bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of Sweep Efficiency of Water Injection under Fracturing-Conditions Process
Authors: Muñoz Mazo Eduin O. , Montoya Moreno Juan M. , Schiozer Denis J. 
Published: December 2007

Abstract
Water injection performance depends on the petrophysical reservoir properties and fluid-flow characteristics. Reservoir simulation models should include rock properties variation and rock-fluid interactions and, when it is necessary, geomechanical phenomena.
When water Injection above Fracture Propagation Pressure (IFPP) is used, its effects over the reservoir model performance, and specially, on waterflooding sweep efficiency, become a critical point to be assessed. Quantification of these effects using parameters such as the Recovery Factor (FR) and Net Present Value (NPV) is important for the water injection project dimensioning and to determine the feasibility and usefulness of the injection process to be implemented.
Water injection under fracturing conditions is an important method to overcome the production decline caused by the injectivity loss in reservoirs with water injection. Also, the modeling of injectivity loss and fracturing processes are subject of several studies, which aim to understand these processes in order to enhance the results to be used for the reservoir development strategy proposal.
The objective of this work is to quantify, using Sweep Efficiency and NPV as study parameters, the effects of anisotropies on the production performance during a waterflooding under fracturing conditions. The methodology proposed considers the simulation of scenarios in which the injectivity loss is represented by an analytical decline model, and the fracture is represented using a virtual horizontal well. This proposal is implemented in order to show the effect of the water injection – injectivity loss – fracturing process on the reservoir behavior. Three different fluid models were used to illustrate their effect in some production parameters and usefulness of fracturing process in several scenarios.
The results show the applicability of water injection under fracturing conditions in different scenarios. In addition, this work shows the importance of the reservoir parameters into the injectivity loss and fracture propagation models, the significance of the FR and NPV in the quantification of these effects. Finally, the relation between the heterogeneity degree and production parameters is presented.
Formation Damage Mechanisms and Their Phenomenological Modeling—An Overview
Authors: Civan Faruk 
Published: December 2007

Abstract
A review and phenomenological modeling of the various processes causing reservoir formation damage are presented. The mechanisms involved in the migration, deposition, and mobilization of the fine particles and inorganic and organic precipitates are described physically and mathematically. The various problems created by fine particles at the pore surface, clogging and dislodgment of the pore throats, aggregation, and interface particle transfer processes in multi-phase fluid systems flowing through porous media are described. The implications of the various mechanical, chemical, and thermal processes on the behavior of the particles are discussed. The various types of shock phenomena and their effects on the particulate processes are explained. The alteration of the pore connectivity, preferential hydraulic paths, permeability and porosity of porous media as a result of the various particulate processes are formulated. The phenomenological modeling of the particulate processes in single- and multiple-porosity reservoir formations is presented. The applications may concern with the damage by particles, injectivity decline in waterflooding wells, formation damage by drilling mud invasion, formation damage in naturally fractured reservoirs, asphaltene deposition, and sand production and gravel pack damage.
Residual-Oil-Induced Injectivity Impairment During PWRI
Authors: Vaz A. S. L. , Bedrikovetsky P. , Furtado C. , de Souza A. L. S. 
Published: December 2007

Abstract
Injection of water with oily particles happens during waterflooding by re-injection of produced water (PWRI). The injected oily particles are captured by porous rock causing decrease of permeability and consequent injectivity decline. Maintenance of the injection rate results in increase of pressure gradient near to well, snap-off the residual oil and additional formation damage due to released drops retention.
We study effects of residual oil mobilization in well vicinity due to pressure gradient increase and, consequently, the increase of capillary number. The mobilized oil ganglia perform snap-off, move together with the injected water; they are captured by rock causing additional formation damage.
The system of governing equations includes mass balances for oil, for particles and equation for desaturation curve. The analytical model derived includes expressions for suspended and deposited particle concentrations, for velocities of concentration fronts and for injectivity decline.
The main result is an additional formation damage induced by residual oil.
Comparison of the injectivity decline models with and without residual oil allows estimate the efficiency of the near-well area treatment by solvent in order to remove residual oil and to reduce injectivity decline.
Another important application of the model is determination of residual oil with PWRI from routine coreflood tests on relative phase permeabilities. If one injects produced water, the formation damage caused by the capture of injected particles and release of excessive residual oil fraction must be taken into account.
A Comprehensive Model for Injectivity Decline Prediction during PWRI
Authors: Paiva R. , Bedrikovetsky P. , Furtado C. , Siqueira A. G. , de Souza A. L. S. 
Published: December 2007

