bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing Reservoir Permeability to Hydrocarbons With Microsolution Technologies
Authors: Gwartney Gary , Stephen Mark , Leeds C. Monty , Rea Tony 
Published: December 2007

Abstract
The focus of this paper is to discuss the importance of controlling multiple phase interfacial tension between all solids, liquids and gas phases associated with the drilling, completion and maintenance of wells. Particular emphasis will be placed on mature reservoirs, low pressure reservoirs, under saturated reservoirs, low perm reservoirs and their relative hydrocarbon production potential sensitivities associated with the interactions between the fluids and chemicals introduced during the various phases of the life of the well. Supporting laboratory studies and field case histories will be included.
Optimizing reservoir potential in mature, low pressure, under saturated and low perm reservoir environments requires a pro-active engineering design for the well construction and maintenance processes. The intermediate bridge technology between the reservoir and the mechanical equipment throughout the wells existence are the fluids employed to drill, cement, complete, workover and stimulate the well. These fluids and components therein are the primary bridge technologies for enhancing mechanical performance during the well construction process. More importantly these fluids are the primary foreign contact medium with the reservoir and therefore are secondary only to the reservoir quality in defining production potential.
Fluid and chemical selections are therefore dependent upon the rock and insitu fluid characteristics of not only the reservoir but all exposed formations during the drilling process. In all cases, fluid selection should focus on limiting the transference of free fluid from the bulk fluid phase to the reservoir, controlling highly mobile fluid invasion and optimizing surface forces between the rock, fluids and gases associated with the imbibition and invasion processes. Controlling the negative aspects of these interactions with micro-solution technologies minimizes filtercake lift off pressures, optimizes flow back of imbibed and invaded fluids during the drilling and completion processes and minimizes phase trapping. Employing micro-solution technologies in the workover processes improves remediating fluid efficiencies, idealizes the reservoirs permeability to hydrocarbons and the reservoirs production potential.
Surface Facilities Development for Mature Fields
Authors: Morales Rafael , Navarro Jorge 
Published: December 2007

Abstract
This work shows the main considerations adopted and proved successful for oilfield reactivation and production increase through the handling of very high gross production flow rate with high water/oil ratio. The execution strategy is focused on maximizing the production anticipation in the short-term by taking maximum advantage of the existing facilities and, in the mid- term, by developing facilities with new systems sized with flexibility and supplying them timely. All of these allowing to take advantage of the most suitable technologies existing in the market for handling, separation, treatment and disposition of high produced water flow rates, during the lifetime contract for each oilfield.
Examples of this approach are the study cases presented related to water injection for secondary recovery and disposal purposes. The knowledge obtained during the development and operation of a given mature field, has been adapted for its application in another field, and so on, considering particular features and different contractual terms, allowing PESA to success in very mature oilfields with apparently very restricted development opportunities.
Measuring CO2 in Coalbed Reservoirs
Authors: MacDonald Steven A. 
Published: December 2007

Abstract
Carbon Dioxide in aqueous coal reservoirs has import implications for a number of different applications. Detection and quantification of CO2 for sequestration, enhanced recovery of methane and/or naturally occurring CO2 can give valuable information that affects engineering decisions. In-situ Raman spectroscopy has been utilized to provide laboratory quality spectra of reservoir fluids in aqueous geological reservoirs. These spectra can be analyzed in real time to quantify the amounts of CO2 found in the reservoir. This gives the ability to monitor, spatially and temporally the amounts of CO2 in the reservoir.
New Oxidizing Breaker for Filter-Cake Removal at Low Temperature.
Authors: Albonico P. , Cobianco S. , Bianchi D. , D'Aloisio R. 
Published: December 2007

Abstract
The new generation of Drill-In Fluids have been developed to mitigate the potential of damage the producing formation and eliminate the need for post-completion cleanup. However depending on the reservoir features and the architecture selected for completing the well a significant reduction of the well productivity or injectivity can be caused by filtercake formation. The common approach is the application of breakers such as acids, strong oxidizers or enzymes. When an oxidizer treatment is the preferred option, high concentration solutions are usually applied at temperatures higher than 50-60 °C. Recently, the requirement of an effective oxidant breaker, as an alternative to acid, in low temperatures acid-sensitive reservoirs promoted an extensive research activity, which lead to a new cleanup treatment capable of effectively reducing the damage induced by the polymers which form the filtercake.
In this paper the performance at laboratory-scale of a new oxidizing agent is reported and some guidelines for its application including the possibility to delay its action are provided. The new breaker system consists of two components: a solution of hydrogen peroxide at a very low concentration (1-2% v/v) and an iron complex activator.
By coreflooding tests the effectiveness of this breaker to remove the external filtercake and the polymers, which entered the formation, was identified. Experimental results showed that this type of oxidants can degrade the polymers contained in the filtercake also at temperatures as low as 35°C, generating non-damaging by-products characterized by very low molecular weight. A delayed action of the breaker can be obtained by modifying the oxidizer concentration and the type of iron complex. Finally some results on the behaviour of the developed system in heavy brines including CaCl2 and CBr2 are presented.
Sand Control Robustness in a Deepwater Development: Case Histories From Girassol Field (Angola)
Authors: Petit G. , Foucault H. , Iqbal A. 
Published: December 2007

