bluuebunny/crossref_metadata_2025_split huggingface dataset:
Full-Field History-Match of Stacked Reservoirs across Fault Blocks to Investigate Cross-Fault Block Communiation
Authors: Jeboda Olatunji , Ambastha Anil , Eme Vincent 
Published: August 2015

Abstract
A stacked series of fault juxtaposed reservoirs across four fault blocks in an offshore field were being considered for further development, but communication across fault blocks remained an uncertainty even after 40 years of production from these reservoirs. Providing a reliable forecast associated with a development plan required understanding of the impact of these faults to the reservoirs’ historical production and how it may impact future development opportunities. A full field simulation model containing all the reservoirs in the field, which can capture the impact of the communication across the fault blocks was built but due to the large number and coarse scale of grid blocks as well as mulyiple reservoirs, it was decided to use the results from the pressure-match work done on the full-field model and work with smaller, but finer scale, full-field simulation models with less number of reservoirs which were more likely to be communicating to produce a model which could answer these questions and provide a reliable forecast associated with the development opportunities.
This paper describes a full field, three-dimensional, three-phase, black-oil simulation model of several reservoirs in Bayelsa field (not real name) which was used to investigate across fault block communication and identify further development opportunities in these reservoirs.
A Time Function Havlena and Odeh MBE Straight Line Equation
Authors: Buduka Stanley , Biu Victor T , Sylvester Okotie 
Published: August 2015

Abstract
The straight line model introduced by Havlena and Odeh require plotting of the underground recoverable function F against the oil plus dissolved gas expansion function Eo or gas cap expansion function Eg or the connate water and rock properties Efw or a combination of these drives depending on the existing reservoir drive. The consequence is that the estimation of the initial oil in place and cumulative oil produced do not considered the timing factor of the average production of the field life. Hence, this paper present an alternative Havlena & Odeh model in which the reservoir functions such as F are plotted against E per cumulative time making reservoir engineers to appreciate the reservoir behaviour at each time space/limit and also act as a check to the original Havlena and Odeh model. The average production per day is used as against the cumulative production. An appropriate equation and method of analysis is show in this paper. Nevertheless a practical field case is considered. Result from the new model maintained relevant trend with the old Havlena and Odeh model with error factor of 0.043%, hence suitable for predicting reservoir performance as a function of time and also estimating initial oil in place and cumulative production.
From Exploration to Development: The Value of Formation Pressure While Drilling Applications
Authors: Okoroafor Rita Esuru , Nkanga Akanimoh , Okoli Fanyama , Babatunde Folasade , Danison Idang , Akinnagbe Timothy 
Published: August 2015

Abstract
The varied applications of formation pressure data analysis have been realized using state-of-the-art acquisition methodology. The methodology which involves customized workflows in order to achieve the objectives for Formation Pressure While Drilling (FPWD) acquisition has reduced stationary time, improved data precision, ensured better depth management and reduced tool lost-in-hole.
The case studies are wells located in various offshore and deep-water fields in the Gulf of Guinea. Well types include exploration, appraisal and development. Well architecture includes vertical, slightly deviated and highly deviated wells. The objectives for FPWD in these wells ranged from optimizing drilling, formation evaluation, understanding extent of depletion, acquiring information for completion decisions, and ultimately to aid in safe well drilling.
In one of the exploratory wells, the FPWD tool was used to validate wireline formation pressure measurements. The study not only shows that there were cost savings in this methodology, but also reliable information about the reservoir was available in real time to make critical decisions before the bottom-hole-assembly was pulled out of hole. In one of the appraisal wells, data obtained while drilling enabled safe drilling to total depth (TD) with optimum mud weight, and also effectively determined fluid types and contacts. In the high-angle development wells, FPWD was effectively used to gather information to aid in reservoir characterization and management.
This paper demonstrates the suitability of FPWD applications in exploratory, development and production wells. It also shows how cost savings can be achieved by deploying formation-pressure-while-drilling technology for drilling-related applications, formation evaluation and reservoir management.
The paper also demonstrates the flexibility of FPWD for different well architecture and well conditions. Having the data in real time aids in quick operational and completions decision making based on the objectives of acquiring the data.
Impact of the National Content Act on Deep Water Offshore Development in Nigeria
Authors: Echendu J. C. , Iledare O. O. 
Published: August 2015