Abstract
Injectivity decline is a chronicle disaster during produced water re-injection (PWRI); the phenomenon has been widely reported in the literature for North Sea, Gulf of Mexico and Campos Basin fields. The damage happens due to solid and liquid particles in the re-injected water. The injectivity decline prediction is important for planning and design of PWRI, of injected water treatment and of well stimulation procedures. The reliable prediction should be based on mathematical modelling using well injectivity index history and laboratory data.
The mathematical models for deep bed filtration of particles and for external filter cake formation have been developed and adjusted to coreflood and well data by numerous authors (Sharma, Khatib, Wennberg et. al.). Here we add modelling of external cake erosion during well closing by the growing cake and filling the well by the erosion particles and develop a comprehensive model.
The comprehensive model predicts very peculiar injectivity index (II) curve: initial II increase due to displacement of oil by less viscous water, slow II decline due to deep bed filtration, fast II decrease during external filter cake formation, II stabilization due to cake erosion during the rat hole filling by the eroded particles and further II decrease during well column filling by erosion products.
The model is implemented in Excel; the software SPIN Simulates and Predicts the INjectivity.
We present in details the history matching for three injectors (field X, Campos Basin, Brazil), showing good agreement between modelling and well data. The obtained values of injectivity damage parameters lay in the same rage intervals as those calculated from laboratory corefloods.
New Method to Squeeze Perforations and Reduce Sand Production
Authors: Ramon F. , Galacho N. , Crotti M. A. 
Published: December 2007

Abstract
This paper describes a new method to squeeze perforations using non toxic chemical products. The product, belonging to the cyanoacrilate family (Ref 1), reacts with connate water dramatically reducing rock permeability in the injected intervals. Some technological solutions using this methodology are discussed. A variation of this methodology can be used to reduce or control sand production in low consolidated sandstones.
At the present time, useless perforations are plugged by squeezing cement into the perforating tunnel. The proposed alternative method is to eliminate fluid conduction through the perforations blocking the permeability in the surrounding formation. To obtain this, non toxic, low cost chemical products are injected to react with connate water, generating a mechanical resistant structure with negligible permeability. A simplified alternative allows for sand control. In this case the proposed methodology the products react partially with connate water, bridging together the sand grains. The chemical product is similar to that used to squeeze the perforating, but at lower concentrations. Several lab tests have been run to check the principles and limits of the chemical products used.
Consequently, it is now available a new system to plug useless perforation by injection of a chemical product, at low cost and operationally safe.
Using this new methodology it is possible to minimize cost and time during workover operation.
Holistic Fracture Diagnostics
Authors: Barree R. D. , Barree V. L. , Craig D. P. 
Published: December 2007

Abstract
Since the introduction of the G-function derivative analysis, pre-frac diagnostic injection tests have become a valuable and commonly used technique. Unfortunately, the technique is frequently misapplied or misinterpreted leading to confusion and misdiagnosis of fracturing parameters. This paper presents a consistent method of analysis of the G-function, its derivatives, and its relationship to other diagnostic techniques including square-root(time) and log(Δpwf)-log(Δt) plots and their appropriate diagnostic derivatives. Actual field test examples are given for the most common diagnostic curve signatures.
Characterization of Sulfate-Scaling Formation Damage from Pressure Measurements
Authors: Bedrikovetsky P. , Marotti M. , Lima Neto I. A. , Carageorgos T. 
Published: December 2007

AbstractMixing of sea- and production waters during waterflooding of offshore oil reservoirs results in reaction of barium and sulphate ions causing precipitation of barium sulphate with consequent rock permeability decrease and well productivity decline. The reliable productivity decline prediction is based on mathematical modelling with well-known model coefficients. The sulphate scaling system contains two governing parameters: the kinetics coefficient characterising the velocity of chemical reaction and the formation damage coefficient showing how the permeability decreases due to salt precipitation.Previous works have derived analytical-model-based method for determination of both coefficients from breakthrough concentration and pressure drop during laboratory coreflood on quasi steady state commingled flow of injected and formation waters. The current study extends the method and derives formulae for calculation of two scale damage coefficients from just pressure drop measurements during two corefloods with two different ratios "formation water: seawater".Data from series of three corefloods on commingled injection with three different "formation water: seawater" ratios, were treated. Equality of scaling damage parameters as obtained from three different floods in similar artificial cores validates the method proposed.
Attaining Performance, Deliverability and Cost-Effectiveness with Solid Expandable Tubular Systems
Authors: El-Mofty Wael , Rivenbark Mark 
Published: December 2007

