bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of Lens Surface Shape Based on Theory of Plates and Shells
Authors: Jin Yu-chen
Published: October 2023

The purpose of this article is to improve the accuracy and expand the force analysis of the lens by using the theory of plates and shells and reciprocal theorem. The first one concerns the deflection expression of a circular lens of equal thickness supported at several uniform points. The second calculates the deflection of the lens under its own weight, and then starting from known Zernike coefficient, PV value and RMS value in optics, the first 37 Zernike coefficients are obtained. The third compares the Zernike coefficients and lens center deflections of partic-ular cases. The derivation process based on plates and shells theory and reciprocal theorem is given in details. As validation, the lens deflec-tion expression is applied to calculate 4 points support, the predicted re-sults illustrate great agreements with the finite element simulation solution. Finally, the proposed method has shown great potential for engi-neering analysis and may also bring inspirations for optical field, as well as other plate and shell theory system.
AE-BEGAN based Synthetic Data Augmentation for Sample-Limited High-Dimensional Problems with Application to NIR Spectral Data
Authors: Luo Xin-Yue , Fan Xing-Rong , Zhang Xian-Ming , Chen Tian-Yu , Huang Chun-Jie
Published: October 2023

Synthetic data augmentation holds substantial research and application value in scenarios characterized by limited samples and high dimensions. It enhances the analytical ability and efficiency of spectral analysis models. This paper proposes Autoencoder-Combined Boundary Equilibrium Generative Adversarial Networks (AE-BEGAN) as a new method for augmenting synthetic data in scenarios with limited samples and high dimensions, with a specific emphasis on near-infrared (NIR) spectral data. The spectral data first undergoes preprocessing procedures that encompass advanced noise reduction algorithms and techniques for removing abnormal samples, guaranteeing elimination of unwanted disturbances and outliers. Then, the pre-processed data is utilized to train the AE-BEGAN model, which generates augmented synthetic samples. Finally, real NIR spectral data obtained from lubricant samples exhibiting different water contents were employed to validate and test the performance of the model. The experimental results demonstrate that the AE-BEGAN model outperforms other GANs in generating synthetic data of high quality and diversity, as quantified by two evaluation metrics, α-Precision and β-Recall with scores of approximately 0.86 and 0.28, respectively. The application case study confirms that the AE-BEGAN model exhibits the capability to generate derived NIR spectra and expand the number of spectra in scenarios with limited samples and high dimensions.
Research and application of anti - corrosion cement slurry in formation water corrosion environment
Authors: Min Jiang-ben , Zhang Jian , Wan Xiang-chen , Chen Xiao-rong , Wang Wen-bin , Tang Kai
Published: October 2023

Corrosion of cementing cement ring causes the cement ring permeability to increase, resulting in serious casing corrosion. The casing corrosion perforation leads to an increase in water content of oil wells, low driving use of water injection wells, and imbalance of injection and production well patterns. Therefore, on the basis of conventional cementing cement, epoxy resin emulsion non-penetrating agent and corrosion inhibitor composed of rust and antibacterial materials are added to reduce the corrosion and permeability of cementing cement and reduce casing corrosion. The cement sample permeability experiment shows that adding 10% non-permeability agent and 2% corrosion inhibitor to low-density cement reduces the cement stone sample permeability from 0.075mD to 0.021mD, a decrease of 3.57 times. In the conventional density cement, adding 10% non-penetrating agent and 2% corrosion inhibitor, the permeability of the cement stone sample decreased from 0.041mD to 0.0009mD, a decrease of 4.56 times. The evaluation experiment of cement stone anti-corrosion performance shows that adding 10% non-penetrating agent and 2% corrosion inhibitor to cement can increase the corrosion resistance of cement samples by 6 times. At the same time, the thickening time and compressive strength of cement stone samples remain unchanged compared with conventional cement. Optimizing the technological measures of supporting anti-corrosion tools, and summing up a set of anti-corrosion cementing technology through the field application of anti-corrosion cement slurry, which provides strong technical support for the development of cementing technology under the corrosive environment of formation water in the oil field.
Division Method of Dynamic Flow Units in Fluvial Reservoir at Ultra-high Water Cut Period
Authors: Sui Yingfei , Cui Chuanzhi , Qian Yin , Jia Peifeng , Lu Shuiqingshan , Chen Mengxin
Published: October 2023

The heterogeneity of fluvial sedimentary reservoir is serious. The division of flow units in the early stage of development can provide a good guidance in the well pattern distribution and reservoir production. Due to the huge changes in the oil-water system in the long-term development reservoir, the flow units divided at the initial stage are difficult to guide the production when entering the ultra-high water cut period. Therefore, it is necessary to redefine the division indicators and methods of flow units, so as to provide support for the formulation of efficient regulation and control technology. Starting from the definition of flow unit, this paper establishes the percolation coefficient as the characteristic index of percolation capacity. Combined with the percolation characteristics of fluvial reservoir, the dynamic flow unit division method with percolation coefficient and water cut as division parameters is established. Through the division results of typical models of fluvial reservoir, it can be seen that the four types of flow units divided by the dynamic flow unit method in this paper can play a great guiding role in the later formulation of regulation and control measures. The verification of reservoir examples shows that the division results of dynamic flow units of fluvial facies can well reflect the remaining oil enrichment areas in the reservoir and classify the remaining oil enrichment areas. At the same time, the dynamic flow unit changes continuously with the development process, which can more clearly show the producing degree of each remaining oil enrichment area after the regulation and control measures. This provides a key support for formulating targeted and efficient reservoir development technique.
Research and Practice of Intelligent Separate Production Technology with Cable in Huabei Oilfield
Authors: Chen Ya-jun , Xu Zhi-yuan , Ge Dong-wen , Zhang Xu , Huang Bo-hua , Wang Tao
Published: October 2023

