bluuebunny/crossref_metadata_2025 huggingface dataset:
Pipeline Failure Offshore California: Effective Oil Spill Response in an Environmentally Sensitive and Politically Charged Area
Authors: Rose David J.
Published: December 2007

An oil spill in marine waters offshore California can be a devastating and disastrous event. Many factors can be managed to minimize the environmental, political, and financial impacts from such a spill. Among these factors are preplanning, careful execution of a sound response, and proactive attention to the media. This paper examines these factors and others as they relate to a recent spill of 163 barrels of crude oil caused by a catastrophic failure of the 20-inch wet oil pipeline in the Point Pedernales field. In the end, the effort was hailed by agencies as a "text-book" response.
Protection of Sensitive Biological Habitats and Resources in Relation to Offshore Oil and Gas Development in the Gulf of Mexico
Authors: Rogers R. M. , Avent R. M.
Published: December 2007

The Minerals Management Service (MMS) has oversight responsibility for leasing, exploration, and development of submerged Federal lands on the U.S. Outer Continental Shelf (OCS). Pursuant to the OCS Land Act, as amended, the MMS Environmental Studies Program was initiated in 1973 to evaluate the environmental effects of oil and gas activities on the OCS. This paper is designed to present some of the environmental issues in the Gulf of Mexico (GOM). Emphasis is placed on several sensitive and important biological and habitat resources of special concern.

These include topographic features of the Western GOM, pinnacle trend of the Eastern Gulf, deepwater chemosynthetic communities, protected species, and coastal wetlands and barrier islands. Each resource is briefly described and the reasons for concern given, whether for legal and/or specific environmental considerations. These may include various mandates (e.g., the Endangered Species Act and the Marine Mammal Protection Act); high productivity, diversity, or biomass; aesthetics; refuge for important species (e.g., fisheries species); rarity or distribution; and vulnerability. Each resource is discussed with respect to past and present research activity, status of knowledge, types of petroleum activity deemed potentially harmful, and special governmental regulatory action required.

Special emphasis is placed on protection of deepwater chemo-synthetic communities. As oil and gas development has proceeded into deepwater environments, the potential of disturbing these fragile forms due to man's activities has increased. Research, largely funded by the MMS, has revealed dozens of sites having chemosynthetic animals that are well-established, high-density communities worthy of protection. In addition to their function as highly productive islands of life supporting a wide variety of life, they provide excellent natural scientific laboratories. Subsequent information on Gulf chemosynthetic communities led the MMS to require that industry protect them from the physical effects of exploration and production.
Rigs-to-Reefs Policy, Progress, and Perspective
Authors: Dauterive L.
Published: December 2007

The Minerals Management Service (MMS) has updated its policy affecting oil and gas platform abandonment and removal procedures that should facilitate efforts between coastal states and oil and gas companies in the development of better offshore Rigs-to-Reefs (RTR). Over the past 12 years oil and gas companies have donated 128 platforms for construction of reefs in the Gulf of Mexico (GOM). Through partial platform removals and the elimination of explosives in the RTR conversion process, companies can now conserve reefs with higher profiles and less trauma to platform-associated reef organisms. Providing the industry with more productive offshore disposal alternatives and options can lead to reduction of abandonment cost and preservation of environmental values, thereby generating more incentives to convert platforms to reefs. In addition to producing 100% of the gas and 97% of the oil on our Nation's Federal Outer Continental Shelf (OCS), GOM OCS platforms provide for the largest artificial reef complex in the world.
E&P Site Restoration in Sensitive Wetland Environments
Authors: Kudla M. S. , McDole B. W.
Published: December 2007

Four years after completing two exploration projects in the Sabine National Wildlife Refuge, Vastar Resources, Inc., recently conducted an evaluation of its wetlands restoration and enhancement efforts in the refuge. Close inspection of the project areas indicates that the company's restoration efforts were successful in promoting a healthy and vibrant wetland ecosystem, supporting a plant community composition and percent surficial coverage approximate to that of undisturbed marsh.

In this paper, the authors discuss the various techniques utilized in access road and drill site restoration that revitalized this sensitive wetland environment. Techniques discussed include: Maintenance of pre-existing water flows;Systematic selection and use of native soils to construct road dumps and ring levees;Protection of existing vegetative root networks;Improved indigenous seed bed preparation;Creation and use of ecotones to promote habitat diversity and increased wildlife production; andConversion of roadbeds and ring levees to nesting and resting habitat.

