bluuebunny/crossref_metadata_2025_split huggingface dataset:
BlowFlow – Next Generation Software for Calculating Blowout Rates
Authors: Karlsen Hans Christian , Ford Eric P. 
Published: June 2014

Abstract
A blowout is known to be the most severe event that can happen during explortation of petroleum resources. Oil-spill preparedness is important in general, particularly in the arctic region where uncertainties about consequences are high and contingency planning for major accidents requires extra attention. Calculations of blowout rates and durations from potential blowouts is an important part of environmental risk management, both in the planning phase of a well and during otherwell activities.
BlowFlow is a software tool that has been developed for risk based evaluation of blowout scenarios in order to quantify blowout flow rates, volumes and durations. The results can be used as input to Environmental Risk Analysis, to dimension the emergency preparedness organization and identify both probability and consequence measures in the oil-spill preparedness planning. BlowFlow is meant as a cross-disciplinary tool for communication between petroleum, reservoir, drilling and HSE engineers. The basic design has been inspired by the guidelines given in [1]. Based on a fixed definition of potential blowout scenarios, BlowFlow provides probability distributions of potential blowout rates, durations and volumes for that can be used as input for the Environmental Risk Analysis. Since there are large uncertainties involved at the stage when such an analysis is performed, a stochastic modeling approach is used, i.e. Monte Carlo simulations and spline interpolations, based on multi-discipline expert input.
Real-time Measurement from Instrumented Wireline Mechanical Intervention Tools Reduces Risk and Improves Efficiency
Authors: Govil Amit , Guldahl Arne 
Published: June 2014

Abstract
Various well intervention techniques are used to enhance well productivity during the lifetime of a well. In general, perforation and stimulation retrievable bridge plugs are used for isolating zones during workover. Traditionally, retrievable plugs are recovered using wireline jars or powered mechanical shifting tools. During pulling or pushing operation, very limited information, such as surface cable tension, is available to the operator. In recent years, a new generation of wireline intervention tools has been introduced that enable real-time measurement and control of anchor force, anchor diameter, pull/push force, stroke length, stroke speed, and wellbore temperature and pressure.
This paper describes the application of real-time measurements in a recent operation in the Norwegian Sea.
Using Crosswell Data To Enhance History Matching
Authors: Ravanelli Fabio , Hoteit Ibrahim 
Published: June 2014

Abstract
One of the most challenging tasks in the oil industry is the production of reliable reservoir forecast models. Due to different sources of uncertainties in the numerical models and inputs, reservoir simulations are often only crude approximations of the reality. This problem is mitigated by conditioning the model with data through data assimilation, a process known in the oil industry as history matching. Several recent advances are being used to improve history matching reliability, notably the use of time-lapse data and advanced data assimilation techniques. One of the most promising data assimilation techniques employed in the industry is the ensemble Kalman filter (EnKF) because of its ability to deal with non-linear models at reasonable computational cost. In this paper we study the use of crosswell seismic data as an alternative to 4D seismic surveys in areas where it is not possible to re-shoot seismic. A synthetic reservoir model is used in a history matching study designed better estimate porosity and permeability distributions and improve the quality of the model to predict future field performance.
This study is divided in three parts: First, the use of production data only is evaluated (baseline for benchmark). Second, the benefits of using production and 4D seismic data are assessed. Finally, a new conceptual idea is proposed to obtain time-lapse information for history matching. The use of crosswell time-lapse seismic tomography to map velocities in the interwell region is demonstrated as a potential tool to ensure survey reproducibility and low acquisition cost when compared with full-scale surface surveys. Our numerical simulations show that the proposed method provides promising history matching results leading to similar estimation error reductions when compared with conventional history matched surface seismic data.
Hydrocarbon Flow Assurance: Low Rate and Pressure Gas Field Experience
Authors: Olayemi S. , Cano M. , Sanchez S. , O'Shea C. , Letendre F. , Solc P. , Verney M. , Maru M. 
Published: June 2014

