bluuebunny/crossref_metadata_2025_split huggingface dataset:
A New Technique to Support Future Energy Exploration of Continental Sedimentary Basin: BWH Full-Frequency Fidelity and Amplitude Preserving Processing Technology
Authors: Bao Yi , Wang Cheng , Chen Shu-min , Wang Jian-min , Chen Zhi-de , Pei Jiang-yun , Wu Jia-yi 
Published: April 2019

Abstract
The existing seismic data in the deep layer of Songliao Basin have low vertical resolution, poor imaging accuracy and weak ability to depict anisotropy of seismic data, so the seismic data can not meet the geological requirements of fine target characterization. In order to identify thinner reservoirs and smaller faults in deep and complex structural areas, to complete sequence subdivision on volcanic rocks of Yingcheng formation and the dense sand of Shahezi formation, BWH seismic data acquisition is deployed in Anda sag. Aiming at the characteristics of clear description of BWH wave field but low SNR. A Full-frequency Fidelity and Amplitude preserving processing Technology (Flow) supported by surface consistent time-varying pulse deconvolution and viscoelastic medium prestack time migration and depth migration techniques is formed. Compared with the old data, the target band width of the BWH data has been widened by 15 Hz, the imaging quality of the complex structural area is improved obviously, and the prediction coincidence rate of the thin sand body over 8m is increased by more than 10 percentage points. The thin interbed is developed in continental sedimentary basin, and the horizontal heterogeneity is serious. The BWH acquisition and full frequency amplitude preserving processing technology will bring a new solution for fine target exploration in deep and complex structural area of Continental Sedimentary basin.
Great Breakthroughs and Key Technologies in Exploration of Ordovician Deep Buried Hill in Northern Jizhong Depression
Authors: Zhang Yiming , Tian Jianzhang , Yang Dexiang , Chen Shuguang , Liu Xing , Hou Fengxiang , Tian Ran , Zhang Chuanbao 
Published: April 2019

Abstract
The study area is located in the Langgu sag of Northern Jizhong depression, Bohai Bay Basin, East China. In order to achieve exploration breakthrough in deep buried hill, key engineering technologies are developed and used to accurately demonstrate important target identification by recognizing new hydrocarbon accumulation patterns resulting from the analysis of multi-stage structure-controlled trap mechanism and the detailed study of controlling factors over high-quality Ordovician reservoirs based on new high-accuracy 3D seismic data. This study reveals a new evolution mechanism of buried hill controlled by structural superposition, experiencing "the uplift from thrusting in Indo-Chinese to early Yanshan epoch, uplifted block faulting into horsts in middle Yanshan epoch, horsts tilting into belt in Eocene, and belt reversion into trap", and thus puts forward a new mechanism for reservoir forming controlled by a superposition of "dolomite, karsting, and faulting". Three types of reservoir development are identified, including "regional layered pore, local block micropore-fracture, and fracture hole pore layer-block composite", and an accumulation pattern in deep buried hill is constructed, characterized by "efficient hydrocarbon supply from gas-type source rock, predominant migration through fractured surface-nonconformity surface, and stratum- and mass-controlled accumulation", which has guided the 40 years' exploration of Ordovician Yangshuiwu buried hill zone and made a great breakthroughs. Novel relevant exploration technologies have been developed, involving high-accuracy imaging, high-precision well logging identification of hydrocarbon reservoir, ultra-high temperature deep drilling and completion, ultra-high temperature carbonate reservoir stimulation, etc, which solve a worldwide problem that has restricted the exploration of the ultra-high temperature buried hill for many years. These technologies make possible the highest daily production of over 100 m3 oil and 0.5 million m3 gas respectively and sustain a high and stable production for a long term, which guarantee the clean energy supply for Beijing-Tianjin-Hebei region.
Visco-Acoustic FWI for Imaging Beneath Complex Gas Clouds
Authors: Wang Min , Xie Yi , Xiao Bingmu , Ratcliffe Andrew , Latter Thomas 
Published: April 2019

