Petroleum Science最新文献_第4页

Failure evaluation mechanism of cement sheath sealing integrity under casing eccentricity during multistage fracturing 多级压裂过程中套管偏心情况下水泥护套密封完整性的失效评估机制

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.04.013

A microannulus (MA) is the primary reason for sustained casing pressure in multi-stage fractured-shale gas wells. However, the effect of the casing eccentricity on the long horizontal section has not been considered. In this study, a full-scale integrity tester for cement sheaths is adopted to measure the cumulative plastic deformation. Numerical models are applied to evaluate the development of the cumulative plastic deformation and quantify the MA width considering casing centralization and eccentricity in the context of multiple loading and unloading cycles. Subsequently, the influences of the eccentricity distance and angle, cement-sheath mechanical variables, and different well depths on the cumulative sheath plastic deformation and sheath MA development are explored. The research results demonstrate that casing eccentricity significantly increases the cumulative sheath plastic deformation compared with that of the casing-centered condition. Consequently, the risk of sealing integrity failure increases. The accumulated plastic deformation increases when the eccentricity distance increases. In contrast, the initial plastic deformation increases as the eccentricity angle increases. However, the cumulative plastic deformation decreases after a specific loading and unloading cycle count. Affected by the coupled influence of the internal casing pressure and fracturing stages, the width of the MA in the horizontal section increased from the toe to the heel, and the casing eccentricity significantly increased the MA width at each stage, thus increasing the risk of gas channeling. Finally, an engineering case is considered to study the influence of casing eccentricity. The results show that cement slurries that form low and high elastic moduli can be applied to form a cement sheath when the fracturing stage is lower or higher than a specific value, respectively. The results of this study offer theoretical references and engineering support for the integrity control of cement sheath sealing.

微空洞（MA）是多级压裂页岩气井套管压力持续存在的主要原因。然而，套管偏心对长水平段的影响尚未得到考虑。本研究采用全尺寸水泥护套完整性测试仪测量累积塑性变形。在多次加载和卸载循环的情况下，应用数值模型评估累积塑性变形的发展，并量化考虑套管集中和偏心的 MA 宽度。随后，探讨了偏心距和偏心角、水泥-护套力学变量以及不同井深对累积护套塑性变形和护套MA发展的影响。研究结果表明，与套管居中状态相比，套管偏心会显著增加护套累积塑性变形。因此，密封完整性失效的风险增加。当偏心距增大时，累积塑性变形也随之增大。相反，初始塑性变形随着偏心角的增大而增大。然而，在特定的加载和卸载循环次数之后，累积塑性变形会减小。受套管内部压力和压裂阶段的耦合影响，水平段的 MA 宽度从趾部到踵部均有所增加，套管偏心率显著增加了每个阶段的 MA 宽度，从而增加了气体通道的风险。最后，考虑了一个工程案例来研究套管偏心的影响。结果表明，当压裂阶段低于或高于特定值时，可分别使用形成低弹性模量和高弹性模量的水泥浆来形成水泥护套。该研究结果为水泥护套密封的完整性控制提供了理论参考和工程支持。

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引用次数: 0

Insight into evolution of invasive patterns on fingering phenomenon during immiscible two-phase flow through pore structure 洞察不相溶两相流通过孔隙结构时指状现象的侵入模式演变

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.05.009

Understanding fingering, as a challenge to stable displacement during the immiscible flow, has become a crucial phenomenon for geological carbon sequestration, enhanced oil recovery, and groundwater protection. Typically governed by gravity, viscous and capillary forces, these factors lead invasive fluids to occupy pore space irregularly and incompletely. Previous studies have demonstrated capillary numbers, describing the viscous and capillary forces, to quantificationally induce evolution of invasion patterns. While the evolution mechanisms of invasive patterns have not been deeply elucidated under the constant capillary number and three variable parameters including velocity, viscosity, and interfacial tension. Our research employs two horizontal visualization systems and a two-phase laminar flow simulation to investigate the tendency of invasive pattern transition by various parameters at the pore scale. We showed that increasing invasive viscosity or reducing interfacial tension in a homogeneous pore space significantly enhanced sweep efficiency, under constant capillary number. Additionally, in the fingering crossover pattern, the region near the inlet was prone to capillary fingering with multi-directional invasion, while the viscous fingering with unidirectional invasion was more susceptible occurred in the region near the outlet. Furthermore, increasing invasive viscosity or decreasing invasive velocity and interfacial tension promoted the extension of viscous fingering from the outlet to the inlet, presenting that the subsequent invasive fluid flows toward the outlet. In the case of invasive trunk along a unidirectional path, the invasive flow increased exponentially closer to the outlet, resulting in a significant decrease in the width of the invasive interface. Our work holds promising applications for optimizing invasive patterns in heterogeneous porous media.

