bluuebunny/crossref_metadata_2025_split huggingface dataset:
Improving Marcellus Shale Performance Using PDC Bits with Optimized Torque Management Technology, Cutting Structure Aggressiveness and Unique Roller Cone Steel Tooth Cutting Structures
Authors: Brown Randy , Meckfessel Britney 
Published: February 2011

Abstract
The low formation unconfined compressive strength (UCS) and low abrasiveness in build and horizontal sections of a Marcellus shale well, relatively green PDC and roller cone dull bits, and the desire to drill fast at high build rates with one bottomhole assembly (BHA) facilitate the use of PDC bits with aggressive cutting structures and new torque management technology.
Aggressive PDC cutting structures that inherently drill at higher ROP generate high differential torque and erratic toolface leading to insufficient build rates.
If lower energy input to the PDC or less aggressive bits are employed to manage torque, instantaneous rate of penetration (ROP) can be lower.
Along with this, drillstring friction can result in less consistent and lower weight on bit (WOB), or high differential torque requiring lowered operating parameters and additional toolface resetting.
Due to these issues, instantaneous ROP and feet per day will be lower. This can also affect downhole tool loading and reliability and also toolface control, which can reduce build-up rate (BUR) capacity.
In build sections where PDC bits do not demonstrate planned build rates, roller cone bits are run to achieve the planned well path. The roller cone bit is used to manage torque and a unique tooth design is used to increase ROP over traditional bits.
This paper investigates the implementation and optimization of new torque management technology combined with the use of managed cutting structure aggressiveness of PDC bits and a unique roller cone bit cutting structure to determine the effects on operating parameters, toolface control, build rates, well path trajectory, cutting structure efficiency, feet drilled per day, instantaneous ROP and time savings.
Employing the new torque management technology on optimized, aggressive PDC cutting structures can result in faster drilled sections due to higher instantaneous ROP and less time spent in non-productive steering operations.
Production Analysis and Well Performance Forecasting of Tight Gas and Shale Gas Wells
Authors: Ilk D. , Currie S. M. , Blasingame T. A. 
Published: February 2011

Abstract
Estimation of reserves in tight gas and shale gas reservoirs is problematic due to the low to ultra-low permeability characteristics of these reservoir systems. The sole application of conventional decline curve analysis methodologies often yields erroneous reserve estimates. Therefore, the use of theoretically-based production analysis techniques has become a must to analyze well performance and estimate reserves.
The primary objective of this work is to develop a systematic workflow, which integrates model-based production analysis and rate-time relations, for the analysis/interpretation of well performance data in unconventional reservoirs. The major steps in the proposed workflow are:Diagnosis of production data.Construction of a base well/reservoir model utilizing static well/reservoir data as well as completion/stimulation parameters.Extrapolation of the model to predict well performance along with the use of rate-time decline relations.
The proposed methodology is demonstrated using data from unconventional reservoirs, including a horizontal well with multiple fractures. We present the application of rate-time relations to provide estimates of time-dependent reserves. The use of βq,cp-derivative is also illustrated in distinguishing data characteristics as well as identifying issues associated with data.
A New Approach to Drilling Hard Chert Contaminated Carbonate Formations in Kazakhstan
Authors: Donald Hugh H. 
Published: February 2011