Abstract
Successful implementation of solid expandable tubular technology provides a viable example of how reservoir management, petroleum engineering, drilling and technology work in harmony to achieve the ultimate goal—high rate of internal return and expeditious payback. Slimming big-foot wells while minimizing the tapering effect of casing profiles is one of the most cost-effective and technically challenging objectives in modern well designs; this has become safely possible in candidate wells with solid expandable tubular systems.
The technology involves downhole cold-working of steel pipe by expanding the diameter beyond its elastic limits to the permanent plastic deformation region. Studies on hoop-stress resilience during expansion, as well as the mechanical and chemical properties of post expanded pipe promoted the technology for field applications.
The ability to expand casing in situ enables hole size maintenance and conservation of internal casing diameter for increased completion and production efficiency. Smart deployments of solid expandable systems to deliver larger production/injection hole diameters have enabled their use as conduits for surface-controlled selective production/interval isolation devices. This feature has enabled geo-steered laterals to be drilled for extended departures, exposing maximum possible surface area of the reservoir for optimum drainage. Drastic improvements of power water injection placement and reliable zonal isolation as an outcome of smart deployment of this technology have resulted in maximizing efficiency of water-flood and other secondary recovery techniques.
This paper analyzes the value propositions of integrating solid expandable tubular technology in candidate wellbore construction designs. It also addresses the effects of improved reservoir architecture on long-term production profiles and analyzes the positive environmental impact of the technology with parallel focus on techno-economic feasibility and constraints.
Modeling of Facies and Net-to-Gross Ratio Conditioned by Seismic Attribute Maps
Authors: Ferreira Guedes Carlos Conforti , Sarzenski Darci Jose , dos Santos Renato Luiz Almeida , de Almeida Costa Flaviana 
Published: December 2007

Abstract
The facies and net-to-gross ratio (NTG) modeling methodology presented in this paper has been successfully applied on geological characterization of a giant field at Campos Basin, offshore Brazil. Such methodology aimed to preserve the seismic attribute original trend for NTG property in the facies model. In this way, more reliable horizontal parameters could be determined. These are usually hard to obtain, due to the scarceness and huge spacing between wells in an oilfield at its initial development stages.
The technique may be described as follows: Choice of a seismic attribute that shows good correlation with average NTG at wells using programme Log Property Mapping (SIS-Schlumberger Information Solutions). After that one must elaborate a non-reservoir average distribution map (NR=1-NTG map).Generation of reservoir facies proportion maps (three altogether) obtained by facies proportion interpolation at the wells (collocated co-Kriging) using the NTG distribution map as a secondary variable.Determination of horizontal variogram parameters. These are used in the non-reservoir facies simulation (from NTG distribution map) and correlated with vertical variogram range, obtained from well data.Determination of horizontal variogram parameters for each of the three reservoir facies using ratios between horizontal variograms range (two directions) and the vertical ones.Determination of NTG, naming 1 for reservoir facies and 0 for non-reservoir facies.
In the modeling phase, mainly in the upscaling step, a particular interval named inter-stratified has been given special treatment. It shows a NTG value around 50% (against a 85% value for the field as a whole) and has been defined in order to preserve the critical reservoir heterogeneities. Once treated in a different way during the upscaling step, its characteristics can be preserved during the scale transfer, and consequently improving history match.
New Attempt in Improving Sweep Efficiency at the Mature Koluel Kaike and Piedra Clavada Waterflooding Projects of the S. Jorge Basin in Argentina
Authors: Paez Yañez Pablo Adrian , Luis Mustoni Jorge , Relling Maximo F. , Chang Kin-Tai , Hopkinson Paul , Frampton Harry 
Published: December 2007

Proposal
Most of the mature waterflood projects at the San Jorge Basin have been affected by two main problems, poor displacement and sweep efficiencies, both have limited the recovery factor achievable.
This paper presents a field trial of a new reactive particulate system in an attempt to improve this volumetric sweep efficiency. This particulate system is being used to treat selected injectors operated by Pan American Energy in the Koluel Kaike and Piedra Clavada fields, located in the southern part of Argentina. The main purpose of this field trial is to demonstrate the ability of the new system to improve oil recovery by diversion of injected water into the poorly swept zones around the thief zone or streaks.
This state-of-the-art technology is able to propagate deep into thief zones and has a novel mechanism of action to overcome the observed limitations in conventional polymer flooding and gel processes. The particles are manufactured having properties which allow it to propagate through porous media with the injection water. Once in the reservoir and under the influence of heat the particle expands to a size that can block pore throats, so water injected after treatment is diverted into less efficiently swept zones.
The paper will describe in detail the mechanism and selection criteria of reservoirs and wells to apply the mentioned IOR technology. Theoretical and practical issues involved at the design of the application, as well as operational and logistics aspects will be also included. Finally, it will include the updated information available from the ongoing pilot tests.
Offshore Exploration in the Golfo San Jorge Basin: A Technological Challenge 100 Years after the Discovery of Oil in Well 2
Authors: Clavijo Ricardo , Effendi Yudistira , Ortin Anna 
Published: December 2007

