bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic Liquid-Level Determination of Liquid Loading in Gas Wells
Authors: Rowlan O. L. , McCoy J. N. , Podio A. L.
Published: December 2007

Acoustic liquid level tests are performed successfully on many different types of wells throughout the world. The most common application of an acoustic liquid level instrument is to measure the distance to the liquid level in the casing annulus of a well. A less common technique is acquiring an acoustic fluid level by "shooting" the well down the tubing. The results from this type of test on a gas well can be used to determine 1) the amount of liquid and backpressure on the formation, 2) the gas rate into tubing, 3) the equivalent fluid gradient below the liquid level, and 4) the flowing bottom hole pressure. In this paper, surface acoustic data (via shooting down the tubing) and bottomhole data were acquired simultaneously to confirm the calculated results from the acoustic data. The benefit of using the portable fluid level instrumentation is such that it permits a simple cost effective test to be conducted quickly to immediately identify underperforming gas wells due to liquid loading problems. The information obtained during this straightforward test provides critical data in determining the well's potential and the ideal artificial lift technique. Fluid level instruments can be used to inexpensively determine liquid loading and its severity for gas wells as opposed to traditional methods, which are more intrusive and costly.
Assessment and comparison of CO2 corrosion predicition models
Authors: Woollam R. C. , Hernandez S. E.
Published: December 2007

A number of different CO2 corrosion rate prediction models have been developed for application in oil and gas production systems and are readily available in the literature or as industry standards. These models vary from the empirical models to the more recently developed mechanistic models.

In this paper a number of CO2 corrosion rate prediction models are compared. In addition to the obvious criteria of comparing the predicted corrosion rates, the models were also compared for other characteristics such as ease of implementation and insight into the main drivers of the predicted corrosion rate.

Using as input the water-chemistry of condensed water, the output from each of the CO2 corrosion prediction models was compared over a range of temperatures and pressures. A common source dataset was used as input for each of the models.

For the range of input values, the suite of selected models generated results which were comparable for lower temperatures and pressures. At higher temperatures and pressures where the effect of the precipitation of iron carbonate would be expected to be influential then the outputs from the models differed. This was in part because in some cases iron carbonate precipitation was not included, but in other cases this difference was due to the alternative implementations of the effect of iron carbonate precipitation.

As would be expected the mechanistic models are the more complex to implement with some being such that specialist computer code is required to numerically solve the systems of equations. However, for all the complexity of implementation, the mechanistic models have the particular strength of providing greater insight into the critical variables driving the overall corrosion mechanism and hence suggest strategies for minimizing the CO2 corrosion risk during design and operation and are therefore to be recommended.
An Oil and Gas Decision-Making Taxonomy
Authors: Mackie S. I. , Welsh M. B. , Lee M. D.
Published: December 2007

Business under-performance in the upstream oil and gas industry, and the failure of many decisions to return expected results, has led to a growing interest over the past few years in understanding the impacts of current decision-making tools and processes and their relationship with decision outcomes. Improving oil and gas decision-making is thus, increasingly, seen as reliant on an understanding of what types of decisions are involved, how they should be made in order to be optimal, and how they actually are made in the "real world".

There has been significant work carried out within the discipline of cognitive psychology, observing how people actually make decisions. However, little is known as to whether these general observations apply to decision-making in the upstream oil and gas industry. Nor has there been work on how the results might be used to improve decision-making in the industry. This paper documents the development of a theoretical Oil and Gas Decision Making Taxonomy (OGDMT) that seeks to lay a "level playing field" decision space within which to judge the processes and tools of optimal decision-making as the first step in this research.

The OGDMT builds on established ideas in the human decision-making literature, but is itself novel, and involves four different dimensions: level of investigation; task constraint; value function; and the information structure of the environment. It is concluded that decision scenarios at different places in the taxonomy will likely involve different decision-making tools, data and processes for the achievement of optimal decision-making.

The results of this work can be applied, for example, to the question of whether decisions about reserves should be made using deterministic or probabilistic tools, data and processes.
Efficient Management of Production Losses to Increase Production
Authors: Tarmoom Ihab Othman , Khan Ayyaz Mahmood
Published: December 2007

Enhancing the field oil/ gas production, safely & without damaging the reservoir, in today's era is the top-most priority of each Operator. The fields' sustainability and aging facilities with integrity & HSE concerns, coupled with high market demand have presented real challenge to ADMA-OPCO. Accurate accounting of the field sustainable capacity/ development plans, strict compliance with good reservoir management guidelines/ practices, excellent planning of field activities (operations & maintenance, projects, rigs & barges, reservoir monitoring) and vigorous follow-up/ coordination at implementation stage have helped ADMA-OPCO to minimize the production losses. Initial gains resulting from short-term actions are 5 % & ADMA-OPCO is aiming at 15% or above improvement in production losses through medium to long term actions.