These techniques were employed as part of an ecosystem approach to wetlands resource management, involving the restoration of the multiple values and functional attributes of this unique ecological system.
In-Situ Characterization of Residual NAPL Distribution Using Streamline-Based Inversion of Partitioning Tracer Tests
Authors: Yoon S. , Barman I. , Datta-Gupta A. , Pope G. A.
Published: December 2007

Identifying the location and distribution of NAPL (Non Aqueous Phase Liquid) in the subsurface constitutes a vital step in the design and implementation of aquifer remediation schemes. In recent years, partitioning interwell tracer tests (PITT) have gained increasing popularity as a means to characterize NAPL distribution in-situ. In this method, a conservative and a partitioning tracer are injected into the contaminated site. The chromatographic separation between the conservative and the partitioning tracer can be used to infer NAPL distribution. The conventional approach to the analysis of the tracer response uses a first-order method of moments to compute average NAPL saturation. Such methods are limited due to the one-dimensional approximation and consequently can not provide detailed spatial distribution of the NAPL.

In this paper we discuss a streamline-based inversion approach for partitioning tracer response to estimate spatial distribution of NAPL saturation in the subsurface. Our approach relies on an analytic sensitivity computation method that yields sensitivities of the partitioning tracer response to subsurface parameters such as porosity, permeability and NAPL saturation in a single streamline simulation. We can then use efficient techniques from geophysical inversion to match the field tracer response and estimate subsurface parameters. For characterizing NAPL saturation we follow a two-step procedure. First, we match the conservative tracer response that provides us with a permeability distribution. Next,the partitioning tracer response is matched by varying the NAPL saturation distribution in the subsurface. The non-uniqueness in the solution is addressed through the use of regularization techniques and/or prior information.

The proposed technique has been applied to synthetic as well as field examples. The synthetic example is used to validate the procedure using tracer response from a 9-spot pattern. The field example is from the Hill Airforce Base, Utah where partitioning tracer tests were conducted in an isolated test cell with 4 injection wells, 3 extraction wells and 12 multi-level samplers. Tracer responses from 51 sampling locations are analyzed to determine permeability variations and NAPL saturation distribution in the test cell. Finally, a performance comparison with another commonly used inversion method viz. simulated annealing, shows that our proposed approach is faster by about three orders of magnitude.
Measurement of Solute Transport from an Earthen Reserve Pit During Drilling and Post Closure Operational Phases: Part I. Site Characteristics and Experimental Design
Authors: Deuel Lloyd E. , Hokanson Shawn , Holliday George H.
Published: December 2007

This paper reports the construction and experimental design of the first known instrumented earthen reserve pit. The instrumentation allowed the measurement of solute transport from a field reserve pit during drilling operations and after pit closure. The field study, conducted in Brazos County Texas, shows the limitations and advantages of the various instrumentation techniques utilized. Accordingly, other investigators can avoid use of inappropriate or unnecessary monitoring devices. Additionally, limited field data are discussed. The field study, which is the basis for this paper, consists of 3 parts: Site Characteristics and Experimental Design, Field Measurement, and Laboratory Analyses and Interpretation. This paper presents the Site characteristics and Experimental design for the reserve pit. No other field study attempts to capture solute migrating from a reserve pit, measure the chemical constituents and explain the mechanism impeding or excluding contaminant migration. The authors rely on lysimeters, soil moisture cups, monitoring wells, and electrical resistance sensors in obtaining the field data. The lysimeters and soil moisture cups function well. However, the moisture cups provide more useable data. The resistance sensors provided no useable data. Parameter analyses for soil cores taken in the pit area at pre-drilling and post-closure operational phases correlated well with soil water monitoring device data, substantiating the observations of insignificant solution migration. Further, the data are confirmed by analyzing monitoring well data over a period of more than 2 years.
Technical Solutions for Environmental Problems: Novel Drilling Formulations to Minimize Environmental Impact
Authors: Friedheim James E. , Patel Arvind
Published: December 2007

The use of synthetic-base muds (SBM) has increased steadily since their introduction in the Gulf of Mexico early this decade. Research into SBM has centered on assessing the likely environmental impact of cuttings discharges. This impact is potentially affected by various factors, not the least of which is the synthetic-base fluid itself, related to the chemical composition of the mud.

New technology in the form of synthetic mud formulations can further reduce the environmental impact of cuttings and the associated fluid. These novel formulations aid in pollution prevention associated with the discharge of drill cuttings into the receiving environment. These new technologies include: Unique emulsifiers that allow wellbore surfaces and cuttings to change from an oil-wet state to a water-wet stateNew synthetic-base materials that allow cuttings to disperse readily into the water columnNovel brine phases that benefit the disposal of cuttings via land farming

This paper discusses these approaches in formulating and engineering synthetic-base muds can reduce the overall environmental impact of a drilling operation.
Creation of an Integrated Environmental Information Management System for the Environmental Impact Evaluation of Petroleum Activities
Authors: Heintz John V. , Calinao Bernardita , Katkhouda Ryme
Published: December 2007

