bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimal Grid System Design for SAGD Simulation
Authors: Shin Hyundon , Hwang Taeho , Chon BoHyun 
Published: June 2012

Abstract
The steam-assisted gravity drainage (SAGD) process is currently the widely used one among the in-situ recovery methods to produce bitumen from Alberta oil sands in Western Canada. A thermal process requires very small grid size to provide the better description in the reservoir simulation model than the coarse grid; however the simulation runtime will take longer. The relationship between the number of grids and runtime is not linear but exponential. It is important to design the proper grid size giving reasonable results with shorter runtime.
In this study, the optimal grid system design has been investigated through numerical simulation sensitivity studies for the SAGD process. A 1×25×1 m (i, j, k direction; j is wellbore direction) grid size is accepted as a standard size for the SAGD simulation. Grid size sensitivity study has been conducted to determine the maximum grid size that shows a closer result to the 1×1 m case and also the impact of grid size in j-direction as well as the i/k ratio in SAGD simulation.
The simulation results shown an i/k ratio is more important than a grid size itself. Based on the CSOR and oil production as well as steam chamber shape, the 2×2 m grid case is closer to the 1×1m case results than 3×1 m case. For the grid size optimization in the wellbore direction (j direction), the grid size of over 25 m cases are no big difference in both production and steam chamber shape for a homogeneous model, and there is no steam chamber propagation to the j-direction. The maximum grid size in j-direction to see the wellbore end effect is 10 m in this study. Considering the reservoir heterogeneity, if shale barriers exist, the impact of grid size in j direction is more important and the smaller grid size is required for the proper numerical simulations to describe steam chamber development in field scale SAGD project. For j-direction grid design, a hybrid type of grid system, a fine grid size in wellbore end zone and regular grid size in wellbore zone, may help to see the steam chamber development with saving a degree of simulation runtime.
Experimental Evaluation of Dispersion and Diffusion in a UTF BItumen/n-Butane System
Authors: Frauenfeld Ted , Jossy Chris , Jossy Eddie , Wasylyk Brad , Diaz Brigida Meza 
Published: June 2012

Abstract
Laboratory experiments at Alberta Research Council (now Alberta Innovates Technology Futures) have indicated the potential for improving the recovery of bitumen and heavy oil, and a substantial reduction of SOR relative to SAGD, by the addition of substantial volumes of light hydrocarbon to steam as an enhancement of SAGD. Many scaled lab model experiments have been completed, some of which have identified solvent/steam ratios that outperformed low pressure SAGD. In order to more reliably scale the results of these experiments, it was desired to measure the rate of oil production and hence solvent front advance rate in field permeability sand. The experiments were isothermal to simplify the numerical simulations. Three experiments were completed, one at 68°C one at 80°C and one at 100°C. The respective butane pressures were 700 kPa, 1020 kPa and 1450 kPa. The respective oil rates were 52.5 g/h, 62.3 g/h and 63.2 g/h. Solvent front advance rates were 7.81 cm/d, 9.0 cm/d and 9.42 cm/d. These rates translate into SAGD-like rates when extrapolated to a field size project.
Hydrophobically-Modified Cellulosic Polymers for Heavy Oil Displacement in Saline Conditions
Authors: Bai Jiang , Wassmuth Fred R. , Jost Robert W. , Zhao Liyan 
Published: June 2012