Efficient short, medium and long term production planning has taken key role in the management of hydrocarbon field operations. The market demands & increase trends, coupled with high oil prices have become so attractive for Operating Companies and Shareholders that every barrel of oil is essentially required to be lifted. Production targets today are set to the maximum available field potential, while ensuring facilities integrity & respecting reservoir guidelines for maximum sustained recovery.

The paper below will discuss the elements of production losses, analyze their relative impact on production capacity (referred to as "Effective Capacity") and recommend tools to efficiently manage the production losses with the objective to increase production. Although the discussion is more focused to large offshore operating oil fields, the principles can equally be applied to any onshore/offshore field.
Applicability of Horizontal Drilling Techniques in Iran: A Field Case Study in BiBi Hakimeh Field, Southwest Iran
Authors: Kalantari-Dahaghi AmirMasoud , Moghadasi Jamshid , Gholami Vida
Published: December 2007

Bibi hakimeh field, one of the biggest Iranian fields that has an important role in daily production of oil and gas, was discovered at 1961 by drilling well no. 1 and at 1964 the well started producing oil. Stratigraphic thickness of this field is 400 meter that increases in northern direction. And it has relation with Bangestan formation. Bibi hakimeh field is an oil saturated field which has a pressure of 2263 psi and a temperature of 147 °F at gas oil contact. Horizontal drilling techniques are applied for such "thin reservoir" which the vertical drilling depth is not enough.

This paper investigate the applicability of horizontal drilling technique in well # 74 Bibi hakimeh field that there was a need to use the horizontal drilling techniques, but this technique didn't have very good results in this field and the most horizontal wells that were drilled in this field had an equal or lower production than vertical wells. This method has advantages and disadvantages that are explained in this paper. The flow rate of vertical and horizontal wells is almost the same, but with respect to the geological structures and low reservoir thickness there was a necessity to drill horizontally. In this study the advantages and problems which horizontal drilling is dealing with are described. In addition some good data from wells that drilled horizontally in this field are available.
Primary Cementing in Permafrost Conditions—A Process
Authors: Radojevic Dean , Shafeyeva Yelena
Published: December 2007

By coupling dedication and commitment with the correct application of proven technology, primary cementing in permafrost conditions can produce long-lasting zonal isolation in the wellbore. Obtaining effective hydraulic sealing between cement and casing and cement to formation the operator may thus avoid unnecessary repairs, well shut-in and lost production.

Establishing good communication with the Tyumenniigiprogas Technical Instituee and operators well ahead of designing the job helps to identify all relevant factors influencing the potential outcome of the cementing operation and overall well turnout.

Ten wells were cemented in the Novo Zapolnarnaya field (Russian Arctic region) using the newly proposed blends; they all were successfully put on production without indication of crossflows. Slurry design considerations and operational placement suggestions are given to help reduce the chance of primary cementing failure over the producing lifecycle of the well.
Analysis of Rate Dependence in Transient Linear Flow in Tight Gas Wells
Authors: Ibrahim M. , Wattenbarger R. A.
Published: December 2007

Many tight gas wells (permeability less than 0.1 md) exhibit linear flow through their transient period. This transient period may last for years in some cases. It has been learned that this behavior differs in many ways from radial flow behavior. This paper reports another import difference between linear flow and radial flow - rate sensitivity.

It has been shown and accepted for years that real gas pseudo-pressure can be used to apply analytical solutions to transient radial flow. However, it has been noticed that analytical solutions can be in serious error when applied to transient linear flow. Specifically, the slope of the t departs from the analytical value as the flow rates or degree of drawdown become higher.

This paper demonstrates the rate/drawdown sensitivity of transient linear flow. Then a correction factor is presented which corrects the slope of the plot and improves the accuracy of kAc and OGIP, as calculated from production/pressure performance.
Multifactor Evaluation Technology for Casing Damaged Wells
Authors: Zhu Jun , Wang SuLing , Liu He , Wang Jingmei
Published: December 2007

Being a maturing field that has been developed for over 40 years, Daqing Oilfield has nearly 40 years of water flooding development history. One of the major problems that Daqing Oilfield is currently faced with is severe casing damage of both producers and injectors. Factors influencing casing damage are numerous, heightening difficulties in prediction and comprehensive analysis. In the past, casing damage mechanism research emphasizes on casing strength in respect of well drilling, fault and shale in respect of geology, and water injection pressure in respect of reservoir. Yet the accuracy for trouble shooting based on single factor analysis is quite low. To conduct casing damage mechanism research, the influence of multi-factors on casing damage should be considered comprehensively to draw a correct conclusion. Therefore, research on multi-factor evaluation technology and its application in casing damaged wells is implemented.