AbstractExploration for, and production of, hydrocarbons in Kazakhstan frequently involves drilling extremely hard-carbonate sequences, which contain high concentrations of chert. Historically, in almost all cases, bit records show that these formations have been drilled with tungsten carbide insert (TCI) roller-cone style bits and occasionally polycrystalline diamond compact (PDC) bits. Both rotary and positive displacement motor (PDM) assemblies have been used.Drilling extremely hard-carbonate lithologies has been accomplished with PDC and TCI bits, but with the presence of chert, this becomes a considerable challenge. Depending on the nature of the chert (e.g., disseminated or nodular) it may well be impossible for a PDC bit to drill with the PDC cutting structure failure mechanism being catastrophic breakage sustained by the high modulus of elasticity (i.e., brittle) PDC diamond tables.The cutting structure failure mechanism for a tungsten carbide bit tends to be the degradation, through breakage and chipping, of the gauge row cutting structure. This in turn will induce severe wear of the heel rows and shirt tail areas, as they attempt to maintain gauge. Severe shirt tail wear and subsequent loss of shirt tail material will invariably result in premature seal exposure and seal/bearing failures.Despite advances in PDC and roller-cone tungsten carbide insert designs, the drilling of extremely hard carbonates characterized by chert concentrations as high as 65% remains a considerable challenge with slow rates of penetration (ROP) and costly trips to change out bits.This paper outlines the introduction of a new drilling system for this type of application in Kazakhstan, in the form of natural-diamond impregnated bits run in conjunction with high-speed turbines. A discussion of the drive systems and drill-bit evolution is presented. The definitive parameter for quantifying drilling efficiency is cost per meter (CPM), and several such examples of resounding CPM reduction are illustrated.
Upscaled Multi-Phase Flow Properties of Fracture Corridors
Authors: Ahmed Elfeel, M. , Couples G.. , Geiger S.. , Ma J.. 
Published: February 2011

Abstract
Fractured reservoirs contain around 60% of the world’s remaining oil reserves. Fracture corridors have been noticed as a major architectural element in outcrops of fractured rock and are known to affect recovery by providing high-permeability flow conduits. Simulations of fractured reservoirs using multi-porosity and multi-permeability models has proven to be challenging, with ever-changing modifications being proposed since the introduction of the dual porosity model in the 1960s. To increase the reliability of reservoir simulation of fractured reservoirs, we propose a new workflow to represent fractured reservoirs by coupling Discrete Fracture and Matrix (DFM) models for fracture corridor properties (which uses finite element and finite volume methods), and the conventional single porosity simulation(which uses finite difference methods).
Relative permeabilities of fracture corridors are upscaled over a single grid block size using DFM models based on an unstructured mesh that accommodates fracture corridor patterns and characteristics. The upscaled relative permeabilities are transferred into a single porosity simulation model to reproduce the behaviour of fractured reservoirs without resorting to the transfer functions.
Various fracture patterns and apertures were studied to investigate their impact on flow properties. Also, different multiphase upscaling techniques were investigated based on the dominant driving forces and the type of boundary conditions used in the upscaling process.
A performance match was done between two models, a fine-mesh DFM model and a simple coarse single porosity model that uses the upscaled relative permeabilities. The models behaved similarly. Recommendations are derived as to how to use appropriate upscaling methods. The new workflow complements and may even have the potential to eliminate the need for classical dual-porosity models.
An Integrated Geomechanics Workflow for Caprock-Integrity Analysis of a Potential Carbon Storage
Authors: Khan S.. , Han H.. , Ansari S.. , Khosravi N.. 
Published: February 2011

Abstract
Ensuring long-term containment of CO2 is critical for a safe geological storage of carbon. Although Carbon Capture and Storage (CCS) is feasible in depleted hydrocarbon fields, it can pose significant risk to safety and the environment if its containment is not ensured. An integrated geomechanics workflow to evaluate caprock integrity is presented in this paper. This approach integrates reservoir simulation which typically computes variation in formation pressure and temperature with geomechanical simulation which models variation in stresses. Coupling between these two simulation modules is done iteratively until an equilibrium state between formation pressure and stress is achieved within a given tolerance. The efficiency of this approach is demonstrated through a case study of a proposed carbon storage site in Canada where an injection rate of 600 tonne/day for 25 years is planned.
Use of Time-Lapse Seismic Data for Heterogeneity Characterization During CO2 Sequestration in Saline Aquifers
Authors: Rey A.. , Taware S. V. , Datta-Gupta A.. 
Published: February 2011