Abstract
In the early life of most gas wells, there is sufficient reservoir pressure and flow rate to assure reliable evacuation of associated fluids from the reservoir/wellbore to the surface facility. In unconventional plays and in the case of Deep Basin gas field, this natural flow phase is usually short with a characteristic hyperbolic decline. When gas flow reaches critical velocity i.e. the minimum required velocity to lift out the liquids, pressure drop as a result of the hydrostatic head of liquid that is being left behind in the wellbore, increases till the well eventually stops flowing.
Reduced rates and ultimate recovery due to liquid loading has significant impact on the economics of tight gas developments. The methods (timer cycling, foam, plunger, velocity string) presented in this paper are relevant to many low rate and low pressure gas wells. These methods have been used singly or in combination to optimally utilize the reservoir's energy for long term flow assurance. Cost, rate and estimated ultimate recovery of the deliquification decision have been key driving factors in the pursuit of effective hydrocarbon flow.
Challenges and lessons learned thus far for deliquification decisions in Deep Basin are discussed, including the criteria/requirements for each method, inflow performance, wellbore hydraulics, water dynamics (formation and condensed water), scale deposition, associated secondary benefits/complications and field data showing impact.
Rheological Properties of an Amine Oxide Viscoelastic Surfactant With Application in Well Stimulation
Authors: Aryanpanah S. , Nasr-El-Din H. 
Published: June 2014

Abstract
The use of proper fluid system is one of the most important factors in the success of well stimulation processes like hydraulic fracturing and matrix acidizing. Viscoelastic surfactant (VES) based fluids are among stimulation fluids which recently have been used with promising results. The rheological properties of a tallow amine oxide amphoteric surfactant base fluid with applications in matrix acidizing and hydraulic fracturing have been studied. To find the linear viscoelastic region, the stress amplitude sweep tests were conducted in the constant frequency of 1 Hz and the shear stress range of 0.1 to 10 Pa. The linear viscoelastic region has been found to be between 0.1 to 1 Pa. Then, the effect of stress amplitude and temperature on elastic modulus (G′), viscous modulus (G″) and complex modulus (G*) have been investigated and the results were interpreted on the basis of Cates' tube theory. The frequency sweep tests have been carried out within the frequency range of 0.01 to 4 Hz and the constant stress amplitudes of 0.1, 0.5 and 1 Pa. For the evaluation of the effects of temperature on the properties of the VES solution, the tests have been done at the temperatures of 25, 28, 30 and 35°C and constant stress amplitude of 0.1 Pa. The results of experiments at the constant temperature and different stress amplitudes showed that the increase in stress amplitude caused an increase in transition frequency and widen the viscous dominant region. In the other hand, with increase in temperature at the experiments with constant stress amplitude, the transition frequency decreased and the VES solution showed the dominant elastic behaviors. The results of frequency sweep tests in the form of Cole-Cole plots showed that the surfactant system highly deviated from Maxwell's mono relaxation model and, therefore, the stress relaxation mechanism in the fluid found to be the combination of reptation and breaking of wormlike micelles. These results can be used to better understand the rheological properties of VES-based fluids and manipulate their properties for using in well stimulation processes.
Mitigating Vibration with Roller Reamer Technology Improves Drilling Efficiency in Hard/Abrasive Formation, Sao Francisco Basin, Brazil
Authors: Mario Breton , Julio Mayol , Martin Gerlero , Oscar Rojas , Gerardo Leon , Joao Pedro Tocantins 
Published: June 2014

