bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Nanoparticle Based Applications in Oilfield: From Sand Consolidation to Water Shutoff
Authors: Kalgaonkar Rajendra , Alnoaimi Khalid , Wagle Vikrant 
Published: October 2019

Abstract
The present paper describes the development of unique chemistries for plugging and sealing water producing zones and binding produced sand in unconsolidated formations. This is achieved by tuning the surface chemistry of the nanoparticles to act as either conformance sealants or as sand binders. Wherein the sealants would completely seal-off the water and gas producing zones, the binders would consolidate the produced sand while maintaining the reservoir permeability.
The sealing and binding mechanisms of the nanoparticles are based upon triggered chemistries to achieve delayed gelling activation to ensure proper placement of the treatment into the target zone and avoid premature plugging of pipe lines, coiled tubing or other tubulars. The treatment can be placed downhole as a single pill. When the surface chemistry is tuned for the nanoparticles to act as binders for sand consolidation, the pill has high affinity to the solid surface and therefore is less prone to build up in the pore space. Once cured at reservoir temperature it forms a thin layer of hard gel around the surface of the sand particles, cementing the sand grains together at the same time maintaining open porosity to ensure easy flow of hydrocarbons and injected water. When the pill is deployed as a sealant for water conformance, it occupies the available pore space to seal-off the water producing zones. The newly developed systems can be effectively applied as sealants or binders up to BHST of 300°F.
The surface modified nanoparticles were studied for their abilities to consolidate loose sand and at the same time maintain good permeability in case of binders, while to plug and seal water producing zones in case of conformance sealants. The static and dynamic gelation times were evaluated up to 300°F. It was shown that the gelation time of the nanoparticles can be controlled by surface chemistry modification, pH alterations as well as by adjusting the concentration of the activator, which is advantageous as it allows the treatment to remain pumpable over predictable periods of time. The effects of shear rate on gelation time and viscosity buildup are presented. Regain permeability studies showed that permeability could be controlled by specific surface modifications of the nanoparticles.
The novelty of this paper is that it not only describes the development of unique nanoparticles for water conformance and sand control, but also provides a selection criteria for applying the surface modified nanoparticles for these downhole applications.
Key Technologies and Practice of Ultra-HTHP Drilling in South China Sea
Authors: Xu Dongsheng , Yang Jin , Zhao Ying , Huang Yi , Luo Ming , Chen Yuan , Li Lei , Yang Yupeng , Wang Jie , Zhang Minghe 
Published: October 2019

Abstract
Ultra-HTHP reservoirs are Contained in the deep strata of Yingqiong Basin in the South China Sea. The formation pressure coefficient is about 2.30, and the reservoir temperature is about 230℃. So the reservoir has the characteristics of low pressure bearing capacity and high collapse pressure, it poses great challenges to drilling operations.
Aiming at the difficulties of Ultra-HTHP wells, we carried out a series of studies. Firstly, We have done 2170 sets of experiments on rock properties to study drillability and viscoplasticity of rocks, the test conditions is 200℃ with confining pressures of 20 Mpa, 35 Mpa and 50 Mpa. Secondly, focusing on the problems of large surface casing and high risk of anti-collision in HTHP cluster wells, We improved drilling efficiency by pre-inclination drilling and anti-collision drilling. Finally, to protect reservoirs and reduce pollution, we invented a dual-effect drilling and completion fluid system with megatherm resistance.
After decades of research and public relations, we had completed a series of successful exploration and practice. Based on the law of viscoplastic change of rock under HTHP and rock breaking mechanism, we innovatively expounded a composite impactor acceleration tool with rotating and axial high frequency impact force characteristics. According to the principle of jet pump, a new type of speed-increasing jet-suction bit with bottom jet and reverse jet-suction dual-fluid channel had been creatively invented, it can increase the ROP of Ultra-HTHP wellbore by 162%. Ultra-HTHP cluster well surface drilling, pre-inclination, anti-collision one-trip high-efficiency drilling technology realizes the cluster well large-scale borehole drilling, pre-inclination, anti-collision three-in-one operation mode, it reduced the risk of anti-collision while improving the operation time, the single well construction period saved 2.5 days, and the average drilling cost saved 600 thousand RMB per day.Compared with conventional solid-phase drilling and completion fluids, the dual-effect drilling and completion fluids have high temperature, high density and low solid content decrease by 20%, mud cake thickness decreases by 60%, and permeability recovery value increases from 70% to more than 90%. Compared with the single well cost of cesium formate system in the world, single well saves 48 million RMB.
Ultra-HTHP wells had been successfully drilled 16 wells in the South China Sea, and the success rate is 100%. The average drilling cycle reduced from 175 days to 52 days, it is of great reference value for Ultra-HTHP drilling. It can be recommended to make Ultra-HTHP offshore areas such as the North Sea of Britain and the Gulf of Mexico of the United States.
Accurate Prediction of CO2 Minimum Miscibility Pressure Using Adaptive Neuro-Fuzzy Inference Systems
Authors: Hamdi Zakaria , Chenxi Dong 
Published: October 2019

