bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Gravel Packing and Filter Cake Removal in Horizontal Wells Applying Shunt Tubes and Novel Carrier and Breaker Fluid
Authors: Saldungaray Pedro M. , Troncoso Juan C. , Santoso Bambang T.
Published: December 2007

Gravel packing long horizontal sections is an exceptional challenge in itself due to the lengths now being completed. When simultaneous gravel packing and effective mud cake removal is considered, the complexity of the process is compound, posing a more demanding challenge to the completion process. Previously, to gravel pack a horizontal well it was necessary to seal off the wellbore from the formation to such an extent that substantial circulation could be maintained during gravel packing. This implied the need of a filter cake in place that needed to be removed in a separate treatment after the gravel packing operation to achieve an efficient completion. The introduction of screens with shunt tubes eliminates the need for well circulation during the gravel packing operation, and therefore simultaneous removal of the filter cake while gravel packing becomes a viable possibility.

In this paper we present an integrated approach to gravel packing and removal of the drill-in fluid filter cake. This was achieved by a combined application of a surfactant based carrier fluid in an enzyme and chelant breaker solution using shunt tubes for open-hole gravel packing. The shunt tubes ensure complete packing by allowing an alternate path for bypassing sand bridges that may form in the screen and formation annulus, due to excessive leak off. The carrier-breaker fluid ensures contact of the breaker with the filter cake in the entire interval during and after gravel packing.

Clean up efficiency tests, fluid rheological behavior and fluid design are presented together with field case histories. These case histories demonstrate that gravel pack placement and well productivity index have been improved with respect to previous practices, while simultaneously reducing overall completion cost.
Upheaval Buckling of Gas Injection Pipelines Onshore Abu Dhabi - A Case Study
Authors: Saadawi Hisham
Published: December 2007

Upheaval buckling is a potentially serious problem for buried pipelines operating at high temperatures and pressures. In recent years, this problem has been receiving wide attention in the oil industry. Most of the published literature deals with offshore applications in the North Sea. The problem of upheaval buckling, however, is not limited to offshore pipelines operating in a cold climate, but can also affect onshore pipelines in a desert environment.

Shortly after commissioning a major gas project onshore Abu Dhabi, some sections of the injection gas pipelines protruded through the trench and the soil cover. Extensive investigations were carried out to analyze the problem, identify the causes and remedy the situation. This paper describes a case study of the problem of upheaval buckling of high pressure gas pipelines in a desert environment.
A New Correlation for Gas-condensate Dewpoint Pressure Prediction
Authors: Humoud A. A. , Al-Marhoun M. A.
Published: December 2007

The paper presents a new empirical correlation to predict the dewpoint pressure of gas-condensate fluids from readily available field data. The new correlation relates the dewpoint pressure of a gas-condensate fluid directly to its reservoir temperature, pseudoreduced pressure and temperature, primary separator gas-oil ratio, the primary separator pressure and temperature, and relative densities of separator gas and heptanes-plus fraction. The correlation was developed based on field and laboratory PVT analysis data of several gas-condensate fluid samples representing different gas reservoirs in the Middle East. Additional data sets, not included in the development of this correlation, were used to validate the new model’s accuracy. Based on the error statistical analysis results, the new model outperforms the existing correlations.
Geological Modelling: Backbone in Developing A Mature Oil Field (Jorang Field Case)
Authors: Kurniawan Kurniawan , Syaefuddin Asep , Bailey Terry , Santoso Hendro Hari
Published: December 2007

Maximizing production from a mature oil field is a current and future CaltexPacific Indonesia (CPI) challenge. Developing a good geological model, thefirst stage of the process, helps visualize the location of potential remainingoil reserves and identify new drilling opportunities. A development package of3 Horizontal and 2 vertical wells that accommodated a trade-off between riskand opportunity was made to develop these potential areas of remaining oilreserves. Numerous challenges, such as the accuracy of structure prediction andreal time well re-design, occurred during the execution of the developmentplan.

This paper shares some of the experiences, software tools, and bestpractices used to identify hydrocarbon potential, to design well paths beforeand while drilling, and to develop economic scenarios for monitoring theexecution of the drilling program.
Noise Induced Health Risk Assessment & Mitigation Measures Thereof At Gas Compression Stations
Authors: Bose C. , Acharya A. K.
Published: December 2007

The paper deals with noise induced health risk assessment study in Gas Compressor Stations (GCSs) where sound level varies between 85 to 105 dBA. On routine audiometry test survey on 200 employees working in GCSs, approximately 6% of them were found to have been affected due to noise induced illness. Thereafter a joint team comprising experts from HSE cell and labour union representatives carried out survey of 19 such stations, identified the root causes and suggested remedial measures (both technical and administrative decisions). The entire case study was a unique approach of participation of Labour Union in Management to resolve HSE related problem.
Formation Fines Stabilization Using Surface Adsorption Polymerization: Field Application of an Emerging Technology
Authors: Saldungaray Pedro M. , Caretta Fausto , Sofyan Muhammad
Published: December 2007

Wells in a field offshore South East Sumatra, Indonesia, produce oil at very high rates and water cut. Under these conditions the reservoir is susceptible to fines migration with the associated pore plugging and production decline. Conventional acid treatments to dissolve fines in the near well bore have been effective for limited periods. However after some days or weeks of production, rates have been observed to fall as fines once again migrate, accumulate and plug the formation and gravel pack. Retarded mud acid formulations -that claim fines stabilization- have also been put into practice in an attempt to solve the problem. These formulations have also been ineffective and fines migration remained an unsolved problem.