In both industrialized and developing nations, environmental impact assessment has now become a standard tool for project decision making. This paper proposes the creation of a Integrated Environmental Information Management System (IEIMS) to share environmental information gathered by participating companies and organizations. Data gathered during the completion of field studies and Environmental Impact Statements (EIS) would be submitted and made available to participating members through access to a secure website on the internet. The resulting system would reduce the time and cost of environmental data reproduction, make individual company/organization data available for public use and improve the efficiency of the EIS process through the minimization of many common challenges including: ◾The organization, management and integration of large volumes of information;◾The duplication of data collection for lack of a mechanism to efficiently store and share environmental data and facilitate access and manipulation;◾The difficulty in conducting time series analysis and ecological modeling◾Time constraints imposed during EIS preparation◾Vagueness and imprecision of environmental information
Impacts of the Alameda Corridor Transportation Project in Metropolitan Los Angeles
Authors: Ripaldi Carl Peter
Published: December 2007

Background

The Alameda Corridor is a consolidated railroad link between the Ports of Los Angeles and Long Beach and the regional and national rail systems linking the nation. The Alameda Corridor Transportation Project is a 32 kilometer (20 mile) rail corridor, centered along Alameda Street, extending from downtown Los Angeles to the Ports, within which is proposed a consolidation of freight railroad service to the Ports. Such service is currently being provided by the Union Pacific/ Southern Pacific (UP/SP) and Burlington Northern Santa Fe Corporation (BNSF) railroads (Figure 1). The Alameda Corridor Transportation Project has been developing over the past 14 years. In 1985 an Alameda Corridor Task Force was formed which in turn led to the creation of a joint powers organization called the Alameda Corridor Transportation Authority in 1989. A joint Environmental Impacts Report/ Environmental Impact Statement (EIR/EIS) was prepared for the project. The Final EIS was issued in February 1996, and a record of decision was issued in May, 1996.

The initial design work and EIS/EIR preparation commenced in 1991. A program management contract for work on the Alameda Corridor was issued to a joint venture team of four firms in the Los Angeles area; Daniel, Mann, Johnson & Mendenhall; Moffett and Nichol Engineers; Jenkins, Gales, Martinez Engineers and TELACU. The Alameda Corridor Engineering Team (ACET) is a joint venture of these four engineering companies that provides design engineering, environmental compliance and construction management services for the project.
Managing Peer Assists – Case Study of Improved Extended Reach Drilling Performance
Authors: Judzis A. , Stoltz D. S. , Wolfson L.
Published: December 2007

Drilling operations on the North Slope of Alaska are noted for best in class performance and innovations such as slim hole designer and multi-target wells. The opportunities for Extended Reach Drilling (ERD) are also enormous given the reserves that can be accessed in areas such as Niakuk field, Milne Point, Endicott and Prudhoe Bay satellites (Fig. 1). Continued development of the Niakuk field is almost entirely dependent upon cost effective high departure wells, however Shared Services Drilling temporarily suspended two wells during 1997 due to drilling problems.

As a result, Shared Services Drilling comprising BP Exploration and Arco Alaska staff conducted a ‘peer assist’ to review all aspects of their ERD operations from concept stage through well construction. Unique to the process were uncertainties in the problems to be solved as well as the accelerated pace dictated by the drilling schedule. The latter requirement was onerous and required a large group of ‘ERD specialists’. Contributing to the peer assist were partners, major suppliers as well as experienced ERD operations personnel worldwide. The overall purpose was to bring to bear the global ERD expertise from contractors and partners such that the risk of failure would be significantly reduced.

The holistic approach was highly successful in identifying the nature of the problems. This paper describes the methodology used to manage various projects recommended by the ‘examiners’ at the peer assist as well as specific outcomes related to ERD operations. The main areas of concern included wellbore stability, hole cleaning and hydraulics management, mud system optimization, tool integrity, and planning processes.

As a result of the post peer assist studies, drilling performance at Niakuk has improved. Current well plans now incorporate the major findings of the studies and more aggressive ERD wells including re-entry of the suspended wells are back on the drilling schedule. There is also an increased alignment of goals with partners, allowing increased planning time on ERD wells. Thus the significant attention to ERD as a project along with some staff adjustments has resulted in the development of a ‘center of ERD expertise’ in Alaska.
Deepwater Rig Anchoring: Key Lessons Learned and Ways Ahead
Authors: Foulhoux L.
Published: December 2007

Since 1996, the ELF Group has been involved in a number of deep water drilling campaigns, especially in West Africa. Converted rigs have been used and proved satisfactory. Structural modifications for increased payload and/or deck space, as well as subsea equipment and riser upgrades are all important issues to consider when upgrading a rig for deep water. But this paper will more specifically deal with another important issue which is mooring system upgrade.

The JIM CUNNINGHAM, operated by READING & BATES and the SEDCO S700 operated by SEDCO FOREX, have been under contract with ELF, to drill in WEST AFRICA in water depths between 600m and 1400m. Due to the particular configuration of each rig, different solutions have been adopted for mooring system upgrade, which are compared in the paper. Deployment method, anchor handling requirements and efficiency are discussed. In both cases, experience and co-operation between the drilling contractors and ELF teams brought significant improvement and optimisation into the preparation and into the performance of the rig moves. Key learning's throughout ELF experience of deep water anchoring are presented.

