bluuebunny/crossref_metadata_2025_split huggingface dataset:
Finding a Needle in a Rusty Hay Stack… Knowing Where to Start With 30,000km of Pipelines!
Authors: Petersen A. G. , Sivokon I. S. , Webster S. , Lane D. 
Published: December 2007

Abstract
TNK-BP plans to invest a significant amount of money in improving the integrity of its pipeline network over the next 5 years. The question that needed to be solved is where do we start? With a pipeline network that consists of over 43,000 individual lines that have a combined length of over 30,000 km selecting the right pipelines to replace, inspect and inhibit is not a trivial task. The task is made even more difficult when it is considered that when TNK-BP was formed it consisted of 600 legal entities, which did not have common processes and ways to store data. To address this problem a risk model was built which used data that could easily be collected for the pipelines in the company. After testing in the Volga-Urals and West Siberian regions the company then undertook a large data collection exercise. Using the risk model all pipelines have been ranked according to their probability and consequence of failure, and the data has been used to ensure that the investment in pipeline replacement, corrosion control and inspection are targeted to the areas where the biggest impact can be made. The exercise has also made it possible to understand how much investment may be required, because there is now a clear picture of the lengths of pipelines that have experienced failures. Pipeline prioritisation has answered the question where do we start, and is also helping us to answer the next question – when will we get there?
Evaluation of Activity Coefficient Models in Prediction of Wax Appearance Temperature
Authors: Ghanaei Ehsan , Esmaeilzadeh Feridun , Kaljahi Jamshid Fathi 
Published: December 2007

Abstract
In order to prevent wax formation phenomenon, it is essential to be able to predict the cloud point temperature by using a reliable thermodynamic model. The description of the solid phase non-ideality is the main obstacle in the modeling of the solid-liquid equilibrium of hydrocarbons.
In this work, 25 combinations of five models (regular solution theory, UNIFAC, predictive UNIQUAC, predictive Wilson and ideal solution model) for the description of solid and liquid phases have been surveyed to get the best results near the experimental data without using any adjustable parameters. For validating the models, ternary, quaternary and multi-component systems as the experimental data have been used.
The results show that for the C14-C15-C16 ternary and multi-component systems, the best models are predictive Wilson-regular solution and predicitve Wilson-predictive UNIQUAC, respectively, for the description of non-ideality behavior of solid and liquid phase. For the C18-C19-C20 ternary and quaternary systems the best models are predictive UNIQUAC-UNIFAC and predictive UNIQUAC-regular solution, respectively, for the description of solid and liquid phase behavior. These models, in comparison with multi-solid models, show better agreement with the experimental data.
Eliminating Additional Drilling Expense Due to Well Stability Problem in Laminated/Fractured Nahr Umr Shale Formation
Authors: Waragai Tatsuhiko , Yamamoto Koji , Tokuda Noriyuki 
Published: December 2007

Abstract
The wellbore stability problem of Nahr Umr (N.Umr) shale formation was the major drilling problem in an offshore field in UAE. The stability problem in the field was much severer than that in other offshore fields in UAE.
The stability problem had become worse since year 1997, when the usage of diesel in water-based drilling mud as a lubricant was prohibited for environment protection. To tackle the stability problem, mud weight was increased as the conventional method to avoid shale caving, which was successfully applied in the other fields. However, the problem could not be solved.
Accordingly, "Joint Study of N.Umr Shale Instability Problem" was commenced in year 2002. The historical review for actual drilling records since year 1991 was conducted to estimate the possible root cause of the stability problem. Intensive data acquisitions such as open hole logging and coring were performed, and the obtained data were used for chemical and mechanical analyses to recognize the nature of the N.Umr in the field. A geo-mechanical model was developed based on the analyses, and the mechanism of the stability problem was identified by simulations using the model. The following main findings were found out through the study;
The N.Umr shale in the field is laminated/fractured. The stability problem occurs due to the mud penetration into laminations/fractures, which causes the mechanical failure. Increasing mud weight is not a solution for the N.Umr in the field. Effective hole cleaning is another key factor, since the hole angle of the wells in the field is in most critical range for hole cleaning (30-50 deg.).
A new operation guideline was established based on the study results, and has been implemented since June 2004. No well sidetracking due to the stability problem has occurred after the implementation, while additional expenses were spent due to well sidetracking in years 1999-2003.
This paper describes the history of the shale stability problem in the field, the summary of the joint study, the new operation guideline and the actual operation results after its successful implementation.
Dynamic Production Optimization in Khafji Offshore Field
Authors: Ghoniem E. O. , Al-Khaldi M. A. , Samizo N. , Al-Thuwainy A. 
Published: December 2007