Abstract
Commercial polymer floods have generally used partially hydrolyzed Polyacrylamide (HPAM) as the polymer of choice, since HPAM generates high viscosities in relatively fresh brines at a reasonable cost. In high salinity or hardness brines, the anionic charges on the HPAM polymer chain interact with the dissolved cations, shrinking the hydrodynamic size of the polymer molecules. The smaller hydrodynamic radius generates lower viscosities and requires higher polymer concentrations. In order to reduce the polymer loading in saline brines, a series of hydrophobically modified biopolymers have been synthesized. The non-ionic nature of hydroxyethyl cellulose (HEC) provides an ideal polymer back bone since it does not interact with the dissolve cations. Hydrophobic groups (aliphatic hydrocarbon chains) are attached to the backbone of the polymer to impart associating properties between polymer molecules. The inter-molecular interaction between the hydrophobic moieties led to a significant viscosity increase in comparison to polymers without hydrophobic groups. Several screening steps were used throughout the product development to arrive at practical polymer formulations: 1) Filtration; 2) Sandpack tests; 3) Corefloods in the presence of oil. By varying molecular weight of the base HEC polymer and the amount of hydrophobic content, practical polymer products were developed for polymer flood applications. Coreflood tests showed that the hydrophobically modified HEC generated significant resistance factor in saline brines, outperforming the HPAM polymers.
SAGD Startup: Leaving the Heat in the Reservoir
Authors: Anderson M. T. , Kennedy D. B. 
Published: June 2012

Abstract
Successfully starting up Steam Assisted Gravity Drainage (SAGD) well pairs is crucial in achieving good wellbore temperature conformance and rapid production ramp-up. Performing a SAGD startup effectively and economically is a significant challenge in the industry and reservoirs with mobile water offer an opportunity to optimize and accelerate this process.
A traditional SAGD startup involves steam circulation, where steam is injected into a well down the long tubing string to the toe and fluids are produced back to surface at the heel. Steam circulates across the full horizontal length of the well and conductively heats the near reservoir. In reservoirs with mobile water, there can be fluid losses to the reservoir during circulation, allowing for convective heating of the reservoir.
In a bullheading startup, return fluids are not produced and all injected steam is forced to leak off into the reservoir. By avoiding fluid returns, bullheading offers significant advantages over circulation in terms of thermal efficiency, steam demand, operational simplicity and facility requirements.
This paper examines the effectiveness of a bullheading startup compared to a circulation startup through a simulation study and field trials at Suncor Energy Inc’s Firebag in-situ project.
One-Dimensional Mathematical Modelling of Vapour Extraction (VAPEX)
Authors: Jia Xinfeng , Zeng Fanhua , Gu Yongan 
Published: June 2012

Abstract
Diffusion-convection mass-transfer process in porous medium is one of the major enhanced oil recovery (EOR) mechanisms of Vapor extraction (VAPEX). Previous work tried Fick’s Law to model the diffusion process, and mostly assumes the diffusion coefficient as a constant in the equation. However, the diffusion coefficient factually is a function of concentration, and thus the effect of its gradient should be included in the governing equation. In addition, bulk flow exist during the VAPEX especially during the solvent chamber rising phase, hence the process may be a diffusion-convection process rather than a pure diffusion process as presumed in previous works.
This paper proposes a new one-dimensional (1D) VAPEX mathematical model on the basis of diffusion–convection equation, gravity-based fluid flow equation (Darcy’s law), and mass-conservation equation. The model is directed at a vertical thin cylindrical VAPEX process with injector and producer both setted at the bottom. The solvent chamber is considered as a two-phase area and the oil in it is completely saturated, while the matiral beyond the chamber is thought as in liquid phase. First, the diffusion-convection model is developed to obtain the concentration distribution in the transition zone; the boundary between solvent chamber and transiton zone is seen as moving with time. Second, the drainage velocity of the saturated oil in solvent chamber is calculated and combined with the mass conservation equation, to model the saturation of the oil phase changing with time. On the basis of the saturation model the oil production rate can be obtained.
The recovery factor profile is divided into two distinct stages: solvent diluting-dominated stage and saturated oil flowing-dominated stage. During the first stage, it is found the solvent chamber growing rate tends to be constant; the oil production rate is proportional to the square root of permeability, which constists with the existing VAPEX theoretical model. During the second stage, the production rate is linearly related to the 1.1–1.3 power of the model length rather than the square root of it. This agrees perfectly with the lab observations in previous work.
Production Optimization of a Mature Offshore Asset
Authors: Bates G. , Bagoo D. , de la Calle D. G. , Finol A. , Nazarov R. , Rivas C. , Hernandez M. , Bunraj C. 
Published: June 2012