Abstract
There have been three attempts since the 70s to explore the offshore extension of Golfo San Jorge Basin, a prolific onshore province in Patagonia (Argentina) with more than 100 years of activity. Although some non commercial accumulations were found, none of these attempts was successful to find a discovery with enough oil resources to make an offshore development project viable. In this study we will discuss the reasons for this failure, and the keys for a new attempt in the area.
Besides high crude oil prices have been a triggering factor in this renewed interest, new petroleum system models have allowed the definition of undrilled areas with potential for a feasible offshore development. A number of prospects and leads with moderate geological risk have been defined in these undrilled areas.
The low productivity of Golfo San Jorge reservoirs restricts the possible development options. Chubut Group reservoirs are mainly composed of thin and disconnected fluvial sandstones, with limited petrophysical conditions, leading to multiple independent traps with different reservoir pressures, hydrocarbon types and fluid contacts. Thus, new technologies to be applied in reservoir and production engineering represent a real challenge for the economy of the project.
Different engineering options including new technologies for drilling, testing and production are under study and will be applied to make this new attemp a success. The new reserves consequently incorporated would replace the natural decline of production in the mature onshore areas.
Hydrocarbon Generation, Migration, and Accumulation Related to Igneous Intrusions: An Atypical Petroleum System from the Neuquen Basin of Argentina
Authors: Rodríguez Felipe , Villar Héctor J. , Baudino Roger 
Published: December 2007

Abstract
The stratigraphic record of the Altiplanicie del Payún area, in the Northern Platform of the Neuquén Basin, Argentina, includes Tertiary sills and laccolites that reach thicknesses of up to 600 m. Occurrence of thermally immature oil-prone shales of the Late Jurassic Vaca Muerta and the Hauterivian Agrio Formations is profusely documented in the area. However, when sills have intruded the Vaca Muerta shales, source rock sections become mature, displaying a wide-ranging maturity spectrum spanning thicknesses that exceed 400 m.
Commercial oil accumulations (20-33°API) and oil shows are found along the entire column, both in sandstone/carbonate reservoirs and fractured intrusives reservoirs. Oil-oil and oil-source rock correlations suggest a local generation related to the thermal effect of the intrusive bodies. Concurrently, diamondoid analyses point to mixtures of high-mature (cracked) with low-mature hydrocarbons: oils generated and cracked close to sills are considered to be mixed with oils generated from more distant source rock sections less affected by the thermal effect of the igneous bodies, as they migrate towards the sills and shallower reservoirs.
A 2D model that included the thermal effect of the three main igneous bodies of the area was satisfactory achieved, accounting for thermal maturation, oil and gas generation, migration and accumulation. From the modeling, hydrocarbons migration is favored by elevated generation pressures, source rock fracturing and convective water flows.
The integration of geochemical data and 2D-modeling of petroleum generation and migration related to the thermal effect of the igneous bodies led to the better understanding of this atypical petroleum system.
Hybridizing Genetic Algorithms and Real Options to Approach of the Optimal Decision Rule for Oilfield Development Under Uncertainties
Authors: Lazo Lazo Juan G. , Pacheco Marco Aurélio C. , Vellasco Marley M. V. R. 
Published: December 2007

Abstract
A decision to invest in the development of an oil reserve requires an in-depth analysis of several uncertainty factors. Such uncertainties may involve either technical uncertainties related to the size and economic quality of the reserve, or market uncertainties. When a great number of alternatives or options of investment are involved, the task of selecting the best alternative or a decision rule is very important and complex, due to the considerable number of possibilities and parameters that must be taken into account. This paper proposes a new model, based on Real Option Theory, Genetic Algorithms and Monte Carlo simulation, to find an optimal decision rule for alternatives of investment regarding the development of an oil field under market uncertainty. The objective of this new model is to help decision-making in the following situation: immediate development of a field or wait until market conditions are more favorable. This optimal decision rule is formed by three mutually exclusive alternatives, which describe three exercise regions through time, up to the expiration of the concession of the field. The Monte Carlo simulation is employed within the genetic algorithm to simulate the possible paths of oil prices up to the expiration date. The Mean-Reversion Process is assumed as the stochastic process for the oil price. A technique of variance reduction was also used to improve the computational efficiency of the Monte Carlo simulation.