In order to improve the separate production effect of sandstone reservoir in Huabei Oilfield and give full play to the production capacity of medium and low permeability layers, the intelligent separate production technology with cable is designed and developed. The technology uses cable packer to seal each layer in the well, and a set of intelligent separate production device is connected to the corresponding string position of each target layer. During the production process, the intelligent separate production device can send instructions according to the ground control center Open or close the oil layer to realize the exploitation of any layer and multi-layer co production of any layer. It can accurately measure the liquid production and properties of each section of the well, and calculate the formation permeability, skin factor and other parameters by sections, so as to realize the continuous testing and monitoring function.In the later stage, the switch opening can be adjusted by remote control to adjust the output of each layer in time to meet different production allocation requirements and achieve the purpose of increasing oil and reducing water, which is of great significance to realize the accurate development of the reservoir.
Physical Simulation of Steam Absorption Characteristics in Horizontal Wells of Super Heavy Oil Reservoir
Authors: Yu-Junli
Published: October 2023

In the process of dual Horizontal well SAGD development of super heavy oil, the steam absorption balance of upper horizontal steam injection well is an important factor to determine the development effect of SAGD. The factors affecting the steam absorption of upper horizontal wells involve reservoir permeability, steam injection technology, steam injection parameters, etc. The physical simulation method is used to study the influence degree of each specific factor and improvement measures. Based on the similarity criterion, the reservoir scale model is designed and made according to the oilfield prototype, and the simulation experiment is carried out on the steam absorption characteristics and influencing factors along the horizontal wellbore. The experimental results show that the steam injection rate, non condensable gas, the location of the steam injection string and the reservoir permeability have great effects on the steam absorption of the reservoir. The heating uniformity along the horizontal well can be improved by properly increasing the steam injection speed, adding a certain amount of non condensable gas to the steam, and the position of the steam injection string end in the relatively low permeability area of the reservoir. This achievement has a strong guiding significance for improving the steam absorption balance of horizontal wells and improving the development level of dual level SAGD.
Nitrogen Foam Alternating Flooding Experiment in The Offshore Strong Bottom Water Sandstone Reservoir
Authors: Cai Hui , Zhang Zhang , Tan Jie , Liu-Yan Chun , Zhang Wen-tong
Published: October 2023

The CFD oilfield is located in the Bohai Sea area and is a typical offshore sandstone reservoir with strong bottom water. The characteristic of the rapid increase in water content is that it quickly enters a highly high water content period, and there currently needed to be more potential tapping measures affected by offshore production facilities. The development mode should be changed to explore the development effect of nitrogen foam flooding. This study conducted two experiments. The first experiment is a gas injection expansion experiment, which studied the changes in bubble point pressure, fluid volume, density, and viscosity under different gas injection conditions. The second experiment used a high-temperature and high-pressure oil displacement device and a long core for oil displacement experiments. Two typical sand bodies were selected for the N2 foam oil displacement experiment. The experimental results show that nitrogen injection has little effect on the properties of reservoir crude oil, with a viscosity reduction effect of 12.4% for heavy oil and 20.0% for thin oil. The viscosity of crude oil significantly impacts the selection of alternative media. The channel was prone to blockage and low oil displacement efficiency when injecting a single gas medium into a heavy oil system. The displacement efficiency of thin oil nitrogen foam is 73.28%. The displacement efficiency of nitrogen foam flooding for heavy oil is 43.09%. This study has a guiding significance for developing development plans for offshore sandstone reservoirs.
The Water Problems and Treatment Strategies of Volcanic Gas Reservoir in Daqing
Authors: Li Qiang , Liu Guo-hong , Wang Zhi-rui , Ma Wen-hai , Ma Pin-gang , Li Hao-yang
Published: October 2023