A novel technique to inhibit fines migration through the "Surface Adsorption Polymerization" technique has been used to stabilize the fines around the borehole. The technique is a three-stage process that results in fines being coated with a solid thin polymer film that is stable at high flow (shear) rate locking the fines in place. The validity of the approach has been confirmed with flow tests in cores from the field under study, and has been validated by field results. This paper presents the process followed to implement this technique in the field, case histories and production data of the treated wells.
Experience with the Quantification of Subsurface Uncertainties
Authors: Charles T. , Guemene J. M. , Corre B. , Vincent G. , Dubrule O.
Published: December 2007

Now that tools are available for building 3D earth models, and for quantifying uncertainties on parameters associated with the earth model, it is much easier to understand the impact of all subsurface uncertainties on field production. In the last years, we have accumulated a significant experience and know-how addressing this sort of issues in integrated studies.

We briefly recall how we address the problems, what tools and methodologies are used for quantifying the joint impact of subsurface uncertainties. We discuss the key points in a study : clearly stressing which operational decision will be supported by the uncertainty study.reformulating the problem in terms of an uncertainty study workflow.listing the key subsurface uncertainties impacting the study.translating these key uncertainties into uncertainties on gross-rock volume, oil-in-place or reserves, using the workflow.

Then we illustrate the approach with four field cases. The first example highlights how the joint impact of geometrical, geological and dynamic uncertainties on reserves estimates can be quantified. The second example focusses on the impact of fault sealing on a development decision for an HP-HT field. The third example shows how uncertainty figures can be used to help optimally locate an appraisal well. The last example illustrates how the quantification of structural uncertainties can be used to justify the acquisition or processing of seismic data. We also discuss how new uncertainty quantifications techniques are impacting some of the standard industry workflows. For instance : –scenario approaches can now be run in conjunction with probabilistic approaches.–rather than defining three mini, median and maxi geological models, we prefer to define these models in relation with quantitative parameters of interest, such as OIP and Reserves.

We also stress that all our approach merely consists of translating uncertainties on input parameters into uncertainties on parameters of economic interest. The quality of the result obtained depends on the validity of quantified uncertainties on input parameters.
Water Rise Tracking and Prediction
Authors: Febvre F. , Moinard L.
Published: December 2007

This paper presents two different and simple methods of tracking water rise in a gas reservoir. From the case study of a complex multi-layered sand reservoir of Indonesia, it shows how the two independent approaches were validated, and generalised to other similar reservoirs. The objective is to control the water production, thus extending the life of reservoirs with an active aquifer.

The first method is based on material balance coupled with 3D mapping. The paper shows how water influx which is initially calculated from history match of the material balance, can then be converted into water rise. This approach can be easily implemented on a spreadsheet with some basic input from the geological maps of the reservoir, without the need for any heavy 3D reservoir simulation. Once water rise is calculated, the paper goes on to describe how it can simply be predicted.

The second method is based on reservoir saturation logging. The paper details step by step, the procedure that was elaborated to get direct in situ measurement that could be exploitable despite a complex environment in an ageing field. It describes how the combination of different recorded parameters can reduce the uncertainty from the raw measurement. It also highlights recommendation that were drawn from initial unsuccessful attempts to log through two strings of pipe.

This paper shows how these two methods were validated on the same reservoir when a new well was drilled and tagged the new water contact at the predicted depth.
Post Mortem of a Fast Track Subsea Oil Development
Authors: Guise David R. , Chered Norma Fitri
Published: December 2007

Jangkar-1X was drilled in the first quarter of 1998 and discovered oil and gas in five reservoirs in the Lower Gabus and Pasir Formations. The Jangkar Field is located in the Kakap PSC (Indonesia) and is part of the Wrench Fault Trend which has yielded significant rewards to the Kakap PSC partners. The well was not tested but open hole log evaluation, down hole fluid samples and pressure data confirmed the presence of oil and gas in highly porous and permeable sands. In response to this success, a fast track development plan was formulated which resulted in a second well, Jangkar-2X being drilled, completed and placed on production as a sub-sea oil producer prior to the end of 1998. This fast track development was the result of a strategic decision to pre-purchase the long delivery items required for sub-sea tie-ins in anticipation of a least one successful exploration well in a multi-well drilling program. This paper reviews the basis for the decision to pre-order inventory and documents the strategy and development plan which resulted in this well being placed on production within ten months of the field being discovered as well as the technical and commercial results of the project.
Cost and Risk Reduction Through Innovation: Remotely Actuated Completion Equipment for Deepwater and Extended Reach Wells
Authors: King James
Published: December 2007