指状流体是对不相溶流动过程中稳定位移的挑战，了解指状流体已成为地质碳封存、提高石油采收率和保护地下水的一个关键现象。入侵流体通常受重力、粘性力和毛细力的影响，这些因素导致入侵流体不规则、不完全地占据孔隙空间。以往的研究表明，描述粘性力和毛细力的毛细管数可以量化诱导入侵模式的演变。但在毛细管数恒定以及速度、粘度和界面张力等三个可变参数条件下，入侵模式的演变机制尚未得到深入阐明。我们的研究采用了两种水平可视化系统和两相层流模拟，研究了孔隙尺度下不同参数对入侵模式转变的影响。我们的研究表明，在毛细管数恒定的情况下，在均质孔隙空间中增加侵入粘度或降低界面张力可显著提高清扫效率。此外，在指状交叉模式中，靠近入口的区域容易发生多向入侵的毛细管指状，而靠近出口的区域更容易发生单向入侵的粘性指状。此外，增加入侵粘度或降低入侵速度和界面张力会促进粘指状从出口向入口延伸，从而使随后的入侵流体流向出口。在沿单向路径的侵入干流中，侵入流在靠近出口处呈指数增长，导致侵入界面宽度显著减小。我们的研究成果有望应用于优化异质多孔介质中的侵入模式。

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引用次数: 0

Cavitation cloud impingement and scattering motion of jet in rock breaking process 岩石破碎过程中的气蚀云撞击和射流散射运动

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.05.015

The cavitation cloud impingement of the jet in the rock breaking process was experimentally investigated to reveal the jet erosion mechanism in drilling of petroleum exploitation. Serial erosion tests and flow visualization were performed, where the cavitation cloud motion in the erosion crater was obtained with the designed transparent specimen. Various erosion patterns were identified in the whole erosion process based on the eroded specimen topography. The shallow eroded crater with a shrinking erosion area is generated by the combination of impinging and scattering cavitation clouds. The increase of l_d promotes the development of cavitation cloud σ_c but reduces the impingement frequency f_d, suggesting that the jet aggressive ability is enhanced when the balance between σ_c and f_d is reached. The cavitation cloud motion in the erosion crater was investigated with the transparent specimen. The erosion in the crater at shorter exposure periods T_e is generated by the combination of impingement and restricted scattering of cavitation clouds. With the continuous development of the erosion damage, the jet's aggressive ability is diminished due to the erosion expansion on sandstone, where the cavitation clouds impinge on the target and then collapse and vanish without restricted scattering.

实验研究了破岩过程中射流的空化云撞击，揭示了石油开采钻井中的射流侵蚀机理。对设计的透明试样进行了连续侵蚀试验和流动可视化，获得了侵蚀坑中的空化云运动。根据被侵蚀试样的地形，确定了整个侵蚀过程中的各种侵蚀模式。在冲击和散射空化云的共同作用下，产生了侵蚀面积不断缩小的浅侵蚀坑。ld的增加会促进空化云σc的发展，但会降低撞击频率fd，这表明当σc和fd达到平衡时，射流的侵蚀能力会增强。利用透明试样对侵蚀坑中的空化云运动进行了研究。在较短的暴露周期 Te 下，侵蚀坑中的侵蚀是由空化云的撞击和受限散射共同作用产生的。随着侵蚀破坏的不断发展，由于砂岩上的侵蚀扩展，射流的侵蚀能力减弱，空化云撞击目标，然后坍塌并消失，没有限制性散射。