In order to realize the development strategy of “stabilizing oil and increasing gas and simultaneously boosting oil and gas”, Daqing Oilfield has continuously strengthened the exploration and development of deep natural gas resources since the discovery of Xushen gas Field. The volcanic gas reservoir is the main gas producing area of Songliao Basin. Through “internal excavation and external expansion”, natural gas production has maintained a trend of growth for 12 consecutive years. However, due to the development of fractures and bottom water in volcanic gas reservoir, the development contradiction caused by gas well water is increasingly prominent as the gas field development enters the end of stable production stage. Therefore, on the basis of the understanding of four types of effluent water in volcanic rock reservoir, this paper carries out the analysis of the production dynamic characteristics of typical gas wells, and identifies the difficulties faced by gas wells with different types of effluent water. Through field tests, economic and feasible treatment measures are explored, including continuous circulation gas lift of strong water breakthrough gas well in fracture vertical direction, intelligent foam drainage gas production of weak water breakthrough gas well in fracture vertical direction, and deep water unlocking of gas well in pore vertical water cone and gas reservoir with high water saturation gas reservoir effluent water, which provides technical support for the sustainable and efficient development of volcanic gas reservoir.
Lithology and Lithofacies Characteristics of Deeply Buried Clastic Reservoirs in Alternating Wet-arid Climate and its Hydrocarbon Significance
Authors: Li Jian-ping , Qiu Zi-ying , Li Hong-yi
Published: October 2023

There have been series of HPHT (high temperature and high pressure) reservoirs with good quality and high productivity discovered in the Triassic Skagerrak Formation in the Central Graben of the UK North Sea. The bottlenecks for further E&P activity are the complicated depositional facies and high reservoir heterogeneity. The main reservoir space is a mixed porosity network composed of primary pores, micro-pores, secondary pores, secondary micro-pores and micro-fractures. Reservoirs of the Skagerrak Formation have greatly varied lateral connectivity as well as poor vertical connectivity. In the case of sufficiently high pressure differentials, hydrocarbon can be fed from high-potential area to low-potential area. There is no simple linear relationship between depth and reservoir quality. The primary depositional texture (grain size/sorting/clay content, etc.) linked to facies has a fundamental control on reservoir quality. Clean and well sorted cross laminated sandstone has the best reservoir quality, while the reservoir quality of planar laminated sandstone decreased due to increased degree of compaction caused by mica drapes. The reservoir quality of the fine-grained ripple cross laminated sandstone is even poorer than that of the planar laminated sandstone, due to abundant mica and clay drapes. Mottled bioturbated sandstone is fine grained with high clay content, which is more muddy because of containing burrows and insect larva. Pedoturbated sandstone has the poorest reservoir quality due to severe dolomite cementation. The dominant detrital material of the Skagerrak Formation is feldspar that provides abundant secondary porosity by alteration and dissolution. Chlorite coats are commonly developed and stained with residual oil or bitumen, which clearly inhibits quartz cementation and feldspar overgrowth. The presence of these clay coats contributes to the preservation of anomalously high porosity at depth in the cleaner and coarser grained fluvial channel facies. The Skagerrak formation facies is a dryland fluvial-lacustrine depositional system which is controlled by fluctuations of depositional base level due to salt mobilisation. The Skagerrak formation consists of several cycles that are vertically separated by lacustrine mudstone. The reservoir permeability system is composed of active fluvial channel sandstones, terminal splay sandstones, abandoned fluvial channel sandstones, minor channel sandstones connecting fluvial channel and terminal splay, as well as low-permeability faults, while the active fluvial channel sandstone is the “sweet spot”. The analysis of controls on deeply buried reservoir quality is significant to precisely predict “sweet spot” in the Skagerrak Formation.
Ni/ZnO@ZSM-5 Reaction Adsorption Desulfurization Catalyst for Octane Number Improvement
Authors: Guan Ze-kun , Zhang Yu , Zhao Ting , Liu Yun-qi
Published: October 2023

Reaction adsorption desulfurization technology is one of the main means of gasoline desulfurization. In this work, ZnO nanoparticles were prepared by pyrolytic oxidation using ZIF-8 as precursor. ZnO spheres with particle size of 5 nm can be formed after the pyrolysis of Zif-8. Ni/ZnO5nm prepared by equal volume impregnation method can achieve 99.2% desulfurization rate at 390°C, which has more excellent desulfurization performance compared to Ni/ZnO100nm. Ni/ZnO@ZSM-5 was synthesized by in-situ growth-pyrolysis oxidation-equal volume impregnation method. In the reaction adsorption desulfurization process of FCC gasoline, the desulfurization rate reached 99.5%, and the aromatic content in the product increased by 10.7 percentage points, showing excellent octane number improvement. This work provides new ideas for the synthesis of ZnO nanoparticles as well as novel reactive adsorbent desulfurizers, and promotes the development of S-Zorb process.
Effect Analysis of Demagnetization of Permanent Magnet Synchronous Motor for Electric Drilling Tool on Air-gap Flux Density
Authors: Zhang Qing-xue , Cui Jun-guo , Xiao Wen-sheng , Mei Lian-peng , Tan Li-ping
Published: October 2023