Abstract
In an offshore mature asset workover jobs involve high cost and operational risk that impact on the profitability of the projects. Non-rig interventions are a more sustainable approach to effectively sustain production. The fact that some reservoirs are depleted while many are water flushed often result in modest incremental gains. Due to the age of the asset, several wells present mechanical issues which make any intervention more challenging. The non-rig methodology has proven to be well-suited to these conditions.
This paper will describe the criteria and technology used to mitigate the production decline of the TSP (Teak, Samaan & Poui) asset located off the south-east coast of Trinidad. TSP is a mature oil field which has been producing for almost 40 years. The main constraints for flow assurance are sand production, scale and paraffin deposition, high IGLR, skin damage, high water cut, depleted reservoir and mechanical problems. A variety of non-rig interventions have been employed since 2006 in order to mitigate the mentioned constraints and therefore maximize production from the field. These interventions include tubing and formation acid/de-wax jobs, gas lift valve changeout, addition of new perforations, tubing punch, sand clean out, thru-tubing gravel pack and other jobs aimed to acquire information such as pressure surveys and cement, production, reservoir saturation and multi finger logs. These jobs, together with regular gas lift optimization exercises and re-activation of previously shut-in wells, have proven to be quite effective at slowing the natural production decline.
An annual technical and operational screening of all wells (active and shut-in) is performed and the under-performing wells are identified and targeted for the non-rig campaign and reactivation. In addition to that, multi-rate tests are carried out throughout the field prioritizing those critical wells. This ensures that the injection gas rates are at their optimal values, maximizing the oil rates and saving injection gas volumes.
The non-rig, well re-activation and GLO campaigns have maintained the annual production decline of the TSP field between 8 to 12% while facing operational and reservoir issues inherent in an aging field.
Improve Mature Fields Management by a New Method to Evaluate the Contacted Pore Volume Evolution
Authors: Serrano G. D. , Sancho Costa V. L. , Hryb D. E. 
Published: June 2012

Abstract
Mature field redevelopment involves the choice and implementation of different extraction techniques. This issue becomes more complex when the producing section is composed of isolated multilayer reservoirs with long and different production history which necessitates precise mangement of injection and production rates layer by layer and well by well. Geological discontinuities (Faults, pinch outs) also need to be taken into account when considering the injection of fluids in a multi-layered reservoir.
The present work, which involves a water flood, shows a method to define the contacted pore volume (CPV) evolution in time by dynamic simulation history matching, and thereby to determine the regions in each of the layers where changes in injection policy is justified. With the CPV defined at the end of the history match, the method allows an evaluation of the efficiency of the legacy secondary recovery scheme, and defines the corrective actions to improve it in each layer. This method is based on distribution of pore volume (PV) as function of water saturation i.e. PV(Sw) at each time before and after starting the injection in the reservoir. As a result, we can obtain the evolution of CPV since injection started, and then calculate the evolution of oil in place (OIP) in the CPV and compare this with total production of the layer considered, obtaining the efficiency of waterflooding layer by layer in different areas of the field. Extrapolating CPV(t) with the actual injection patterns allows an assement of CPV at the end of field concession, and gives us a base case forecast of future field behaviour.
As conclusions we observe that, this method is an easy and fast tool to determine the contacted pore volume evolution, and the efficiency of waterflooding. Further this method gives an estimation of Ultimate Contacted Pore Volume (UCPV) with the actual (or improved) injection configurations on a regional basis which allows further opportunity to be identified. The integration of this information with the actual field condition facilitates optimization of the water injection pattern and improves waterflooding productivity throughout the reservoir extension.
The Evolution of the NCMA Well Start-up Philosophy
Authors: Madray R. , Manrakhan S. 
Published: June 2012