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引用次数: 0

A novel framework for predicting non-stationary production time series of shale gas based on BiLSTM-RF-MPA deep fusion model 基于 BiLSTM-RF-MPA 深度融合模型的页岩气非稳态生产时间序列预测新框架

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.05.012

Shale gas, as an environmentally friendly fossil energy resource, has gained significant commercial development and shows immense potential. However, accurately predicting shale gas production faces substantial challenges due to the complex law of decline, nonlinear and non-stationary features in production data, which greatly repair the robustness of current models in predicting shale gas production time series. To address these challenges and improve accuracy in production forecasting, this paper introduces a novel and innovative approach: a hybrid proxy model that combines the bi-directional long short-term memory (BiLSTM) neural network and random forest (RF) through deep learning. The BiLSTM neural network is adept at capturing long-term dependencies, making it suitable for understanding the intricate relationships between input and output variables in shale gas production. On the other hand, RF serves a dual purpose: reducing model variance and addressing the concept drift problem that arises in non-stationary time series predictions made by BiLSTM. By integrating these two models, the hybrid approach effectively captures the inherent dependencies present in long and nonstationary production time series, thereby reducing model uncertainty. Furthermore, the combination of BiLSTM and RF is optimized using the recently-proposed marine predators algorithm (MPA) to fine-tune hyperparameters and enhance the overall performance of the proxy model. The results demonstrate that the proposed BiLSTM-RF-MPA model achieves higher prediction accuracy and demonstrates stronger generalization capabilities by effectively handling the complex nonlinear and non-stationary characteristics of shale gas production time series. Compared to other models such as LSTM, BiLSTM, and RF, the proposed model exhibits superior fitting and prediction performance, with an average improvement in performance indicators exceeding 20%. This innovative framework provides valuable insights for forecasting the complex production performance of unconventional oil and gas reservoirs, which sheds light on the development of data-driven proxy models in the field of subsurface energy utilization.

页岩气作为一种环境友好型化石能源资源，已经获得了重大的商业开发，并显示出巨大的潜力。然而，由于页岩气产量数据具有复杂的下降规律、非线性和非平稳特征，准确预测页岩气产量面临巨大挑战，这极大地削弱了现有模型预测页岩气产量时间序列的稳健性。为了应对这些挑战并提高产量预测的准确性，本文介绍了一种新颖的创新方法：通过深度学习将双向长短期记忆（BiLSTM）神经网络和随机森林（RF）相结合的混合代理模型。BiLSTM 神经网络善于捕捉长期依赖关系，因此适用于理解页岩气生产中输入和输出变量之间错综复杂的关系。另一方面，RF 具有双重作用：降低模型方差，解决 BiLSTM 预测非平稳时间序列时出现的概念漂移问题。通过整合这两个模型，混合方法有效地捕捉到了长时间非稳态生产时间序列中存在的固有依赖性，从而降低了模型的不确定性。此外，利用最近提出的海洋捕食者算法（MPA）对 BiLSTM 和 RF 的组合进行了优化，以微调超参数并提高代理模型的整体性能。结果表明，所提出的 BiLSTM-RF-MPA 模型能有效处理页岩气生产时间序列的复杂非线性和非平稳特性，从而实现更高的预测精度和更强的泛化能力。与 LSTM、BiLSTM 和 RF 等其他模型相比，所提出的模型具有更优越的拟合和预测性能，性能指标平均提高了 20% 以上。这一创新框架为预测非常规油气藏复杂的生产性能提供了有价值的见解，为地下能源利用领域数据驱动代理模型的发展提供了启示。

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引用次数: 0

Complementary testing and machine learning techniques for the characterization and prediction of middle Permian tight gas sandstone reservoir quality in the northeastern Ordos Basin, China 用于表征和预测中国鄂尔多斯盆地东北部中二叠统致密气砂岩储层质量的互补测试和机器学习技术

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.08.008

Zi-Yi Wang , Shuang-Fang Lu , Neng-Wu Zhou , Yan-Cheng Liu , Li-Ming Lin , Ya-Xin Shang , Jun Wang , Guang-Shun Xiao