AbstractThe effects of heterogeneity in Carbon Capture and Storage (CCS) in saline aquifers have been investigated extensively and are known to have important bearings on the storage capacity of the aquifer. In CCS projects, the time-lapse seismic survey has been proposed as a valuable tool for monitoring of CO2 movement. However, the potential of the time-lapse seismic data for heterogeneity characterization and geologic model updating has not been fully explored. One of the biggest challenges in the quantitative use of time-lapse seismic data during CCS is the complex movement of the CO2 influenced by compositional effects, geochemical reactions, phase changes and gravity segregation.In this paper, we first introduce compositional streamlines to understand and visualize the flow and transport of CO2 in the presence of mineral precipitation/dissolution, residual trapping and buoyancy effects. To start with, individual component fluxes are generated by a finite difference fully implicit compositional simulator incorporating all the relevant physics of CO2 sequestration. The fluxes are then utilized in novel streamline tracing algorithms to generate phase and component streamlines depicting the movement and the trapping of CO2 in the aquifer. Next, we utilize the compositional streamlines to determine the sensitivity of the time-lapse seismic attributes specifically, interpreted saturation differences, to changes in reservoir properties such as permeability and porosity. The sensitivities are then used in an inverse modeling algorithm to calibrate the geologic model to time-lapse seismic data. The outcome is an improved description of permeability heterogeneity that is consistent with the 4-D seismic response and improved predictions of the CO2 storage capacity.We have investigated the benefits of time-lapse seismic data integration in improving the performance assessment of CO2 sequestration using examples involving CO2 injection under realistic conditions. The first example examines the value of the 4-D seismic data integration in the estimation of storage capacity. The second example systematically studies the impact of viscous to gravity ratio on the performance of time-lapse seismic monitoring and heterogeneity characterization during CCS.
Corrosion and Selection of Alloys for Carbon Capture and Storage (CCS) Systems: Current Challenges
Authors: Chambers B.. , Kane R.. , Yunovich M.. 
Published: February 2011

Abstract
Corrosion by CO2 causes significant metal loss when compared with equivalent pH acid system, because, unlike proton reduction in conventional acid-based corrosion, there is a concomitant reaction here, stemming from direct reduction of un-dissociated carbonic acid. Given that carbonic acid is weakly ionizing acid, oxidizing and corroding potential of acidic CO2 system is significant.
Experience shows that if the liquid water quantity in stream is limited and the system consistently operates above the dew point, high CO2 partial pressures can be handled in carbon steel equipment. However, when water condensation occurs, corrosion rates of steel due to carbon dioxide corrosion can be in range of 10 to 20 mm/yr. Therefore, appropriate phase behavior modeling, including ionic descriptions of different, relevant components and system speciation is an important aspect of this and any corrosion study.
In the present case of CCS, the stream can also contain "trace" compounds such as SO2, NOx and Hg that arise from fossil fuels and their combustion. Interactions between the species involved in "normal" carbon dioxide corrosion and these stream constituents pose an extreme risk of corrosion to steel and possibly certain corrosion resistant alloy (e.g.13Cr through alloy 825) equipment and which is not predicted by commonly used corrosion prediction methodologies.
Oil and gas industry has accumulated substantial experience and material technology to mitigate CO2 corrosion, which includes substantial laboratory data collected at high temperature and pressure conditions in service environments. In addition, corrosion models have been developed for assessment of service environments, phase behavior and effects of impurities, along with corrosion prediction and alloy selection that are widely used in the petroleum industry.
The paper addresses the following aspects of corrosion-related challenges to CCS equipment and systems, specifically focusing on the metallic materials employed for the service:Predominant corrosion/cracking mechanisms and other materials issues resulting from implementation of CCS processes.Relevant and current practices and experience relative to corrosion control and materials selection and the impact of variations in process conditions.Materials and corrosion research gaps analysis for optimizing materials performance of CCS systems.
The Significance of Caprock Sealing Integrity for CO2 Storage
Authors: Busch A.. , Amann A.. , Bertier P.. , Waschbusch M.. , Krooss B. M. 
Published: February 2011