Eliminating intervention during well completion reduces operating expense and risk. In deepwater, horizontal and extended-reach applications, remote actuation systems for setting completion tools are reducing well intervention and completion time without compromising reliability or safety. This paper will detail the operation of two commercially successful technologies that permit remote actuation. This paper will also examine the reduction of risk and rig time expense through the use of remote actuation systems and outline the selection process for determining the correct technology for a given application.
Preventive Maintenance of Electric Submersible Pumps and its Relationship to Root Cause of Failure Analysis
Authors: Limanowka W. A. , Degen S. , Benwell G.
Published: December 2007

We live in working environments where it is difficult if not career limiting, to say "no" to job assignments from bosses and colleagues. Pulling before catastrophic failure is normally not done, except in rare instances. Units are rarely pulled until total electrical failure occurs and the unit will not restart. Many times these restart attempts, after the systems have gone to ground, destroys the evidence needed to determine the reason for failure.

Proper diagnostics of a unit that shuts down on overload could, in many instances, reduce repair costs for the unit, provided they are pulled prior to restarting. However, this is not the general procedure in the field. Many lease operators do not have the equipment or training to troubleshoot ESP systems after they have gone down and, being pressured for production will automatically attempt a restart as soon as they discover the failure.

Producing wells can be monitored, and corrections in operation such as incoming power, wellhead pressure, casing pressure, etc., can reduce the stresses and increase the life of an ESP system. Also, use of proper monitoring techniques can aid in determining needs for replacing equipment and can reduce the repair costs if units are pulled and/or resized prior to catastrophic failure. The operator is the most important determining factor on run-life and is probably the least trained in the operating and design limitations of ESP systems. Further improvement in RCFA in the ESP field is undoubtedly in the hands of the ESP users. More manufacturer-user RCFA teams working together are becoming necessary to extend ESP run times.

The objective of this paper is to provide modifications to Root Cause Failures Analysis (RCFA) methods, specific to ESP applications and show how many of the methods can be applied as Preventive Maintenance in the ESP field. It will be supported by case study from the Meekwap field where the "Time between Failures" (TBF) was tripled as a result of close cooperation between field operator and ESP manufacturer.
Long Stroke Pumping Systems in Deep Well Applications – Field Study
Authors: McCannell Deana , Holden Derek R.
Published: December 2007

This paper compares and illustrates the effectiveness of a unique reciprocating rod artificial lift system as applied to Gulf Canada Resources in the Swan Hills area of Northwest Alberta, Canada. The applicable wells produce between 280bbls/day and 695bbls/day of high water cut fluid from depths ranging from 7200ft to 9500ft.

The system used includes a long stroke-pumping unit, high strength continuous rod, and a big bore-tubing pump. The unique features of the components within the system have proven to reduce production costs by improving failure rate and other associated operating costs.

In order to determine the benefits of this unique pumping system, the direct well pulling expenses and limitations for the concerned wells will be compared to the other lift systems used in the field.
Recommended Practices for Slim-Hole Steam Injectors
Authors: Castrup Suzanne Griston
Published: December 2007

Single-string and multi-string slim-hole completions have become popular in recent years as an inexpensive means of injecting steam into shallow, low pressure sands. While slim-hole injectors appear to be simpler and cheaper to drill and complete, wellbore heat losses can be excessive at low injection rates. In addition, if a good bond is not achieved during primary cementing, thermal stresses, incurred once steam is injected, increase the likelihood of tubing failure and steam channeling behind pipe. Therefore, an appropriate tubing size and weight must be used to prevent well failures.

For example, initial slim-hole steam injectors completed with 2-3/8 inch and 2-7/8 inch tubing are no longer advisable because of insufficient mechanical integrity. Similarly, poor cement bond in triple-string slim-hole injectors has resulted in a high percentage of well failures. Consequently, the costs associated with tubing deformation, poor steam containment, and high wellbore heat losses cannot be ignored when considering slim-hole injectors for a steamflood project.