Now, for ELF to continue to drill extensively and deeper offshore West Africa, it has been necessary for us to investigate new mooring configurations and new mooring components. Since December 1997, the SEDCO S700 has been equipped with one polyester line inserted into the rig mooring system and taking its own share of the loads. Latest results of the instrumentation data processed are presented. In the meantime, ELF has evaluated the potential for doing preset mooring in West Africa. Great benefits of this method are discussed in the paper, through the analysis of various mooring configurations.
Application of Aerated-Fluid Drilling in Deepwater
Authors: Nakagawa Edson Y. , Santos Helio , Cunha J. C.
Published: December 2007

Underbalanced drilling (UBD) has proven to increase reservoir productivity in several areas around the world. Due to the advantages gained by using this technology, offshore application has also been increasing lately, but it has been restricted solely to fixed platforms. However, with the deepwater drilling trend in the industry, it is imperative that this technology becomes technically and economically viable for application from floater units as well. This paper presents the design and planning of an offshore well to be drilled with aerated-fluid technology. Although the operation is not planned to be underbalanced, the well will be the first one to be drilled from a floating vessel using aerated fluid technology. The paper describes the approach taken to overcome the challenges posed, including the involvement of several companies in a Joint Industry Project to speed up the learning process and the steps related to critical areas, mainly hydraulics and equipment. The article finally discusses the most important points that still need improvement to make UBD a reality in offshore operations from floating units.
Quantification of Economic Damages Resulting From a Breach of Joint Venture or Joint Operating Agreement
Authors: Acuna H. G. , Garb F. A.
Published: December 2007

Engineers are often called upon to quantify the economic consequences or "damages" suffered by one or more participants in a law suit, insurance claim or before an arbitration panel. The cause of such economic loss or damages may be the result of an accident or the overt action by one or more of the parties of the agreement or by third party intervention.

This paper presents the differences and applicability of two types of economic evaluations to estimate damages. The first method is the Fair Market Value (FMV) approach traditionally used in cases of confiscation or expropriation that may result from interventions from a third party outside the agreement. The second method is a Loss of Bargain (LOB) approach to estimate damages caused by breaches by one or more of the parties of the contract.
Using 3D Integrated Modelling to Manage the Fractured Natih Field (Oman)
Authors: Eikmans H. , Hitchings V. H.
Published: December 2007

A 3D full field dynamic simulation model was constructed for the fractured carbonate Natih field in northern Oman, and was used to update the long-term reserves outlook of the field. The field is presently being produced from a 30-m oil rim in the fractures by gas-oil gravity drainage (GOGD). According to the simulation model, further promoting GOGD by lowering the oil rim in the fractures will increase the cumulative oil production from the field over the next 30 years by about 8 million m3.

The basis of the dynamic simulation model is a detailed geological model for both the matrix and the fracture/fault network. These are combined into a fine grid 3D static model for the matrix and the fracture properties. In order to generate a coarse grid 3D dynamic simulation model an efficient upscaling route is constructed, which includes pseudo relative permeability curves, based on an analytically derived saturation profile for the gas-oil gravity drainage process. The resulting dynamic model represents the full 3D geometry of the field and all of the more than hundred wells. After analyzing the different flow processes and understanding their dependency on basic rock and fluid data and their contribution to the recovery, a very good match of overall field performance was obtained over the 30 years of production history. Although the 3D model was constructed to support and optimize field development in general, its first application was to revisit the 30-year ultimate recovery under fracture oil rim lowering.
API Filtrate and Drilling Fluid Invasion: Is There Any Correlation?
Authors: Santos Helio , Villas-Boas M. B. , Lomba R. F. T. , Sá C. H. M. , Oliveira S. F. , Costa J. F.
Published: December 2007

Filtrate invasion is one of the most important parameters to be controlled in a drilling fluid. Excessive filtrate invasion causes huge and, in some cases, permanent damage to the well. Among the main effects caused on a reservoir by excessive filtrate invasion are: difficulty, or sometimes impossibility, of identifying hydrocarbon reserves from logs and permeability reduction, that can turn an otherwise good well into a non commercial one.

Nowadays, the invasion properties of a fluid is usually estimated by the API filtrate test. However, this procedure uses a filter paper to simulate the permeable formation, what is not realistic, since the structure of real permeable formations is quite different from the one in that "porous" medium.