Abstract
Wells in the Girassol field, offshore Angola, are situated in very deep water and have being completed in unconsolidated sandy turbiditic reservoirs. Today in Girassol which includes also Jasmin reservoir, 29 wells have been completed and connected to production facilities and pressure maintenance is coming from 13 water injectors and 2 gas injectors. The completion strategies employed have included mainly stand alone screens in open hole and cased hole frac-packs.
A review of the design for both producers and injectors, along with the criteria related to the sand characteristics, and offshore implementation of the completions will be described.
Production strategy recommendations to minimize the sand risk during well start-up and ramp-up and also well steady-state production will be given.
This paper will provide an overview of the behavior of both sand control techniques after 5 years of production and injection. An in depth analysis of the different productivity/injectivity characteristics such as drawdown values applied and PLT observations during these 5 years allow us to draw some general recommendations for these types of sand control techniques when used in a similar geological environment. Impact of the measured drawdown values, on the sand control robustness will be described.
Well Productivity in North Sea Chalks Related to Completion and Hydraulic Fracture Stimulation Practices
Authors: Vos Bart , de Pater Hans , Cook Chris , Skjerven Tommy , Frederiksen Rene , Soerensen Carsten , Ormark Kjetil 
Published: December 2007

Abstract
The Joint Chalk Research (JCR) initiative is set up by a group of operators and partners in the Southern North Sea. The objective of the initiative is to increase the ultimate recovery in their respective chalk assets to 60%.
Analyzing the different production technology options used in the assets thus far was the next step in better understanding the different recovery increment options. The initial 4 year productivity from 4 assets was analyzed.
This paper presents the results of a study focused on increasing the understanding of productivity drivers using a database on well productivity related to different completions, stimulations and production options. The database contains 56 wells from 4 different assets and 750 acid and proppant treatments in 663 perforated intervals.
It was found that the absolute total production per interval is similar for all assets; however the drawdown applied in 1 asset is 4 times lower than the other assets.
The performance of the wells in most assets dropped strongly over time, except in the low drawdown asset. It was found that in addition to transient effects, it is likely that a decline in hydraulic fracture completion efficiency also contributes to this decrease in production performance.
The low drawdown asset has a much better normalized production performance than the other assets. Other factors might also influence this result, however, compelling evidence has been found that the much lower drawdown may cause the better performance over time.
The normalized recovery of propped fracced wells was better than the acid treated well in 2 of 3 assets using both stimulation types. The higher recovery of the propped treatments was mainly from better productivity over time compared with the acid fracture treatments. However, the initial productivity of the acid fractured well was much better, hence the economic balance could still tip to the acid treatments.
The analysis showed that, for all assets except one, there is a significant difference in the performance of acid fractured wells and propped fractured wells over time. Indications are that production declines are not only due to depletion, but also related to deterioration of the completion efficiency as a function of pressure drawdown and suboptimal efficiency of acid treatments. An extensive statistical analysis indicated a strong dependency on asset grouping, which hampers the extrapolation of experience from one asset to the others
Management of Steamflooding in Nine Spot With Fiber-Optic in Observation Wells
Authors: Silva M. F. , Izetti R. G. , Pinto H. L. C. Pereira , Santana A. P. S. C. , Couto I. R. 
Published: December 2007

