bluuebunny/crossref_metadata_2025_split huggingface dataset:
Opportunities to Improve the Success Rate of Coiled-Tubing Operations
Authors: Engel S. P. , Mackey P. 
Published: December 2007

Abstract
Coiled tubing has been an invaluable tool to the oil and gas industry for some forty years. Each time that coiled tubing is rigged up and run into a well it carries with it a risk that the objective of that run will not be met. This paper analyses that risk based on some two years continuous records in the Asia Pacific Region and finds that the average rate of a successful run is 82% over a 23-month period. A database of about 1200 runs demonstrates the type, cause and frequency distribution of failures. Risk management options are reviewed and potential solutions offered.
The cause of failures is most frequently attributed to unknown well conditions. However, inadequate job planning, operator errors and equipment failures also have a significant contribution. The levels of technical complexity demands are escalating. In balance, there are increasing operational skill levels, equipment reliability improvements and a better focus on pre-job planning. This, then, tends to hold the status quo at a constant frequency over time. In order to increase the rate of success, lowering the difficulty of the jobs attempted and/or increasing the operating and equipment reliability will be required. Simplicity and reliability tend to go hand in hand. However, there is a general industry temptation to over-engineer and overcomplicate both the work scope and the equipment. The result may be viewed as unreliable and perhaps, not cost effective coiled tubing solutions.
The opportunity exists to significantly reduce the run failure count. This could be achieved by lowering ambitions and allowing equipment and skill levels to ‘catch up’ with established industry coiled tubing solutions. It then raises the question "Is it better to do something simple well or to risk failure with technical ambition?" This paper concludes that the current failure rate can be improved upon with various corrective actions. This is essential in order to progress to further technical advancements.
Improvements in Coiled-Tubing Window-Milling Operations Cut Costs and Increase Reliability, Prudhoe Bay, Alaska
Authors: L. Jeffrey , Johnson Bryan , Wilson Steve , Luckey Kenneth J. , Collins William 
Published: December 2007

Abstract
The original through-tubing window milling procedure was designed to run through 4-1/2" tubing, milling a window in the 7" casing below the tubing tail. The window was milled off a pre-set mechanical whipstock that was set on electric line before the coiled tubing unit was moved over the well. It generally took 2 to 3 mill runs before an effective exit window was obtained in the 7" casing.
The goal of the project was to obtain an effective one-trip window exit. The milling assembly had to reduce the torque and work effectively with minimal weight on bit to allow deployment on 1-3/4", 2" and 2-3/8" coiled tubing. By milling the window in one trip versus 2 trips, approximately 12 hrs of rig time could be saved.
Coiled-Tubing Cement Squeeze in Colombia's Casanare Field
Authors: Tarazona F. , Stephens R. , Crow W. 
Published: December 2007

Abstract
This paper discusses recent coiled tubing (CT) cement squeeze planning and operations conducted in the Casanare Field in Colombia. Zonal isolation for gas shutoff was identified as a critical factor to help reduce the GOR for wells that would otherwise shut in due to gas handling limits of the production facility. The planning phase included a cement laboratory audit that was used to identify the reason for discrepancies of the cement design between the laboratory conditions and the full scale mixing trial. Voltage variation during laboratory tests was identified as a major factor which affected the mixing energy. Another source of discrepancy between the laboratory results and the sample batches with field equipment was the amount of energy imparted to the system by use of centrifugal pumps. Cement design properties were critical to achieve sufficient thickening time and filter cake quality in the presence of relatively high reservoir temperature and reduced formation pressure. Discretionary disposal of several batches of cement was required until those design parameters were met. Communication and crew training were fundamental to identifying and resolving problems, especially in an area that had not yet conducted this type of operation.
Automating Candidate Selection for Coiled-Tubing Drilling
Authors: Brown M. , Nas S. , Lusted I. 
Published: December 2007