This paper discusses current drilling and completion practices and addresses the benefits and risks associated with slim-hole steam injectors. The short-term economics of initial low drilling and completion costs are compared to the long-term economics of efficient steam placement to target sands using single-string and multi-string slim-hole injectors. Recommended practices and guidelines are presented for proper, cost-effective application of slim-hole injectors to improve steamflood performance.
Developments and Application of a Four-Parameter Instrument Withstanding High Temperature of Heavy-oil Thermal Recovery
Authors: Dai Peiwen , Wang Zuoqing , Wu Guowei , Zhang Yi
Published: December 2007

A new method is presented in this paper, which is used to measure four-parameters, namely down-hole pressure, temperature, flow rate and steam quality, on thermal recovery for heavy oil. Throttling action of the instrument itself and down-hole vortex shedding sensors combine to measure both flow rate and steam quality. According this method, an instrument has been developed which makes use of steel wires to go up and down, metal heat-insulating bottles to insulate heat, a down-hole SCM to gather and store data, a host computer on the ground to redisplay and deal with the results. Calibrations indoor and applications on the spots prove that the measuring errors of pressure and temperature are less than 0.5%, mean square root errors of flow rate and steam quality less than 6%. It can meet the expectations of the thermal recovery testing for heavy oil.
The Use of a Simulation Model to Optimize Reservoir Management in a Very Mature 24Z Reservoir, Elk Hills, California
Authors: Estremadoyro Julio G.
Published: December 2007

The 24Z Reservoir is a very mature field located on the western nose of the 29R anticline in the Elk Hills Field (Figs. 1,2 and 3). It has already produced almost 50% of its OOIP therefore, any additional development potential appears very limited. A comprehensive reservoir study was begun in late 1999 with a new geological and petrophysical interpretation to generate an improved reservoir description. As part of this reservoir study, a simulation model was also prepared. The purpose of this model was to better understand and improve the performance of this reservoir; to assist in evaluating any additional development potential and to compare alternative operating policies in formulating an optimized depletion strategy. The results of this simulation model indicate that there is enough potential to justify additional infill development wells. The reactivation of some shut-in down-dip wells and a blowdown of the gas cap were also evaluated.
Extending Downhole Pump Life Using New Technology
Authors: Muth G. M. , Walker T. M.
Published: December 2007

Sand, whether formation sand or frac sand, is produced along with hydrocarbons and water from many wells. This sand can accelerate wear of the plunger and pump barrel, and can also cause the plunger to stick in the barrel. These problems may result in frequent pulling jobs and expensive pump repair costs. The Farr plunger, a newly designed pump plunger and pull rod, has been tested during this past year in numerous oil fields in California. These tests indicate that the Farr plunger has the potential to reduce the pump wear and plunger sticking problems caused by sand production. This paper describes this new design, and the initial results of the field trials.
Statistical Forecast Models To Determine Retrograde Dew Pressure and C7+ Percentage of Gas Condensates on Basis of Production Test Data of Eastern Venezuelan Reservoirs
Authors: Marruffo Ilsis , Maita Jose , Him Jesus , Rojas Gonzalo
Published: December 2007

In this paper are presented correlations to determine the dew point pressure and C7+ content of gas condensate reservoirs, achieved from production parameters that we usually have in the field. To develop this correlations it were collected 146 PVT analysis informs of western Venezuela (Anaco) fields: San Joaquin: 42; Santa Rosa: 26; El Roble: 16; Guario: 4; Santa Ana: 3; El Toco: 3; Zapatos: 15; Mata-R: 15; Aguasay: 13; La Ceibita: 5; Carisito: 4. At the end it were finally used 106 to the final correlations.

The PVT tests results were validated through consistence tests: mathematical recombination and mass balance. After this steps an statistical analysis of the variables was done.

For this, statistical methods were used and they were focused on multiple no linear regressions.

At last the correlations accuracy were the following: dew point pressure showed 5.74 % of average error with a correlation coefficient of 0.82 based on 80 PVT's data, the first C7+ content correlation showed 9.59 % of average error with a correlation coefficient of 0.98 based on 81 PVT's data, the second C7+ content correlation showed 7.85 % of average error with a correlation coefficient of 0.99 based on 90 PVT's data.

The new Retrograde Dew Point correlation that was obtained improves the Nemeth and Kennedy (10) one that forecast dew point with 9.69 % of average error when it is applied on 54 Anaco's PVT analyses which had all the compositional information that it requires; with the new Anaco Dew Point Correlation the average error was 5 % for the same data. This news Anaco correlations allow to improve the characterization and exploitation plans of gas condensate reservoirs without PVT information.
Intelligent Automation for Intermittent-Gas-Lift Oil Wells
Authors: Correa Jose F , Santos Odair G , Inazumi Paulo C M
Published: December 2007

Intermittent gas lift is widely used in the PETROBRAS onshore petroleum fields. The intermittent gas injection in the annulus between the tubing and casing causes a gas lift valve to open. This gas lift valve is a pressure driven valve installed in the lower part of the tubing and controls the amount of gas injected at the bottom of a liquid column held inside the tubing. The injected gas becomes a big gas bubble that carries the liquid column up to the surface. The intermittent cycles are obtained by a motor-valve installed at the surface opening and closing at fixed time intervals (Time cycle – Tc) and remaining open during a fixed amount of time (Time injection – Ti). This work presents the concepts use in a firmware for Programmable logic Control (PLC) especially designed to optimize both Tc and Ti. Based on the tubing and casing pressure continuously acquired by a pair of electronic pressure transmitters (PT) and on artificial intelligence (AI) concepts such as neural nets and fuzzy logic, this firmware performs the pattern recognition of the casing and tubing pressure behavior, executes an algorithm implemented by the user and gives a diagnostic about the performance of the system. With the diagnostic and changing the values of Ti and Tc, the electronic device improves the system performance, reducing the gas consumption and increasing the liquid production. The electronic device is installed at the well site and send to the central office, by request, the data acquired from the well. At the central office, a PC computer with a modem performs a data pooling, well by well, and stores the acquired data in MS-Access type data base for further statistical and historical analysis.
MIC: Microbiologically Influenced Corrosion in Gas Transportation Pipelines
Authors: Raffa Duilio F.
Published: December 2007

