bluuebunny/crossref_metadata_2025_split huggingface dataset:
Uncertainty Analysis using Design of Experiments to Assess the Development Plan of a North Sea Field
Authors: Guerrero Angel , Stephen Karl 
Published: June 2018

Abstract
This study assessed the impact of static and dynamic variables in EUR and NPV in the development plan of a North Sea offshore field with 81 m of water, light oil crude of 40.5 API and 510 SCF/STB of GOR comprised of sandstones from a shallow marine environment in anticline structure separated to the northeast and southwest by a pair of normal faults. The analysis is conducted through the application of different experimental design techniques and the preparation of a comparison between them. Uncertainty analysis has been prepared to characterize the appropriate range for nine variables that affect the oil recovery and net present value of the field development. A Folded Plackett-Burman design was prepared to screen the initial nine variables; the linear regression results show that the oil water contact, permeability anisotropy and net to gross are the significant variables. Also, the residual analysis demonstrated that the proxy equation should be improved to have better predictability in the non-sampled space. In consequence, a D-Optimal and a Central Composite experimental design were prepared for the three significant variables. The regression results show better coefficient correlation and lower least square errors in the D-Optimal design using a full quadratic model and confirmed the oil water contact as the most significant variable of the field. Finally, Monte Carlo Simulation was performed in the proxy model from the D-Optimal design, which resulted in an expected value ultimate recovery of 357 MMSTB. The paper presents an exciting workflow to analyze different experimental design techniques, compare them and use the most suitable to prepare the development plan of a field.
Economical Mature Field Revitalization in Low Oil Prices Environment: A Ten Thousand Incremental Oil Production Case Story in the Drago Complex Field, Ecuador
Authors: Izurieta Alvaro , Cuenca Dario , Pozo Lenin , Padilla Wilson , Bustos Jairo 
Published: June 2018

Abstract
This paper presents the results of the most extensive hydraulic fracturing campaign on the same field in Ecuador, along with the methodology appliedto establish the real field production potential and an incremental oil production of 10,000 STB/d.
The study started with the review of pressure transient analysis (PTA), resulting in updated values of permeability, skin and reservoir pressure, then conventional and special well logs were revisited to get a consistent approach of reservoir pay intervals. The characterization of formation damage mechanism was performed to confirm and complement the results. Strategic execution of the hydraulic fracturing workovers was implemented for fast track execution and to maximize results.
The rigorous and fundamentals-based review showed that additional production potential, on most of the wells in the field, could be achieved by hydraulic fracturing due to the high skin values and the deep penetration nature of the damaged zone. The interventions schedule of producing and nonproducing wells resulted in short deferred production times. All planned jobs were designed with the goal of reaching the maximum production defined by hydraulic fracturing and complete nodal analysis. Most fracturing jobs resulted in folds of increase, FOI, from 2 to 13. The learning curve started from one stage tip screen out, TSO, and conventional long fractures, to two stage hydraulic fracturing, pulsed proppant and propped acid fracturing jobs. Economical evaluation showed that the whole stimulation campaign recovered the investment during the third month of execution.
The incremental production outcome from these jobs resulted in ten thousandstandardbarrels per day, 10,000 STB/d, the historical peak oil of the field and the most extensive hydraulic fracturing campaign in the country.
Fault Leakage Assessment Using the Capacitance Model
Authors: Mohamdally Muzaffar , Soroush Mohammad , Zeidouni Mehdi , Alexander David , Boodlal Donnie 
Published: June 2018

Abstract
Fault transmissibility and leakage have significant implications for field development during both primary and post-primary recovery. Whether the fault is sealing or not can directly determine the sweep efficiency and the fate of injected fluids. In addition, fault transmissivity affect the accuracy of in-place volume calculations from material balance techniques. In this paper dynamic data was used to determine transmissibility and leakage of the faults via Capacitance Model (CM).
The CM has been developed from linear productivity model and material balance equation. Its inputs are production/injection rates and bottomhole pressure data (if available). The CM has weight factor for each well pair which determines the degree of connectivity between that pair. These weight factors were used and correlated to the fault transmissibility in this paper. Also, the CM was modified to incorporate the leakage in the system. New term, called leakage factor, was added for each well in the equation.
The model was examined through applying to several synthetic field data generated by CMG software. In synthetic fields, different faults with different throw and transmissibility were built and across the fault transmissibility was evaluated by the model. For creating leaking fault, upward leakage and flow along the fault were examined. Estimated zero leakage factor means no leakage and one means maximum leakage for the wells. The leakage factors not only identified where the leakage was happening, but also determined the amount of leakage by multiplying leakage factor to the net accumulation.
In reservoirs with complex geology and several faults, commonly encountered in Trinidad, all geological and geophysical complexities might not be accurately known. Using alternative methods such as the CM can complement, validate or better determine fault properties such as leakage and transmissibility for proper application of EOR schemes.
Experiment Studies on Horizontal Well - N2 - Viscosity Depressant - Steam Stimulation for Shallow Thin Super-heavy Oil Reservoirs
Authors: Sun Renyuan , Sun Ying , Fan Kunkun , Yang Shikai , Qiao Mingquan , Wang Xuezhong , Yang Yuanliang 
Published: June 2018