Abstract
As fields are becoming more mature and improved reservoir interpretation is identifying so-called "By-passed" hydrocarbons, more sidetracks will be required. Selecting a well to reach a certain target in the reservoir can be a long task as a number of issues have to be considered. Using an auditable process for selecting the optimum sidetrack method and the best wellpath to reach a certain target can take a drilling engineer several months on a multi well development. In order to optimise this process all of the relevant parameters have to be considered. An automated system using a database now allows quick identification of the correct sidetrack method and selects the most suitable wellpath for the sidetrack. This fully transparant method starts with the reservoir target and then works through all the issues associated with the well selection process.
This paper describes the Candidate Selection Methodology, examples of the criteria utilised to evaluate the suitability of the Drilling Technique and examples of the speed of Selection for a candidate Well and the output of the process.
A Comprehensive Model and Computer Simulation for Underbalanced Drilling in Oil and Gas Wells
Authors: Fan Jun , Gao Changliang , Taihe Shi , Liu Huixing , Yu Zhongshen 
Published: December 2007

Abstract
This paper presents an advanced dynamic model and computer simulator for underbalanced drilling. The model is formulated based on the theory of multiphase transient flow referring to the drilling mud, water, oil, gas and solid particles. All the important factors affecting underbalanced drilling have been taken into account comprehensively in the model, including IPR relation, physical properties and mass transfer behavior of fluids, flow regime and phase migration features, geometry and deviation of wellbore as well as the different operating modes which may be carried out in practical underbalanced drilling.
A specific numerical approach is adopted for solution of the theoretical models and on the basis, an advanced computer simulator is developed for undertaking simulation, study and planning of underbalanced drilling operations. The computer simulator differs from existing simulators because it is fully dynamical and interactive with users. Researchers and users can change different operating modes according to their will at any time during simulating process just as they are really performing an underbalanced drilling operation. The simulator can track all the complicated and complex conditions in underbalanced drilling process, and all the related parameters and profiles of parameter distribution along wellbore at any time can be shown dynamically.
Through a number of simulating computations, tests and verifications, it is shown that the model and simulator are valid and in accordance with actual drilling practice under different and complicated conditions. It is of great importance for consummating underbalanced drilling theory and on the spot application. A typical simulation result and case study are also presented in the paper.
Experimental Study on Carrying Capacity of Cuttings in Annulus for Air/Mist Drilling
Authors: Liu Huixing , Fan Jun , Yan Renjun , Yu Zhongsheng 
Published: December 2007

Abstract
Nowadays the use of air and gas as a circulating medium for drilling oil and gas wells is becoming an attractive practice because of its great advantage over conventional mud drilling. However, the occurrence of some troubles due to poor carrying capacity of cuttings in air/mist drilling is not uncommon. Meanwhile, the determination of air/gas injection rate desired to undertake air and gas drilling is also closely related to the actual moving regularity of cuttings in annulus. It is obvious that researches on migration rate and carrying capacity of cuttings within borehole are essential to air/mist drilling. Although there are some theoretical models for prediction of cutting migration velocity and therefore the carrying capacity of cuttings, experimental studies are also essentially important because of the complexity of actual liquid, gas and solid multiphase flow in wellbore and the uncertainty of theoretical models. In this paper, some experimental studies were performed to investigate the moving regularity and carrying capacity of cuttings in wellbore. Some comparisons between the testing results and theoretical models are also presented in the paper. It is seen that such a study is valid and effective in prediction of the migration velocity and analysis of the motion regularity of cuttings in borehole. Therefore, the required practical air injection rate to keep the necessary carrying capacity in air/mist drilling can be determined definitely.
Integrating Technological and Financial Uncertainty for Offshore Oil Exploration: An Application of Multiobjective Decision Analysis
Authors: Suslick Saul B. , Furtado Ricardo , Nepomuceno Francisco 
Published: December 2007