Abstract
When drilling operations commenced in Sao Francisco basin, the operator knew the exploratory well campaign would present a major investment. However, as operations progressed the well costs and time exceeded assessments mainly drilling the 8½″ production hole section through two hard and abrasive formations. Due to the unconventional nature of the reservoir, well costs must be held to a minimum in the exploration phase to ensure each project is economically viable. To accomplish the objective, several tool technologies were analyzed and proposed with the aim of reducing down-time and tool failures. One of the main issues identified was the high level of shock and vibration (S&V) observed while drilling the Macaubas and Paranoa formations. The environment had a negative impact on drilling efficiency and contributed to tool failures and excessive wear on BHA components leading to additional trips and preventing the operator from achieving higher ROP and run lengths.
After an engineering analysis, the drilling team determined the root cause was BHA/bit whirl while along with several other contributing factors related to the challenging hard and abrasive formations. Based on this information, the provider recommended using a roller reamer in the bottom hole assembly (BHA), to mitigate shock and vibration and improve drilling efficiency. Results were positive and the roller reamer reduced NPT and overall well costs in this economically sensitive play. Roller reamers are currently part of standard packed BHA and are being used as a reference for operators experiencing the same type drilling dysfunctions.
Improving Unconventional Completions by Pinpointing Multistage Fracturing with Coiled Tubing: Cases Histories from Burgos Basin
Authors: Lopez-Bonetti E. , Araujo O. , Ortiz J. Ramon , Hernandez J. , Castillo H. , Basurto E. 
Published: June 2014

Abstract
In northern Mexico, from the Burgos basin to the Chicontepec field, horizontal wells have been a viable choice for exploiting hydrocarbons in tight gas and shale reservoirs. Successful drilling and completion of such wells has allowed goals in this complex operation to be reached. The learning curve trend means good knowledge has been acquired and difficulties encountered during completions can be addressed using new techniques available within the area.
To achieve high performance when fracturing multiple zones, the application of an abrasive perforating technique using coiled tubing (CT) has proven a very effective alternative for acquiring optimum results. This has been particularly true for applications in highly deviated and horizontal wells. Although this technique has been applied in others regions since 1998, its implementation within this region has only become more common during the past three years.
Using field experience with actual cases, this paper illustrates the available technologies and techniques that have become a new process in this region. Because of the undisputed completion and production results, pinpoint multistage fracturing is becoming the preferred completion technique used by the operator and will be used extensively as more horizontal wells are scheduled to be drilled and completed in upcoming years. Similarly, this has been the preferred choice when the formation is estimated to produce liquids.
Impact of the Heavy-Oil Properties in the Slug-Flow Characteristics
Authors: Brito A. , Marquez J. , Ruiz R. , Cabello R. 
Published: June 2014

Abstract
Slug flow is the most common flow pattern presented in multiphase flow gas-liquid pipelines for highly viscous liquids. In this sense, it is important to know how this flow pattern behaved when oil viscosity increases in order to improve the operation and design of surface facilities, such as: pipelines, separators, flow conditioners, risers and multiphase equipments as pumps and flow meters, and also to reduce the corrosion and erosion effect in the systems. This requires a rigorous study of slug flow characteristics, i.e.: slug holdup, slug length, translational velocity and slug frequency as well as pressure gradient and liquid holdup in the pipe. For these reasons, it is necessary to carry out experiments that allow a better understanding of slug flow pattern and improving mathematical models to predict slug characteristics.
In this work, an experimental study of three different gas/liquid systems is presented. This includes liquid viscosities of 1cP, 430cP, and 960cP and the liquid viscosity effect in slug flow characteristics such as: flow pattern transition, slug translational velocities, slug lengths, pressure drops, holdup, and slug frequency.
Quantifying Thin-Bed Modeling Contribution on Characterization of Bypassed Oil for Improved Oil Recovery
Authors: Martino L. A. , Loss M. Laura , Ucan S. , Thompson A. , Morettini E. 
Published: June 2014