Abstract
The anelastic effects of the earth can cause frequency dependent energy attenuation and phase distortion, especially when gas clouds are present. To correct these unwanted effects for proper imaging, both the velocity and quality factor (Q) models need to be accurately estimated. With FWI offering the capability to obtain higher-resolution models than tomography, visco-acoustic FWI (Q-FWI) is highly desirable for inverting both Q and velocity models together.
The visco-acoustic wave propagation in an anisotropic medium and the gradient computation for model parameters can be implemented in the framework of FWI. However, the similar radiation patterns between velocity and Q make the joint inversion non-trivial (Malinowski et al., 2011; Plessix et al., 2016). Based on the observation that the absorption effects vary with frequency, we can use a range of frequencies to decouple the effects of velocity and Q anomalies. The dispersion relationship helps to reduce the cross-talk between the velocity and Q estimation and provides meaningful updates of these two parameters. The proposed Q-FWI, driven by diving-waves for jointly estimating velocity and Q, is applied on both synthetic and real data to validate its effectiveness.
Study of Ultra-Dry CO2 Foam Fracturing Fluid Enhanced By Graphene Oxide
Authors: Lv Qichao , Li Zhaomin , Zheng Rong 
Published: April 2019

Unconventional oil and gas resources such as shale gas, shale oil, CBM, tight gas and oil have attracted more and more attention worldwide in recent years. However, most of the formations of unconventional oil and gas are suffering from poor geological condition, thus the resources can not be developed without fracturing stimulation. Conventional hydraulic fracturing usually consumes a huge amount of water and also leads to the pollutions of surface water and even residential water. In addition, the formation damage caused by incomplete gel breaking, adsorption of polymers, clay expansion and water blocking are still not fully eliminated.
Thus, in this work, ultra-dry CO2 foam stabilized by graphene oxide (GO) were explored to get a fracturing fluid characterized by low water consumption, environmental friendliness, high efficiency and low formation damage. The foam quality of fracturing fluid in the study was higher than 90%, thus the water consumption of fracturing fluid was lower than 10% of total volume. The foam stability, rheology and dynamic filtration were studied by using a large-scale fracturing fluid test device.
The results showed that the stability and thermal adaptability of ultra-dry CO2 foam were enhanced by the addition of graphene oxide. The interfacial dilatational viscoelastic modulus of CO2/liquid was increased when the graphene oxide was used with saponin, implying that the bubble film interface became solid-like; The ultra-dry CO2 foam enhanced by the graphene oxide showed a shear thinning behavior. The effective viscosity of ultra-dry CO2 foam was increased by adding graphene oxide and its viscosity was higher than 50 mPa·s at a shear rate of 100s-1; Moreover, compared to pure surfactant foam, the filtration control performance of ultra-dry CO2 foam was also enhanced by graphene oxide. At a filtration pressure difference of 3.5MPa, the filtration coefficient of ultra-dry CO2 foam was decreased significantly by the addition of graphene oxide. Although the core damage caused by foam with graphene oxide was slightly higher than that of pure surfactant foam, the permeability damage was still below 10%, implying that the foam as a fracturing fluid is relatively clean to formation.
Ultra-dry CO2 foam fracturing fluid stabilized by graphene oxide provides a new high-performance fracturing system for unconventional oil and gas at water-deficient area. This study will be beneficial to fracturing applications characterized by low water consumption, environmental friendliness, high efficiency and low formation damage.
Pressure Transient Behaviour for Alternating Polymer Flooding in a Three-Zone Composite Reservoir
Authors: Kang Xiaodong , Zeng Yang , Zhang Jian , Tang Engao , Wei Zhijie , Cheng Shiqing 
Published: April 2019