Abstract
In CO2 gas injection, the oil recovery rate of the miscible flooding is significantly higher than that of the non-miscible flooding. The miscibility of oil and CO2 can only be achieved when pressure is above the minimum miscible pressure (MMP), hence MMP is an important parameter for the optimal design of the CO2 injection in the reservoir. The MMP can be determined by traditional methods such as experimental and empirical correlation approaches. The experimental method is accurate but time-consuming and expensive, while the correlation methods are efficient but have limited application range due to its theoretical assumption's limitation. Thus, a more efficient and accurate method for MMP measurement is in need. Artificial neuro network (ANN) is an effective tool for engineering estimation, hence some MMP prediction model based on ANN was proposed by researchers, but the accuracy of models still can be improved. In this study, four factors (heavy hydrocarbon molecular weight, reservoir temperature, volatile and intermediate ratio oil) of MMP were designed as input, MMP as output, and ANFIS model is constructed for MMP prediction, the accuracy is estimated by the root mean square error (RMSE). The simulation results indicate that the ANFIS model has higher accuracy (average RMSE=1.846) and wider application range than those traditional correlation approaches (best-performed correlation RMSE=4.25). ANFIS runs faster and cheaper than the experimental approach. Among all the ANFIS models, the hybrid algorithm optimized ANFIS with Gaussian member function is most accurate with RMSE=1.44. BP algorithm optimized ANFIS with PSigmoid membership function produces the largest error (RMSE=2.83). Therefore, the ANFIS model developed in this study is more accurate and time-saving than traditional methods in predicting MMP and is more accurate than the previous neural network MMP prediction models.
Applications of Interbed Multiple Elimination
Authors: Qi Qunli , Ye Zaibing , Gao Kai , Li Guanmei 
Published: October 2019

Abstract
Multiple contamination both surface related and interbeded are common and known to hinder the interpretation, reservoir characterization and inversion studies. Surface related multiple is always present and strong on marine data, but not often a problem on land data. Interbed multiple is rather dependent on the subsurface structures and not always obvious, however in presence of strong subsurface reflectors, interbed multiple contamination could be marked, this article mainly focus on IME – Interbed Multiple Elimination. Two methodologies including data driven Extended SRME IME in combination with radon transform based demultiplex and ISS (inversion scattering series) based IME are introduced. Good demultiple results are demonstrated by case study.
Optimization Of Large Gas Cap Development Plan Though Pilot Learning Leading to Significant Cost Saving
Authors: Agrawal Pawan , Keshtta Osama , Draoui Elyes 
Published: October 2019