This work describes a simple rigsite test, very similar to the standard API filtration test, except for the fact that the filter medium is a sand bed, instead of the filter paper. A number of fluids commonly used in the oil industry were tested using both the traditional (API) and the new (BR) filtration procedures. The most important differences observed in the results are highlighted, clearly demonstrating that there is no correlation between the amount of filtrate collected from both tests.
Fracture Stimulation of Shallow, Unconsolidated Kern River Sands
Authors: Jones Jeff , Soler Diego
Published: December 2007

Texaco has been experimenting with a mini-fracture stimulation process to increase production in the Kern River Field of California. 33 wells have been treated to date with average oil production doubled. A recent fracture stimulation test performed with surface and downhole tiltmeters resulted in significant cost saving due to reduced treatment size and reduced fluid injection. Texaco is planning on extending the test of the process to the rest of the Kern River field in 1999.
Improved Static Mixer Design for Achieving Equal Phase Splitting at Pipe Junctions
Authors: Stoisits R. F. , Pinto M. T.
Published: December 2007

In many operations such as steam injection, production line splitting and simultaneous water and gas injection, it is desirable to split a stream of multiphase flow into two or more substreams. In these types of operations it is essential that all the sub-streams have the same gas/liquid ratio as the main stream.

A significant problem in multiphase flow splitting is the phase separation which occurs at branches in a piping 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.

The conventional practice for multiphase flow splitting is to mix the phases before the pipe junction. This is usually achieved using static mixers of the helix type. These mixers consist of an axial sequence of static propellers of the same diameter of the pipe in which they are located. The energy required to mix is provided by the moving fluid. Adequate mixing is often difficult to achieve in large diameter pipes with low mixture velocity.

An improved static mixer using packed bed technology was developed and tested in the laboratory with air and water. Laboratory results indicate this improved mixer can achieve equal phase splitting in 6" pipe with mixture velocities which are an order of magnitude lower than those required by helix type mixers.
Field Experiences with Stable Mul™, A Non Damaging Micro Emulsion Used as Drilling Fluid for Heavy Oil Formations in Venezuela
Authors: Zabala E. , Luongo A. , Parra E. , Méndez J. , Arocha J. , Carrasquero J.
Published: December 2007

The Stable Mul system is a unique water external micro-emulsion. The internal phase can be 60-80% hydrocarbon, with the preferred ratio being 70%. The basic components are: water, oil of any type (mineral, vegetal, diesel, polyalpha-olefins, etc.), emulsifier and stabilizers

Some characteristics of the Stable Mul system are:

Low density system (solid free), initial mud weight 7.4 PPG No formation damage Excellent carrying capacity. Stable to temperature up to 300°F.

The Stable Mul has been successfully used as drilling fluid for horizontals, verticals and multilateral wells. Up to August 1998, more than 100 wells have been drilled, some of them with horizontal section longer than 3000 feet. As Drilling fluid, Stable Mul increases R.O.P. with minimum or not risk of stuck pipe, lost of circulation or formation damage.

Wells drilled and/or completed with Stable Mul increased their production rate about 30 % in comparison to wells drilled with water base (polymer) or oil based mud. Due to the excellent results obtained with Stable Mul as Drilling, completion and work-over fluid in Venezuelan operations, we believe that this valuable experience needs to be shared with the rest of the world.
A Simpler, More Effective Method for Cementing Surface Casings in Shallow Gas Zones: A Case History
Authors: Abdul-Rahman R. , Rae Phil , Abdullah M. N.
Published: December 2007

Cementing the upper casing strings in wells that traverse shallow gas sands has often been a troublesome process. The top zones are often weak and this prevents the use of high-density slurries that are gas-tight. When a combination of low-density lead slurry and high-density tail slurry is used to reduce the hydrostatic to prevent lost circulation, the concentrations of cement additives required to make the lead slurry gas-tight are usually too high, and cost can be prohibitive. There are also problems associated with the use of the combination of extended lead/neat tail slurries. While such jobs are routinely done, the transition point where the cementers need to switch slurry density from low-density lead to high-density tail can be a weak link as far as smooth density control and job continuity are concerned. Eliminating this transition point potentially improves the entire operation by maintaining consistent slurry density, a parameter widely recognized as critical to cement properties.

This is done by utilizing a single, high-performance, reduced-density slurry that is made gas-tight by two additives, A highly efficient, filming fluid loss agent, combined with a lightweight, active particulate, provide both short and long-term gas stopping properties. This prevents primary gas migration and minimizes the risk of long term leakage due to secondary migration through the set cement column. The not-insignificant permeability of conventional extended cements is a key point that is often overlooked. Yet, it is the principal reason for gas build-up in the annuli of large numbers of wells. Considering the grave consequences of gas leakage around offshore installations, from the standpoint of safety, as well as environmental and economic concerns, any system that helps minimize the problem is advantageous. This paper presents case histories where the process of cementing surface casings in shallow gas was made simpler and more effective by the approach described.
Selective Hydraulic Fracturing of Multiple Perforated Intervals with a Coiled Tubing Conduit: A Case History of the Unique Process, Economic Impact and Related Production Improvements
Authors: Zemlak Warren , Lemp Stephen , McCollum Rick
Published: December 2007

This paper is a followup to SPE 46031, and will expand on economical shallow gas fracturing techniques utilizing a coiled tubing conduit. Hereinafter in this paper, the name CoilFRAC™ will used in place of the phrase ‘Coiled Tubing Conveyed.

