bluuebunny/crossref_metadata_2025_split huggingface dataset:
Performance of Scale Inhibitors in Squeeze Application
Authors: Brod M. 
Published: December 2007

AbstractThis paper reports an investigation into the relative performance of scale inhibitors in squeeze treatment in conditions typical of the U.K. North Sea. The methods used were to run laboratory core tests, model the results using the new computer software "SQUEEZE", and compare the outcome with field experience.At low water throughput rates, satisfactory modelling could be achieved assuming a simple Freundlich isotherm, although there is evidence that this does not represent a true equilibrium situation. At higher water flows, certain products deviate from the Freundlich isotherm. The deviation takes the form of a reduction in the rate at which inhibitor return concentration goes down with time or cumulative production. The return curve may remain at a level almost until depletion. It was not found possible to model these deviated curves.For a moderate deviation from the isotherm, the decline is arrested at a low scale inhibitor concentration and effective squeeze life is extended. As water throughput increases further, the plateau occurs at a higher concentration and depletion is brought forward. The critical water production rate for a specific product in the cases studied was about 5000 bbl/D.
The Modelling and Design of Scale Inhibitor Squeeze Treatments in Complex Reservoirs
Authors: Sorbie K. S. , Yuan Ming Dong , Todd A. C. , Wat R. M. S. 
Published: December 2007

Abstract
This paper describes the formulation and application of a simulation tool for modeling scale inhibitor adsorption squeeze treatments in realistic reservoir formations. In this simulator, a three-dimensional (3D), three-phase black oil reservoir model is used to calculate the larger scale reservoir flows such as the local well layer flow rates and watercuts, and the near wellbore area water saturations. However, a very accurate fine grid near well simulation model is embedded into this reservoir scale calculation which models all of the inhibitor transport, including adsorption/desorption behaviour and dispersion, within the maximum penetration distance of the injected inhibitor. Since this penetration distance may only be tens of feet which is generally much smaller than a single grid block in a reservoir model, a rme radial subgrid is used to accurately track the injection and backproduction of the inhibitor. It is demonstrated that this approach provides a vast improvement over any previous methods of modeling this process.
In the paper, the one layer single well radial model is first presented with examples of its application. This is followed by the description of the full reservoir inhibitor squeeze simulator combining the black oil model and the fine grid radial squeeze model. The application of this simulator to some realistic near-well inhibitor squeeze treatments and the key factors governing the process in a heterogeneous formation are then examined. The issues studied include the following; the form and type of inhibitor adsorption isotherm, the equilibrium/non-equilibrium adsorption/desorption processes, the effect of degree and type of reservoir heterogeneity, the concentration of the injected inhibitor slug and the significance of overflush size.
Removal of Hydrocarbons From Oilfield Brines by Flocculation With Carbon Dioxide
Authors: Burke N. E. , Curtice S. , Little C. T. , Seibert A. F. 
Published: December 2007

Abstract
The objective of this research was to develop a model to describe the removal of dispersed petroleum hydrocarbons from oil-field brines using carbon dioxide in a sieve tray extraction column. The model consists of two parts: hydrodynamics of bubble flow and flocculation. The flocculation part of the model will be presented in this work. The system studied in this work was a brine from a California steamflood. The California brine contained a nominal 1000 mg/L of a heavy, asphaltic crude oil (13.2 °API) and had a total salinity of approximately 500 mg/L. The flocculation model was tested with experimental runs at pressures of 83.75 and 97.54 bar and temperarures of 23.9,37.8 and 65.6 °C. Additional flocculation runs were made at pressures of 14.80,42.38, and 69.96 bar at 65.6 °C. It was determined that the flocculation of the dispersed oil droplets was the result of two separate effects: a pH effect due to the acidity of carbon dioxide and a shear effect due to the rising carbon dioxide bubbles. . It was necessary to use an empirical flocculation efficiency in the model in order to effectively predict removal efficiencies for each operating condition.
Modelling of the Collapse of Unconsolidated Rock Formations During Production
Authors: da Fontoura S.A.B. , dos Santos H.M.R. 
Published: December 2007

Abstract
The definition for the maximum allowable drawdown for sand free production in uncased and cased wellbores is discussed herein. An analytical procedure is developed to evaluate the effective stresses around wellbores during production. This methodology takes into account a general stress field as production. This methodology takes into account a general stress field as well as wellbore inclination and azimuth and allows for the mechanical failure of the formation. A number of computational experiments are carried out to demonstrate the effects of the in-situ stress ratios and formation cohesion upon the maximum allowable drawdown for sand free production. production.