The present article analyzes the intervening factors in the complex phenomenon of the Microbiologically Influenced Corrosion and its relative influences. Basing on this analysis, an information correlation methodology is proposed to establish a monitoring criteria, control and evaluation of associated risk with each factor.

Corrosion rate is the key concept in this problem; there are different types of bacteria capable of increasing this rate. Each type of microorganism will use a different mechanism, varying consequently the set of necessary conditions for this phenomenon occurrence.

To assert that MIC process is occurring it is necessary to know type and quantity of bacteria, coating state, complete characterization of soil and corrosion products, cathodic protection history, leaks, defects assessment, etc. Since several factors are necessary to increase corrosion rate, those in which information acquisition will be easier and economic, should be monitored and will be used as indicators of areas with potential MIC problems. Remaining studies would be accomplished to confirm the problem in each location in particular.

All this information will feed a risk model, which will feedback with each new intervention in the pipeline. Finally a risk map will be obtained for each piping in particular, which will permit an adequate risk and resources management in the company.
The Use of Genetic Algorithms in Well Placement Optimization
Authors: Montes Guillermo , Bartolome Pablo , Udias Angel L.
Published: December 2007

This paper is centered in the optimization of well placement using Genetic Algorithms. A Simple Genetic Algorithm program has been developed and it has been used to optimize well placement in two case studies. The effects of different internal parameters on the algorithm performance have been analyzed and a base case configuration suggested. Future modifications are analyzed.
Bimodal Behavior of Mercury-Injection Capillary Pressure Curve and Its Relationship to Pore Geometry, Rock-Quality and Production Performance in a Laminated and Heterogeneous Reservoir
Authors: Leal Libny , Barbato Roberto , Quaglia Alfonso , Porras Juan Carlos , Lazarde Hugo
Published: December 2007

The determination of pore geometry and pore aperture size from mercury injection tests is a very helpful technique. Due to the amount of pressure data points that can be taken, a detailed characterization of the capillarity of the rocks can be accomplished. The size and geometry of the pores are related to variability in grain size, sorting and packing, as well as to factors such as the mineralogy and the diagenetic history of the formation.

This paper presents the results of the integration of capillary pressure curves, conventional core analysis and petrographical Investigation, in a highly heterogeneous pore geometry, where a bimodal behavior of mercury-injection capillary pressure curves was identified, showing two main types of pore throat, one with a larger flow capacity than the other. This analysis was backed up by thin sections made in adjacent samples, where strong changes in sorting, grain size and increment in the percentage of clay matrix can be seen. The changes in pore geometry observed within such small distances, demonstrate the high heterogeneity of the reservoir rock.

An attempt was made to classify the different rock types present in the reservoir, using the Winland (R35) relationship to calculate pore throat radius based on permeability and porosity. Despite the complexity of the pore system, it was found that R35 can appropriately represent the largest portion of the rock volume with the main pore throat radius that contributes to the flow.

The fact that the mercury capillary pressure curves grouped by rock type always show the bimodal shape, was taken into account in order to understand the wells production in the reservoir, because the performance of the wells will depend on the volume of each main pore throat radius in the completed zones.
Operating Benefits Achieved by Use of Advanced Data Communications for Oil and Gas SCADA Systems
Authors: Ehrenreich Dan , May Diana
Published: December 2007

Supervisory Control And Data Acquisition (SCADA) for monitoring of oil and gas systems is now increasingly implemented for pipelines. One of the most important building blocks in such operations is the communications network.1) Widely used communications media in these systems are fiber-optic links, dial-up and leased telephone lines, analog Trunking radio systems2) and digital wireless networks. Modern communication systems allow sending messages from any remote site to any remote site in addition to the control center. Use of advanced communications protocols allows implementation of networking features, remote diagnostics and calibration ("over-the-air"), up- and downloading of programs, parameters, databases, etc.
The Conformity Assessment Program: Accreditation as a Basis for a Modern System of Regulation
Authors: da Silva G. R. , Freire A. F.
Published: December 2007