Abstract
Castanhal is an onshore heavy oil field located in Sergipe-Alagoas basin northest of Brazil. It is a shallow unconsolidated sandstone reservoir. It has 75 wells where the average reservoir depth is 350m. The oil has high viscosity ranging from 1000 cp to 9000 cp and API gravity ranging from 10° to 16° API.
In early eighties, a small steam injection project was started in the field, but due to operational problems it was interrupted few years later. In that time the oil low prices make the field be practically abandoned: The production was carried on by very few wells without any fluid injection. In 2003, some successful experiences with frac pack and horizontal wells lead to a renewed interest in the field.
Geological and numerical studies have been accomplished and a permanent temperature monitoring technology was selected to improve the reservoir knowledge and validate the studies. Among the monitoring technologies available in the market DTS (Distributed Temperature Sensing) was selected. It allows a complete wellbore-temperature profile in few minutes if needed. In this case four observetion wells were equipped with an optical fiber placed along the entire length of the well. This paper will present a steamflooding pilot in a nine spot, with four temperature observation wells completed with frac pack to avoid sand production and DTS to improve the understanding of steam breakthrough in the producer wells and the steam path in the injection well. The information support better decision making to increase steam injection efficiency.
Generation of a Compositional Model to Simulate EOR Processes for the Complex Fluids System of the Carito-Mulata Field, Venezuela
Authors: Rodríguez F. , López G. L. , Bello J. , Skoreyko F 
Published: December 2007

Abstract
The Carito-Mulata field is located in eastern Venezuela. This field is ranked as a giant oil producer because of its 240,000 STB/D current oil production and its 6.5 MMMSTB original oil in place. It is possible to observe a significant compositional gradient from seventy-five fluid samples taken at different depths, over a column of fluids of approximately 4000 feet thick. This complex system changes from a gas condensate at the top to an under saturated black oil down the flank. The depth of the Gas-oil contact is estimated at 14,040 feet.
The Carito-Mulata field has been operated and characterized traditionally in four blocks (Central, West, North and South). The fundamental goal of this study is to establish a compositional model that can represent areally and vertically the complex fluid system using an Equation of State (EOS), which represents a big challenge considering the huge number of laboratory experiments. This EOS will be used for EOR simulations under gas and nitrogen injection processes.
The Peng-Robinson EOS was used to match the PVT experiments. Included in the matching parameters was the variation of the saturation pressure of the gas condensate due to nitrogen injection. A swelling test using black oil crude with the injection of gas condensate was also fitted, as well as stacked core miscible experiments of gas condensate displaced by nitrogen injection. Finally, a set of PVT tables were generated for the compositional numerical reservoir simulator.
The most important result that has been obtained of this project is to prove that a single Equation of State can model the complex thermodynamic behavior of three areas that were previously modeled as isolated. Considering that the field could be under nitrogen or natural gas injection, the Equation of State generated in this study will allow the numerical simulation to predict the impact of these processes on the ultimate hydrocarbon recovery.
Evaluation of Polymer Gel Diverters for a High-Temperature Field with Special Focus on the Formation Shape Factor—An Important Parameter for Enhancing Matrix Placement of Stimulation Chemicals
Authors: Stalker Robert , Butler Kristen , Graham Gordon , Wat Rex , Hauge Lars-Even , Wennberg Kjell Erik 
Published: December 2007

AbstractDownhole scaling has long been recognized as causing significant damage to the near wellbore area of production wells. Furthermore complex heterogeneous wells, represent a significant challenge to ensuring effective placement and thereby protection along the entire length of the wells, as the injected chemicals (inhibitor or dissolver) naturally enter the higher permeability / lower pressure zones which may leave other zones untreated. Recent publications and field trials have demonstrated the benefits of using modified, lightly viscosified shear-thinning fluids to give more even placement of chemicals in such wells via bullheading. However, when large volumes of polymer gel are used the in situ fluid properties (viscosity) become critical as the fluid penetrates further into the formation. The in situ viscosity affects both the ability to place treatment chemicals into low permeability / high pressure zones and the post-job well clean up. Accurate prediction of the flow behaviour of these gels in porous media depends on the characterization of the physical properties of the reservoir zones, in particular the permeability, effective porosity and most importantly with shear thinning fluids – the formation shape factor. In this paper we present work investigating the suitability of such shear thinning fluids for non-damaging chemical interventions for an HPHT field. The paper will describe thermal stability tests and novel techniques developed to characterize non-Newtonian fluid behaviour under flow conditions between 120°C and 170°C. Results from bulk, coil and core tests will be included. The paper will also describe test protocols developed to investigate the parameters which could influence the formation shape factor. The work clearly demonstrates the significant impact that the shape factor has on diverting fluid into the low injectivity zones. The results will help achieve more even chemical placement and therefore improved scale protection/removal in the wellbore following treatments in complex wells.
Return Permeability Measurements—Proceed with Caution
Authors: Scott H. E. , Patey I. T. M. , Byrne M. T 
Published: December 2007