AbstractThe safe long-term storage of gas/CO2 in spatially limited underground volumes requires the combination of a structural trap with intact structural integrity and a suitable low permeability caprock (seal). The occurrence of natural gas reservoirs proves that certain lithotypes do provide efficient seals which can prevent leakage of gas to the atmosphere over long geological time periods (millions of years). In order to assess the risk of CO2 leakage through caprocks on top of potential storage sites to the surface one has to consider both, the present sealing capacity of the rock and its likelihood to alter in contact with CO2.The aim of this paper is to provide an overview of mechanisms affecting sealing integrity of intact (non-fractured/faulted) caprocks. Although certain caprocks can be suitable for hydrocarbons over geological time periods, CO2 in contact with the seal may pose additional risks. Depending on the lithofacies and the amount of reactive mineral species, CO2/water/rock interactions might alter the caprock, physical adsorption on organic matter or mineral surfaces will affect sealing integrity and interfacial properties will affect capillary entry and fluid transport behaviour.
Multiphase Analysis for CO2: Water/Mixed-Gas Adsorption on Coals
Authors: Mohammad S. A. , Robinson R. L. , Gasem K. A. 
Published: February 2011

Abstract
Traditional modeling of gas adsorption on wet coals does not include water as a separate adsorbed component; instead, the adsorbed water is viewed as a "pacifier" of the coal matrix. In this work, we modeled gas adsorption on wet coals by considering water as an active component in a binary mixture. Specifically, we used the simplified local-density/Peng-Robinson (SLD-PR) model to investigate the effect of the water present in coals on gas adsorption under the conditions encountered in coalbed methane (CBM) and CO2 sequestration applications. To conduct this study, our previously acquired measurements for high-pressure CO2 adsorption on wet coals were utilized.
When water is treated as one of the adsorbed components in a high-pressure gas adsorption system, as many as three phases may coexist at equilibrium. To investigate the phase behavior of CO2/water adsorbed gas mixtures on wet coals, a new algorithm was developed to facilitate a Gibbs energy-driven multiphase analysis of this system. The algorithm uses a phase-insertion technique, which involves formally inserting a third (liquid) phase and solving a three-phase flash problem, wherein the three phases are the adsorbed, bulk gas and liquid phases. At equilibrium, the total Gibbs energy of the system is calculated based on the phase distribution obtained at each step. This calculation is repeated sequentially with incrementally increased amounts of the inserted third phase. A Gibbs energy analysis for CO2/water mixed gas adsorption on wet coals was conducted utilizing this new algorithm.
Results involving CO2/water mixtures on four well-characterized coals indicate that the SLD-PR model is capable of representing the adsorption of these highly asymmetric mixtures within the experimental uncertainties. The Gibbs analysis of these coals indicates that there is a third phase present in systems that contain large amounts of moisture. The third, water-rich phase appeared typically at the higher pressures in the isotherm.
Lenses Heterogeneity Effects on Water Alternating Gas Injection in Oil Wet Porous Media
Authors: Al-Wahaibi Yahya. M. , Al-Hadrami Abdullah. K. 
Published: February 2011

Abstract
This paper reports the results of extensive experimental and numerical studies of the effects of well-defined heterogeneous oil-wet porous media (lenses) on simultaneous first contact miscible water alternating gas (FCMWAG) displacements. Flow displacement and effluent profiles have been obtained from well-characterized laboratory experiments in two-dimensional heterogeneous beadpacks. The effects of WAG ratios have been examined. All experiments were then modeled using IMPES finite difference simulator without using history matching (all simulations used directly measured porous media properties as inputs) to quantify the accuracy of the simulation when modeling the FCMWAG displacements in a porous media with lenses heterogeneity. Results revealed that neglecting lenses heterogeneity will cause incorrect reservoir engineering interpretation; for example that of core floods for absolute permeability, relative permeability and residual oil saturation determinations.
Capture and Sequestration of CO2 Produced by In-Situ Combustion Pilot Project, Orinoco Oil Belt, Venezuela: A Mineral Carbonation Laboratory Assessment
Authors: Perez M.. , Barrios M.. , Vasquez P.. , Losada R.. , Salcedo M.. , Perozo H.. , Ortega P.. , Diaz M.. 
Published: February 2011