Electric drilling tools have been developed in the field of drilling because of their high efficiency. As the core component of electric drilling tool, permanent magnet synchronous motor(PMSM) provides power for drilling tool. However, in the process of drilling, the permanent magnet of PMSM will appear demagnetization.The value of air-gap flux density affects the performance and efficiency of the motor directly. Demagnetization faults are divided into uniform demagnetization and local demagnetization.In order to study the influence of demagnetization of PMSM on the air-gap flux density, mechanism of permanent magnet is analyzed Firstly, and then establishing numerical model with analytical method. Finally, simulation motor demagnetization using finite element method(FEM) based on Maxwell. No-load and load operating state are analyzed under the two fault modes are considered in this paper, and compared with the healthy state of the motor. The analytical results show that when the demagnetization fault occurs in the motor permanent magnet, the air-gap flux density will decrease accordingly.The FEM method results show that with the increase of uniform demagnetization rate, the flux density of the air-gap almost decreases in proportion to the increase of demagnetization rate. The demagnetization of single pole permanent magnet has little effect on the magnetic density of the nearby permanent magnet, but it will lead to the imbalance of the whole electromagnetic field of the motor. The air-gap flux density can be used as a characteristic index to judge the fault of demagnetization.
Development of Predictive Model for Wax Formation in Deep-water Pipeline Using Machine learning
Authors: Sultana Farhana , Abdallah Elhassan Mostafa , Dong Shaohua , Mukhtar Yasir M. F.
Published: October 2023

Wax deposition in deep sea pipelines can affect oil and gas production. It happens when the pipeline temperature drops below the wax appearance temperature, causing the wax to solidify and stick to the pipeline walls. This paper discusses the limitations of current models in predicting wax deposition in pipelines and proposes the development of more complex, intelligent models that are accurate, resilient, and adaptable to novel input-output scenarios. It also highlights various methods for preventing wax deposition, including the use of chemical inhibitors and thermal remediation techniques. The paper aims to develop a neural network modeling approach for predicting wax deposition potential in producing reservoirs to prevent accumulation before removal. The parameters that were used are wax molecule concentration gradient at pipe wall, temperature gradient at pipe wall, reported wax deposition rate, the pipe wall shear stress, and crude oil viscosity. The radial basis function neural network (RBFNN), is based on the machine learning technique. RBFNN is a good choice for building a predictive wax deposition rate model because it is highly accurate, robust to noise and outliers, computationally efficient, can model complex nonlinear relationships, suitable for real-time applications and requires less training data. The RBF neural network is constructed using MATLAB. The outcomes and experimental data are consistent with a 1.5 percent relative inaccuracy when compared to prior studies. The R^2 value was 0.9906, R value was 0.9953 and the RMSE value was 0.8598. The RBF neural network-based approach for predicting wax deposition rate was successful.
Differential Diagenesis and Pore Evolution Characteristics of Different Sedimentary Microfacies Reservoirs of Bioclastic Limestone: A Case Study of MB2-MC1 Section in X Oilfield in The Middle East
Authors: Yu Yi-chang , Li Zhi-wei , Shen Bo-heng , Wang Rui-rui , Song Shi-qi , Guo Rui , Li Feng-feng , Wang Jiu-zhou
Published: October 2023

In order to clarify the differential diagenesis of different sedimentary microfacies of bioclastic limestone in Cretaceous M Formation in the Middle East and systematically analyze the characteristics of reservoir pore evolution, the data of regional geology, well logging, core, cast thin section, scanning electron microscope, three-dimensional CT and conventional porosity and permeability test are comprehensively used, taking MB2-MC1 section in X oilfield as an example, starting from the diagenesis and pore evolution of bioclastic-arene shoal, the characteristics of diagenesis of each sedimentary microfacies in different environments are analyzed, and the differential diagenesis, pore evolution process and its influence on physical properties are studied. It is showed that the reservoirs of MB2-MC1 section are mainly developed in the ramp shoal and platform margin shoal. The shoal facies can be further subdivided according to the type of bioclastic debris. The sedimentary microfacies determine the original fabric and bioclastic type of M Formation, and then control the diagenetic sequence and strength. Each sedimentary microfacies mainly experiences different degrees of mud crystallization and burrows in seawater environment, dissolution and cementation in atmospheric freshwater environment, compaction, pressure solution and dolomitization in burial environment. High energy microfacies have the characteristics of non-selective dissolution, mainly developing intergranular pores and intergranular dissolved pores. Medium energy microfacies have the characteristics of selective dissolution, mainly developing mould pores and intragranular pores. The medium-low energy microfacies have the characteristics of moderate cementation, moderate compaction and moderate-weak dolomitization, mainly developing intragranular pores and visceral foramen pores. The low energy microfacies have the characteristics of strong cementation, strong compaction and moderate dolomitization, mainly developing micropores, intercrystalline pores and visceral foramen pores, which are non-reservoirs.
Reservoir Analysis for A Low Recovery Factor Mature Reservoir with A Gas Cap and Large Aquifer: A Proposed Coning Correlation
Authors: Yi Xuan , Liu Zhao-ran
Published: October 2023

With the development of reservoir engineering and management, enhanced oil recovery (EOR) techniques are becoming increasingly sophisticated. Generally, the recovery factor (RF) for a conventional reservoir can range from around 10% to 60% after four decades of production, with an average recovery factor of around 35%. While the RF of the NGJ field with high porosity (0.25) and permeability (300 to 600 md) is 6.11% after producing for over 40 years, which is rare in such good reservoir conditions. In this work, some classic techniques and several advanced methods were utilized to investigate the reason behind the low RF for this reservoir.

