

Computational modeling of vapor cloud explosions in off-shore rigs using a flame-speed based combustion model

Abstract Computational modeling is a useful tool in determining the consequences from vapor cloud explosions. Here an approach that uses a flame-speed based combustion model is evaluated. Various scenarios of explosions in full-scale off-shore modules are simulated and compared to available test data. The ignition location of the cloud and available venting paths are found to affect the overpressure field in and outside the module. For end ignition cases, the combustion of gas pushed out of the module is found to play a key role. Using the flame-speed based model with appropriate effective flame speeds is found to provide accurate simulations.

From offshore rigs to pipeline transmission stations, KCH/Ceilcote combats corrosion

From offshore rigs to pipeline transmission stations, KCH/Ceilcote combats corrosion

Controlling Buildings: A New Frontier in Feedback

The protection of civil structures, including their material contents and human occupants, is without doubt a worldwide priority of the most serious current importance. Such protection may range from reliable operation and comfort, on the one hand, to survivability on the other. Examples of such structures leap to one's mind, and include buildings, offshore rigs, towers, roads, bridges, and pipelines. In like manner, events that cause the need for such protective measures are earthquakes, winds, waves, traffic, lightning, and-today, regrettably-deliberate acts. Indications are that control methods will be able to make a genuine contribution to this problem area, which is of great economic and social importance. In this article, we review the rapid recent developments which have been occurring in the area of controlled civil structures, including full-scale implementations, actuator types and characteristics, and trends toward the incorporation of more modern algorithms and technologies.

Controlling buildings: a new frontier in feedback

The protection of civil structures, including their material contents and human occupants, is without doubt a worldwide priority of the most serious importance. Such protection may range from reliable operation and comfort, on the one hand, to survivability on the other. Examples of such structures leap to one's mind, and include buildings, offshore rigs, towers, roads, bridges, and pipelines. In like manner, events that cause the need for such protective measures are earthquakes, winds, waves, traffic, lightning, and-today, regrettably-deliberate acts. Indications are that control methods will be able to make a genuine contribution to this problem area, which is of great economic and social importance. In this article, we review the rapid developments which have been occurring in the area of controlled civil structures, including full-scale implementations, actuator types and characteristics, and trends toward the incorporation of more modern algorithms and technologies.

‘Green money’ in the bank: firm responses to environmental financial responsibility rules

Financial responsibility rules are an increasingly common form of environmental regulation. Currently, the operators of landfills, underground petroleum storage tanks, offshore rigs, and oil tankers must demonstrate the existence of adequate levels of capital as a precondition to the legal operation of their businesses. Environmental financial responsibility ensures that firms possess the resources to compensate society for pollution costs created in the course of business operations. In addition to providing a source of funds for victim compensation and pollution remediation, financial responsibility is thought to motivate better decision-making, particularly regarding the management of long-term risks. This article describes firms' strategic responses to financial responsibility rules and their implications for the promise of financial responsibility as a complement to conventional environmental regulation. © 1997 John Wiley & Sons, Ltd.

‘Green money’ in the bank: firm responses to environmental financial responsibility rules

Financial responsibility rules are an increasingly common form of environmental regulation. Currently, the operators of landfills, underground petroleum storage tanks, offshore rigs, and oil tankers must demonstrate the existence of adequate levels of capital as a precondition to the legal operation of their businesses. Environmental financial responsibility ensures that firms possess the resources to compensate society for pollution costs created in the course of business operations. In addition to providing a source of funds for victim compensation and pollution remediation, financial responsibility is thought to motivate better decision-making, particularly regarding the management of long-term risks. This article describes firms' strategic responses to financial responsibility rules and their implications for the promise of financial responsibility as a complement to conventional environmental regulation. © 1997 John Wiley & Sons, Ltd.

Recent developments in offshore rig/ platform evacuation

During severe storms, evacuation systems for offshore rigs and platforms currently in use have proven themselves to be inadequate. Typically, during deployment of a lifeboat, it is often damaged to the point of not being seaworthy before it reaches the ocean surface. This is especially the case for cable-launched boats where a pendulum-like motion of the craft on its cables is often set up. It is less of a problem for free-fall lifeboats. Even when a craft reaches the ocean surface intact, high winds and waves can drive it back against the rig/platform structure. This paper describes the state-of-the-art of evacuation. It focuses on two new systems being developed by the authors in Newfoundland, Canada.

A Method for Handling Gas Kicks Safely in High-Pressure Wells

Summary The risk of overloading an atmospheric mud/gas separator (MGS) during high-volume gas kill operations can be minimized. This paper presents the theory and procedure for minimizing this risk for high-temperature/high-pressure (HT/HP) wells. The method can be used to set criteria for selecting the kill method and for separator sizing. Introduction The number of HT /HP wells being drilled in the North Sea has increased rapidly. Pressures >15,000 psi are common with associated temperatures>350°F. The drilling and exploitation of these reservoirs have been described as the new challenge to the drilling industry. However, serious well-control incidents have compelled the industry to re-examine the equipment and procedures used to drill these wells. This paper examines a major shortcoming identified recently: the ability of rig equipment to separate and vent large gas volumes from mud safely. Venting rates from kicks in high-pressure wells can approach the equivalent production of a commercial gas well. If the separator is overloaded, gas will be blown back into the shale shaker room and other mud-processing facilities, creating an extremely hazardous environment with a high explosion risk. Also, live crude, condensate, and drilling mud will be expelled by the gas through the gas vent line. On offshore rigs, where the vent line often discharges at the top of the derrick, the liquids will fall back to the drilling rig or platform. This creates a fire or explosion hazard. The volatile condensate/oil mixture will accumulate close to the deck in any void space and can be ignited by a spark. The hazards of MGS blowdown are apparent. High reservoir pressures and temperatures increase the surface gas volume per unit volume of gas influx. The ability of rig gas-processing equipment to handle such increased volumes concerns the industry. Normal practice does not take into account the limitations of the separator but instead concentrates on well control, assuming that the MGS can handle whatever gas volume is present. The problem is clear. As we continue to explore for oil and gas in deeper and higher pressure reservoirs, we often exceed the safe operating limits of the MGS. Separator modification and redesign has improved its capacity considerably, but space restrictions, especially on mobile rigs, impose an inherent limitation. Our lack of understanding of the complex separation process has done little to improve operating procedures and practices.