Abstract
Oil companies are presently facing a competitive scene due to high pricevolatility and increasing complex decisions. In this scenario, firms shouldhave adequate decision tools to evaluate cost and benefit impacts from thefinancial, environmental, technological, and market factors. This paperdescribes a methodology where a decision-maker explicitly considers twoobjectives when evaluating new petroleum opportunities in an offshore area-financial and technological gain. The Multi-Attribute Theory (MAUT) is usedsimultaneously to consider the technological challenges of the capitalbudgeting process in an exploration and production firm. Prospects from fivedifferent basins in an offshore area comprising distinct risk and objectiveswere selected for the proposed study. The methodology presented in this workdemonstrates that in some mature areas the advantages to exploration arerestricted further only to financial gain, based upon the present economicpotential of the basin. On the other hand, other seemingly less attractiveareas, such as deep horizons in deep-water basins, may represent potentialtargets for new exploration as a result of the interaction of financial gainand technology advancement. The proposed model can provide significant insightinto petroleum exploration and guide managers to better investment decisions aswell as provide information to decision makers regarding the efficiency oftechnological gain at the firm level.
A Methodology to Collect and Assess Data for Characterization of a Company's Hydrocarbon Resource Base
Authors: Bolling John D. , McKee Michael L. , Reiter Doris F. , Freeman Stephen C. 
Published: December 2007

Abstract
This paper describes a systematic, consistent methodology to collect reserve and economic information for characterizing a company's oil and gas resources. The authors firmly believe value is realized, both internally and externally, by being able to effectively characterize a company's hydrocarbon resources. The methodology is comprised of four elements: resource definitions, tying resources to production forecasts, valuing resources, and assessing uncertainty. A data collection process is outlined so that the same data can be used for multiple purposes including long range planning, portfolio management, regulatory reporting, reserve management, technology planning, and establishing performance targets. Finally, implementation issues associated with developing a company hydrocarbon resource characterization are reviewed. The paper is a summary of processes developed by ARCO from 1998 to 2000 to better characterize company resources and manage its portfolio of assets.
Sustainable Growth Journey
Authors: Abbott Robert E. , Unruh Gary L. 
Published: December 2007

Abstract
Conoco believes that sustainable development is a comprehensive way of approaching business to ensure that financial excellence is achieved in concert with environmental performance and social responsibility. It is not just a fad to be considered today and forgotten tomorrow. A culture based on four "core values" of environmental stewardship, safety, valuing all people and business ethics has provided a strong foundation for our commitment to sustainable development.
Conoco has been involved with activities and initiatives around the concept of sustainable development for a number of years. Conoco is an active member of the World Business Council for Sustainable Development (WBCSD) and a founding member of the Gulf of Mexico and North Sea regional Business Councils for Sustainable Development. In 2000, the company has earned the distinction of being a component of the Dow Jones Sustainability Group Index, which tracks the performance of the top 10% of sustainable companies in the world. Oekom Research AG also ranked Conoco number one in 2000 among 23 energy companies in corporate responsibility.
Sustainable development efforts have been focused upon: (1) Improving the sustainability of existing operations, (2) Expanding beyond traditional hydrocarbon businesses, (3) Integrating sustainable development into core business strategy and engaging stakeholders, and (4) Fostering innovation and technology to achieve sustainable growth. A managerial position was created to assist leaders in developing mindsets that will enable sustainable growth. Tools for measuring performance against sustainable development criteria are under development and outside resources are sought to help broaden our perspectives. Operations around the world are identifying better, more sustainable ways of doing business that meet the "triple bottom line" of financial, environmental and social accountability. In addition to evolving business approaches, technology development in areas of carbon fibers, natural gas refining, and environmentally enhanced motor fuels offer exciting prospects to meeting future energy and resource demands. In September, 2000, the gas-to-liquids (GTL) project team was selected by the U.S. Department of Energy as a recipient of an R&D grant under their "ultra-clean fuels" program.
While proud of our leadership role, Conoco is by no means satisfied that we are where we need to be. Our approach is to obtain competitive advantage by growing sustainable businesses and adopting a corporate policy and strategy to achieve this objective.
Estimating kv/kh Ratio for Conductive and Nonconductive Shales and Mudstones
Authors: Kasap Ekrem 
Published: December 2007