In this study, an integrated approach for diagenetic facies classification, reservoir quality analysis and quantitative wireline log prediction of tight gas sandstones (TGSs) is introduced utilizing a combination of fit-for-purpose complementary testing and machine learning techniques. The integrated approach is specialized for the middle Permian Shihezi Formation TGSs in the northeastern Ordos Basin, where operators often face significant drilling uncertainty and increased exploration risks due to low porosities and micro-Darcy range permeabilities. In this study, detrital compositions and diagenetic minerals and their pore type assemblages were analyzed using optical light microscopy, cathodoluminescence, standard scanning electron microscopy, and X-ray diffraction. Different types of diagenetic facies were delineated on this basis to capture the characteristic rock properties of the TGSs in the target formation. A combination of He porosity and permeability measurements, mercury intrusion capillary pressure and nuclear magnetic resonance data was used to analyze the mechanism of heterogeneous TGS reservoirs. We found that the type, size and proportion of pores considerably varied between diagenetic facies due to differences in the initial depositional attributes and subsequent diagenetic alterations; these differences affected the size, distribution and connectivity of the pore network and varied the reservoir quality. Five types of diagenetic facies were classified: (ⅰ) grain-coating facies, which have minimal ductile grains, chlorite coatings that inhibit quartz overgrowths, large intergranular pores that dominate the pore network, the best pore structure and the greatest reservoir quality; (ⅱ) quartz-cemented facies, which exhibit strong quartz overgrowths, intergranular porosity and a pore size decrease, resulting in the deterioration of the pore structure and reservoir quality; (ⅲ) mixed-cemented facies, in which the cementation of various authigenic minerals increases the micropores, resulting in a poor pore structure and reservoir quality; (ⅳ) carbonate-cemented facies and (ⅴ) tightly compacted facies, in which the intergranular pores are filled with carbonate cement and ductile grains; thus, the pore network mainly consists of micropores with small pore throat sizes, and the pore structure and reservoir quality are the worst. The grain-coating facies with the best reservoir properties are more likely to have high gas productivity and are the primary targets for exploration and development. The diagenetic facies were then translated into wireline log expressions (conventional and NMR logging). Finally, a wireline log quantitative prediction model of TGSs using convolutional neural network machine learning algorithms was established to successfully classify the different diagenetic facies.

在本研究中，利用适用性互补测试和机器学习技术，介绍了一种用于致密气砂岩（TGSs）成因面分类、储层质量分析和线性测井定量预测的综合方法。该综合方法专门针对鄂尔多斯盆地东北部的中二叠统石河子地层致密气砂岩，由于孔隙度和微达西范围的渗透率较低，该地区的作业者往往面临着巨大的钻井不确定性和更高的勘探风险。本研究利用光学显微镜、阴极荧光、标准扫描电子显微镜和 X 射线衍射分析了碎屑成分和成岩矿物及其孔隙类型组合。在此基础上划分了不同类型的成岩面，以捕捉目标地层中 TGS 的岩石特征。结合 He 孔隙度和渗透率测量、汞侵入毛细管压力和核磁共振数据，分析了异质 TGS 储层的机理。我们发现，由于初始沉积属性和后续成岩改变的不同，不同成岩面之间孔隙的类型、大小和比例存在很大差异；这些差异影响了孔隙网络的大小、分布和连通性，并改变了储层质量。我们将成岩面划分为五种类型：(ⅰ)晶粒包覆面，具有最小的韧性晶粒，绿泥石包覆抑制了石英的过度生长，大的晶间孔隙主导了孔隙网络，孔隙结构最佳，储层质量最高；(ⅱ)石英加固面，表现出强烈的石英过度生长，晶间孔隙度和孔隙尺寸减小，导致孔隙结构和储层质量下降；(ⅲ)混合胶结面，各种自生矿物的胶结增加了微孔，导致孔隙结构和储层质量变差；(ⅳ)碳酸盐胶结面和(ⅴ)致密胶结面，晶间孔隙被碳酸盐胶结物和韧性晶粒充填，因此孔隙网络主要由孔喉尺寸较小的微孔组成，孔隙结构和储层质量最差。储层性质最好的晶粒涂层面更有可能具有高产气性，是勘探开发的主要目标。然后，将成岩面转化为线性测井表达式（常规测井和核磁共振测井）。最后，利用卷积神经网络机器学习算法建立了 TGS 的线性测井定量预测模型，成功地对不同成因面进行了分类。