Abstract
The gas lift, by limited capacity of 25 MMSCF/D, was introduced for Khafji field in 1988 which could successfully sustain target rate until mid of 2004. Even though, additional artificial lift energy was planned as long term solution due to the increase of field water cut and depletion of reservoirs, production optimization was found to be the best way to sustain field target until commissioning of these new facilities. For that purpose, general optimization and gas lift allocation models have been built and applied for Khafji field as presented by Ghoniem et al1.
Although, production system modeling is a powerful technology to optimize and understand the whole production system, the individual well modeling hence dynamic nodal analysis and the reliable field measurements are still highly contributed to increasing oil rate. Consequently, the present work is a further and more comprehensive optimization study for Khafji crude production by:
Updating the previously built optimization models Screening for new effective wells for gas lift operation Review the design of existing gas lift installations Optimizing the choke size for many natural flow wells Practical adaptation to the dynamic process of production optimization.
As a result, several high productivity wells were selected and put recently on gas lift operations, also gas lift re-design was made for many wells. Furthermore, wellhead choke size was optimized for many natural flow wells. As a result, a significant marginal oil gain was obtained and confirmed by field measurements. Also, a lot of recommendations for gas lift operations and for mature oil fields were concluded.
Use of the NMR Diffusivity Log To Identify and Quantify Oil and Water in Carbonate Formations
Authors: Di Rosa D. , Gyllensten A. , Li W. , Georgi D. , Tauk R. 
Published: December 2007

Abstract
We report a successful example using the 2D NMR technique for determining oil-water contact (OWC) in difficult carbonate environments. We applied an NMR diffusion-based interpretation method to identify oil, water, and transition zones and to quantify the oil saturation in a limestone reservoir. Hydrocarbon typing and saturation determination from NMR logging usually require high contrasts of intrinsic or apparent relaxation times and/or diffusivity. Many carbonate reservoirs in the Middle East contain large-sized pores, which coupled with low relaxivity of carbonates results in long T1 and T2 times for water. Further, because light oil has a long relaxation time, there is little T2 contrast and small polarization contrast between water and oil. When these reservoirs contain very light or high-GOR oils, the diffusivity contrast between oil and water is also less pronounced. Hence, it is difficult to distinguish between the oil and water signal with most NMR hydrocarbon typing techniques. The example shows that a diffusion log reconstructed from 2D NMR interpretation works well even for marginal diffusion contrast cases. Furthermore, we present a modification to the Coates permeability model that is applicable to carbonate formations having partially connected vugs.
Restoring Well Integrity in a Critical Gas Pilot Injection Well
Authors: Al-Ashhab Jamal K. , Khan Naeem , Boyd Douglas 
Published: December 2007

Abstract
Appearance of abnormally high pressure in the 9 5/8" X 13 3/8" casing annulus of a pilot gas injection well located offshore Abu Dhabi, alerted staff to a potentially serious situation from both safety and economic viewpoints. The subject well is a critical component of a pilot project to test the effectiveness of gas injection towards improving oil recovery. Based on this and other data, decisions on long-term reservoir development involving considerable investment will be made. The well was drilled and completed in 1999 as dual gas injector into two, Lower Cretaceous limestone reservoirs and put under gas injection in 2001. Abnormally high pressure was observed in the 9 5/8" × 13 3/8" annulus after three months of injection. A multidisciplinary task force was formed with a mandate from senior management to locate the source of leaking gas, the communication path to surface and recommend remedial actions. A risk assessment ranked the danger to the 80 million U.S. dollar platform and personal as high. As a result, gas injection was halted and visits to the platform minimized. Evidence gathered from the well records and newly acquired diagnostic logs suggested the existence of poor or no cement behind the 7" liner and 9 5/8" casing providing a conduit for gas to surface. Moreover, the existence of two abandoned holes penetrating the shallowest reservoir and located at short distance from the currently active bore hole were recognized as potential pathways for gas to surface. Extensive remedial cementing operations were performed including: (1) block squeezes behind one and two sets of production casing above the source reservoir, (2) cement circulation squeeze between production and intermediate casings through mechanically drilled holes. The high annulus pressure was thought eliminated but soon returned after injection commenced. A decision was made to convert the nearby un-perforated Gas Observer to water injection for the shallowest reservoir and continue gas injection into the deepest reservoir of the original well.
Techniques Used to Monitor and Remove Strontium Sulfate Scale in UZ Producing Wells
Authors: Al-Ashhab Jamal , Al-Matar Hassouneh , Mokhtar Shahril 
Published: December 2007