Abstract
With sand control being an issue for many operators; there is a prevalence of Open Hole Gravel Pack (OHGP) completions used in offshore reservoirs. Gravel packing is an industry recognized method of stabilizing the well bore and controlling sand in gas and oil producing wells. But while ensuring the longevity of the well it also entraps the filter cake formed by the reservoir drilling and completion fluids. These factors result in a lower production rate well and the need for higher drawdown. Therefore it is essential that the filter cake be removed along the length of the wellbore to ensure no unnecessary restrictions to production.
This process requires an integrated approach to well start-up. It begins with the completion fluid used and ends with the start-up/bean-up procedure. The completion fluid type is essential in determining the lift-off pressure required by the filter cake. This pressure needs to be accounted for by the start-up rates used. Subsequently this start-up rate must be achieved in a safe and timely manner to ensure that the completion is not compromised, via the bean-up procedure. This necessitates the need for synergy between Subsurface, Well Engineering and Operations departments.
The North Coast Marine Area (NCMA) operated by BG Trinidad and Tobago consists of 17 horizontal OGHP gas production wells; hence it is imperative that a well thought out start-up philosophy to ensure well productivity. The sands, which these wells are completed in, are characterized by their thin laterally extensive nature. These sands show relatively homogenous reservoir quality profile with good lateral connectivity. Currently NCMA produces from the M2, M4 and M6 packages, each with a NTG over 95%. These wells have been drilled in three phases over the past decade, the last being October 2009 to March 2010.
This paper describes these improvements, challenges to the program and attempts to examine the results to determine any relative gains in productivity of the wells.
Overcoming Oil/Water Measurement Obstacles in Heavy Oil Production
Authors: Mohajer Kam , McWhorter Craig 
Published: June 2012

Abstract
The unique problems associated with heavy oil production largely revolve around the issue of viscosity. Production technologies used to overcome the viscosity issue, such as steam injection and water flooding, increase produced water levels at heavy oil wells. Accurate knowledge and monitoring of any produced water is key to production optimization; however, accurate measurement of water content relies on a homogenous flow, and the high viscosity of heavy oils makes high flow velocities and thus, homogeneity, particularly difficult to achieve.
While sampling standards acknowledge the need for a homogenous flow, no such standards currently exist for oil/water measurement. API MPMS Chapter 8.2 details the various combinations of velocity, pipe installation, and mixing devices required to achieve homogeneity for sampling and one can borrow from this standard for minimum requirements for oil/water measurement. However, mixing elements and piping configurations can create a pressure drop and are still subject to inconsistencies and complications from varying fluid velocities, densities, viscosities, etc., and none of the mixing elements are capable of creating a constant velocity.
The addition of a circulation or measurement loop to the main pipeline creates a consistent environment and homogenous flow for optimized measurement conditions, regardless of varying fluid conditions. The loop utilizes a pump in line with a suction nozzle to extract a representative flow from the main pipeline for oil/water measurement and an injection nozzle to inject that flow back into the pipeline upstream of the suction nozzle. The size of the pump and mechanical design of the injector must be appropriate to increase velocity and create mixing sufficient enough to generate a homogenous flow in the portion of the main pipeline between the injection and suction nozzles. Homogeneity is maintained in the loop itself by a high velocity of 10–15 fps-well above API minimum requirements. An oil/water measurement device or OWD is placed at the pump outflow where flow conditions remain constant regardless of variations in the main pipeline.
Nucleotide Diversity in Waxy Gene and Validation of Single Nucleotide Polymorphism in Relation to Amylose Content in Chinese Microcore Rice Germplasm
Authors: Wei‐Hua Qiao , You‐Tao Chen , Rong‐Sheng Wang , Xin Wei , Li‐Rong Cao , Wan‐Xia Zhang , Qing‐Wen Yang 
Published: June 2012