Abstract
Alternating high and low concentration polymer flooding has been proposed and applied in some offshore oilfields to improve polymer flooding efficiency, but the research of pressure analysis in alternating polymer flooding reservoir is rare, this work presents a numerical pressure analysis method of three-zone composite model for formation evaluation. The type curves have seven regimes in three-zone composite model. The characteristic is the obvious upturn of pressure derivative curve in transient regime between high concentration and low concentration polymer solution. Formation parameters can be interpreted by history matching and formation evaluation can be conducted based on this model. As an important part of formation evaluation, formation damage as a result of adsorption of polymers in porous media is evaluated by comparing the interpreted permeability with the original value before polymer flooding. The field test data proves that this proposed method can accurately evaluate reservoir characteristics in alternating polymer flooding reservoirs, which emphasizes the potential application of this method in petroleum industry.
Mathematical Model of Acid Wormhole Expansion When Combining Diverting Acid with Solid Diverting Agent
Authors: Li Nianyin , Kang Jia , Zhang Qian , Wu Yu , Zhang Haotian 
Published: April 2019

Abstract
Considering characteristics of complex carbonate reservoirs (e.g., high depth, high temperature, and fracture cave development), this paper simulates expansion of the acid wormhole when combining diverting acid and a solid diverting agent for acid fracturing. Using the theory of reaction kinetics, tests of diverting acid reaction kinetics, and flow reaction experiments on the long core and parallel core, this paper presents tests of the acid–rock reaction for a mathematical model of acid diversion. On the basis of a rheological behavior test of diverting acid, we studied the influences of Ca2+ concentration, pH, fiber concentration, and temperature on acid system viscosity. Then, we established a mathematical model of changes in diverting acid viscosity under a multi-factor cooperative control mechanism. On the basis of the kriging method, we established a three-dimensional (3D) geological model involving a random normal distribution and spatial correlation of multi-fracture and pore-permeability properties. We used four models (acid rock reaction rate, viscosity change, 3D acid wormhole expansion, and fluid–solid coupling) of a complex system to study dynamic cooperation characterization of diverting acid and a solid diverting agent under multiple factors. Simulation results show that the temporary plugging of acid and expansion of acid wormholes are mutually restricted. The solid diverting agent blocked the fracture, and a dense filter cake formed at the start of the fracture; thus, the physical flow direction of diverting acid changed, the acid wormhole length increased, and filtration of diverting acid declined to improve the acid's effect. Diverting acid and solid diverting agent work more effectively together. This paper is novel because we consider the respective influences of Ca2+ concentration, pH, flow rate, diverting acid rheological properties, injection parameters, and solid diverting agent concentration on the synergistic steering of steering acid and a solid diverting agent. We then establish a mathematical model to reflect complex stratigraphic conditions and objectively describe the acid flow reaction. We also innovatively solve the problem of predicting acid wormhole expansion given complex fractures and uneven pore distribution. Findings provide a theoretical basis and technical support for the application of acid fracturing in complex carbonate reservoirs.
Novel Plant-Based Particulate and Fibrous LCM Products for Loss Control while Drilling
Authors: Amanullah Md , Arfaj Mohammed , Alouhali Raed 
Published: April 2019

AbstractNovel fibrous and particulate LCM products of variable mechanical characteristics and chemical composition were developed using physio-mechanical treatment and processing of various waste components of date palm trees available each year as pruning wastes, post crop harvesting wastes, waste generated after making cookies and confectioneries and also the waste arising due to the removal of deceased and non-productive date trees.Experimental tests conducted using PPT apparatus at 500 and 1500 psi pressure and 250 °F temperature using 2 mm slotted disc demonstrated the efficient sealing and blocking for all of the particulate and fibrous LCM products either immediately after the application of the overbalance pressure or after a while. Some of the LCM products showed instantaneous sealing capacity after the application of overbalance pressure. Several commercial LCM products were also tested and evaluated using the same concentration and test conditions for comparative assessment of the performance of the newly developed LCM products. Interestingly, all of the new LCM products showed similar or better performance than the equivalent commercial products. Engineered fiber blends developed using the date palm industry waste also showed similar or better performance than the commercial or currently used LCM blends. Experimental results also indicated the suitability of date palm industry waste in replacing some of the synthetic fibers used by the industry in commercial LCM blend design. All these experimental results indicate that the date palm industry wastes are potential sources of raw materials for various product development for oil and gas field applications.
Fluid Discrimination Using Bulk Modulus and Neural Network
Authors: Liu Changcheng , Ghosh Deva , Salim Ahmed Mohamed Ahmed , Chow Weng Sum 
Published: April 2019