Abstract
Numerical simulations require homogenized grid block properties. Often depositional processes build up high, low or no permeability units even on a grid block scale. Anisotropy is a result of homogenization of these laminations and other types of heterogeneity. kv/kh ratio is a measure of anisotropy in absolute permeability. A robust kv/kh ratio is essential for accurate field performance predictions.
Some kv/kh ratio calculation techniques were suggested in the literature for stochastic non-conductive shales. However, the lack of more generalized and simplistic techniques for 3-D numerical models is apparent
In this study, we developed Streamlines, Incomplete Layers, and NTG (Net to Gross) techniques to calculate kv/kh ratio of a 3-D grid block with conductive and non-conductive flow-barriers. A typical numerical grid block was populated with sand and shale intercalations from zero to more than 25% shale volume. kv/kh ratios for 15 cases were calculated with the above analytical techniques. Two shale permeabilities, l.e-4, and 4.0 mD were considered. 15 cases were simulated and results were compared. The comparisons indicate that the analytical methods all gave similar results to numerical kv/kh ratios for impermeable shales. Only Incomplete Layers and NTG techniques yield acceptable results for permeable shales. A field case history match, where NTG technique was used, was also presented.
Producing the Well in Artificial Lift By a Subsurface Compensated Pump: A New Production Method
Authors: Buchman Smil S. 
Published: December 2007

Abstract
This paper presents a new production method in which the reservoir energy spent to lift the production from perforation-depth to the dynamic liquid level is replaced by surface energy, and consequently the well daily rate and cumulative production is increased by 200 – 250 %. The method can be used in any well at any time.
The paper is based on the analysis of how the reservoir energy generated by the expansion of the reservoir fluids is used to produce the well:
PROFITABLE USAGE: Moves the production through the pay zone into the well bore.
WASTEFUL USAGE: Sends the reservoir energy to:Overcome the liquid friction along the production flow path.Lift the production from perforation-depth to the dynamic liquid level.
Present production practice recognizes and reduces only the reservoir energy wasted to overcome the liquid friction through the pay zone by using better and cleaner perforations, acidizing, fracturing, and other techniques. When less reservoir energy is used to overcome the frictions through the pay zone, the well performance, in both rate and cumulative production, is increased.
To date all artificial lifting methods are spending surface energy only to lift the production from the dynamic liquid level to the surface. However, the energy needed to lift the production from perforation-depth to the dynamic liquid level, the largest waste of reservoir energy, is now overlooked and has not been recognized as the most important way to significantly increase well performance. The proposed new production method substitutes the reservoir energy by surface energy in order to lift the production from perforation-depth to the dynamic liquid level. Accordingly the well performance in day rate and cumulative production is increased by 200 – 250 % compared to the actual well performance.
The quickest and easiest way to produce the well according to the new production method, is to run a subsurface compensated plunger pump assembled from the API Spec-11AX parts, and work with the same beam pump. A subsurface compensated pump, is a liquid lifting device, which can not be drawn by the well pressure.
Competency Ingredients for the Successful Petroleum Professional in the New Millennium
Authors: Fattahi B. , Riddle S. O. 
Published: December 2007