Abstract
Improved oil recovery is more sensitive to sub-log scale heterogeneity than primary recovery processes. Determination of porosity, net-to-gross, saturation and permeability, both magnitude and direction, at scales below log resolution is often required in secondary and tertiary processes and can have an impact on the estimation of original hydrocarbon in place, by-passed oil and recovery factors.
Conventional log interpretation and conventional static modeling workflows may not capture sub-scale log heterogeneities, often due to the averaging involved in the upscaling process. Even though log values have been generally calibrated to plug scale (cm3) measurements, they are averaged over volumes much larger than their scale(s) of key heterogeneity.
This paper compares the simulated response derived from conventional and from effective property and lamina-scale modeling in three different oil bearing formations in the Argentinian Neuquen Basin, namely Quintuco, Sierras Blancas and Lotena Formations. All three Formations are candidates for waterflood developments and enhanced recovery processes options are being examined.
Permeability, porosity, saturation and net-to-gross ratio were determined by constructing high resolution models that enabled capturing sub-log scale heterogeneities. These models were subsequently upscaled at representative elementary volumes and the derived effective properties were used in building simulation models through different upscaling methodologies.
Results of the two scale models for each reservoir are compared. Strengths and weakness of the applied methodology, as applied to these specific cases, are evaluated and discussed.
Applying Mohr-Coulomb Cycle to Step-Rate Test: An Innovative Rock Mechanics Equation in Extreme Unconsolidated Formations
Authors: Suzart W. , Cayo M. , Jaramillo J. , Alarcon X. , Barragan E. , Calvachi C. , Torres C. , Mantilla A. 
Published: June 2014

Abstract
There are sand formations that do not have a minimum contact pore space cemented. Typically, these sands have very low toughness, high permeability, and high porosity. Such factors allow fines and solids migration. The consequence of this scenario is the increase of workover interventions and equipment damage/erosion caused by sand flow, thus resulting in increasing cost, lost time, and insufficient production. Drilling these formations is challenging. Taking core samples to perform rock mechanic tests in a laboratory is also a difficult task. Additionally, there are cases where wells do not have sonic dipole surveys to help with evaluations. Usually, the samples are not uniform, have cracks, are broken, or completely dispersed, making their application in rock mechanic characterizations impossible.
The presented methodology applies the Mohr-Coulomb cycling test for the first time to actually process step-rate, fracturing, and falloff tests. Field tests using this technique have shown good correlations and obtained reliable curves for hydraulic fracturing simulators. A package of rock mechanics equations described in the oil industry are evaluated and tested in field scale.
Many times, engineering teams must have a source of equations which can easily calculate required parameters to be used for sieve analysis, gravel pack, and fracture pack projects. Basically, the methodology is reliable because of the equations of theoretical soil mechanics (Terzagui 1943), Mohr-Coulomb, and field practices of determinations of minimum in-situ stresses and overburdens. After field test confirmations, the objective of this matter is to present correlations of Terzagui (1943) and Mohr-Coulomb equations to be used during gravel, fracture pack, and hydraulic fracturing operations. The methodology has an important presence during the study to help minimize risk during these jobs and obtain good approach simulations because, as previously discussed, this type of sandstone makes obtaining formation samples challenging. Equations can provide a good number of useful calculations and help reduce operational risk when performing these types of well completions or treatments.
Swelling of Elastomers in CO2 Environment: Testing Methodology and Experimental Data
Authors: Daou F. , de Miranda C. R. , de Oliveira J. L. , Engelke B. , Borman C. , Le Roy-Delage S. , Lungwitz B. 
Published: June 2014