Abstract
Field presented here is giant heterogeneous carbonate field consist of multi-stacked reservoirs, located in offshore Abu Dhabi. It consists of a very large rich gas cap with oil rim. Current development plan is oil production from oil rim with peripheral water injection & crestal gas injection. Long Term Development Plan "LTDP" of field consists of co-development of oil rim (through water injection at GOC) and gas cap (through partial gas recycling) to maximize oil, condensate & gas value. Details of LTDP are in Ref. 7. To further maximize condensate value, mid-term plan is complete gas recycling by production of rich gas through gas cap producer located downdip of structure and injection of dry gas through gas injector located in the crest.
To de-risk midterm plan, a gas cap producer pilot has been drilled in one of prolific reservoir. Main objectives of gas producer pilot were to reduce uncertainty of CGR, assess gas well capacity & assess gas offtake impact on oil rim. This paper presents optimization of gas cap development in terms of number of wells, trajectory, location & completion based on learning of gas cap pilot.
Literature data indicate that below dew point pressure, gas condensate reservoirs exhibit growth of a condensate bank around the wellbore, which effectively reduce the relative permeability to gas flow & well capacity. Flow in near wellbore region is also impacted by saturation dependent inertial forces (non-Darcy flow). On the other hand at high capillary number improvement in gas relative permeability counteracts the PI reduction. All this effects have been considered in gas cap development.
In this study using a fit for purpose sector model extracted from full field model, all the three phenomenon's non-Darcy effect, condensate blockage and relative permeability improvement at higher capillary number has been studied for different well trajectories such as vertical well, deviated well and horizontal well. Based on simulation results horizontal well was chosen for piloting to minimize impact of condensate blockage, gas turbulent effect and produce the condensate reservoir more efficiently. Sector model was fine-tuned based on pilot results which were further upscaled in the full field simulation. Based on pilot learning well trajectory, location & completion has been optimized for different flow units which leads to significant cost saving.
Multi-Disciplinary Data Integration as Key to Resolve Complex Structural
Authors: Gruber Wilfried , Ghedan Shawket , Rouis Lamia , Eid Tarek , Eldali Magdi Abdelhad , Gibrata Muhammad Antonia 
Published: October 2019

Abstract
The Cheleken area holds a series of hydrocarbon accumulations along a transpressional ridge (Apsheron trend). Seismic data is key to understand each field's structural setting and complexity especially in the inter-well space. Previous data interpretations could not overcome limitations and ambiguities of data quality leading to a range of possible interpretations. This study presents how integration of well data and structural style concepts into the seismic workflow results in a structural model matching all data and field characteristics.
Interpretation of band limited thus low-resolution seismic data in context of a complex structural setting across a thick deltaic succession is challenging. In order to avoid over-interpretation and non-systematic patterns all available information was integrated into the interpretation process. From preliminary identification of the master fault and stress regime, a classical Riedel shear system was recognized. Prevailing fault plane geometries at each deformation stage were defined and applied to guide fault delineation at larger scale. Linking interpreted faults to corresponding well markers, identified by layer doubling or missing sections, required considerable effort due to the high number of deviated wells, but strongly reduced ambiguities.
The central part of the Lam field forms a positive flower structure across the productive Red Series. A strike slip system with helicoidal fault geometry is the prevailing structural style. Such fault system originates from a single master fault at large depth. Transpressional deformation led to the formation of Riedel faults that root in the main fault. Ongoing deformation resulted in the additional formation of P- faults connecting the Riedel faults at larger depth only. At the same time, Riedel faults steepen while propagating upward, but die out at the top of the Red Series. This resulted in structural highs developed as updomings between the en-echelon patterns of the Riedel faults. These show reverse offsets on the flanks but typically only minor throw when passing the central sections of the updomings. A second, relatively younger set of normal faults was identified which did not match the strike slip system interpretation. These faults crosscut the older faults in the shallow succession and indicate a recent extensional regime.
Exceptional situations require exceptional effort across multiple disciplines to arrive at a common understanding for hydrocarbon fields. Success keys were to find the balance between data driven and model driven results and to allow for a certain degree of simplification. The latter was substantial in the construction of a model that captures the main field characteristics but avoids unnecessary detail in terms of structure and subsequently hydrocarbon distribution.
Prediction of Water Saturation for Tight Sandstone Reservoirs by Using Array Dielectric Logging ADL
Authors: Guo Haopeng , Zhang Haitao , Li Gaoren , Yan Xuecheng , Zhang Wenjing , Wang Yanmei , Xiao Liang , Liu Die 
Published: October 2019