Abstract
Hydrocarbon prediction using the rock physical parameters is a common technique in the oil and gas industry. However, the rock physical parameters are controlled by porosity, the volume of clay, pore-filled fluid type and lithology simultaneously. Many methods are proposed to predict the existence of hydrocarbon. This paper proposes a new method ΔK which is the difference between the real bulk modulus and the bulk modulus in the brine- substitute case. The algorithm is validated through stochastic numerical modelling. The brines are separated by the ΔK, and the gas can be detected with acceptable accuracy. Furthermore, a model using deep learning approach is trained to predict the ΔK. The trained model is effective that the predicted values using this model have a strong correlation with the original ΔK. The ΔK can be applied to the data which contains Vp, Vs and density using this approach model. In this study, the ΔK is applied to the Marmousi II dataset to examine the performance and yields a good result. The combination of the deep learning and the ΔK improves our ability in hydrocarbon prediction.
Prediction of Poisson's Ratio for Carbonate Rocks Using ANN and Fuzzy Logic Type-2 Approaches
Authors: Abdulraheem Abdulazeez 
Published: April 2019

Abstract
Young's modulus and Poisson's ratio describe the elastic behavior of rock. It is extremely important to determine these parameters in order to minimize the risk associated with the oil and gas well engineering. The estimation helps in several areas of drilling and production such as well placement optimization, design of completions, mud weight calculations, and hydraulic fracture geometry. Each one of these factors play a part in maximizing the recovery of hydrocarbons and in taking crucial decisions for an appropriate field development strategy.
Poisson's ratio is second most important parameter in understanding the elastic behavior of the rock and plays a critical role in almost all processes such as drilling, reservoir simulation, and production. It is an essential component in geomechanical earth model (GEM).
The Poisson's ratio is estimated based on empirical models and artificial intelligence models. These models are construction from data that has different types of uncertainties. This paper presents an Artificial Neural Network (ANN) as well as Fuzzy Logic Type-2 (FLT2) approach for prediction of static Poisson's ratio. FLT2 is able to incorporate the uncertainties in measurements and still give a robust solution to a given problem. Well log data is used as input and laboratory determined static Poisson's ratio is used as output in the artificial intelligence (AI) tool. The data were collected from a range of experiments conducted on carbonate rocks covering a wide range of input and output values.
The model takes care of uncertainties in the input and output data and is therefore a better approach in establishing a relationship between them and in predicting static Poisson's ratio for new input data.
Implementation of a Scalable Distributed Cloud Computing Platform for Fast Real-Time Reservoir Development
Authors: Gutierrez Edgar , Wu Mark Hsu-Hsiang , Dong Weixin , Efimov Ivan 
Published: April 2019

Abstract
Recent developments of new ultra-deep logging-while-drilling (LWD) resistivity tools have increased usage for on-demand computational infrastructure. The tools are capable of providing much deeper determinations on formation geologies than conventional electromagnetic (EM) resistivity tools, allowing more accurate real-time wellbore adjustment and optimization. This technique efficiently explores reservoir insights for maximizing oil production; however, the time to process raw measurements into useful geological information is long owing to the complexity and large amount of data associated with the tools. The conventional computation platforms are not efficient enough for both real-time and post-well formation evaluations based on this tool's measurements.
This paper introduces a high-performance computing (HPC) platform which provides flexibility among different deployment architectures and large-scale cloud infrastructure. This enables numerous computational resources to quickly process raw data and provide the information needed to successfully steer a well. The new HPC platform has 50% more efficiency compared to conventional parallelization methods, such as Open Multi-Processing (OpenMP), using same amount of CPUs. Furthermore, faster computation is achievable owing to the scalability of the HPC implementation as well as the flexibility of available assets in the cloud or on-premises environments, which are beneficial for applications with heavily computational requirements and short time constraints.
Understanding the Geomechanical Challenges and Risk Mitigation in Sichuan Shale Gas Drilling, China
Authors: Gui Feng , Wang Shanshan , Bordoloi Sanjeev , Ong See Hong 
Published: April 2019