Abstract
The key objectives of National Content Act (NCA) of 2010 in Nigeria aim to enhance operational efficiency and drive costs down in the medium to long term by encouraging indigenous participation and ownership of assets in the oil and gas industry. Its implementation in the industry is to facilitate the industrialization process by manufacturing and fabricating components and other requirements needed in the industry locally. The Act is expected to stimulate investments and create opportunities for Nigerians to participate in the oil and gas industry in Nigeria.
The passage of the NCA in 2010 and the subsequent formation of the Nigerian Content Development and Monitoring Board (NCDMB) have facilitated the emergence of indigenous companies operating in both the upstream and downstream sectors of the petroleum industry. Certainly, some achievements have been made in terms of policy guidelines, usage of made-in-Nigeria pipelines, increased in-country fabrication tonnage, employment and training strategy to mention a few; yet about 90% of the industry annual budget is still spent abroad. This signifies that much more could still be achieved than accomplished thus far.
This paper investigates the implications of foreign expenditure as proposed in the Petroleum Industry Bill 2012 (PIB 2012) in Nigeria. The paper also evaluates the likely impact of national content contribution to the national economy. Further, the paper examines the effects of the negotiable limit of deductible foreign expenditure on project performance using Discounted Net Cash Flow (DNCF) model framework.
It is observed that as the expenditure domiciled locally increases, the contractor Internal Rate of Return (IRR) increases with a corresponding higher value added to the investment than otherwise, assuming the homogeneity of a dollar spent abroad and locally. The marginal increment to the contractor in terms of IRR or Net Present Value (NPV) is higher in comparison to the marginal effect to the mineral owner in terms of Discounted Government Take (DGT), ceteris paribus. It is, however, recommended that a range for the negotiable limit be specified to avoid an open-ended discourse. Investors are seemingly better off if they reduce foreign expenditures and purposefully engage and develop national capacity as evident.
Low Salinity Water Injection for EOR
Authors: Chandrashegaran Premkumar 
Published: August 2015

Abstract
Low Salinity Waterflooding is one of the emerging oil recovery techniques which has gained its popularity in the past decade. Many experiments and laboratory works have been conducted since its oil recovery potential was discovered in late 1960s. Wettability alteration in the reservoir is said to be the main cause in enhancing oil recovery. Nevertheless, the effectiveness of this type of oil recovery is very much dependent on the initial reservoir conditions, in particular, the connate water saturation, rock physics and connate water salinity. This work is to run simulations on ECLIPSE 100 simulator to show the effect of injecting low salinity water into a reservoir. A simple static model was created to mimic a real reservoir. Reservoir is of three phase with oil, gas and water and consists of one injector and one producer just to simulate the effect of injecting a low salinity water and a normal salinity, or seawater. Effect on oil recovery was observed by conducting sensitivity studies on rock physics; both injection and reservoir brine salinity; tertiary recovery option; polymer injection using low salinity water solution; and grid refinement. A difference of 14% in oil recovery is observed when lower salinity water is used to inject compared with normal salinity water. The effect on oil recovery also showed distinct difference when the connate water salinity is changed with difference up to 28% with low saline reservoir water. Polymer injection with low salinity water gave 4% increment in recovery compared to injecting with higher salinity water for the same concentration of polymer. This can indeed give better cost savings when opting for polymer injection, where a lower concentration or amount of polymer is needed with the use of low salinity water.
Abang Field: An Integrated Approach to Maximizing Volumes Growth
Authors: Alim Chimereucheya N. , Ajibola Olayode , Udoh Isonguyo 
Published: August 2015

Abstract
The Abang field located Offshore Nigeria was discovered in 1992 and commenced production in 2012. The field consists of a 3-way structural closure on the footwall of a very large regional down-to-the-basin growth fault and Deepwater Confined Channel Complex (CCC) environment of deposition.
Key uncertainties in the field include the lateral stratigraphic continuity of the reservoir and the degree of communication across the shales separating the sand intervals. The seismic quality in this region is fair and the pre-development geologic / simulation model is inadequate to address post-drill learnings.
Early post-production dynamic pressure data indicated that observed pressures were higher than predrill estimates. This led to several Material Balance (MBAL) analysis based on a range of Aquifer-Hydrocarbon ratios (AHR) was used to estimate the hydrocarbon volume in the reservoir and test indications of communication across the sands. The analysis indicated that a volume significantly greater than the initial estimated Stock Tank Original Oil-in-Place (STOOIP) is required to match the observed pressures.
Subsequent integration of reservoir performance and geologic data drove the re-evaluation of the seismic interpretation and re-mapping of the field. The new maps buttressed the MBAL volumes estimate and consequently led to the planning of a drillwell to validate the predicted volumes and test the lateral extent of the reservoirs.
The drillwell results confirmed the opportunity identified and validated the volumes estimate from MBAL resulting in a three-fold increase in EUR and potential for additional drilling / resource add in the field. Interpretation of the drillwell RFT pressure data also led to a new understanding of the degree of communication across the sands.
This paper describes the methodology of how early post-production material balance (MBAL) analysis as well as cross-functional collaboration supported volumes growth in the field and tripled recoverable hydrocarbon.
Maximizing Recovery from Peripheral Waterflooding: Case History of Two Water Injectors
Authors: Adegboye Phillip , Okpan Olu 
Published: August 2015