Introduction
Large oil and gas reserves stored in rock formations known as unconsolidated or weakly cemented sands are known to exist in several areas. In general, these low-strength rocks do not support the stresses that are generated during the flow of the produced fluid through the formation and eventually faliure will occur causing the breakout of the rock. The positioning of the failed rock mass around the wellbore dictates the conditions for the removal of solids from the formation and its transport by the produced fluid. The transport of solid by the produced fluid is known to be the cause of a number of undesirable problems such as damage to submersible pumps, plugging off the case perforations, and, eventually, total invasion of the production column.
In order to address the questions associated with the production of solids and its impact on the economics of the reservoir expolitation, it is mandatory to have a scheme to predict whether and when a given rock formation subjected to a given production rate will produce solids.
Ideally, for the purpose of selecting a proper completion scheme and of planning the well production strategy, the completion engineer should be planning the well production strategy, the completion engineer should be able to define the maximum allowable drawdown that guarantees sand free production throughout the operational life of the well. This paper production throughout the operational life of the well. This paper discusses some of the necessary steps involved in the determination maximum allowable drawdown for sand free oil production. Initially, a conceptual model for sand production is presented in which both the sufficient and necessary conditions for sand production are highlighted. This conceptual model is used as a background to review critically the existing sand production prediction tools as well as to formulate guidelines for the production prediction tools as well as to formulate guidelines for the development of new analytical prediction methods.
Cation Exchange Capacity Data Derived from Well Logs
Authors: Ramirez Miguel Orlando 
Published: December 2007

ABSTRACT
The Cation Exchange Capacity (CEC) of a formation is an important parameter for the correction of resistivity measurements in the calculation of water and hydrocarbon saturations. Clays in sands provide an electrical conductive path that is related to CEC. This conductivity is parallel and in addition to the conductivity obtained from the pore water. As a result, formations with clay minerals present will be less resistive than if they were the simple systems of quartz and fluids used in most models which are erroneously evaluated since the hydrocarbon saturation decreases. Normally, the only way of determining CEC is in the laboratory, but this way is expensive, and suffers from significant dispersion of results due to differences in laboratory effectiveness in cation replacement, removal of excess cation as well as possible interference. This paper describes the results obtained by calculating CEC from well logs, using the normalized Qv concept of the Juhasz equation. Qv is the cation exchange capacity per unit total pore volume and is calculated from the FDC/CNL and natural gamma ray spectral logging information. A very large and high quality log and laboratory data from low oil gravity shaly sands of the Orinoco Oil Belt was used in order to obtain accurate results. Laboratory measurements of CEC made in cores and sidewall cores, and CEC calculated from a geochemical model, show a remarkably good agreement with the continuous CEC log derived values.
Multiphase Pipeline: A Solution to Cost Savings in Offshore Production
Authors: Guy Jean-Michel , de Merville Eric , Bernicot Michel 
Published: December 2007

ABSTRACT
Offshore production is always considered as a costly and hazardous business.
Multiphase production concepts applied to sealines may lead to considerable reduction in production costs and potential safely hazards due to simultaneous presence of men and production equipment on offshore platforms.
TOTAL experience in multiphase flow transportation systems was once again used for the development of HIDRA field in Tierra del Fuego (Argentina).
This original development scheme comprises two unmanned offshore wellhead platforms linked together by a 3.6 km long 14" sealine. The overall production is then routed without separation to the onshore processing facilities via a 12.8 km long 20" sealine.
This article describes the operating experience of such system on Hidra field and in particular the ways to cope with the hydraulic behaviour of the sealines and its consequences.
Paraffin Precipitation in the Formation in Dom João Field, Brazil
Authors: Romeu Régis Kruel , Khalil Carlos Nagib , Rabinovitz André 
Published: December 2007

ABSTRACT
Despite prolonged water injection and a number of reservoir studies, only 10% of the original oil in place has been recovered during 43 years of production from shallow reservoirs in the Dom João oil field, Recôncavo Basin. The formation temperature being close to the pour point of the crude oil raises the possibility for the ocurrence of paraffin precipitation in the reservoir. A field stimulation test was performed using a nitrogen generation system/emulsion (SGN/EMULSÃO) technique. Two nitrogenated salt solutions, emulsified in a selected organic solvent, were injected into the formation through a single well; their reaction released both nitrogen and heat, in turn yielding a capacity to remove paraffin deposits. A comparison between the production rates and oil compositions before and after stimulation indicates that paraffin deposition was occurring inside the formation. A possible explanation for this phenomenon would be the cooling effect resulting from a post-migration uplifting of the the formation.
Development of a Subsea Module Deployment System for the Disps Project
Authors: Rodda Norman , Paritt Stephen 
Published: December 2007