ABSTRACTThe waxy protein primarily controls the synthesis of amylose, which is a key determinant of rice (Oryza sativa L.) cooking and processing qualities. Knowledge of the diversity of waxy gene in Chinese rice is essential to validate molecular markers for marker‐assisted selection and to trace the origin of Chinese glutinous rice. The waxy (Wx) gene in the wild rice has rarely been studied, and the origin of Chinese glutinous rice is not well understood. The objectives of our investigation were (i) to identify the diversity of Wx and molecular markers for marker‐assisted breeding and (ii) trace the origin of Chinese glutinous rice. We examined the sequence variations for the waxy gene of 98 accessions of cultivated rice and 134 accessions of wild rice from a previously established microcore collection of Chinese rice germplasm. A total of 51 and 226 single nucleotide polymorphisms (SNPs) or insertions or deletions were found in the cultivated rice and the wild rice, respectively. Wild rice accessions had much higher diversity than cultivated rice and nonglutinous rice had much higher diversity than glutinous rice whereas the genetic diversity of indica rice was similar to that of japonica rice. Polymorphisms of CTn microsatellite, G/T SNP, and 23‐bp insertion in the waxy gene and their relationship to amylose content were explored using cultivated rice. The G/T allele and 23‐bp insertion were better associated with amylose content than with the CTn alleles, and they were validated as molecular markers for marker‐assisted selection. All the wild rice accessions with 23‐bp insertion or T allele came from South China and the glutinous rice originated from wild rice of South China parallel with indica and japonica differentiation.
Direct and Marker‐Assisted Selection for Resistance to Common Bacterial Blight in Common Bean
Authors: Duncan Robert W. , Gilbertson Robert L. , Singh Shree P. 
Published: June 2012

ABSTRACTCommon bacterial blight (CBB) caused by Xanthomonas campestris pv. phaseoli and X. campestris pv. phaseoli var. fuscans is a seed‐borne disease that can significantly reduce yield and seed quality of common bean (Phaseolus vulgaris L.). Disease resistance is the most effective management strategy, but most common bean cultivars have no CBB resistance. Marker‐assisted selection (MAS) shows promise as a method to facilitate pyramiding CBB resistance between common bean gene pools. This study compared the efficiency of direct disease resistance selection (DDS) and MAS for the pyramiding and transfer of CBB resistance into dark red kidney bean. Direct disease resistance selection and MAS were applied independently, from the F1 through the F5, in an inter‐gene pool double‐cross population, Wilkinson 2/dark red kidney (DRK) 2//DRK 1/VAX 3. Replicated trials were performed in the greenhouse and field in 2006 and 2007 to assess levels of CBB resistance in 15 breeding lines independently developed with each method. Under high disease pressure, in two greenhouse environments, 12 resistant breeding lines were obtained with DDS compared with six using MAS, and the overall CBB mean disease severity index was 3.3 for DDS and 4.2 for MAS. Under moderate disease pressure in the field, there was no significant difference (p > 0.05) between the responses of breeding lines developed by the two selection methods. The cost of DDS was US$1.55 per plant compared to $2.03 for MAS.
Pollen Tube Growth After Intergeneric Pollinations of iap‐Homozygous Sorghum
Authors: Bartek Matthew S. , Hodnett George L. , Burson Byron L. , Stelly David M. , Rooney William L. 
Published: June 2012

ABSTRACTHybridization within sorghum [Sorghum bicolor (L.) Moench] has been the primary means of creating genetic diversity for improvement. While considerable variation exists within S. bicolor, traits such as biotic stress tolerance could be improved if secondary and tertiary germplasm pools were accessible through hybridization. Sorghum germplasm possessing the inhibition of alien pollen (iap) allele has enhanced the ability to make successful wide hybridizations between secondary and tertiary gene pools. However, the range of this efficacy has not been tested. Pollen from Miscanthus Andersson, Pennisetum Rich., Sorghastrum Nash, and Zea L. was transferred to the stigmas of S. bicolor lines Tx3361 (with the iap allele) and ATx623 (without the iap allele). Pollen of all genera exhibited tube growth, but the frequencies of germination and growth rates varied among species and accessions within a genus. Significantly more pollen germinated and grew into the pistils of Tx3361 than ATx623. Pollen grains were noticeably more numerous on stigmas of Tx3361, implying that factors within Tx3361 may also affect pollen adhesion. The results indicate that the potential for intergeneric hybridization of S. bicolor via Tx3361 will vary based on the individual species and accessions within a species that are used as pollinators.