The wells in the area of study are located in southeastern Alberta. The reservoir pay intervals in these shallow gas wells consist of high clay content, low permeability sandstones with interbedded shales. The wells in the study have multiple zones of interest and further discussions will be based on these multiple zones.

Due to the economics involved using conventional fracturing methods, the wells in this study have been treated with a unique multiple fracture program which allows access to typically bypassed pay.

Treating multiple zones in a given well within one day has given the producer a new realized ROI by reducing well production downtime and economically increasing production. This technique has been continually improved and modified through unconventional designs since 1996 to what is today a very effective routine method of stimulating and increasing production today.

The case study will define and present production and production logging data, relative to the associated costs, to demonstrate the impact this service has had on the operators' selection of workover candidates and new well optimization.

Coiled Tubing technology has provided an efficient and economic alternative to bridge plug and service rig type of zonal isolation techniques when stimulating more than one zone of interest.
Full-Scale Coiled Tubing Fatigue Tests With Tubing Pressures to 15,000 Psi
Authors: Headrick D. C. , Rosine R. S.
Published: December 2007

In recent years, the performance envelope of coiled tubing (CT) has expanded because of improvements in tubing manufacture and the prediction of low-cycle fatigue life. More accurate life predictions have been achieved with data from laboratory-scale and full-scale CT fatigue tests. To date, most testing has evaluated only tubing pressures below 10,000 psi. Fatigue models at higher pressures remain unvalidated.

This paper presents results from new, full-scale fatigue tests performed at 7,500 to 15,000 psi. CT with 90,000-psi minimum yield strength was cycled to failure at internal pressures of 7,500, 10,000, 12,500, and 15,000 psi. The measured fatigue-life values helped validate the fatigue model used for CT job design, and allowed the model™s further refinement.

Additional data are presented for full-scale fatigue tests performed with extended tubing-stroke lengths. This testing verifies the correlation between the tubing life observed in controlled, full-scale, short-stroke fatigue tests and the fatigue life observed in field applications with significantly longer stroke lengths. Measurements and analyses of tubing-diameter growth during high-pressure cycling are included.
Slimwell Concept – Innovative Coiled Tubing Completion Technology
Authors: Head Phil , Turner Dan , Cameron Gerald , Bottazzi Franco , Hanson Tim , Holst Tor-Kristian , Al-Rawahi Salim
Published: December 2007

This paper will present the results from a joint industry project (JIP) the object of which was to provide an effective solution to ‘slimming’ down the wellbore geometry whilst overcoming the associated drawbacks of slim annuli, such as surge and swab pressures during casing installation and circulation pressures while cementing.

The objective of the system is three fold;

First, to enable a conventional sized wellbore across the reservoir while significantly reducing the size of the upper hole and casing. Second, to enable an existing well with a 7″ casing/liner across the reservoir to be significantly deepened, maintaining the option for several casing points, and finally, The capability of an effective means of installing high integrity lateral liners.

The common approach throughout all of the well construction processes described in this paper is a series of liners, with tiebacks to previous liner tops as required.

With the current trend towards smaller riser and casing configurations, particularly in deep water operations, this innovative development now allows a broader range of options for well architects. A well with all the necessary casing points and contingencies can be accommodated within a jointed riser as small as 11″ internal diameter, whilst maintaining a hole size across the reservoir capable of significant production, well servicing and data gathering. Reeled drilling, reeled risers and the reeled well construction process made possible with this innovative development offers the real possibility of constructing low cost "Finder well" for exploration of hydrocarbons both in deep and shallow waters.
Laying Large-Diameter Coiled Tubing Offshore in the Arabian Gulf: A Case History
Authors: Sherwin Tom , Bauld Jim
Published: December 2007

The installation of offshore pipelines from a lay barge can be difficult, costly, and time-consuming. The barge generally proceeds along the pipe lay-path via winches that pull in on preplaced anchors positioned ahead of the barge. As the barge draws up to these anchors, the anchors must be periodically moved ahead and reset. Dynamically positioned ocean-going vessels temporarily equipped with coiled tubing (CT) equipment can help operators greatly reduce the complications associated with laying offshore flowlines. Recently, a service company specializing in coiled tubing operations worked with a major operator to lay continuous strings of 3,000 to 5,000 ft of large-diameter, coiled tubing flowlines between several offshore platforms in the Arabian Gulf. Modified CT well-service equipment was installed on a vessel equipped with dynamic positioning (DP) capabilities. A remote-operated-vehicle (ROV) and sonic transponders allowed operators to determine the location of the flowlines as they were placed on the seabed. Using this approach, operators successfully laid three lines in significantly less time and at a significantly smaller expense than would have been required by conventional barge-lay methods.
Optimizing Coiled-Tubing Training with Computer Simulation Modeling
Authors: Ross D , Kehler T. , Proctor R. , Campbell B.
Published: December 2007