Abstract
Reservoir X01 and X02 are among the biggest reservoirs in AA field located in shallow waters offshore Nigeria. Production started from both reservoirs in 1965. By year 2001, the reservoir pressure in both X01 and X02 had each depleted by about 45% from their initial pressure. Furthermore, the reservoirs were observed to exhibit multiple pressure regions and fluid contacts at dynamic condition resulting from stratigraphic variation and differential production and injection across the reservoirs. Water injection commenced in 2002 into both reservoirs through peripheral waterflooding. It was observed that only the eastern regions of the reservoirs were benefitting from the water injection. By year 2011, reservoir pressure and production from the western region of both reservoirs had depleted significantly; several wells quit production while others had their production rate reduced. Utilizing historical pressure data, production data and other reservoir information, dynamic simulation was constructed to assess the impact of drilling two water injectors, Inj-03i and Inj-05i, in the western areas of reservoirs X01 and X02 respectively. The injectors were needed to provide pressure support as well as to improve sweep efficiency.
In October 2011, Inj-03i and Inj-05i commenced water injection into the western region of X01 and X02 reservoirs respectively. By February 2013, reservoir pressure in the western area of X01 reservoir had risen to 1700 psi, from its pre-water injection value of 1000 psi. Similarly in the western area of X02 pressure increase of 300 was observed post water injection in Inj-05i. Three wells that had earlier quit production in X01 reservoir were restored back to production while two shut-in wells in X02 reservoir were also restored to production. A total incremental production of 5,500 BOPD was attributed to the improved performance in the two reservoirs as a result of the drilling of the two water injectors. Recent flowing and static pressure data were valuable in designing production restoration jobs.
Improving Hydraulic Cement Isolation In Subsea Operations. OML 126 Wells (Phase 1&2 FDP) – A Case Study
Authors: Okoli Ugochukwu , Nwagu Chike , Tayo Ajimoko , Hope Okwa 
Published: August 2015

Abstract
The importance of a good cement bond between the casing and the formation cannot be over emphasized, it is a critical component of well architecture for ensuring casing mechanical support, protection from fluid corrosion, and most importantly isolating permeable zones at different pressure regimes to prevent hydraulic communication. The quality and integrity of a cement job can determine how long a well remains stable and productive without requiring repair.
In the phase one Field Development of the OML-126 block, poor quantitative and qualitative cement bonds were observed in the porous sandstone regions. Following the approval for cased hole designs in the phase 2 Field Development in the same block, it became necessary to investigate the problem in order to ensure proper hydraulic isolation, and the required structural back-up to perforate the casings for cased hole completions.
The study of the reviewed wells developed in the same subject field (OML-126), as well as wells from other fields with similar depositional characteristics. These wells were used to investigate if the petrophysical properties of the formation (porosity, permeability, wettability) had its influence on the qualitative placement of cement.
This paper discusses in sequence how progress was made to achieve the required structural support and hydraulic isolation. Firstly, there was a review of the cementing contractor's design procedures, and recommendations to use a standard API practice to check the rheological properties of the drilling fluids prior to pumping in hole. Then use of water and oil swellable packers in shaly formations as a back-up to primary cementing, to help provide the required hydraulic isolation to prevent early gas cusping and water coning into the wellbore, during production. Lastly, the use of special additives like Microbond HT and Micro-Matrix for primary cementing operations. Micro-Matrix, providing the required characteristic to help plug and seal-off hydrophilic pores in sandstone formations, Microbond HT expanding to isolate any channels left as a result of the drilling fluid not being properly displaced, or water wet to effectively place the cement.
These methods all proved effective as the required hydraulic isolation was achieved, which was confirmed by Cement Bond Logs (CBL) prior to completion.
Genetic Diversity for Russian Wheat Aphid Resistance as Determined by Genome‐Wide Association Mapping and Inheritance in Progeny
Authors: Dahleen Lynn S. , Bregitzer Phil , Mornhinweg Do , Klos Kathy Esvelt 
Published: August 2015