Abstract
Conventional hydrocarbon saturation estimation methods based on porosity and resistivity curves cannot be well used in our target formations due to the difficulty of the determination of necessary input parameters. The formation water resistivity was heavily affected by the various salinity. The water salinity was considered to have little effect to the delectric constant, especially for the delectric constants measured with frequency higher than 200 MHz. In this study, we proposed a new model to predict water saturation from the array delectric logging (ADL) data in the Chang 8 Formation of Penyang region, west Ordos Basin, west China. This model was similar with the classic Archie's equation in form, whereas the involved parameters were much easily to be determined. Based on the lab delectric constant measurements of 6 typical core samples, we determined the input parameters in this new model. Meanwhile, considering the effect of pore structure to delectric measurements, a model of calculating various mε from porosity was established. By using the proposed model, we processed several wells with which the ADL data was acquired, the consecutive water saturation curves were calculated. Comparisons of predicted water saturation with irreducible water saturation, core derived results and the drill stem test (DST) data illustrate that this model was reliable. The advantage of this model was that it can be used to precisely calculate water saturation in any formations with various formation water salinity, whereas the conventional methods lost their role.
Advanced Logs and Seismic Driven Geomechanics in Complex Sandstone Reservoirs for Drilling Optimization
Authors: Nasreldin Gaisoni , Gibrata Muhammad A. , Rajaiah Nanthakumar , Elsadany Karim , Aly Omar , Al Asadi Yousif Mohamed , Knispel Ricarda , Eid Tarek , Rouis Lamia , Eldali M.A.. A. , Skelhorn Richard , Oweni Tarek , Mukherjee Anubrati , Subbiah Surej Kumar 
Published: October 2019

AbstractSandstone reservoirs of the South Caspian basin in Turkmenistan are currently undergoing further development—with the addition of deviated wells. The localized depletion occurring in some of the offshore fields in this area has thus far triggered a host of geomechanics-related challenges—including wellbore instabilities and poor hole quality. In anticipation of further depletion over the remaining fields life, geomechanics effects will become more pronounced and the associated technical and economic challenges facing these fields may increase.To assist in future well planning and field development, and to diagnose the problems already encountered in the existing vertical wells, 3D seismic-driven mechanical earth models (MEMs) were built. These covered the main sandstone reservoirs as well as the shaley formations. This integration of data from drilling operations, open hole logs, core, seismic and formation pressure measurements provided a constrained and consistent description of the prevailing in-situ state of stress, pore pressures and rock mechanical properties. These geomechanical models were further improved by accounting for historical depletion in the fields considered. The depletion modelling was performed numerically using a simulator performing finite difference fluid-flow calculations. The results obtained and understanding gained were then considered in the analyses of wellbore stability for future wells.This paper describes these geomechanical analyses and modelling—including the data integration to assess wellbore stability at the current level of depletion.
Mothballing Initiative Ensuring Operations Efficiency for Inactive Facilities
Authors: Yassien Diaa , Al-Ghaferi Mohamed , Al Janahi Mohammed , Al Jaberi Fawzi , Albadi Mohamed , Al Katheiri Ghalib , Al Shehhi Zayed , Al Belooshi Fares 
Published: October 2019