Three-layer feed forward neural network model is used to make the casing damage formation factors corresponding to the input vectors of the neural network. Factors causing casing damage such as water invasion in mudstone, pressure performance, geological features, casing performance, and stress field etc. are described as a series of real numbers between 0 and 1. More often than not, these factors are difficult to be described through mathematical methods, but a blurry value can be given by experts. Thus, a blurry vector for casing damage factor is composed of multi-factors, that is to say, the output of neural network is correspondent to the present working status of casings, which can be given by experts based on their experiences, and the output value is a description of the present working status of the casings. The given casing damage data is used as instructor signal to train the network, and following training, the network can perform the prediction of the working status of casings.
The New Hydraulic Fracture Design Method and Good Performance in a Deep and Naturally Fractured Volcanic Gas Reservoir in China
Authors: He Liu , Yongping Zhang
Published: December 2007

Due to the existence of multi-fracture and the extension in volcanic gas reservoirs, the success ratio of stimulation is very low as well as the stimulating scale. Based on the unique simulation model for fracturing development and growth during the stimulation, some important topics were studied: (1) the effect of the natural micro-fracture and stimulating parameters vs. the formation and extension of the stimulated fractures. (2) The magnitude of the affecting by different characters of the natural micro-fracture in the reservoir vs. the scale and success ratio of treatments. A new method was summarized to determine the operation indicators in real time on site. And this paper also introduced a series of main fracture controlling technique including: plug with rubber plug, plug with silty sand, displacement compensation at far end of the wellbore, etc. Two logging data from two wells in a large-scale stimulating process are presented in this paper, which proves the necessity and validity of the studying for the main fracture controlling technique in volcanic rocks. This method can also be used as a good reference for stimulation in the similar gas reservoirs.
Controlling Surge Due to Accidental Shutoff Fast Closing Value at Terminal Station of an Oil Pipeline
Authors: Wang W. , Gong J.
Published: December 2007

Changes of transportation materials, operating parameters or equipments of pump stations, will induce surge in oil transfer pipeline. And surge generated by accidental Shut-off fast closing valve could be more destructive, since the valve closure duration is limited, then the induced surge pressure would be much higher, so controlling surge of this kind is indispensable. Based on the characteristic method, this paper establishes a numerical calculation and simulates the pressure variation process, when fast closing valve at terminal station is accidentally shutted off in an product pipeline. Upon the upper result, further research combining the boundary condition of relief system is carried out, with the purpose of getting optimal surge control measures through relief system.
A Rigorous Composite-IPR Model for Multilateral Wells
Authors: Guo B. , Ling K. , Ghalambor A.
Published: December 2007

Use of multilateral wells for oil and gas production has gained strong momentum in the past five years. However, most of the wells do not deliver hydrocarbon fluids at expected flow rates. One of the reasons is that the well planners over-estimate the productivity of wells using inaccurate methods for predicting composite IPRs of well laterals. A more accurate method for predicting composite IPR of multilateral wells is highly desirable. This paper fills the gap.

Starting from terms that petroleum engineers are familiar with, a general mechanistic model was developed to combine the fluid flow from individual laterals. The model allows different IPRs of laterals and permits cross-flow between laterals. Pressure losses in both vertical and curvic hole-sections are rigorously considered. Oil and gas wells are treated differently. By combining the composite IPR model with Poettmann and Carpenter correlation, a computer simulator was developed for predicting multilateral well production rate. A case study with measured production rate indicated a 3.1%-error accuracy of the computer model, which is much better than other existing methods. This work provides petroleum engineers a reliable and user-friendly tool for designing and analyzing multilateral wells.
Quantification of Uncertainties for Drilling Induced Formation Damage
Authors: Ding Y. , Renard G. , Herzhaft B.
Published: December 2007

It has been widely recognized that formation damage due to drilling fluid has a huge impact on well productivities. The degree of formation damage can be studied using a numerical model. However, uncertainties in the prediction of productivity loss need to be investigated. To quantify these uncertainties, experimental designs combined with the Response Surface Methodology are used to assess the impact of uncertain parameters on formation damage. This approach allows to identify the most influential parameters on well productivity loss and to estimate the risks of formation damage. A good control of the most sensitive parameters can limit productivity loss. This approach provides key recommendations for the selection of drilling fluid to maximize well performance.
Applying Integrated Project Management Methodology to Hydrocarbon Portfolio Analysis and Optimization
Authors: Adekunle Sholarin Ebenezer
Published: December 2007

Aligning hydrocarbon investments with constantly shifting business goals and priorities continue to be a major challenge for E&P staff. In spite of the best efforts of international oil companies (IOC) to rebuild their in-house engineering and project management capability, an unacceptable number of oil field development initiatives continue to either fall short of, or simply miss their target completely. This is further exacerbated by insufficient supply of technical staff with experience in managing very large and complex projects. There is no end to the myriad of factors that can contribute to project failure and, as a result, petroleum industries have invested heavily to improve the predictability, producibility and quality of their output. While, techniques such as estimating, risk assessment, process management, deliverables management and project management improve project execution, they fail to address the more critical issue of scheduling and achieving satisfactory cost performances.