Firstly, some of the principal challenges for ANP-the Brazilian Regulatory Agency for the petroleum industrial segment - are presented: a) the diversity and the great number of Plants / Facilities and Economical Agents; b) the peculiar context after a monopolistic scenario, in evolution to a liberal one, regulated in a efficient way by the Brazilian Government. Secondly, the bases, the guidelines and the expected results of a Conformity Assessment Program are showed; in a simply overview, the program consider that Authorized Entities by the National Accreditation Organism - INMETRO - would evaluate the expected performance of the petroleum "Players", according to international rules and to specific Regulations. Finally, it is presented a Planning for development and implantation of the Program, including its stages, in an outlined 5W + 2H method (WHAT - WHY - WHO - WHERE - WHEN - HOW and HOW MUCH).
Using Tracers to Characterize Petroleum Reservoirs: Application to Carmopolis Field, Brazil
Authors: Aparecida de Melo Maria , de Holleben Carlos Roberto , Almeida Alcino Resende
Published: December 2007

A specific area under water injection in the Carmópolis field, Brazil, is been considered a candidate area for a polymer pilot project for mobility control. A reservoir characterization and an evaluation of the polymer performance in this high heterogeneous reservoir were required. For this purpose, radioactive, fluorescent and chemical tracers were applied associated with polymer in a reduced area.

The tracer technology has an enormous potential use in Petrobras scenario and this Carmópolis field application was an opportunity to obtain know-how. This paper describes the basic steps from the laboratory tests to the final application including design and programming of field operation. The interpretation of the results using a new approach is also addressed.
Geological Constrained Log Filtering as a Basis for Scale Transference
Authors: da Silva A. , Remacre A. Z.
Published: December 2007

The choice of adequate scaling procedures is a crucial issue to geological reservoir modeling. The integration of fine scale geophysical well logging and petrophysical data with seismic data, and the procedures of transferring information from detailed geological models to large scale, dynamic reservoir models have been theme of intense debate in the literature.

In this work, we propose a new approach that is focused on filtering well logging data in order to control data entry for seismic inversion and subsequent reservoir modeling.

Spectral analysis using Fast Fourier Transform is performed for a set of wells arranged around a single line along the axis of the reservoir. Lithological geophysical logging (GR, sonic, litho-density and neutronporosity log) were fourier-transformed and their power spectra were analyzed. Observed main frequencies were compared to geological derived information in order to retain only significant architectural elements of the reservoir.

Logging data are filtered for these frequencies and the resulting medium scale features are used to model synthetic wells from which the data for seismic inversion were derived. This procedure minimizes higher frequency entries at a level where they can be adequately scrutinized under a very effective geological framework.

The proposed approach effectively handles with the various scale levels of geophysical and geological acquisition by filtering information from detailed logging data, retaining important geologic features characterization, and avoiding the introduction of high frequency noises for seismic inversion algorithms.
Hydrotreatment of Oil Fractions For The Production of Low-Sulfur Diesel
Authors: Albertos Fernando
Published: December 2007

In Europe there is a continuous increase in the demand for diesel fuel. Also, regulations to reduce tail pipe emissions to the atmosphere impose new and more stringent specifications; for diesel transportation fuel, main pressure being on the reduction of sulphur and polyaromatic concentration, reduction of density and decrease of final boiling point. For example, maximum sulphur level allowed now is 350 ppm, with reductions to levels of around 50 ppm foreseen in the short term. Further reductions (even to less than 10 ppm) are also on the horizon.

Hydrotreatment (HDT), as a variety of processes, is the main tool available to the refinery industry to improve diesel quality. This paper deals with the reach of hydrotreatment (HDT) technologies to adapt diesel fuel to the new regulations. The discussion is centred on three aspects: feed processability, process conditions and catalysts employed.

Feed processability is studied in terms of how some feed properties such as sulphur content and specific gravity have an effect on the HDS conversion. Correlations are shown that explain the effect of such variables. Main process conditions such as space velocity and hydrogen partial pressure are studied, and their effect on the product sulphur level is shown. Typical CoMo and NiMo hydrotreatment catalysts are compared upon on the perspective of actual and future specifications. Changes in product properties occurring during hydrotreatment (aromatic content, cetane index and specific gravity) are also shown.

This comprehensive study of the HDT process allows us to estimate hydrotreatment requirements to adapt our refineries to future specifications of the diesel fuel.
Case History: First Coiled-Tubing-Conveyed Live Well Intervention Run From a Semi-Submersible Platform in Brazil to Increase Perforation Length in a Deep Water Horizontal Wellbore
Authors: Rosetto Ilton , Schoener-Scott Martin , Etcheverry Carlos Fulvio , Almeida Jose
Published: December 2007

This paper will describe the first coiled-tubing-conveyed perforating (CTCP) jobs performed offshore in a horizontal well in the Campos Basin, Rio de Janeiro, Brazil.

The operation was needed to obtain the objectives sought after for this well and also to provide a "learning curve" for a major job that was to be run subsequent to this job using the same method. The second job was to be in a water depth of 968 ft., and more than 1,000 ft. of guns would be run. Both jobs will be discussed in this paper along with the advantages gained on the second job from the first experience.