Abstract
Scale deposition in completion strings is becoming a threatening problem to produce and safely operate wells completed in the Upper ZAKUM (UZ) oil field. Calcite or Calcium Carbonate (CaCO3) scale mostly found in the upper part of the production string, and Celestite or Strontium Sulphate (SrSO4) mostly found in the lower part of the production string, are the common type of scales encountered in Upper ZAKUM producing wells. Injection seawater (rich in Sulphate) and formation water (rich in Strontium ions) mix in the reservoir and/or wellbore under varying conditions resulting into Strontium Sulfate Scale formation in downhole equipment. While CaCO3 scales are possible to be removed by the use of common acids and wireline tools, Strontium Sulphate scale requires special techniques to remove chemically and/or mechanically, and present the most challenges to achieve complete removal.
This work will describe ZADCO scale management strategy to monitor and remove Strontium Sulfate scale in Upper Zakum producing wells. A scale prediction simulator is used to identify wells with high scaling risk. Scale Risk Matrix (SRM) is being developed to classify the scale risk in each well. The Chlorides content, the percentage sea water in the produced water, the production rate, the percentage water cut and scaling index are the main parameters that are used to calculate the overall scaling risk for a certain string. The wells classified as high scaling risk wells, are included on a monitoring list for periodical scale checks by running gauge cutters on slickline. Scale samples are collected and sent to the lab for analysis and scale type identification.
The category of strings with a scale thickness less than 0.25" are treated with a chemical scale dissolver, the wells containing scale thicker than 0.25" are treated with downhole cleaning tools run on Coiled Tubing.
In 2005, ten wells severely scaled with Strontium Sulphate were mechanically treated using Coiled Tubing, Mills and motor, high pressure rotating tool with Sterling Beads* and Polymer as the cleaning fluid. Most of the job objectives were not completely accomplished due to severe hard scaling conditions.
Competency Management: Value, Approaches, and Challenges
Authors: Brett J. F. , Salah M. G. , Lilly Larry L. 
Published: December 2007

Abstract
In the upstream petroleum industry, what is the true economic value of developing and managing the individual competencies of technical professionals? This paper uses two approaches to value competency development. The first uses historical data to assess the impact of the competency shortage during the 1980's boom and compare its net effect with what we might expect over the next few years. The second method builds a formal competency development business case using full-cycle economics. Both of these analyses indicate that competency management is likely to be financially beneficial in the near future— possibly up to 20% of total E&P expenditures. The paper then describes approaches to reliably manage competencies and outlines several challenges with each approach.
Evolution of Gas Bubbles From Offshore Wells
Authors: Emenike C. O. , Afghoul Ali Chareuf , El Mzien Nabil , Latifi Laid 
Published: December 2007

Abstract
In year 2002, gas bubbles from seabed were observed around well casing at some of Upper Zakum platforms.
During the investigations of this phenomenon it was noticed that the gas from the annuli (tubing X 9 5/8" casing and 9 5/8" casing X 13 3/8" casing) was having high hydrogen content. Concern was raised when the hydrogen content of the analyzed gases was as high as 99%.
In view of the potential risk to operators posed by this high concentration of this highly inflammable gas (H2), a multi - disciplinary team was established to investigate the source of hydrogen and subsequently to develop measures to protect the environment, personnel and ZADCO assets. The taskforce was also asked to produce an operational guideline to safely operate and work in such an atmosphere. Subsequently, chemical thermodynamics and kinetics / mass transfer models were used to identify sources of hydrogen and subsequent transfer of hydrogen from sources to the annuli. Eventually these theoretical analyses were reconciled with tubular inspection findings. These and other factors are discussed in the paper.
Reliability of Cement Bond Log Interpretations Compared to Physical Communication Tests Between Formations
Authors: Boyd Douglas , Al-Kubti Salah , Khedr Osama Hamdy , Khan Naeem , Al-Nayadi Kholoud , Degouy Didier , Elkadi Antoine , Al Kindi Zaid 
Published: December 2007

Abstract
Two classes (sonic and ultrasonic) of cement bond log tools are run in tandem as part of ZADCO's standard cement evaluation program. The effectiveness of these tools and their evaluations are often challenged and are not regarded as a replacement for reservoir inter-zonal communication tests performed between producing reservoirs on every well. Consequently the value of continuing to run these tools was raised by management. In response, the reliability of these tools and their interpretations for determining the existence of poor behind casing cement quality and possibly hydraulically communicating layers was critically and systematically examined by a dedicated team of ZADCO and Schlumberger technical professionals. The criteria used to judge the usefulness of these logs was the present or not of communication behind casing as determined by the physical test. For the twenty-eight wells examined, twenty-five of the cement log interpretations matched the communication test results. One well which communicated had 10 feet of apparent good cement with the remainder poor. Its cement log suffered from eccentralization which negatively affected the cement bond log interpretation. Two wells with long intervals of excellent cement on logs suffered behind casing communication. The reasons for this remain unresolved but are a source of constant discussion. Possible explanations for the mismatch between cement evaluation log interpretation and the physical test results are explored.
Producing Dry Oil From a Transition Zone: Should This Be Called a Wedge Zone?
Authors: Efnik Mohamed Saleh , Hafez Hafez , Haajizadeh Masoud , Hamawi Mohamed , Al-Mansori Maisoon , Kenawy Maher , Abdulla Faisal 
Published: December 2007