Abstract
Many papers have described different techniques and procedures for core floods that measure permeability "return permeability" to evaluate the magnitude of formation damage caused by fluid(s) used in operations (e.g. drilling muds, completion fluids). Often these measurements of permeability are used to make critical decisions for field development and well construction design.
This paper demonstrates with examples, the danger on having used only the permeability measurements to determine the extent of formation damage. Commonly, laboratory core flood tests will have used core cylinders cut to 1.5 inch diameter and short lengths (less then 4 inches) unavoidably limited by core retrieval. Short core samples may be useful if the depth of formation damage was restricted to within the core length, however would have been misleading if any damaging affects extend further than this. Formation damage effects commonly extend further than the length provided by short core samples. The extent of formation damage that occurred would not have been identified by using permeability but requires identification by performing comparative before and after test geological analysis techniques. Subsequently the extent of damage must be scaled from the laboratory to the field by experts in an attempt to extrapolate what those damaging effects have on field injection and/or production. Formation damage that caused alteration(s) to any core sample should be identified by comparing before and after test permeability measurements combined with all other analysis. The nature of any damage mechanism(s) would unlikely to have been identified by just some or any one measurement alone. Scanning Electron Microscopy (Dry and Cryogenic), Energy dispersive x-ray spectrometry (EDS), X-ray Diffraction Analysis and Thin Section Analysis should be incorporated to properly determine the nature and extent of formation damage.
The examples in this paper have never previously been published and they represent a continuing evolution in our understanding of formation damage measurements and mechanisms. Examples of mechanisms such as fines migration, fluid retention and mud body damage will be presented and discussed in terms of their potential impact on return permeability measurements.
In-Situ Stress Profiling in the Agency Draw Field, Utah
Authors: Rajappa Bharath , Conley John T. 
Published: December 2007

Abstract
This paper presents a method to calibrate the dipole sonic log data to the stress measurements derived from injection/ falloff tests. Generally stress data that is calculated from logs used for hydraulic fracture models is based on the poroelasticity model. It is often seen that independent stress tests and calculated log values differ significantly. In this paper, the strain-corrected method proposed by Blanton et al.1 is utilized to yield results that compare well with actual field data. The paper also compares methods used to calibrate stress data in the sand layers. Calibrated stress data is then used to develop a correlation between closure stress data and volume of shale for each well.
This work reviews and presents in-situ stress data gathered in various intervals in two wells in the Agency Draw field of the Uinta Basin in Uintah County, Utah. The primary targets for completion are multiple gas-productive sandstone intervals in the Blackhawk, Castlegate, Sego and Mesaverde formations. These low permeability (0.005-0.05 md) intervals cover a gross vertical extent of 1500-2000 feet. The wells in the field are completed with multiple fracture treatments, and then all perforated intervals are commingled in an effort to drain as many productive sandstone lenses as economically as possible.
Based on this correlation, stress data is input into pseudo-3D hydraulic fracture models to yield meaningful treatment designs. Post-treatment radioactive tracer survey data is then compared to the height growth predicted by the fracture model.
The paper details the importance of proper input data required for frac models and some of the pitfalls associated with incorrect assumptions.
Visualization of New Production Opportunities from Reservoir Characterization of Muri Field, Venezuela
Authors: Malavé A. , Carpio G. , Bolívar M. , Khan K. , Bello J. 
Published: December 2007

Abstract
The object of this work was Muri Field, which is located in eastern part of Venezuela. The expectations for this field were high at the beginning of the study. Firstly, the high oil quality of 30 °API; secondly, this field is located near another one under enhanced oil recovery processes with high production rate; and finally, the field has been inactive since 1.994.
This paper presents the use and results of a detailed Reservoir Characterization Model in the evaluation of opportunities for the drilling of new production wells. Applying conventional petroleum engineering methods, numerical simulation, and teamwork carried out the study.
Muri Field had a structural model generated from a 2D seismic interpretation. This model presented high simplicity and little coherence with the actual well information; being necessary to update it. This reservoir study considers a new structural model, based on a 3D seismic interpretation with a structural frame fitting actual data allowing optimizing the exploitation plans. The use of numerical simulation allowed strengthening the conventional reservoir engineering analyses and enhancing the production expectations for the area. The results are based on teamwork and the application of the available technology.
This new engineering study enabled to better evaluate the vertical communication in the field as well as the unification of four different reservoirs; all of them located in the geological formation with higher potential. As a consequence the official field limits were extended, and a lateral communication was established with a large producing field in north of Monagas State. The most relevant results were a two (2) fold increase in recoverable reserves and the evaluation of new exploitation scenarios. The locations of new producer wells were defined taking into account the new boundary area between Muri and the surrounding fields, to improve the final recovery.