Abstract
The In Situ Combustion Pilot Project (ISCPP) is an ongoing testing effort aimed at assessing the efficacy of this thermal process to increasing recovery factor in the exploitation of heavy oil reservoirs from Orinoco Oil Belt (Venezuela). The process is expected to produce 3 to 7 million cubic feet/d of combustion gases, with an anticipated composition of 20% CO2(g) and 80% N2(g). As an option for Carbon Capture and Storage of produced CO2, mineral carbonation in caustic byproducts (liquor and red mud) from alumina production was assessed at lab scale. Byproducts were characterized showing pH values 12 - 14 and important quantities of NaOH. Caustic liquor and red mud were exposed to gas blends (ambient pressure and temperature) with 10 and 20% CO2(g) in N2(g), as well as pure CO2(g), until reaching pressure stabilization into liquid-gas system. Red mud suspensions with various densities were exposed as well to gas blends during several cycles. Saturation point was reached when consumption of NaOH was completed, resulting in the precipitation of Na2CO3. Results showed that caustic mud has a CO2 capture capacity of 7.9 kg CO2(g)/m3, or 19 kg Na2CO3/m3 reaching pH 8.3 at carbonate equilibrium. On the other hand CO2 capture capacity of the red mud was 87 kg CO2(g)/m3. Thermogravimetric analysis of red mud (270 - 670 °C) shows less than 2% mass loss which is a good indicator of actual CO2 sequestration. ISCPP will produce around 77000 ton CO2(g) in 3 years of operation, and caustic liquor from alumina process will have sufficient capacity for its complete capture. Results revealed the existence of an important sink for CO2(g) to be produced in Orinoco Oil Belt, which would diminish as well the hazard of caustic liquor and red mud.
Use of a Mechanistic Model To Forecast Cement-Sheath Integrity for CO2 Storage
Authors: Bois A-P.. , Garnier A.. , Galdiolo G.. , Laudet J-B.. 
Published: February 2011

AbstractImplementation of CO2 storage in geological media requires a proper assessment of the risk of CO2 leakage from the storage sites. In particular, it is necessary to evaluate the risk that cement sheaths represent leakage pathways as this could occur if cement becomes damaged or when debonding exists at one of the interfaces of the cement sheaths.Tests performed in the laboratory have shown that there exist two types of mechanisms that could lead to cement-sheath loss of integrity: mechanical degradation, when cement is submitted to compressive or tensile loadings that are too high, or chemical degradation. The worst case is when both mechanisms occur at the same time or one after the other. For example, a cement sheath that is damaged before entering in contact with a degraded fluid will allow this fluid to penetrate deeper in the cement sheath, hence accelerating cement chemical-degradation.Hence, it is of paramount importance to understand the mechanisms that could lead to a cement-sheath loss of integrity before CO2 storage. This is with this objective, that we have been working on a mechanistic model that accounts for the various modes of cement-sheath loss of integrity after cement has been placed: a) cement volume-variations during hydration due to chemical shrinkage/expansion; b) cement volume-variations during hydration due to cement heat-production; c) contraction (dilation) of the casing due to a decrease (an increase) in mud density/temperature; d) cement volume-decrease due to pore collapse; e) thermal cycling.This paper has two objectives: presenting the mechanistic model and using this model to show that cement sheath loss of integrity not only depends on cement properties but also on the well architecture and well history.