As the number of project opportunities grows, the corporate or financial planner is faced with an increasingly difficult task. Projects originally viewed or ranked as non-core or materially insignificant to the majors may have the potential to significantly impact the portfolio of an independent.

The main objective of this study is to explore the strategic significance of modern portfolio theory and its applicability to various oil and gas investments. In order to achieve this objective, the paper combines the strategic project management principles with hydrocarbon portfolio analysis. We draw on documentary sources (PMI's Guide to PMBOK, petroleum companies’ annual reports, status reports from existing hydrocarbon projects and so on). The paper demonstrates how modern risk techniques can facilitate the decision-making process in E&P operations.
A Novel Solution To Flow Profiling With An Improved Production Logging Tool In Short String Section Of Dual String Completions
Authors: Cig Koksal , Gok Ihsan
Published: December 2007

The new production logging tool string and interpretation technique were established in order to solve the surveillance limitations in the short string section of the dual completion wells. The logging program was initiated in Kuwait Sabriyah Field where there are two major producing formations: Mauddud Carbonate and Burgan Sandstone Formations. The wells were completed with dual production strings due to distinct fluid and reservoir properties in these formations.

Water injection was implemented in Mauddud Formation in late 2000 after a successful waterflood pilot program. The wells having water injection are mostly located in the short string section of the dual completions. The monitoring of the water breakthroughs and finding the bypassed oil became crucial for the field development. Understanding of the reservoir required logging these sections. The conventional wireline logging was regarded as a difficult and unsafe operation due to complicated nature of the production strings and the risk of wireline logging tool entangling. The earlier practice was to utilize the workover rig and to remove the two production strings before performing any wireline logging in the well. This operation was not only costly and time consuming but also pausing the production from Burgan Formation.

The new logging string and interpretation technique were developed to survey the short string section of the dual string completions without utilizing a rig. The logging operation consisted of conveying the production logging tool with a coiled tubing through the short string section of the dual completions. Flow profiles and water entries were confidently obtained in many wells with the new interpretation technique.

This paper presents the history of the short string logging operations in the North Kuwait Fields and highlights the improved coiled tubing conveyed logging tool string and the recent interpretation technique in order to overcome the problems due to completion restrictions.
Crude Stabilizer Using Localized Underpressure Generation
Authors: Valente Antonio , Granadeiro Adriano
Published: December 2007

The process of efficiently degassing and dewatering crude oil is a permanent concern in the industry from both, economical end environmental perspectives.

Oil and gas separators are utilized to achieve this purpose and are an integrant part of the surface separation equipment designed to handle the fluids produced from oil and gas wells and segregate it into oil/water and gas. They are installed either at the central processing plants or near the production wells.

The oil and gas separators consist normally in two families; the two stage-oil/gas separators and the three stage-water/oil/gas separators.

Their efficiency, translated by the quantity of gas separated from the crude oil is dependent upon

Physical chemical and electrochemical characteristics of the crude Process operating temperature Process operating pressure Equipment rate of throughput Size and configuration of the separator other factors

When the crude degassing process is not complete, then, at some point in the distribution circuit, for example at the refinery or while loading tankers, substantial amounts of associated gas will be released without control to the atmosphere, causing environmental damage (VOC emissions) a primary cause for the global warming, direct economical loss since part of the saleable product is lost and in some cases upset in the client's process due to high RVP.

Recognizing escalating concerns namely the potential increase in sea levels and flooding in coastal areas due to global warming, the actual market conditions of efficient utilization of hydrocarbon resources associated with zero flaring and venting targets are clearly sending the message that the development of complementary technologies targeting the enhancement of actual process conditions has become an obligation of all players involved.
Financing Strategies for the Procurement of Gas Projects in Developing Countries
Authors: Ellafi J. , Al-Thani F. , Merna A.
Published: December 2007