To be a leader in coiled tubing technology today requires not only state of the art technology but also professionally trained operators and engineers. The coiled tubing service line within the petroleum industry is experiencing an exponential growth in technology. For example, the use of coiled tubing is frequently encountered in combination with other service lines such as drilling, cementing, stimulation, logging, well testing, et al. As demonstrated above, coiled tubing services are very much multi-disciplinary.

Typically, oilfield personnel have achieved their skill level from hard work and hands-on experience. However, in today's industry, hands on training cannot keep pace with the developments of coiled tubing related services. Due to the immeasurable costs associated with job failures attributed to human error or incompetence, it is essential that personnel receive the proper training to elevate them to the level of competence required.

One of the most outstanding accomplishments pertaining to coiled tubing training has been the implementation of coiled tubing simulators. A coiled tubing training simulator serves much the same purpose as a flight simulator does in the aeronautical industry. Students can run a coiled tubing unit and execute a real life well scenario while being challenged by a multitude of complications involving stripper leaks, BOP failures, tight hole, parted pipe, stuck pipe, etc. The main components of a coiled tubing simulator are the student station, graphics display, sound system, instructor facility and the main multi-tasking I/O computer. In addition to operating the main control consoles, the students are responsible for defining and graphically installing, function testing and pressure testing the proper surface equipment, coiled tubing string and BHA configurations required for the particular scenario. During a job simulation, the instructor can activate a multitude of problem situations that the student will need to respond to properly, to accomplish the pre-defined objectives. All of this training can be done in an accident free environment without the loss of well production or equipment. In one week of training a student may experience many different well control procedures that in the past may have taken years to experience.

The authors' intent of this paper will be to discuss the rapid growth of the coiled tubing industry and the demand for competent operations and engineering personnel required to implement emerging technologies. Secondly the advantages and process of implementing a competence based progression program to meet the personnel demand will be reviewed. Thereafter, the synergistic benefits derived from the utilization of a coiled tubing simulator to provide accelerated training and assess personnel competence levels will also be discussed. Lastly, an outline of a comprehensive coiled tubing training program, developed to compliment a competence based progression approach will be presented.
Sensitivity Analysis of Hole Cleaning Parameters in Directional Wells
Authors: Li J. , Walker S.
Published: December 2007

The major differences between conventional rotary drilling and Coiled Tubing drilling are the absence of pipe rotation and the continuous circulation of drilling fluids.

In rotary drilling the circulated fluid must be selected to support the cuttings while making a connection. In slide drilling, the circulated fluids can be continuously circulated. This capability greatly aids the use of gasified fluids in underbalanced drilling. In slide drilling, the pipe does not rotate; while in rotary drilling, the pipe rotation enhances the cuttings transport by the agitation effect due to the pipe rotation and vibration.

For a typical Coiled Tubing drilling job, the challenge is achieving the circulation rate required to keep the hole clean. Current field practice is to perform frequent wiper trips.

The economics of hole cleaning are crucial to the industry and therefore we seek answers to questions such as:

What is the change in the cuttings bed height when the fluids flow rates are altered? How long does it take to clean out an existing cuttings bed? Is there a need to remove the cuttings bed fully before resuming drilling?

In this study, 600 tests were conducted and a new computer program was developed for the prediction of cuttings transport in the multi-phase system (gas+liquid+cuttings). The sensitivity of cuttings bed height with respect to liquid/gas volume flow rate ratio, in-situ liquid velocity, ROP, inclination angle and circulation fluid properties was conducted. The hole cleaning time with both circulation mode and wiper trip is also discussed. The results from the sensitivity analysis presented in this paper indicate that: i) the fraction of the circulation liquid has a significant impact on the cuttings transport in underbalanced drilling with gasified fluids, ii) among different variables, the in-situ liquid velocity is the most important variable for cuttings transport, iii) the hole cleaning time decreases non-linearly with increasing fluid circulation rate.
Applications Engineering For Composite Coiled Tubing
Authors: McClatchie D. W. , Reynolds H. A. , Walsh T. J. , Lundberg C.
Published: December 2007

The addition of composites to the range of materials available for coiled tubing manufacture has raised a number of issues. An understanding of the advantages and limitations of this new material will serve to more clearly identify the niche for composite coiled tubing in oilfield service.

Current assumptions as to what diameter of coiled tubing is suitable for a particular application are no longer valid. The change in stiffness for any given coiled tubing diameter associated with a custom designable composite matrix requires careful modeling of all forces acting on the tubing during well interventions.