The first procedure required perforating of a 262-ft. interval in a 92-degree horizontal well using 2 in., 6 SPF super deep penetration scalloped guns that would be coiled-tubing deployed through 3-½ in. production tubing. The operation was to be performed from a semi-submersible platform, and the running and retrieving of the perforating guns would have to be accomplished without killing the well so that damaging completion fluids would not come into contact with the reservoir. Requirements for the job were that a safe method be used and that equipment and operational costs be kept at minimum so that a greater return on investment could be realized.

Operational conditions included the following: Perforation was to be conducted with the well in an underbalanced condition so that no formation damage would be sustained.The operation had to be run from a semi-submersible 5that was set in a water depth of 430 ft. (2nd job performed in a water depth of 968 ft.)The gun assembly would have to pass through a 2.81-in. minimum ID.

He two jobs were completed under live well conditions, and both were successful. The estimated cost saving from elimination of 3 days of rig time for the second job was approximately $360,000.

Even more significant for this technology, there are no documented jobs in which this perforation length has been attempted anywhere in the world from a semi-submersible or where the water-depth distance was used as a lubricator for the guns.
Natural Gas Supply/Demand Balance: The Case of Trinidad and Tobago
Authors: Ransome Godfrey , Furlonge Haydn
Published: December 2007

Given the anticipated development of the natural gas industry in Trinidad and Tobago, this paper addresses the supply-demand balance. A mathematical model was developed to determine the optimal reserves addition profile which meets all projected demand scenarios. It was shown that there is a need to boost reserves by up to 39 tscf in a 20-year period to satisfy a high demand scenario and to maintain a minimum reserves to production ratio of 25 years. This substantial volume would undoubtedly pose a significant exploration challenge to the country. However, substantial exploration activity is taking place and the prospects are promising.
Geostatistical Modeling and Simulation of a Compartmentalized Deltaic Sequence, Ceuta Tomoporo Field, Lake Maracaibo, Venezuela
Authors: Smith Richard , Bard Wade , Corredor Jairo , Herweijer Joost , McGuire Simon , Antunez Angel , Block Tatiana , Lazarde Natyuliz
Published: December 2007

The Ceuta Tomoporo Field is a recent development in the Maracaibo Basin ofVenezuela. Recent changes in environmental constraints have allowed PetroleosDe Venezuela S.A. (PDVSA) to begin field development on-shore, adjacent to theexisting development in Lake Maracaibo. A detailed geostatistical model isrequired to make predictions of risk, reserves assessment, and developmentstrategies for potential on-shore development that is now approved. This paperdescribes the geostatistical model and simulation that was performed.

The geological description used to describe the reservoir is based on datafrom 41 wells in the area. The majority of the wells have been drilled in thelast 3 years. Core data is limited, so core data from other wells outside thedevelopment, and vertically similar but different sections, were acquired andevaluated to describe reasonable expectations of porosity and permeability frompotential Eocene reservoir intervals. The geostatistical modeling techniquerequired a unique algorithm performed on normalized well logs to predictdefined rock types associated with expected depositional sand facies.

The geostatistical model was built for a gross interval of approximately 700feet, including the reservoir units commonly referred to in the Maracaibo Basinas units Misoa B3.4 to B6.0. Three environments of delta-marine, distributary-delta, and fluvial-deltaic were identified as a guide to localizeddepositional events. Geostatistical modeling based on 2-foot vertical intervalswere simulated and up-scaled to 73 reservoir simulation layers. Simulationhistory matching of 12 years production data required no adjustments to porevolume but compartmentalization, as evidenced by repeat formation testing (RFT)data, suggests that the structural interpretation can be improved. Waterinjection was simulated to assess reservoir pressure maintenance as a fieldmanagement alternative.

The project identifies the potential to extend present and futuredevelopments in Lake Maracaibo from completely off-shore to include on-shore.The techniques utilized in this work have been successfully demonstrated andare thus transferable to other projects.
Interference Among Acoustic Positioning Systems in Campos Basin, Brazil: A Company's Approach
Authors: Silveira Alexandre C. , Silva do Couto Luiz
Published: December 2007

Exploration and production in deep water has been a challenge to oil industry over the last years. To develop fields in over 1000 meters water depth, Petrobras had contracted most of the total fleet of Dynamic Positioning – (DP) rigs around the world and also anchor handling and special purpose vessels. Work-over operations as well wet Christmas trees installation and the deployment of manifolds and pipelines have been carried out at same time in a small area. The operation scenario can be a target circle of 5 km radio, which can comprise four rigs and others DP vessels operating at the same time. The purpose of this paper is to report how we have managed to control this critical situation and reduce the interference among the acoustic positioning systems of these vessels. For that reason, we have been assuming new technical and administrative procedures. In deep waters the signal to noise ratio at the surface transducer is the critical point. Because of the high nominal ranges required in this application, the acoustic bandwidth is very narrow, less than 30 kHz. The interference problem became more critical during the ionosphere scintillation periods, when the rigs positioning system relied solely on acoustics systems. By controlling the acoustic environment and looking for new technologies, we think we are hoping to reduce this kind of problem. The paper shows how we have controlled the acoustic environment in those areas of interest and how we have plan operations to reduce the possibility of an accident. In addition it also shows graphics and tables that will help the reader to fully understand what we have done.
Opportunities for Redevelopment of Mature Fields by Determinations of Hydraulic Units for Commingled Production
Authors: Villalba Marlene , Mendez Osmary , Marcano Cruz
Published: December 2007

In the Eastern Venezuela, Anaco area, there are about 50 mature fields of condensates and light oil which still have reserves ranging between 50 and 300 million barrels. However, a good portion of the remaining reserves are still trapped due to inefficient drainage and production declination.