Numerous financial and contractual strategies are available to finance gas projects. In developing countries gas projects are financed and developed under different contractual strategies including; Production Sharing Contract, International Joint Venture Contracts or hybrid Project Finance strategies. These contractual strategies play a vital role in allocating risks involved in the procurement of gas projects. Gas projects are, in many cases able to access traditional forms of financing but the huge capital required to develop new gas projects to meet future gas demand may necessitate innovative approaches to be developed. This paper outlines the economic benefits to both public and private sectors for the adoption of Build-Own-Operate-Transfer (BOOT) strategies for the procurement of gas projects in developing countries (DCs). A comparison of the economic parameters of three strategies is also presented.
The Way the Oil Companies Tackle the Field Production Monitoring Problems in Russia
Authors: Ipatov A. I. , Kremenetskiy M. I. , Gulyaev D. N.
Published: December 2007

Field production monitoring problems in Russia are not related only to procedures; they also concern managerial issues. Usually there is no special department within an oil company that would interpret the well-test and production-logging results for their further use for production enhancement. "Sibneft" company is a rare exception where the results of all surveys are processed and interpreted in a specific department which constitutes a part of the company's structure and controls the well testing and production logging activities. The problems related to the well testing and production logging techniques are basically due to difficulties inherent to the production of residual reserves. Conventional well testing and PLT methods are poorly conclusive when applied in reservoirs with low permeabilities and poor producers with high watercuts. Sibneft implements therefore the welltest procedures that involve long swabbing stage followed by downhole well shut-in as well as long lasting welltests using memory remote control gauges including pressure gauges run into the well at the pump inlet. Stand-alone gauges such as pressure, temperature, spinners and watercut gauges are used for monitoring commingled production. Global technology for permeability adjustment based on logging, well testing, production logging and production data was worked out in Sibneft. Thus, 3D permeability cubes were generated for the most of the reservoirs and matched to the well-testing history; the relative distributions of flow properties being derived from log data. Problem of monitoring of the flow composition in the wells producing multiphase liquids and especially the horizontal wells is still poorly solved in Russia.
Clean Up Water Blocking in Gas Reservoirs by Microwave Heating: Laboratory Studies
Authors: Li Gao , Meng Yingfeng , Tang Hongming
Published: December 2007

Water blocking caused by fluids invasion during drilling, completion and stimulation has been suspected to reduce gas well deliverability or even result in no gas productivity. To date, an effective method has not been reported to eliminate such water blocking after many studies and trials conducted worldwide. In this paper, a new technique that utilizes microwave (MW) heating to clean up water blocking in sandstone gas reservoir was presented. First, the feasibility of this new method was discussed, and then the pilot experiment aimed to investigate the efficiency of water blocking mitigation by MW was described in details including core sample preparation, experiment equipment, method, conditions, procedures as well as data analysis, etc. Next, the result from the experiment was also given which shows: after MW heating(2450MHz, 600W, 40minutes), 1) no obvious change occurred in both composition and crystal structure for those samples without crystal water, while samples contained crystal water such as gypsum and smectite dehydrated rapidly in about 2min and their microstructures have been changed; 2) random micro-fractures are likely to be induced by MW heating in low permeability sandstones and larger pores have been produced; 3) water saturations of watered samples have decreased rapidly and consequently their gas deliverability increases greatly. At last, it is concluded that water blocking clean up by MW heating has encouraging future in field application, further laboratory studies for the next phase of this project was also stated in this paper.
Reliability Improvement at ADGAS
Authors: Saez Faisa
Published: December 2007

When the assets are in the operative phase the goal is to get the most from the investment. In order to achieve this, the facilities/equipments have to perform with high levels of reliability and safety. During operation, there is a continuous cycle that consists of Operation operating the assets until there is an interruption (trip or breakdown), then Maintenance repairs the asset as soon as they can in order to reduce the impact of the interruption. The cycle depicted above is too reactive and expensive (but still can be found in many organizations). Thus, other strategies have to be implemented in order to reduce the "speed" (failures) of the cycle. The common strategies for this are focused on preventive/predictive maintenance with the aim of avoiding/detecting the failures before they happen or become worse. Normally, techniques like Reliability Centreded Maintenance are used to establish the right maintenance tasks (preventive maintenance, predictive maintenance, run to failure) and Risk based Inspection (RBI) is used for setting the right inspection activities. Such techniques introduce mitigating actions to prevent onset of failures in service and/or to reduce their consequences. However, it won't eliminate all of the problems in the facility since there are still soft issues that have to be addressed with another strategy like Root Cause Analysis. This paper will present ADGAS experience in implementing two (2) Reliability Methodologies: Reliability Centred Maintenance, and Root Cause Analysis.
A New Porosity Partitioning-Based Methodology for Permeability and Texture Analysis in Abu Dhabi Carbonates
Authors: Al Arfi S. , Heliot D. , Li J. , Zhan X. , Allen D.
Published: December 2007

A new methodology for porosity and permeability analysis in Carbonates with Inter-granular and Macro porosity is presented. This methodology uses NMR log data, and electrical image data when available, to partition porosity into micro, meso and macro components - and then uses that partition to reconstruct the permeability and do a facies analysis.