Abstract
In order to develop the super-heavy oil reservoir with thin layer, low reservoir temperature and shallow depth in CF oilfield of China, a new technology of HDNS (Horizontal well, viscosity Depressant, Nitrogen and Steam) was proposed and a series of experiments were conducted and the factors effecting oil recovery factor were analyzed. The self-designed equipment, which includes the steam generation system, gas injection system, chemical injection system, the sand-parking sample system, the temperature-controlled system, the metering system of produced fluids and the data collecting system, was used for the experimental studies. Experiments shows that the displacement efficiency increases with the increase of the steam temperature and the injection rate of steam, but too high steam injection rate will decrease the displacement efficiency because of Steam channeling. Compared with steam huff and puff, the displacement efficiency of viscosity depressant assisted steam (DS) increases about 20% because of the thermal chemical effect. The viscosity depressant, N2 assisted steam huff and puff (DNS) can increase the displacement efficiency in about 18% by using the synergistic effects of viscosity depressant, N2 and steam. In the process of DNS stimulation, the viscosity depressant can reduce the viscosity of super heavy oil combined with the effect of steam, which is called as thermal chemical effect. The N2 can prevent the steam chanelling in the reservoir and decrease the heat loss in the process of steam stimulation. The DNS stimulation can effectively reduce the oil viscosity and the steam injection pressure, expand the steam sweep efficiency. By using this technology, Block X of CF oilfield has been successfully developed in these years.
Casing Centralization and Pipe Movement in Cementing Operations for Improved Displacement Efficiency
Authors: Guzman Jose , Mavares Francisco , Monasterios Eloy , Massirrubi Luis 
Published: June 2018

Abstract
Casing centralization and reciprocation during a cementing operation can help improve the efficiency of annular mud displacement and provide a basis for analyzing the percentage of mud displacement efficiency. This information is necessary when developing a mitigation plan for any cementing operation's risk assessment when centralization and pipe movement are considered as operational variables.
A state-of-the-art, three-dimensional (3D) finite displacement efficiency simulator analyzes the percentage of mud displacement efficiency when these four main possible scenarios are considered: low, medium, and high centralization and casing reciprocation during the cementing operation. This paper discusses three case studies validated by a risk assessment process developed during the cementing job design stage in which higher standoff and casing reciprocation suggest improved mud displacement efficiency and low fluid channeling when the cementing operation is finished. Cement bond log (CBL) results are discussed and shared when high standoff and casing reciprocation scenarios are considered.
Results of this study include the following observations and conclusions: Casing reciprocation helps improve displacement efficiency, which can provide improved cement bonding.If casing reciprocation movement is not possible, high casing centralization standoff can be an effective design technique because it can be used to enhance mud displacement efficiency in cementing operations. Wellbore stability is not compromised by equivalent circulating density (ECD) increments resulting from the reduction of annular clear space when using centralizers.Design risk assessment should include a comparative scenario analysis to mitigate the potential risk of poor mud displacement efficiency when considering casing centralization with medium to high standoff and casing reciprocation.At some point, casing reciprocation will not be a factor of improvement for mud displacement efficiency when sufficient standoff is considered for cementing operation designs. This scenario can help mitigate any likelihood of poor mud displacement efficiency if the casing is not reciprocated because of operational factors.Even though high casing standoff yields high percent displacement efficiency, it is recommended to follow the primary cementing operation's field practices as discussed.
A comprehensive practical analysis to prepare a cementing risk assessment included in an operation's program is reviewed. It considers low and high casing centralization as well as pipe movement as variables to help improve cement placement.
Low Salinity Water Injection in a Clastic Reservoir in Northeast Brazil: An Experimental Case Study
Authors: Almeida Alana , Patel Rajan , Arambula Carolina , Trivedi Japan , Soares João , Costa Gloria , Embiruçu Marcelo 
Published: June 2018