Abstract
There is a common mis-understanding about the transition zone in which both water and oil should be mobile.
This paper will illustrate that in the transition zone only oil is movable above the Free Water Level (FWL) at normal gravity conditions. Putting wells on production in the transition zone produce dry oil unless the drawdown pressure disturbs the normal gravity conditions.
To avoid any confusion among geoscientists and reservoir engineers, we introduce new term called the "Wedge Zone", where the water saturation increases down flank towards the oil-water contact as a result of gradual increase in the micropores with bounded water due to diagenesis and cementation. The intensity of the diagenesis (cementation) is related to the timing of oil migration and entrapment.
Four wells that had been drilled in an onshore field in the Middle East in the Wedge Zone and have producing dry oil for the last two years. As result of repositioning the new wells based on the Wedge Zone concept, an extra amount of recoverable oil will be added.
The Modeling techniques over this zone have been revised resulting in changing the concept of modeling the transition Zone to that modeling of a Wedge Zone. As a consequence, the model prediction of sweep efficiency is also impacted.
An Approach for Production Enhancement Opportunities in a Brownfield Redevelopment Plan
Authors: Cuauro Antonio , Ali Mohd Izat , Jadid Maharon Bin , Kasap Ekrem , Friedel Torsten 
Published: December 2007

Abstract
Betty is an oil field discovered in 1968 and produced since 1978. With the objective of rejuvenating the asset, a multidisciplinary optimization team was built. The standard practices for production enhancement opportunities include logging, nodal analysis and well engineering technologies. Usually, the older the field, the more challenging to achieve additional reserves. This paper outlines an integrated approach for achieving these opportunities, reducing the risk on oil recovery associated with the various enhancement initiatives. The objectives of this paper are to present (i) how using numerical simulation to support and improve the strategies for production enhancement opportunities identified by the standard screening exercises in a brown field and (ii) how to optimize redevelopment plan for maximum recovery.
First, several increased well production opportunities were identified based on the standard methodology. Then, to reduce uncertainties and risks associated with proposed activities, full field numerical simulation model was run and results were reconciled. This was followed by incorporation of the surface facility constraints to identify bottlenecks. The comparison between standard analysis and the new approach gave a more reliable platform for predicting field performance. Results also added valued information for optimizing further infill drilling targets. Lessons learned and recommendations for future development campaigns on other fields were established.
After 6 months of implementation and monitoring, the proposed initiatives have achieved some 13% increase in the total oil production; savings 14 MMUS$ by reducing the number of infill wells planned, and creating an additional ultimate oil recovery of 4.98 MMstb. In the future, implementation of all opportunities will produce sufficient information for optimizing infill drilling and work-over campaigns on Betty Field.
The application of this innovative approach to brownfields helped identifying new opportunities, which have been a key factor in the rejuvenating Betty Field.
ADCO ESP Pilot
Authors: Hashim Hafsa A. 
Published: December 2007

Abstract
In one of ADCO's mature fields several horizontal oil wells have ceased to flow due to the high water cut. In order to accelerate data acquisition on well, reservoir and ESP performance at these higher water cuts, an ESP pilot project was performed in three wells.
ADCO's past experience with ESPs in some of the main fields in deep, high temperature and GOR wells (250 deg F and 700 scf/bbl, respectively) has been poor and discouraging. To ensure that future ESP applications in these fields are successful, a comprehensive review was conducted by ADCO and industrial shareholders (ISH) to determine the root causes of the previous failures and recommend methods to improve current practices.
In accordance with the recommendations, a multidisciplinary team was set up to plan and execute the ESP pilot project. The project team was responsible for the tendering, designing and engineering aspects, gathering the reservoir data, finalizing the completion strategy, equipment sizing, installation, commissioning and monitoring.
The result of this effort was the successful installation and running of ESPs in two of the field's oil wells. The project success is of paramount importance as it can lead the way for future ESP applications in similar harsh downhole conditions.
This paper discusses ADCO's approach to overcome the past difficulties it had in running ESPs in deep and hot oil wells starting from the review up to the installation and commissioning.