Application of this methodology to eight wells in four Abu-Dhabi on-shore fields is presented. The results obtained are compared to core permeability, formation tester mobility and a traditional Reservoir Rock Type classification.

The main conclusions are:

The methodology and its underlying model of pore-to-pore connectivity are widely applicable to the major Carbonate reservoir formations in Abu Dhabi. The methodology can be applied without whole core. We established optimum formation specific parameter values which give reasonable results when compared with results obtained by using parameters that best fit core data on a well-by-well basis. The interpretation results are therefore robust and analyst-independent. Spot measurements of permeability or mobility, from formation test data or sidewall coring, are strongly encouraged to further tune the parameters and increase confidence in the results. When available, electrical image data help identifying and quantifying the Macro porous zones. NMR logs respond to both the pore size and to oil properties. In one well the oil signal dominated and it was not possible to compute an accurate permeability.

The log derived facies correlate with the broad features of the traditional Reservoir Rock Type definitions in use.
The Challenges of Building Up a Geological and Reservoir Model of a Late Ordovician Glaciomarine Gas Reservoir Characterised by the Presence of Natural Fractures
Authors: Le Maux T. , Murat B. , Chauveau A. , Amamra M. , Mesdour K.
Published: December 2007

The field, a Late Ordovician gas condensate reservoir located in the Illizi Basin of the Algerian Sahara Desert, was put on production 6 years ago. It is the off-centred gas cap of a greater oil reservoir whose production was initiated by Sonatrach in 1967. The reservoir is characterised by its extreme geological complexity. The Late Ordovician (Unit IV) corresponds to a glacial period in the Saharian Basins. The heterogeneity of the reservoir – especially the strong variations in thickness - is such that it is extremely difficult to predict the performance of new wells, even when located in a well developed area. The presence of fractures organised in corridors increases even further the reservoir complexity.

This paper presents the ways in which those challenges have been tackled in order to obtain both a reliable geological and dynamic model. It is shown how this characterisation was made possible by the integration of all the available information: seismic, geological and dynamic data.

The matrix modelling was performed though the definition of electrofacies. Outcrop observations, depositional models as well as seismic data were used to define the internal layering of the geological model.

The fracture model was achieved by integrating the curvature of the top reservoir horizon. It was confirmed and refined through comparison with borehole imagery (BHI) logs and dynamic data (mainly well tests and historical production data). Fracture conductivity was adjusted such that well productivity was respected. The outcome was a Discrete Fracture Network (DFN) model that was then upscaled and integrated into a single medium dynamic model.

The final outcome is a dynamic model in which the history matched process was greatly improved. The predictability of the model was tested in an under-developed area of the field where new wells have recently been drilled. A fairly good agreement between the model and the reality was found in areas already appraised. In completely undeveloped area, the model was less successful.
Bottom-Up Approach of Project Execution
Authors: Ramana Narra Venkata
Published: December 2007

The paper proposed highlight the significant challenges being faced in implementing Brownfield Projects.

Brownfield Projects involving major revamp / replacement of the existing facilities pose significant dilemma to the oil producers. While on one side there is an opportunity to implement projects and maximising the profits with prevailing high oil prices, on the other side there is a threat of loosing significant production during revamp works coupled with likely delays the projects may face.

The paper deals with the challenges being faced while arriving at a business decision and once decision is taken, while implementing the revamp works. A systematic analysis of the risks and preparedness to face the challenges have been dealt in the paper.

The booming oil prices made many companies rushing to implement projects. While the early entrants could get commitment on the available resources, the late entrants are struggling in this front. The Suppliers, Sub-suppliers, Contractors, Equipment manufacturers, skilled Manpower, Service providers are all busy, they are stretched in resources and are refusing to make any additional commitments.

In the above background, companies need to adopt unconventional methods to implement the revamp works. A bottom up approach of resources commitment has been suggested in the paper against the conventional top down approach (EPC Contract).
Multistage Controlled Acid Fracturing: A Unique Acid-Stimulation System Proved Efficient in a Field of Bombay Offshore Basin—A Case Study
Authors: Nainwal S. P. , Agarwal Pawan , Haldar Surajit
Published: December 2007

The pay zones of one of the Bombay offshore field are thin, tight and heterogeneous carbonate reservoirs with typical lithological pattern. The production declined sharply in all the wells within a short period. Achieving an effective stimulation treatment for the wells of this field has long been a recognized challenge. No conventional stimulation methods have succeeded. With unique characteristics, the multi-stage controlled acid fracturing treatment is proved to be highly efficient in this formation.