Abstract
Elastomers are widely used in downhole tools for oilfield applications and are often exposed to gases, such Carbon Dioxide (CO2), and Hydrogen Sulfide(H2S) in addition to the produced hydrocarbons and water. Successful drilling operations and reservoir management involve the use of tools of appropriate metallurgy and sealing materials. Depending on the environment (High Pressure High Temperature, H2S, CO2, or others), the sealing property of the elastomers may fail, leading to HSE (Health, Safety & Environment) and operational related incidents. Examples of such incidents are the undesired production of fluids, contamination of ground water, and the consequent loss of time and profits.
Consequently, the selection of the sealing material used for downhole oilfield applications is critical and needs to be carefully considered, either for short-term drilling operations or for long-term completion activities. Elastomer compatibility studies covering a variety of media such as diesel, oil- and water-based muds, and brine are available in the literature. However, compatibility to super critical fluids like pure CO2 or H2S are not widely documented and even difficult to find in public domain. This paper describes a testing methodology to investigate the behavior of selected elastomers under CO2 environment at different temperatures and pressures. It focuses on the swelling behavior of different materials upon contact with CO2.
Two testing methodologies are investigated. One is using a High Pressure High Temperature autoclave from "Parr Instrument". It allows samples to be simultaneously exposed to two different environments; the wet supercritical CO2 and CO2-saturated fluid. The second is using a High Pressure High Temperature Visio-Cell equipped with a high resolution camera. The benefit of such a set-up is that it allows a "real-time visualization" of individual particles while in contact with CO2.
Results obtained show the HPHT Visio-cell to be the best fit for assessing the behavior of the tested material. Additionally, some components appear to swell less with CO2 than others.
Efficiently Delivering Difficult Tortuous Well Profile Deepwater Brazil Ream-on-Demand System Saves Operator Trip for Tool Change-Out
Authors: Lima Araken , Oliveira Danielle , Breton Mario 
Published: June 2014

Abstract
To reach the reservoir in Campos Basin, deepwater Brazil requires the operator to drill a difficult "S" shaped wellbore geometry through shale and sandstone with UCS (5–15kpsi). To achieve the objective, an operational plan was devised that had two major phases: 1) drill to the base of the reservoir in under-reaming mode building angle from 30° to 80° while enlarging the hole 12¼-in x 14¾-in for 600m; 2) then drill 300m of 12¼-in drop-off section down to 3700m MD. After reaching 12¼-in TD, the plan calls for reservoir evaluation then pumping a cement plug to sidetrack and drill a long horizontal section. Efficiently delivering the relatively deep wellbore as planned would be challenging and present a significant risk because of daily rig-rates approaching $1 millon USD. To ensure all contingencies were considered, the operator initiated an engineering analysis to identify tool/BHA limitations: 1) Using a reamer to drill into the reservoir would have a negative effect on ROP and require the operator to pump more cement for the sidetrack plug; although improved image quality would be achieved by logging in the smaller 12¼-in hole section.2) The operator also considered placing the concentric reamer 300–400m offset from the bit to drill the drop-section without tripping to remove the reaming tool from the BHA. However, this BHA configuration would be susceptible to vibration induced RSS/MWD/LWD damage, drilling dysfunction and would also increase the risk of a parted connection.
To solve the application changes, an engineering analysis was conducted to determine if a new-type ream-on-demand (RoD) tool would be an appropriate solution. Since the RoD tool is equipped with an innovative hydraulic system, it can perform multiple activations/deactivations of the cutting blocks while downhole. Because the RoD system does not require a ball drop to engage, BHA design flexibility is greatly enhanced.
The study used a well records database and numerous offsets runs with a conventional expandable reamer used in Roncador field. A rock-strength identification program, that uses log data including GR and sonic, was applied to determine formation type and foot-by-foot UCS. A hydraulics analysis was performed to determine proper operational and indexing flow rates. Finally, an FEA-based modeling system identified an optimal parameters window (RPM/WOB) to reduce damaging vibration levels while reaming/drilling. The RoD tool was run and drilled a 12¼-in hole into the reservoir without requiring a trip that is required to lay down a conventional ball-drop activated reamer. The new-style BHA also improved ROP when drilling into the reservoir. The RoD system saved the operator between 24–36 hrs of rig time for a cost savings of approximately $1 million USD. The operator plans to keep using the ream-on-demand tool in future applications where the "S" well profile is required.