ABSTRACT
The paper will describe a prototype system developed for deploying equipment packages (modules) without guidelines onto a diverless seabed template in deepwater. The two principal components of the system, namely a negatively buoyant load carrying underwater vehicle (Remote Guidance Vehicle - RGV) and a heave compensated lift wire system (Heave compensation Winch - HCW) have_been designed and manufactured. The RGV was systematically tested in 150 metres of water. This testing demonstrated the suitability of the design and computer simulation for a remotely operated vehicle system to deploy subsea modules in 400 metres water depths and be capable of use in up to 750 metres.
A Systematic Determination of Formation Damage Causes
Authors: Di Giorgi Plínio 
Published: December 2007

ABSTRACTA new approach is presented for determining the source of formation damage. Based on a train of formation damage evaluation, this comprehensive approach endeavors to (1) improve diagnoses of sources of damage relying on our present knowledge of the topic and (2) identify the critical links within the train and suggest possible advances therein so that damage diagnoses may be made more accurate. The crucial question Is our current inadequate theoretical understanding of the links between physical and chemical phenomena and the nature of each damage mechanism.
Automated Interpretation of Drillstem Tests Pressure Data
Authors: Vidal José Oliveira , de França Correa Antônio Cláudio 
Published: December 2007

ABSTRACT
This paper describes a method for automated interpretation of drillstem tests (DST's) for the cases in which the produced fluids do not fill up the drillstring.
The method is based upon the pressure matching of field data with a theoretical fluid flow model through the use of an unconstrained non-linear regression technique, coupled with numerical inversion of Laplace transforms of the wellbore pressure for both flowing and shut-in periods. The parameter gradients required to implement the fitting process have also been obtained by numerically inverting closed form expressions from Laplace space.
A DST has been treated as a ''slug test" with a step change in the wellbore storage coefficient at shut-in time. With this concept it has been possible to interpret flow and shut-in pressure data simultaneously.
Both simulated and field pressure data have been analyzed in order to illustrate the application of the method using a fluid flow model which considers a homogeneous and infinite reservoir system, inclunding wellbore storage and skin effects.
Application of the method presented in this work to field data may yield estimates of reservoir and wellbore parameters such as the formation permeability, the skin effect and the initial reservoir pressure. Such parameters are important to the determination of wellbore condition and to the forecast of hydrocarbon production.
The methodology described in this paper may be used to extend the automated data fitting algorithm to include more complex fluid flow models, such as fractured or composite systems and other flow geometries.
Interfaces for Remote Operation of Subsea Equipment
Authors: Ribeiro Orlando José S. , Conti Fábio Kerr P. , Flores Mário César X. 
Published: December 2007

ABSTRACTThe availability of a Subsea Production System is closely related to the efficiency of subsea equipment maintenance. Therefore, the use of Remote Operated Vehicles (ROV) is a simple and effective method to perform several tasks which can contribute to increase the system availability.This paper presents the ROV interfaces designed for the operation of small valves, connection of hot stab tools and override of Wet Christmas Tree valve actuators.These interfaces will be standardized for the subsea equipment used by PETROBRÁS, after field testing.
Albacora, a Deepwater Giant Field Development
Authors: Pereira de Oliveira Carlos Alberto , Guimarães Dias Marco Antônio 
Published: December 2007

ABSTRACT
Albacora, a giant field located under water depths ranging from 230m to 1,900m, in Campos Basin, offshore Brazil, has an estimated oil-in-place volume of 4.4 billion bbl and extends over an area of 235 km2. The development plan conceived for this field has been divided into three phases, which the first one is a cost-effective pilot production system, which has started field production in October, 1987. This paper describes many alternatives under study by PETROBRAS for installation of the second phase of the field exploitation. Water depths of the wellheads at this phase will reach 1,166m and the start-up is expected to occur in 1994, with a peak production of nearly 200,000 bopd in 1996. The alternatives differ basically in parameters such as the type (semi-submersible, compliant tower, jacket), quantity, size and location of the production units, the type and configuration of the subsea systems, the type of the production and export risers (rigid, semi-rigid or flexible) and also the level of the infra-structure integration. An economical analysis ends the paper and shows that Phase II, besides of performing a pioneer conception at world level, is also a cost-effective production system.
Procelab-Laboratory Methods and Procedures for Oilwell Cementing
Authors: Silva Marins Carlos César , da Rosa Flávio Costa , de Assis Costa Lucelena Ferreira 
Published: December 2007