Studies were carried out to determine the formation rock characteristics and finding a suitable acid system. Acid etching patterns in the formation rocks were seen for different acid systems. Studies demonstrate that a multistage fracturing by viscous frac fluid and alternately acidizing the fracture surface by the improved acid system are giving better etching pattern. Finally, closing the fracture surface and injecting large volume of nitrified acid at a very slow rate further enhances the permeability generated. In this technique, the farthest part of the fractures, the middle part and the fractures near the well bore as well are acidized and etched uniformly by controlling the acid reaction rate at different stages. Laboratory test results on formation cores and field results verify this technique. Temperature survey and pressure transient tests are done before and after stimulation treatment for post job evaluation.

This paper describes the technical basis of the improved acid system. Laboratory test results are included. It also discuses the treatment design, execution and evaluates the fracture geometry. Production comparisons indicates a substantial improvement in well performance following fracture acidizing treatments.

The significance of the paper can be attributed to achieving longer fracture length and creating higher conductivity by better etching through controlled reaction rate of acid for tight and heterogeneous carbonate reservoir.
Improving Piping Integrity for LNG Facilities
Authors: Al Zaabi Abdulla Matar , Aslam Khawar Saleem , Chaudhry Muhammad Akram , Muhammad Nasim Ahmad , Westwood Michael John , Rao Ijaz Ulkarim
Published: December 2007

Piping studies revealed that although the rate of piping leaks including loss of production showed an increasing trend, a strategy can be devised to improve the piping integrity in less than two years with an assurance on longevity.

A multi-disciplined task force team was formed which presented its short term and long term strategy plans. A Consultant's appointment was also recommended. Uniqueness of the strategy was that not only studies should be completed for establishing a database of some 9000 piping and its inspection requirements using industry standards of RBI, but the results must be validated, with the existing performance data, along with forthwith implementation of rectification measures to address the near term and long term threats. The strategy is basically understanding the risk levels and undertaking corrective measures accordingly. RBI analysis and performance modeling were the essential tools in this strategy.

This strategy has proved very successful in dramatically reducing leaks by 78% and reducing the HSE risk to ALARP range with elimination of all production loss in year 2005, i.e. a span of about 2 years from the inception of the presented strategy.
The Road to a Competent and Motivated Workforce
Authors: AlMatroushi Salem
Published: December 2007

In this era of remarkable growth in the petroleum industry, a competent and motivated workforce is a must. ADNOC's Exploration and Production (E&P) Directorate and its operating companies are currently dedicating significant efforts to optimize HR processes like competence assurance, talent management, performance appraisal, potential assessment, career progression, succession planning, rewards and recognition. ADNOC's CEO stated in a 2002 policy document that "ADNOC and its Group of Companies are committed to…attract and retain a motivated and qualified workforce who will be recognized and rewarded according to performance". Therefore, talent identification and management, and subsequently reward and recognition must be top priorities for every manager. This process must be implemented through a coordinated system of recruitment, development and retention.

ADNOC can expect a significant number of new technical graduates joining the company in the next few years from the Petroleum Institute in Abu Dhabi and other institutions in the UAE and abroad. The company must be ready to develop these resources. Future business leaders, technical specialists and perhaps even global technical gurus will not develop by accident. There must a corporate culture of effectively finding, developing, and retaining these talented individuals to continuously improve performance and meet evolving business demands. Successful organizations integrate their HR functions with operations to pave the way for more effective implementation of these HR initiatives.

This paper demonstrates how this integrated approach to HR can be adapted to a multi-company culture in areas like talent identification, talent management, and recognition.
Production Optimization Challenges of Gas Wells with Liquid Loading Problem Using Foaming Agents
Authors: Solesa M. , Sevic S.
Published: December 2007

Decrease of gas production is an indicator that liquid column is probably building up in the well and an additional energy is required to lift the liquid out should be applied to control this situation. Commonly used methods include rod pumps, gas lift, plunger lift, foaming agents, alternate flow/shut-in periods, the use of smaller diameter production tubing and swabbing.

A method has been developed to guide operations managers, engineers and technicians responsible for operations when foaming agents are chosen to provide unloading of accumulated liquid in gas and gas condensate wells.

Depending on the well conditions, surface pressure test data and field surveys data, using different foam agents (sticks and/or liquid), the suitable intermittent system can be selected. Very often the combined production system (intermittent operation combined with launching foam sticks) or only intermittent operation using motor valve or plunger lift has been chosen.

Considering that application of foaming agent essentially promotes gas lift effect to sweep the fluids out of the tubing by adjusting some input parameters, one can simulate an apparent foamed flowing gradient. To select the appropriate correction of calculated holdup factor by using any NODAL software package, the gradients comparison was used for a rough estimation of the modified flowing gradient in the typical application.