ABSTRACTRussian wheat aphid (RWA) [Diuraphis noxia (Mordvilko)] is an increasing problem on barley (Hordeum vulgare L.) throughout the world. Genetic resistance has been identified and used to create barley germplasm and cultivars adapted to the United States. Several mapping studies have been conducted to identify loci associated with resistance, but questions remain, particularly regarding the extent of genetic diversity among resistance sources and improved lines and cultivars. Association analysis of resistant (R) and moderately resistant (MR), unadapted accessions held in the USDA–ARS National Small Grains Germplasm Collection, adapted germplasm lines derived from these accessions, and susceptible (S) elite cultivars was conducted using 4509 single nucleotide polymorphisms (SNPs) to identify markers linked to resistance. Resistance was associated with loci on chromosomes 1H, 2H, 3H, 5H, and 7H at p‐values <0.0001, and the major 1H and 3H loci identified in previous tests were confirmed. However, the genetics of RWA resistance was shown to be complex, and it is likely that loci involved in resistance in some lines were not identified. Nevertheless, this analysis identified diversity among R lines and showed that most of the released RWA‐resistant cultivars had similar genotypes at loci associated with resistance. This analysis also identified R lines that were genetically dissimilar to the released cultivars at these loci. This information can guide parental selection for future breeding efforts designed to capture and deploy greater diversity for RWA resistance among new barley cultivars.
Carbon Allocation Patterns into Proteins and Lipids Associated with Superior Tolerance of Perennial Grass to High Soil Temperature
Authors: Rachmilevitch Shimon , Cohen Itay , Huang Bingru 
Published: August 2015

ABSTRACTPlant adaptation to heat stress may involve changes in C allocation within the plant. The objective of this study was to determine whether heat tolerance of C3 perennial grass species was associated with the alteration of C allocation to proteins and lipids under heat stress. We study the patterns of allocation of newly fixed C through photosynthesis to proteins and lipids of heat‐tolerant thermal Agrostis scabra Willd. and heat‐sensitive creeping bent grass (A. stolonifera L. ‘Penncross’) exposed to high soil temperatures at 37°C or control temperature at 20°C. The allocation patterns of newly fixed C during heat stress into proteins and lipids in various plant organs (shoots, crowns, and roots) were examined using the 14CO2 pulse‐chase labeling technique. High soil temperature reduced the allocation of newly fixed C into proteins and lipids in shoots and roots, resulting in a lower protein and lipid content than control plants for both grass species. The decline in the protein and lipid content and the decrease in the 14C allocation were less pronounced in thermal A. scabra than in A. stolonifera. The more efficient incorporation of newly fixed 14C into lipids and proteins could support the superior tolerance of thermal A. scabra to prolonged periods of high soil temperatures.
Effect of Restorative Protocol on Cuspal Strain and Residual Stress in Endodontically Treated Molars
Authors: Pereira RAS , Bicalho AA , Franco SD , Tantbirojn D , Versluis A , Soares CJ 
Published: August 2015

SUMMARY

Objectives
To evaluate the effect of the restorative protocol on cuspal strain, fracture resistance, residual stress, and mechanical properties of restorative materials in endodontically treated molars.

Methods
Forty-five molars received mesio-occlusal-distal (MOD) Class II preparations and endodontic treatment followed by direct restorations using three restorative protocols: composite resin (CR) only (Filtek Supreme, 3M-ESPE), resin modified glass ionomer cement in combination with CR (Vitremer, 3M-ESPE in pulp chamber and Filtek Supreme in MOD cavity), conventional glass ionomer cement in combination with composite resin (CGI-CR) (Ketac Fil, 3M-ESPE in pulp chamber and Filtek Supreme in MOD cavity). Cuspal strain was measured using strain gauges, and fracture resistance was tested with an occlusal load. Elastic modulus (EM) and Vickers hardness (VH) of the restorative materials were determined at different depths using dynamic microhardness indentation. Curing shrinkage was measured using the strain gauge technique. The restorative protocols were also simulated in finite element analysis (FEA). The shrinkage strain, cuspal strain, EM, VH, and fracture resistance data were statistically analyzed using split-plot analysis of variance and Tukey test (p=0.05). Residual shrinkage stresses were expressed in modified von Mises equivalent stresses.

Results
Shrinkage strain values (in volume %) were Ketac Fil (0.08±0.01) &lt; Vitremer (0.18±0.01) &lt; Filtek Supreme (0.54±0.03). Cuspal strain was higher and fracture resistance was lower when using CR only compared with the techniques that used glass ionomer. The EM and VH of the materials in the pulp chamber were significantly lower for glass ionomer. The FEA showed that using CR only resulted in higher residual stresses in enamel and root dentin close to the pulp chamber than the combinations with glass ionomers (RMGI-CR and CGI-CR).

Conclusions
The choice of restorative protocol significantly affected the biomechanical behavior of endodontically treated molars. Using glass ionomer to fill the pulp chamber is recommended when endodontically treated molars receive direct composite restorations because it reduces cuspal strain and increases fracture resistance.