A dynamic reservoir simulation was constructed on the basis of a statics petrophysical model. Based on the preliminary simulation study, it was found that gas coning is a common problem in the reservoir. Therefore, a concept of coning correlation function (CCF) is proposed, and the procedures for developing the CCF are explained. The critical oil rate was estimated using the Addington correlation and modified through the proposed coning correlation that varies as a function of time. The estimated critical rate through CCF is used to control flowing bottom hole pressure (FBHP) in the prediction scenarios.
A 3D Geological Modeling Method for Grain-size Lithofacies of Tight Sandstone Gas Reservoirs: A Case Study of Xujiahe Formation Gas Reservoir in Sichuan Basin, China
Authors: Shang Xiao-fei , Xiang Yun-fei , Liu Zhong-qun
Published: October 2023

Tight sandstone gas reservoir has strong heterogeneity, and it is difficult to control the change of internal storage and permeability properties by simple sedimentary facies. It is necessary to explore a geological modeling method that can more accurately characterize the distribution of high-quality reservoirs. Taking the Xujiahe Formation gas reservoir in Xinchang area, Sichuan Basin, China as an example, this paper introduces the modeling method of three orders: sand-mudstone facies, sedimentary facies and grain-size lithofacies, so as to realize the spatial characterization of high-quality tight sandstone reservoirs with strong heterogeneity. In this technical process, the sand-mudstone model is first established. Based on the sand and mudstone model, four sedimentary types (or sedimentary facies) of distributary channel, channel edge, interdistributary bay and mouth bar are further divided. The sedimentary facies model is constructed by multi-point geostatistical modeling method. The quantitative relationship between sedimentary facies and grain-size lithofacies is linked by using argillaceous content as a “bridge”. The spatial distribution probability of grain-size lithofacies is constrained by the neural network clustering of argillaceous content and natural gamma-ray data in three-dimensional space. By controlling the types, ratios, and boundaries of grain-size lithofacies through sedimentary facies, and combining probabilistic bodies to cooperate with constraints, precise simulation of lithofacies can be achieved. The grain-size lithology lithofacies model established by this method follows the depositional law in space and has more reasonable contact relations between various sand bodies. The anastomosis rate of the model reached 85% with the new drilling test. This paper provides a new modeling idea for quantitative characterization and prediction of high-quality tight sandstone gas reservoirs, and provides a more accurate model basis.
Research on the Suitability of High-Density Leakage Plugging in Offshore High Temperature and High Pressure Wells
Authors: Li Yan-jun , Liu Shu-jie , Yang Jin , Zhao Yu-hang , Xu Yi-long , Zhu Hong , Zhang Xun , Yang Kai-die
Published: October 2023

A large number of fractured formations are developed in the high-temperature and high-pressure formations of the Yingqiong Basin in the South China Sea. During drilling, the risk of lost circulation is ex-tremely high, which will cause complex downhole accidents and seri-ously affect the drilling speed.In order to realize safe and efficient plugging of HPHT Wells, the following studies are carried out in this paper: Firstly, the characteristics of leakage, types of leakage and plug-ging and prevention mechanism of HPHT formation in Yingqiong Ba-sin are clarified based on core and indoor rock mechanics experiments. Secondly, a simulated plugging evaluation device with high tempera-ture resistance of 180 °C and high pressure resistance of 20Mpa was in-vented and applied to accurately evaluate the reservoir leakage behav-ior in Yingqiong Basin. Finally, a series of anti-high temperature plug-ging agents adapted to different loss types are systematically selected for the first time for different formation fracture types and the plugging effect is evaluated. In this study, through mechanism research, device research and development, accurate evaluation, the shaft wall pressure equivalent increased to 0.1g/cm3 without leakage. It provides technical support for the subsequent ultra-high temperature and high pressure stratum with weak leakage and narrow pressure window.
Study on Bionic Self-healing Cement Slurry System
Authors: Zhao Jun , Zheng You-zhi , Yang Jian , Wang Fu-yun , He Yu
Published: October 2023

Aiming at the technical problem of gas channing in annulus caused by long-term sealing performance failure of cementing cement ring, based on the technical idea of “prevent before plugging” and from the perspective of chemical bionics, a kind of bionic self-healing cement slurry system of dissolving viscosity was developed. The indoor evaluation results show that the cement stone has excellent physical properties. When the compressive strength is reduced by 15%, the elastic modulus of the cement stone is reduced by 41%, showing good toughness and playing the role of “first prevention”. When the damaged cement stone is excited by hydrocarbon, a kind of soluble gel ester can be formed, and the cement stone skeleton can be re-bonded. Under the condition of methane curing, the recovery rate of compressive strength is 99%, the recovery rate of flexure strength is 58.2%, the recovery rate of gas permeability is 96.4%, and the recovery rate of liquid permeability is 100%, playing the role of “post-plugging”. Therefore, it is concluded that the adhesive dissolving bionic self-healing cement technology can effectively realize the late integrity and realize the long-term sealing integrity after the cement ring is broken through self-healing, which provides a powerful technical support for preventing the abnormal annulus pressure, a hidden danger of oil and gas well production safety.
Synthesis and Characterization of a Cationic Micro-crosslinking Polymer and its Application as a Fluid Loss Reducer in Water-based Drilling Fluids
Authors: Wang Zhong-yi , Sun Jin-sheng , Xie Shui-xiang , Huang Xian-bin
Published: October 2023