Abstract
In oil and gas production, certain cases require to shutdown Wellheads or surface facilities for extended period to anable preventive maintenance or reservoir monitoring. The major concern is how to preserve the equipment's from corrosion risk during the shutdown periods. The corrosion potential increases with the presence of sour gases (H2S and CO2) and exposure of piping facilities to sour gase media under high pressure is the main cause for metallic corrosion. Despite well flowing condition to production facilities is designed to have continuous corrosion inhibitor injection which forms a protection film layer as a corrosion control, the shutdown condition diminishes the role of the the protection layer, hence, mothballing was identified as an alternative resolution to ensure piping integrity and corrosion control in place while shutdown duration. In this paper, the sour gases corrosion effect is described by defining corrosion types. Mothballing process is identified based on the preservation concept, duration and different procedures for protection, noted the resources required and mitigation to perform the activities with assigned team members. Downhole tubing and surface facilities piping is also discussed for mothballing while inactive and offline duration of sour gas wells and associated surface piping facilities. Two types of mothballing media are listed based on target equipment for effective results, inhibited diesel was selected for well down hole mothballing, and dry inert nitrogen gas as media for X-mass tree and surface pipe line facilities. Additional improvement and opportunity for operation efficiency is to carry out the mothballing as campaign to optimize the resources for both time with cost saving initiative. Team members from different disciplines required to contribute for mothballing operations, task asssignement for each disciplines as per roles and responsabilities organize stream line all resources to achieve ultimat goal for facilities integrity.
A mutant allele of zeta-carotene isomerase (Z-ISO) is associated with the yellow pigmentation of the ‘Pinalate’ sweet orange mutant and reveals new insights into its role in fruit carotenogenesis
Authors: Rodrigo Maria Jesus , Lado Joanna , Alos Enriqueta , Alquezar Berta , Dery Orly , Hirschberg Joseph , Zacarias Lorenzo 
Published: October 2019

Abstract
Fruit coloration is one of the main quality parameters of Citrus fruit primarily determined by genetic factors. The fruit of ordinary sweet orange (Citrus sinensis) displays a pleasant orange tint due to the accumulation carotenoids, representing b,b-xanthophylls more than 80% of the total content. Pinalate is a spontaneous bud mutant derived from sweet orange Navelate, characterized by yellow fruits due to elevated proportions of upstream carotenes and reduced b,b-xanthophylls. To identify the molecular basis of Pinalate yellow fruit, a complete characterization of carotenoids profile together with transcriptional changes in carotenoid biosynthetic genes were performed in mutant and parental fruits during development and ripening. Pinalate fruit tissues showed a distinctive carotenoid profile at all ripening stages, accumulating phytoene, phytofluene and unusual proportions of 9,15,9´-tri-cis- and 9,9´-di-cis-z-carotene, while content of downstream carotenoids was significantly decreased. Transcript levels for most of the carotenoid biosynthetic genes showed no alterations in Pinalate; however, the steady-state level mRNA of z-carotene isomerase (Z-ISO), which catalyses the conversion of 9,15,9´-tri-cis- to 9,9´-di-cis-z-carotene, was significantly reduced in Pinalate fruit and leaf tissues. The isolation of the Pinalate Z-ISO genomic sequence identified a new allele with a single nucleotide insertion at the second exon, which generates an alternative splicing site that alters Z-ISO transcripts encoding non-functional enzyme. Moreover, functional assays of citrus Z-ISO in E.coli showed that light is able to enhance a non-enzymatic isomerization of tri-cis to di-cis-z-carotene which is in agreement with the partial rescue of mutant phenotype when Pinalate fruits are highly exposed to light during ripening. The defect in Pinalate Z-ISO gene causes a bottleneck in the carotenoid pathway with an unbalanced content of carotenes upstream to b,b-xanthophylls in fruit tissues. Taken together, our results indicate that a spontaneous single nucleotide insertion in Z-ISO is the molecular basis of the altered pigmentation in Pinalate sweet orange mutant and points this isomerase as an essential activity for carotenogenesis in citrus fruits.