Abstract
The drilling of shale gas development wells in the Sichuan Basin has been problematic, with stuck pipe and fluid loss events reported in many wells. These events hindered the development efforts as operators whose aim is to reduce drilling costs and increase drilling speed are faced with developing drilling strategies for more cost effective well delivery. As such, it becomes critical to understand the key mechanisms of borehole failures and fluid losses during drilling of the laterals so that proper mud weights and mud designs can be formulated to overcome the drilling challenges.
To optimize the entire drilling process from different angles, an integrated approach is required to combine the knowledge and expertise from different disciplines. A robust geomechanical model and detailed diagnostics of the borehole instability related problems are key and form the basis for the drilling risk management. To build a robust geomechanical model, several representative areas in the Sichuan Shale Gas play were reviewed using a consistent approach. A general understanding of the in-situ stress conditions and rock mechanical properties of the Longmaxi Shale Gas reservoir was developed by combing data and knowledge in the different areas. Using the geomechanical model, a series of newly drilled horizontal wells was also reviewed so that the main causes of stuck pipes and fluid losses can be determined.
Based on the geomechanical model and drilling experiences review, risks that could potentially cause non-productive time (NPT) during drilling of the planned wells were postulated and listed, and each risk was then assessed in detail so that a thorough understanding of the risk factors can be achieved from different drilling perspectives. Consequently, a multi-disciplinary mitigating solution was proposed in order to help with reducing the occurrence of any borehole instability-related problems. The integrated drilling optimization plan was executed successfully during the drilling of the horizontal wells in the Sichuan Basin.
The increase in understanding of the geomechanical issues in the Sichuan Shale Gas drilling indicated that common trends in shale characteristics are present although it is widely accepted that shale types and stress conditions are different in each field. With the geomechanical models being calibrated from information in different areas, uncertainties are reduced and the robust models in turn provide solid foundations for risk identification and mitigation, leading to successful and economical drilling of the long laterals. However, it is a long and continuous learning process in order to apply this integrated approach effectively. To achieve continuous improvement, the geomechanical model and mitigating solutions need to be refined regularly following the drilling process while further information and knowledge are being acquired in the Sichuan Shale Gas area.
A Multiphase Choke Temperature Model for High-Pressure Gas/Water/Glycol Mixtures
Authors: Jia Wenlong , Yang Fan , Mu JunCheng , Cheng Tingting , Li Changjun , Zhang Qi 
Published: April 2019

Abstract
Co-existence of gas, water and glycol is commonly in produced fluids of high-pressure gas wells due to formation water production and hydrate inhibitor injection. The interaction between the polar water and glycol molecules can affect the phase behavior and subsequent temperature change during gas flowing through chokes at wellheads. This paper presents an isenthalpic flash method based on the cubic-plus-association equation of state (CPA EOS) to calculate the temperature at the downstream of the choke. In comparison with the traditional isenthalpic flash algorithm, this new method accounts for the self- and cross-association between polar water and glycol molecules, yielding more accurate enthalpy calculation results for fluid containing water and glycol as well as choke temperatures. The proposed model is validated with field test data. Results demonstrate that the average absolute deviations between the measured and calculated temperatures at downstream of chokes based on the proposed method are less than 1.6°C even for vapor-liquid-aqueous three-phase mixtures at pressures up to 100 MPa. Results yield from the proposed method are more accurate than those calculated from the SRK EOS combining with the Peneloux volume shift method and the Huron-Vidal mixing rule.