In addition to flat rheology to deal with the wellbore stabilization problem caused by narrow safety density window when drilling deepwater wells, upgrading the mud cake quality by fluid loss reducer and plugging to stabilize the wellbore is also an important measure to deal with this problem. For the existing fluid loss reducers for deepwater water-based drilling fluids, it is difficult to balance the plugging performance. In this study, a cationic micro-crosslinking polymer was synthesized as a fluid loss reducer by reversed-phase emulsion polymerization. N-isopropylacrylamide (NIPAM) and acrylamide (AM) were chosen as the main body of the synthesis to enhance the hydrophilicity of the products. Methacryloyloxyethyl trimethyl ammonium chloride (DMC) was selected to provide cationic groups to enhance the residency of the products in the formation. The molecular structure of ENAD was characterized using infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectroscopy (NMR) and X-ray photoelectron spectroscopy (XPS), and the molecular structure of the product was as expected. The thermal stability of ENAD was analyzed by TGA, and the initial thermal decomposition temperature was 283 °C. The filtration effect of ENAD in BF under different media was evaluated. The experimental results show that ENAD can withstand temperature up to 150°C and has good filtration performance. 16h after aging at 150°C, the API filtration loss (FLAPI) is 8.8mL, the sand bed intrusion depth is 4.4cm, the high temperature and high pressure filtration loss (FLHTHP) is 32mL, the high temperature and high pressure filtration loss of plugging 10μm sand disc is 92mL. After comparing with sulfonated asphalt (FT), it is found that ENAD has better filtration performance. It is found that ENAD has better performance in reducing filtration loss. The mode of interaction between ENAD and the formation and its own mechanism of filtration loss reduction were analyzed by zeta potential analysis and SEM. With the increase of ENAD addition, the absolute values of zeta potential of BF before and after aging decreased from 48.7 and 32.1 to 43.3 and 27.1, respectively. ENAD enhances the interaction force with bentonite particles through its own adsorption properties. The strength of the mud cake is further strengthened by thermal deformation properties. It also enhances the force between the polymer and the formation through electrostatic gravitational adsorption, which further enhances the retention capacity of the polymer in the formation. Compared with conventional fluid loss reducers, ENAD has superior filtration effect and can be used as a fluid loss reducer for deepwater water-based drilling fluids.
Exploration and Application of Acoustic Emission Detection Technology in Leakage Detection of the Bottom Plate of Crude Oil Metal Storage Tanks
Authors: Liu Yu-fang , Shi Li-xin , Sa Qi-er , Zhang Tian-ning , Chai Yan-qiang , Si Xiao-feng , Wang Yu-meng , Li Bing -jun
Published: October 2023

The use of acoustic emission detection technology can conduct online and non-stop detection and evaluation of crude oil metal storage tanks, achieving the integrity detection and evaluation of storage tanks. In order to explore the applicability of acoustic emission detection technology in the leakage detection of the bottom plate of crude oil metal storage tanks, this project carried out online acoustic emission detection of crude oil metal storage tanks, magnetic flux leakage detection after tank opening and cleaning, and compared and analyzed the results of two detection technologies. The adaptability of online acoustic emission detection technology was analyzed and explored. It was found that acoustic emission technology can qualitatively evaluate the corrosion of tank bottom plates, but cannot accurately locate corrosion defects. For tanks with severe corrosion that require maintenance, it is still necessary to open the tank and use magnetic flux leakage and other detection techniques to determine the location of defects. Through comparative analysis of acoustic emission testing technology and magnetic flux leakage testing technology, the results obtained from acoustic emission testing technology are conservative compared to the actual results. It is recommended to upgrade the evaluation of corrosion degree for the acoustic emission evaluation results of crude oil metal storage tanks.
Research and Application of Digital Monitoring System for Pulse Current Cathodic Protection of Oil Pipeline
Authors: Gao Bao-Yuan , Li Zhao-Hui , Huan Tan
Published: October 2023

The transportation of crude oil mainly relies on long-distance buried oil pipelines, which are generally made of steel pipes. Oil leakage often occurs due to corrosion, causing environmental pollution and unsafe accidents. A digital monitoring system for pulse current cathodic protection of oil pipelines was studied, with a focus on the composition and functions of the digital monitoring system for pulse current cathodic protection of oil pipelines. In 2022, the system was applied on two oil pipelines in Tongzhai operation area of the Third Oil Production Plant of Changqing oil field. The system realized the pulse current cathodic protection of oil pipelines to prevent corrosion. At the same time, it can digitally monitor the pulse current cathodic Conservation status status and adjust the working state of the potentiostat, and cooperate with the pulse current cathodic protection monitoring expert system for auxiliary analysis, which has received good economic and social benefits.
Study on Surfactants for Replenish Energy before Fracturing in Tight Reservoir
Authors: Liu Chun-tian , Ma Liang-liang , Wang Zheng-mao , Lu Shou-liang , Song Zhi-rui , Li Xin-xin , Wang Ying
Published: October 2023