Abstract
Several researchers have demonstrated in laboratory experiments and field applications that reducing the concentration of salts and the content of multivalent cations in the injection water may increase oil recovery. This study evaluates the performance of low salinity water injection (LSWI) in oil recovery using a crude oil and synthetic formation water of a sandstone reservoir in northeast Brazil. Two Botucatu sandstone core samples of 6 in of length and 2 in of diameter were used for the coreflooding experiments. The fluids used included a light crude oil sample, and synthetic formation water (SFW) produced from the four main salts of the original formation water (NaCl, KCl, CaCl2, and MgCl2). In Core 1, two injections were carried out at an average reservoir temperature of 60 °C, one using SFW with 200,000 mg/l as secondary recovery mode, and one using SFW diluted 40 times (40xd_SFW) resulting in a low salinity water of 5,000 mg/l as tertiary recovery mode. In Core 2, 40xd_SFW was injected at the same temperature to compare the high and low salinity water effects in the secondary mode. Moreover, zeta (ζ) potential measurements on Botucatu sandstone powder were performed in 6 dilutions of the SFW and deionized water. The experimental results demonstrated an increase in oil recovery and pH when 40xd_SFW was injected in secondary and tertiary modes. The effluent ionic concentration from Core 1 showed the reduction of Ca2+ during HSWI, indicating its adsorption on the rock surface. Most remarkably, Ca2+ concentration increases and the Na+ concentration decreases in the effluent samples in the first LSWI pore volume injected, which suggested ionic exchange of calcium for sodium on the rock surface. Furthermore, Fe2+/Fe3+ and traces of Al3+ were observed in the effluent demonstrating the occurrence of fine migration in SFW and 40xd_SFW. The magnitude of negative ζ potential on Botucatu sandstone increases as the salinity of the brine solutions decreases. Based on that experimental study, it is noticed that a set of LSWI mechanisms occurr simultaneously in Botucatu sandstone, and oil and brine samples from Recôncavo Basin, indicating a potential of application for LSWI in similar Brazilian oil reservoirs.
A Critical Review and Future Trend on Relative Permeability Hysteresis
Authors: Elhaj Murtada , Hashan Mahamudul , Hossain M. Enamul 
Published: June 2018

Abstract
The term "hysteresis" has been used for a long time. The researchers were paying attention because of its wider usages in many disciplines of science and engineering. However, the concept of hysteresis may differ from one discipline to other depending on parameters of interest. The effect of hysteretic on reservoir performance can be either negative or positive. Therefore, evaluation of hydrocarbon recovery techniques will depend on the accurate estimation of the rock and fluid properties. Many researchers believe that hysteresis behaviour in rock properties is related to the concept of unrecovered hydrocarbon. Numerous experimental and mathematical studies are offered to understand the hysteresis of rock properties. However, researchers paid more attention to the relative permeability hysteresis because of its important contributions on mobility ratio toward the oil recovery. The purpose of this paper is to extensively review, discuss and analyze the fundamentals of experimental processes and mathematical models of relative permeability hysteresis. In addition, the importance of relative permeability hysteresis in reservoir engineering is highlighted.
In the literature, no attempt has been made to refer and review the relative permeability hysteresis despite numerous published papers. This paper considers offering a comprehensive critical review and analysis of hysteresis that related to petroleum engineering. A systematic approach to literature survey is followed to offer a future research guideline in the area.
A critical analysis is offered on theoretical and empirical models for relative permeability hysteresis, the types of relative permeability hysteresis, factors affecting relative permeability hysteresis and rock types that are used in the experimental techniques to estimate the hysteresis. This paper tracks the current development on hysteresis and provides insight into future trends on the application of this phenomenon. The overall results show some missing concepts in existing models and experimental processes for the hysteresis. The finding also shows that for a better understanding of multiphase flow in porous media, it is essential to study the relative permeability hysteresis. Finally, this paper offers some recommendations for missing aspect and future research guidelines.
The importance of relative permeability hysteresis in fluid flow through porous media is rebuilt in describing each of the flowing phases. In addition, this study will help in understanding better reservoir performance as well as reservoir description.
Modeling of Foam-Assisted Wellbore Cleanup and Drilling Processes with Both Dry- and Wet-Foam Rheological Properties
Authors: Wang Yanfang , Thiberville Caitlyn , Kam Seung Ihl 
Published: June 2018

Abstract
As advanced drilling technology gains more popularity in the development of unconventional reservoirs and deepwater fields, the demand for an improved drilling hydraulics modeling escalates today. The situation is also true for foam applications that have long been used as a useful means of downhole cleaning and underbalanced drilling methods.
This study investigates how a new foam model, recently developed by Wang et al. (2017), can be applied to a wide range of hole cleaning and drilling scenarios. The model combines rheological properties of wet foams and dry foams by using 9 model parameters (3 to define the range of gas and liquid flowrates and corresponding frictional pressure losses of interest, 4 to fit the power-law rheology of wet and dry foams, and last 2 to capture the sensitivity of foam rheology to gas and liquid rates). These scenarios consider foam circulation into 10,000 ft long wells at different inclination angles with a long vertical, inclined, or horizontal trajectory. The results from this new method are compared with two existing foam modeling techniques, so-called Chen et al.'s model (based on the correlations for wet foams only) and Edrisi and Kam's model (based on wet- and dry-foam rheological properties with 5 model parameters). The results show that, with or without formation fluid influx, the new foam model demonstrates the robustness of the new modeling technique in all scenarios capturing foam flow characteristics better, whenever the situation forms stable fine-textured foams or unstable coarse-textured foams.
Realistic and Promising Technology Measures for SAGD Projects at Low Oil Price
Authors: Liang Guangyue , Liu Shangqi , Liu Yang , Luo Yanyan , Han Bin , Huang Jixin , Bao Yu 
Published: June 2018