This paper presents an analysis method to increase and accelerate production as well as recover additional reserves based on the detection of communication between pay sands. The study have been made in the Santa Rosa Field, which is one of the most important mature volatile oil field in the Eastern Venezuela Basin, with remaining reserves of 321 MMBLS and 4851 BCF. The integration of oil compositional data, gas chromatography and fingerprinting analysis of oils, as well as, pvt data with pressure, well test, production data and geological information have contributed to identify reservoir continuity. The identification of four oil family types into the field was achieved through Geochemistry analysis. Wells correlation reveals significant stratigraphic coalescence, and integration of these results with production and pressure data permitted to identify four hydraulic flow units.

The results of this study helped to understand the vertical and lateral connectivity of the sand bodies and aided in the distinction of areas in the field with the best infill drilling potential, both of which have contributed to optimize well location, recompletion works, and also improved the accuracy of the production performance predicted.
Economic Evaluation of a Multi-Prospect Exploratory Block
Authors: Vukelic M. , Pescara R. , Franco A.
Published: December 2007

This work describes a methodology used to evaluate an exploratory block with 56 prospects and leads. The method is based on Monte Carlo simulations of exploration and development scenarios of the entire block. We obtained probability distributions of production, capital expenditures, cash flow net present values, etc. that allow management to determine the value and understand the risk of the business. The same methodology can be used to evaluate and optimize the exploration portfolio of a company.
A Field Experience Against Corrosion: Performance Report of Bronze
Authors: Olmos D. , Ameglio A. F. , Tapia R. , da Silva L. , Ramirez G. , Poli M.
Published: December 2007

This work describes the experience in the use of Bronze-Aluminum coated sucker rods at Chihuidos de la Sierra Negra and Lomitas fields, operated by REPSOL-YPF (Rincón de los Sauces - Neuquén).

This new material was developed specifically to work in the corrosive environment of the oil producing wells of those fields. This development was a result of a team work, manufacturer and user. Its objective was to find an acceptable solution (technical and economics) for the sucker rods used at these fields.
Experience on implementation of Environmental Management System (EMS), according to ISO 14001, in Complejo Campo Durán, Salta Province, Argentina
Authors: Díaz Norberto Daniel
Published: December 2007

The target of this paper is to transmit the experience of the people of Refinor S.A., about the environment management system implementation, focusing in the motives which caused such a decision, the difficulties we had and the benefits obtained, getting a final conclusion.
New Techniques for Risk and Hazard Management in the Petrochemical Industry
Authors: Chamberlain G. A.
Published: December 2007

In today's regulatory and business environment in the petrochemical industry, the onus is placed increasingly on the plant operator to demonstrate that safety risks are tolerable and as low as reasonably practicable. The physical effects of accidents, such as explosion overpressure, heat radiation and toxic dispersion, have to be calculated to assess the threat to people and whether escalation and further threat are real possibilities. Accurate assessments based on realistic accident scenarios can avoid costly over-design in terms of protective measures and ensure that all hazards and effects are correctly identified. This paper reviews recent developments in the science, validation, quantification and application of these physical effects to improvements in plant safety. Some examples using the latest hazard assessment tools as applied to refineries, gas plants and offshore platforms will be discussed.
Integrated Reservoir Study in El Tordillo Field
Authors: Muruaga E. , Antunez E. , Nogaret C. , Stancel S.
Published: December 2007

An Integrated Reservoir Study was performed in El Tordillo Field, a very complex stratigraphic area located on North Flank of the San Jorge Basin, Argentina. Despite some limited and scarce information, Reservoir Compartments, Barriers and Original Oil/Water contacts were defined by integrating fluid content estimates derived from a Fluid Saturation Model built before, with well production, test and completion data and with the detailed mapping performed during Phase 2. A waterflood project performed in the area, was analyzed in detail in order to get sweep and recovery efficiencies.

Stochastic methods were employed to estimate the OOIP. Based on the Electrofacies results, these methods were statistically used to distribute rock types and properties in space within the volume under analysis. Consequently, statistical ranges of OOIP estimates were obtained for several intervals within the Study Area.

Qualitative Maps of Original Mobil Oil were constructed on the simulation model of the water-flooded area. Qualitative Fluid Movement Maps were constructed from the result of the numerical simulation.