Tight reservoir in the periphery of Daqing oilfield is abundant. However, due to tight lithology, poor physical properties, and insufficient formation energy, water injection is not effective, development effect is not ideal, and utilization degree is low. Therefore, it is proposed to implement energy replenishment before fracturing, integral fracturing, and energy storage after fracturing. In the energy replenishment stage, surfactants with good compatibility with the formation and strong oil washing ability are selected as injection medium to play the dual role of energy replenishment and oil washing, and improve the recovery rate of tight sandstone reservoirs. Surfactants are evaluated by established method; LH anionic surfactant and KR anionic non-ionic surfactant are preferred. Under alkali free condition, interfacial tension of two surfactants maintain at order of 10-3. Recovery degree of surfactants in natural cores reach more than 15%. Field application conducted in 30 wells in Block P, including 27 vertical wells and 3 horizontal wells. Oil is seen in vertical wells at 7.8% flow back rate. The average daily liquid production of the 20 wells that have been pumped is 7.5 tons per day, with a daily oil production of 1.3 tons, and a cumulative oil increase of 223.8 tons per well. The average daily oil increase of a single well in the three months after fracturing a qualified oil well is 5.2 tons, 1.6 times and 2.2 times that of dessert fracturing and overall fracturing in the same period. The average daily liquid production of 3 horizontal wells is 24.2 tons, and the daily oil production is 9.6 tons. The test results show that the overall design of the fracturing energy supplement scheme is reasonable, and the selected surfactant can supplement the formation energy while improving the oil washing efficiency, which will provide technical support for exploring new ways to improve oil recovery in tight reservoirs.
Development and Application of Polymer Plugging Remover for Polymer Injection Well in Changqing Oilfield
Authors: Wan Xiang-hui , Jiang Wen-xue , Xu Yang
Published: October 2023

Water injection is a conventional method to maintain reservoirs pressure and improve production in low permeability oilfield. To decrease high water-cut and further enhance oil recovery, Polymers, such as polymer microsphere, preformed polymer gel, cross-linked polyacrylamide, are extensively used to control injection profile in Changqing oilfield. However, due to the low permeability and narrow pore throats of tight reservoirs, pressure in some water flooding wells increases rapidly after the polymer was injected, negatively affecting the energy supplement of the well cluster. A polymer plugging remover, composed of oxidizer, acid and chelating agent to relieve blockage, was developed with viscosity reduction and structure decomposition. The release period is more than 48 hours, which is conducive to deep-seated plugging removal. After treatment, the average diameter of polymer residue is 39-254nm and the dissolution rate is 15.76-53.42%. The permeability of the core sample plugged with polymer has increased significantly before and after treatment by polymer plugging remover, especially, it recovered by 28.67% for microsphere polymer. Five field tests have been completed successfully in the Jiyuan oilfield of Changqing. Before treatment, conventional acidification was performed in the pilot wells for two times at least, which is proved invalid. However, after polymer degraded by the plugging remover, the injection rate increased by 16.2m3/d, the pressure dropped by 3.4MPa and the validity period has exceeded 130 days on average. The polymer plugging remover provides an alternative way to increase injectability when dealing with high pressure and under-injection wells caused by polymer flooding.
Progress and Suggestions for Fracturing Technologies of Tight Oil in Daqing Oilfield
Authors: Wang Xian-jun , Sun Yu , Wang Wei , Zhang Hong-tao , Gao Xiang
Published: October 2023

Daqing oilfield is rich in tight oil reserves, and it’s a realistic field for increasing the efficiency of Daqing oilfield. After 11 years of technical exploration and practice, based on the idea of integration of geological engineering, Daqing oilfield has formed two technical series, which are volumetric fracturing with tight spacing in horizontal well and network fracturing in vertical well, and realizes three-dimensional reservoir transformation. However, with the exploration and development, the reservoir physical properties gradually deteriorate, and there are some problems such as unclear stimulation mechanism and difficult production improvement in fracturing stimulation. Therefore, based on the introduction of the progress of tight oil fracturing technology in Daqing oilfield, the challenges faced by tight oil fracturing in Daqing oilfield are analyzed. According to the geological characteristics of tight oil reservoir in Daqing oilfield, three concepts are proposed, which respectively are horizontal well fracturing changing from further close cutting to uniform fracture initiation and balanced distribution of sand fluid,vertical well fracturing changing from large displacement, large seam fracturing to moderate displacement, moderate scale multi-branch seam fracturing, fracturing concept changing from “trading initial production for benefit” to “cumulative production for benefits”. And it puts forward 5 relevant technical research directions. It has certain guiding significance for assisting the efficient development of tight oil in Daqing oilfield.
Application of Remote Wireless Intelligent Layered Water Injection Technology in Dagang Oilfield
Authors: Song Zu-chang , Liu Yang , Zhang Yong-tao , Yang Ji-jun , Wang Ying-ying , Li Min
Published: October 2023