The method proposed actions necessary to start foaming agent application. Each step and parameters affecting the process efficiency have been discussed in details. Several case studies have been discussed to confirm the validity of the proposed method.
New Perforating Technique Improves Well Productivity and Operational Efficiency
Authors: Faisal Al-Marri , Khalil Hassan Ibrahim , Salsman Alan , Lawi Majed Shaaban Abu
Published: December 2007

A major challenge identified by ADMA OPCO is the time delay and subsequent lost production between a well being completed with the drilling rig until it is acid stimulated using a multi purpose barge and put on production.

Some wells in ADMA OPCO fields that are perforated using conventional perforating techniques will not produce until stimulated with acid. A new perforating technique has been deployed that creates clean, low skin perforations and allows the well to be produced at commercial rates while waiting for the multipurpose barge and in some cases eliminate the need for stimulation.

This new perforating technique utilizes a unique job design process and specific equipment to ensure the guns are detonated in the correct environment to create a dynamic underbalance* immediately after perforating. Laboratory tests show how this fast acting dynamic underbalance created across the perforated interval is used to clean perforation tunnels and produce low to zero damage perforation tunnels1–2.

This paper describes how this new perforating technique was used in two ADMA OPCO wells to wireline perforate in multiple runs a carbonate reservoir which then produced more than 2500 bbl/day oil before acid stimulation. A fast acting memory recorder was run with the guns to record pressure transients in the well bore at the time of perforating. The subsequent acid matrix job on these wells further improved productivity.

This paper will show the perforating strategy, execution requirements, post job monitoring and the final results. This is the first fully documented case of this perforating technique being used in a carbonate reservoir and the first time this technique has been used in Abu Dhabi.
Aerial Leak Detection for Significantly Improved Integrity Assurance
Authors: Lensing Chad
Published: December 2007

BP gas production operations in North America manages over 15,000 miles of onshore pipelines that make up our vast, complex, and aging gas gathering networks. Surveying these for leaks presents a huge resource challenge using current ground based technology and, in turn, impacts the assurance of the safety and integrity of these operations.

The Exploration and Production Technology Group evaluated new leak detection technologies using laser, thermal imaging camera and a high speed gas sampling detector that were deployed on aircraft and used global positioning systems coordinates to survey gas gathering pipelines. Field trials on gas gathering systems in the North Texas, Anadarko asset showed that the laser and gas sampling based leak detection systems were the most accurate, but the video imaging from the thermal camera made a powerful statement. Helicopters proved to be more suitable in leak detection surveys on gas gathering pipelines than that of fixed-wing aircraft.

The aerial leak detection technologies produce a significant increase in efficiency and productivity in managing the integrity of BP's gas gathering systems. While that improves business performance, perhaps more importantly is the fact that small gas leaks can be easily found before they become big ones. That reduces environmental damage and the potential for leaks to impact the public. The development and implementation of aerial leak detection in BP is being recognized as an integrity tool in providing a significantly improved integrity assurance to its gas gathering operations.
Comprehensive Approach of Core Analysis to Predict Waterflooding Performance in a Heterogeneous Carbonate Reservoir, Offshore Abu Dhabi
Authors: Oseto K. , Al-Amoudi A. , Suzuki M.
Published: December 2007

The horizontal carbonate core samples were devoted to special core analysis to evaluate the field waterflooding performance in offshore Abu Dhabi under the observation of X-ray CT scanner at both fresh and aged states. Judging by visual observation of the surface and X-ray CT scanning, the core is apparently heterogeneous locally having some algal fragments which form vuggy pore spaces and some minerals which can form low porosity region. The main objective of this study was therefore to evaluate the effects of such heterogeneity on waterflooding performance and subsequent oil recovery.

For fresh cores, the results of Amott and USBM tests indicated neutrally wet to water wet nature that contradicted the expected. It was inferred that the contamination of a drilling fluid might alter the original wettability condition. The water flooding experiment with this condition resulted in fairly high oil recovery. X-ray CT scanning supported the result by demonstrating uniform water frontal advancement and high sweep efficiency in consequence. The same manner was applied to an aged core where the results on Amott and USBM tests indicated oil wet nature. The oil recovery was a little less than that for the fresh core but still favorable. X-ray CT scanning demonstrated uniform flow as well. In this way, the experiments proved high oil recovery for the aged cores as well in spite of the locally existing heterogeneities.

Kr curves derived by employing JBN method for both the fresh and the aged cores had a little different shape. The curves for the aged core were verified with on-dimensional coreflood simulation model.

Thus, this paper presents the detail of the waterflooding under X-ray CT scanning and comprehensive approach of the core analysis as a case study.