ABSTRACT
PROCELAB is a manual wrlttten in Portuguese, standardizing laboratory procedures and methods for oilwell cementing, it was cooperatively elaborated by a group of technicians employed by PETROBRÁS and service companies operating in Brazil. its major approach is to assure the reliability of results from tests conducted by laboratories involved with oilwell cement slurries. The manual develops topics which complement the API Spec 10, including from the sampling of cement, water and chemicals to the supply of test results.
Predicting Reservoir Quality in the Cretaceous Maceió Member of the Sergipe - Alagoas Basin, Northeast Brazil
Authors: de Abreu Carlos Jorge 
Published: December 2007

ABSTRACT
Porosity and permeability of the sandstones of the Cretaceous Maceió Member of the Muribeca Formation were studied in 51 cores in the northeastern half of the Sergipe-Alagoas basin of Brazil's passive continental margin. Here the Maceió Member is a feldspathic sandstone that thickens offshore to more than 5.000m. The Maceió includes seven facies ranging from alluvial to submarine fans and includes lacustrine and evaporite environments.
One hundred and thirteen thin sections from plugs were used to systematically quantify 12 pore types and stepwise regression helped to identify the best predictors of plug permeability - intergranular clean pores, intergranular pores with residual solids, and intergranular open pores with carbonate cement. Over 90 clay mineral analyses were made and contributed to the understanding of diagenetic history of the sandstones.
The most important conclusions include the following: Everywhere in the Maceió porosity and permeability are best at the top and highest values occur where it is shallow and near the outcrop. Intergranular secondary porosity is predominant at the top throughout the Maceió and is the best predictor of permeability. Most of the intergranular porosity, especially where the Maceó is shallow, was formed by invasion of meteoric waters. However, minor porosities possibly formed by organic acids in the deeply buried Maceió.
Results of this investigation have been guiding the exploratory geologists encharged for new locations of wells in the Maceió Member.
Effects of the Detrital Composition and Early Carbonate Cementation on Porosity Loss in Sandstones: An Integrated Petrographic and Experimental Approach
Authors: Souza Rogério Schiffer , Elias Vera Lúcia 
Published: December 2007

ABSTRACT
In general, sands at the time of deposition present initial porosity around 40-55%. This primary porosity is reduced by mechanical compaction and/or cementation with increasing burial.
The intensity of the mechanical compaction is a function of detrital mineralogy and grain shape (BENSON, 1981) 1
This paper deals with the relationship among detrital composition, carbonate cement and porosity loss by mechanical compaction.
Statistical analysis from petrophysical data, systematic petrography and experimental analysis were done with sandstones, with variable amounts of ductile grains and carbonate cement.
This study showed that porosity and permeability reduction were more effective in sandstones which present greater amounts of ductile grains. However, petrographic evidences demostrated that early diagenetic process, such as carbonate cementation, can support the mechanically unstable lithoclasts against increasing overburden, preserving the potential porosity and permeability.
Offshore Service Submarine for 1500 m Water Depth
Authors: Freitas Ayres 
Published: December 2007

ABSTRACT
The offshore activities in deeper waters have initiated the development of offshore submarines for subsea work. Several concepts have been produced.
A new concept for a work submarine for operations in water depths up to 1500 m has been developed. This is a short range vessel operating from a base close to the field.
The submarine is powered by a closed cycle diesel engine and propelled by pressure compensated hydraulic thrusters. The life support system has a regenerative CO2 absorption plant.
The submarine can rest on the wellhead protection structure and perform tasks ranging from inspection to module change out and intervention operations. The advantage of the submarine over surface vessels is that it can work close to the subsea site in a calm environment and without the encumbrance of long guide wires and umbilicals.
Reducing Numerical Diffusion in the Modelling of Sharp Saturation Fronts: A Conservation - Law Approach
Authors: Shaw David C. , Dozzo Joseph A. 
Published: December 2007

ABSTRACT
Reservoir studies are often directed at specifically evaluating, amongst other things: The Sweep of Injected Water in a Waterflood, Tracing Injected Gas Through a Field, The Efficiency of a Polymer or Miscible Component Flood. Each of these problems can be completely obscured by the presence of numerical diffusion, which dominates and masks out true, physical saturation changes.
No finite-difference method yet developed which relies on a fixed grid can claim to accurately model any sharp saturation front without degrading it eventually into a smooth, uniform distribution. It is pointless to try and remedy this by increasing the truncation accuracy of the scheme, since it is the physical dynamics of the approximation which are important.
The basic difficulties in capturing and tracing any sharp saturation front with time are best understood by considering the fundamental property laws which are necessary for a physical solution. These are: Conservation Properties, Boundedness Properties, Transport Properties and Shock Capture.
We describe a method based on the finite-element scheme which allows these laws to be closely approximated. In addition, its formulation is such that it can be incorporated easily into existing IMPES black-oil and compositional simulators. The method is validated by comparison with one- and two-dimensional laboratory experiments and by numerical experiments designed to trap shock waves.