A remote wireless intelligent layered water injection technolo-gy is proposed to address the problems of traditional layered water in-jection well testing in oil fields, such as the inability to achieve continu-ous dynamic monitoring of injection parameters, high failure rate, and low success rate of testing and commissioning. The technology consists of a host computer client, a server, a surface controller, and an under-ground intelligent water distributor. The underground intelligent water distributor takes the injected water as the carrier, and uses the fluctua-tion of the water injection pressure in the tubing for signal transmission to realize two-way communication between the ground controller and the downhole intelligent water distributor. The underground intelligent water distributor integrates high-precision pressure gauges, controllable water nozzles, and calculation and control modules to form an intelli-gent control system, realizing the reception of ground down transmitted commands or data, the calculation and control of water injection flow rate of water nozzles, and the storage and upload of underground data. Remote wireless intelligent layered water injection technology has been applied in 43 wells, with a success rate of 100%. The maximum depth is 3897m, and the maximum wellbore inclination is 56.07°. This tech-nology realizes remote control of water injection wells, intelligent au-tomatic measurement and adjustment, real-time data monitoring, and automatic early warning functions, laying a foundation for the con-struction of “Digital Intelligence” oilfield.
Structural Optimization Design of Throttle Valve Core for Intelligent Layered Polymer Injection String Controlled By Cable
Authors: Wang Ying-ying , Chen Jian-guang , Qiao Zhi-xue , Yang Zhao-yun , Song Zu-chang , Yang Hai-chao
Published: October 2023

Optimization Design of Throttling Valve Core Structure for Wired Intelligent Layered Polymer Injection String Abstract: Wired intelligent layered polymer in-jection technology can improve the coverage of polymer flooding, alleviate inter-layer conflicts in reservoir development, and improve crude oil recovery. It is an important component of tertiary oil recovery. However, the layered polymer in-jection technology currently used in most domestic oilfields is still the method of fishing and changing the injection nozzle for testing and adjustment. The alloca-tion efficiency of injection volume testing for each layer is slow, with large er-rors, and it is impossible to monitor polymer injection parameters throughout the process. To this end, research has been carried out on the cable controlled intelli-gent layered polymer injection string. By optimizing a highly efficient and low viscosity loss streamlined layered polymer injection throttling device with contin-uously adjustable gaps, the adjustment stroke is shorter and the measurement and adjustment efficiency is higher. Using finite element simulation, the low shear throttle control unit was studied and optimized. By moving the polymer core up and down slightly in the axial direction, the relative gap between the polymer core and the working cylinder was changed to achieve flow adjustment. At the same time, it is necessary to complete the direct reading measurement and adjustment process to form a single pipe layered polymer injection measurement and adjust-ment integration technology. The cable controlled intelligent layered polymer in-jection matching technology connects with the ground intelligent control system through cables to achieve realtime monitoring and online control of polymer flow, pressure, temperature, and other parameters, improving monitoring accura-cy and efficiency, and providing technical support for the construction of the “Digital Intelligence Oilfield”.
A Performance Testing Method for HRF in Dual Mode Communication
Authors: Long Yan , Chen Yongli , Bai Zhihua , Zhao Xiaoqing
Published: October 2023

In recent years, dual-mode communication technology has developed rapidly. Dual-mode communication technology is a local communication technology that integrates a high-speed power line carrier (HPLC) and high-speed radio frequency (HRF). The performance of HRF is a guarantee for the healthy operation of dual-mode communication. This article studies the performance testing methods of HRF, designs and builds a testing system that combines software and hardware and conducts performance testing on the HRF part of the dual-mode integrated chip. The main tests are on the sending and receiving performance of HRF, and the test results show that the performance of HRF in the dual mode chip meets the relevant performance requirements of the State Grid’s “Technical Specification for Dual Mode Communication Interconnection”. The testing system designed in this article can achieve testing of HRF performance.
Node Deployment Strategy Based on Improved Particle Swarm Algorithm in Three-dimensional Underwater Sensor Networks
Authors: Dai Dongping , Yi Jinwang
Published: October 2023

To enhance the monitoring quality of the underwater three-dimensional target area and address issues such as uneven node distribution, inadequate coverage, and poor connectivity in traditional deployment strategies, a new node deployment strategy based on grid deployment with a variable weight particle swarm algorithm has been proposed in this research paper. Its goal is to minimize the quantity of deployed nodes while maintaining the coverage and connectivity of the three-dimensional wireless sensor networks (UWSNs). Simulation results demonstrate that this deployment strategy leads to good performance of the sensor network, and our approach ensures maximum coverage with the same number of nodes.
NEMP Protection of Antennas in Mobile Communication System: Simulation and Circuit Design
Authors: Zhang Keran , Hao Yun , Zhang Shu , Fan Yangtao , He Xiangyong
Published: October 2023

Nuclear Electromagnetic Pulse (NEMP) is highly destructive to mobile communication systems. This paper targets the RF front door of shortwave and ultra-shortwave antennas, simulates the NEMP excitation and coupling effect of two types of antennas (half-loop and whip) based on the CST Microwave Studio platform (CST), and proposes a circuit design for NEMP protection. The protection circuit reduces the transient peak current to less than 5 A in a standard pulsed current injection (PCI) test. The simulation model and the circuit design may be references for the NEMP/HEMP protection of mobile communication systems.