Abstract
Steam assisted gravity drainage (SAGD) process is widely used in super heavy oil and oil sands projects. These projects generally have higher steam to oil ratio and poor economy, partly because un-uniform steam chamber along the horizontal section forms and it is hard to adjust, affecting by reservoir heterogeneity including muddy interlayer and thief zones. Therefore, it is desirable to explore realistic and promising technology measures for SAGD projects at low oil price.
In this paper, almost all the technology measures for SAGD projects were extensively and deeply investigated in terms of domestic and foreign reports, literatures and on-site experiences. The available research subjects include Xinjiang Fengcheng and Liaohe super heavy oil projects in China as well as ten oil sands project attached to eight corporations in Canada. Better yet, numerous statistics about technology application are reviewed well-by-well, and field application effects for some technologies were verified by deliberate numerical simulation.
Many realistic and enforceable technology measures were systematically analyzed and recommended. Single or multiple stage dilation start-up process assisted by waste water or polymer injection enhanced start-up process significantly. Infilling well pairs or wedge well, and sidetracking horizontal well or fishbone well effectively tapped the unswept remaining oil by steam. The other technologies further improved steam chamber conformance including non-condensable gas co-injection, ICD/FCD technology, differentiated operating pressure strategy, nitrogen plus dispersant foam profile control and other remedial measures, etc. Besides, the present situation and foreground application were summarized and evaluated for several promising new technologies to be studied such as screening low cost mixed solvent to increase solvent recovery, warm solvent gravity drainage (Nsolv) process and in-situ upgrading process assisted by electrical heater or catalytic modification to reduce the capital cost of surface facility, etc.
The paper contains some previously unpublished data of practical experiences, and the findings of this investigation add to the knowledge base information related to improving the SAGD performance and economy of super heavy oil or oil sands projects.
The Geochemistry and Exploration Plays Hidden in Royalty Lease Evaluation Distillation Data of Trinmar Oils
Authors: Paul Simon , Archie Curtis , Gallai-Ragobar Nancy 
Published: June 2018

Abstract
Royalty Lease Evaluation (RLE) distillation analysis was performed on six hundred (600) wells in Petrotrin's Soldado acreage. This data has been traditionally generated for use by Petrotrin's refinery to determine if the crude oil feedstock is compatible to the refinery configuration or if the crude oil could cause yield, quality and production problems. These made for refinery reports have become part of Petrotrin's legacy data. The authors decided to examine this dormant dataset to ascertain what hidden stories it may tell about the oilfields from which they came.
In this investigation no data is generated, but an existing and dormant dataset will be analysed. Several components in a RLE distillation report on crude oil samples will be observed for trends, patterns and relationships. Ternary diagrams and cross-plots will be employed. Specific geochemical revelations from the RLE data will be validated by comparison to conventional gas chromatography data.
This investigation will illustrate how evaporative fractionation, which is a later charge of light hydrocarbons mixing with an emplaced biodegraded oil is evidenced by a phenomenon called the" Gas Oil Anomaly", seen in the RLE data. Essentially this is the absence of any gas oil fraction combined with the presence of light hydrocarbons in the distillation data. It will also be demonstrated that presence of the later charge of light hydrocarbons has been the key factor in the prolific production from the Soldado reservoirs.
Additional analysis of the light oil and gas oil fractions of a crude oil will reveal properties and characteristics that suggest there were different sources for both the originally emplaced oils and the later charge of light hydrocarbons. The data also shows that due to the evaporative fractionation phenomenon there is no correlation with API Gravity, oil viscosity, Sulphur content and depth of the reservoirs in Soldado. It will also be demonstrated that the data can be used as a qualitative tool leading to exploration plays in the Soldado acreage.
Explorationists at Petrotrin will find the results of this investigation to be both useful and provocative as it directs their attention to specific Trinmar Soldado oilfields as deep exploration play areas in a manner that traditional geochemical analyses have not been able to. It also allows the practioners in the Petrotrin Soldado acreage to better understand the productivity and complex fluid distributions in the Soldado reservoirs.