Hardware issues must also be addressed if a new tube material is to be integrated into the existing world wide coiled tubing fleet. Bend radius limitations related to product stiffness will have an impact on the suitability of existing reels and injector goosenecks. Field serviceable flush OD end and repair connections are necessary if composites are to approach the versatility of metal coiled tubing products.

Previous industry efforts have identified three principle applications for composite coiled tubing. Permanent wellbore installations such as velocity, production, and injection strings in harsh environments appear to be an obvious fit. Service strings for workovers also appear to be a good application due to the fatigue characteristics of composite materials. Composite tailpieces have also been proposed to take advantage of the best properties of both materials. The advantages and disadvantages of each application identified by modeling and hardware ultimately decide whether composites are more suitable than conventional coiled tubing materials.
The Reeled Monodiameter Well
Authors: Pointing M. E. , Betts M. J. , Bijleveld A. F. , Al-Rawahi S.
Published: December 2007

This paper examines the technologies required to develop a Reeled Monodiameter Well, a well using expandable coiled casing that maintains a single diameter of well bore throughout. However, a Reeled Monodiameter well will not be available to the industry tomorrow. Slotted expandable tubulars were introduced to the industry in the recent past and are now finding commercial applications. The concept of solid expandable tubulars for oil well applications is the next logical step of this technology. Joint Venture companies have recently been established to develop the concept of solid expandable tubulars and bring them to the market place. Consideration of the whole package reveals that there are various ways of achieving the end objective as described in this paper. There are still key technological challenges, notably in the areas of expandable casings, annular isolation techniques, over gauge hole drilling and novel hanger systems that will have to be addressed before this process becomes everyday reality. Possible solutions to these challenges are presented.
First Underbalanced Coiled-Tubing-Conveyed Perforating Operation Performed in an HP/HT Highly Deviated Well in East Venezuela
Authors: Villarroel Nelson , Almanza Edgar A. , Scott Martin , Vera Isidro , Fernandez Diego , Salazar Arquimedez , Gomez Luis
Published: December 2007

The technology for coiled-tubing-conveyed perforating (CTCP) under extreme conditions has been available for a number of years, but until recently, the techniques have not been used in Venezuela. This paper will describe the first experiences in which CTCP has been used in this area.

The first candidate identified for the application was a new well in East Venezuela. This well was the first high pressure, high temperature (HP/HT) highly deviated deep monobore well completed in El Furrial Field in the North Monagas area that was perforated underbalanced with this technology. Although several traditional perforating methods were initially evaluated, the decision was made to perform the operation underbalanced using rig-assisted coiled-tubing technology because of the following advantages that could be realized from use of this method:

Debris in the tunnel would be reduced, minimizing the potential for formation damage. The debris could be circulated out more easily. The use of kill fluid to control the well would not be necessary. By eliminating the cost of the kill fluid and the resulting costs of handling the returned kill fluid, well costs would be reduced.

The operation was performed in a live well with a 77-degree maximum well deviation and total depth (TD) of 17,907 feet.

Several engineering simulations were performed before the job. These simulations enabled the operator and service engineering personnel to quantify the effects of CT fatigue, lockup, stresses, forces, elongation due to weight and temperature, and buoyancy effects. Other important factors considered were safety, health, environment, quality and well control, taking into account all possible contingencies. Finally, nine (9) coiled tubing runs were performed to complete the well, a total of 1,190 ft of 3 3/8-in., 6 shots per foot (SPF) and 2 ¾-in., 6 SPF guns were run. In all of the coiled-tubing-conveyed perforating runs, the expended guns were retrieved successfully under live well conditions. To retrieve the guns without killing the well, a subsurface flapper-type safety valve, which enabled the operations to be performed under controlled conditions, was used.

Currently, the well is producing 19,621 BOPD through a 1-in. choke and 1,591 psi surface pressure.

Production and wellhead pressure expectations for this well were exceeded.
Force Transmission of Coiled Tubing in Horizontal Wells
Authors: Qiu Weiyong
Published: December 2007

This paper numerically predicts the force transmission of coiled tubing in horizontal wells. The overall friction factor, which is important for assessing the drilling feasibility of horizontal wells, minimizing the occurrence of lockup and other mechanical failures, can be predicted by using back calculation procedure. In the prediction of force transmission, three configurations of coiled tubing, i.e., straight, sinusoidal, and helical configurations, are taken into account.

A number of experiments were conducted by using TUDRP's (Tulsa University Drilling Research Projects) horizontal buckling facility to verify numerical predictions. The experiments involved applying a top load at one end of the pipe and measuring the bottom load at the other end simultaneously. As the applied load is increased continuously, straight, sinusoidal, and helical configurations can be observed. The predictions of force transmission match the experimental results reasonably well. This confirms the feasibility of back calculation procedure to predict the overall friction factor and the accuracy of theoretical contact force.