Abstract
Against a background of mergers and acquisitions, lean organizations and business demands, today's working environment has become more diverse and far more challenging. Globalization of the industry, the advent of instant communication, and rapidly developing technology, more than ever require today's petroleum professionals to maintain their technical competence, broaden their experience, and constantly adapt to the fast paced work environment. The attributes of petroleum professionals in the new work environment will be different from the traditional ones. Now a host of so-called "soft" skills have gained prominence in today's business environment. Technical competence will be defined by how well results are achieved through effective teamwork, leveraging diversity of perspectives and critical thinking and creative problem solving. Petroleum professionals who can quickly learn and develop these competencies will be in a better position to compete for the most attractive job opportunities.
This paper analyzes the workplace expectations for petroleum professionals and proposes the competency ingredients for career success in the New Millennium.
Massive Propped Fractures to Develop Marginal Sandstone Gas Reservoirs
Authors: Orski K. , Combellas R. , Bagherzadeh B. 
Published: December 2007

Abstract
The Pole-du-Nord Project, offshore Netherlands, covers the joint development of four small Lower Slochteren dry gas bearing sandstone reservoirs. The development scheme is the result of extensive studies to mature an optimized project, taking into account the limited size of the fields, the poor petrophysical characteristics and the reservoirs uncertainties. These fields are located within a circle of 3500 meter (11 500 ft) of radius. The target zone is 60 meters (200 ft) thick and 3700 meter (12000 ft) deep.
Extensive subsurface studies demonstrated that the poor productivity of the exploration wells was explained by facies variations due to sedimentological deposit history. The sedimentary pattern is a mixed fluvial, aeolian deposit that leads to a very heterogeneous multilayered reservoir. The horizontal permeabilities range from 0.01 to 40 mD but the main reserves are located in the poor but thickest fluvial facies, with permeabilities from 0.1 to a 0.5 mD. The drainage of each gas pool by one well was proven with specific stochastic geological modeling constrained by DST results and full field flow simulation.
The development with one central platform was by far the most economical solution. The key factor was the well productivity enhancement.
Various possibilities to enhance productivity were screened, including a horizontal multi-fractured well. The selected solution which honored all the constraints (technical feasibility, minimum cost, initial rate and reserves whatever the reservoir heterogeneity) was a massive fracture treatment on two wells out of the four. The target fracture length was 50 meters (820 ft). The uncertainty in the stress distribution across the reservoir made frac height growth prediction tricky and led to several provisional treatment scenarios.
The target drawdown on reservoir was 200 bar, which made the resin coated proppant selection a crucial point.
The S shape profile was also a drilling challenge regarding the departure of these wells.
This paper presents the project reasoning process, the treatment preparation (including a specific care on the fluid formulation and its interaction with the resin coated proppant) and the fracture evaluation.
The project is a technical and economical success. The lessons acquired in Pole-du-Nord will be a reference for further marginal gas field development in this area.
CO2 Acidizing Treatment of a Deepwater Subsea Well without Intervention
Authors: Buie Paul , Ritter Wes , Ellis Richard C. 
Published: December 2007

Abstract
An openhole gravel-pack completion was performed in the vertical section of a high-permeability oil formation in a deepwater subsea well. The openhole section was drilled with a synthetic oil-based drill-in fluid and completed with a circulating gravel pack using weighted brine.
Initial production was satisfactory at over 10,000 BOPD. However, 11 months later, after a constant decline in production, the well was producing at an unacceptable rate of 3,000 BOPD. Analysis of the formation mineralogy from an offset well in the same formation indicated a strong tendency for fines migration. In addition, there was concern that filter cake from the synthetic drill-in fluid could still be in place and would provide some restriction to optimum production rate. A HF sandstone acidizing treatment incorporating a CO2 preflush process for matrix oil well stimulation was recommended.
Since the well was a deepwater subsea completion, a rig intervention would have been extremely expensive. Therefore, the possibility of performing the matrix CO2 treatment through the flow line from the TLP floating production facility was reviewed and determined to be feasible.
Procedures incorporating the use of the permanent downhole pressure gauges for rate and pressure control resulted in restoring a sustained production rate of 7,000 BOPD. The procedure and steps used for determining and executing the final treatment design will be presented.