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引用次数: 0

High-temperature resistant polymer nanocomposites with exfoliated organic-modified montmorillonite nanosheets strongly adsorbed on polymer chains 聚合物链上强烈吸附剥离有机改性蒙脱石纳米片的耐高温聚合物纳米复合材料

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.07.006

Dong-Yin Wang, Chang-Feng Chen, Fei Ju, Yang-Chuan Ke

It has been demonstrated that almost all polymer-clay nanocomposites show higher temperature stability than that of pure polymer, which is attributed to the active exfoliated clay nanosheet firmly adsorbed onto the polymer chains, due to polerization and nucleation effect, the clay nanosheets could protect the polymer chains from destroying. To prove such mechanism, the water-soluble polymer nanocomposites (AAA/SLS-MMT) were synthesized by the in-situ polymerization of 2-acrylamide-2-methyl-propane sulfonic acid, acrylamide, 4-acryloylmorpholine, and organically modified montmorillonite. The techniques of nuclear magnetic resonance, atomic force microscopy and scanning electron microscopy etc., clearly characterized the successful synthesized of sample's structure, the exfoliated MMT nanosheet adsorbed polymer chain's scale, and well-dispersed morphology, espectively. The adsorption model, X-ray photoelectron spectroscopy presented the existence of strong adsorption, while molecular simulation calculations first concluded that the strong adsorption energy was −13032.06 kcal/mol. Thermo-gravimetric-analysis proved the temperature of maximum thermal degradation of powder sample (AAA/1.0 wt% SLS-MMT) was over 298 °C. After ageing at 180 °C for 4 h, the apparent viscosity of 5 g/L AAA/1.0 wt% SLS-MMT aqueous solution was 326.7 mPa⋅s, while that of pure polymer (AAA) was only 8.3 mPa⋅s. This optimized sample has the smallest FL_API value at all test temperatures from 180 to 220 °C in both fresh and salt water based drilling fluid. All the evidences of high temperature resistance indicate that the strong adsorption can enhance the thickness of hydrated shell and adsorption of clay particles in drilling fluid at high temperature. Such mechanism supplied the better way to design high-temperature resistant fluid loss additives for deep and ultra-deep oil and gas formation engineering.

研究表明，几乎所有聚合物-粘土纳米复合材料都表现出比纯聚合物更高的温度稳定性，这是由于活性剥离粘土纳米片牢固地吸附在聚合物链上，由于极化和成核效应，粘土纳米片可以保护聚合物链不被破坏。为了证明这种机理，研究人员采用 2-丙烯酰胺-2-甲基丙烷磺酸、丙烯酰胺、4-丙烯酰吗啉和有机改性蒙脱石原位聚合的方法合成了水溶性聚合物纳米复合材料（AAA/SLS-MMT）。核磁共振、原子力显微镜和扫描电子显微镜等技术清楚地表征了成功合成的样品结构、剥离的 MMT 纳米片吸附聚合物链的尺度和良好的分散形貌。吸附模型、X 射线光电子能谱显示存在强吸附，分子模拟计算首次得出强吸附能为 -13032.06 kcal/mol。热重分析证明，粉末样品（AAA/1.0 wt% SLS-MMT）的最大热降解温度超过 298 ℃。在 180 °C 下老化 4 小时后，5 g/L AAA/1.0 wt% SLS-MMT 水溶液的表观粘度为 326.7 mPa⋅s，而纯聚合物（AAA）的表观粘度仅为 8.3 mPa⋅s。在淡水和盐水钻井液中，该优化样品在 180 至 220 °C 的所有测试温度下的 FLAPI 值均最小。所有耐高温的证据都表明，在高温条件下，强吸附性可以增强钻井液中水合壳的厚度和粘土颗粒的吸附性。这种机理为设计用于深层和超深层油气层工程的耐高温失液添加剂提供了更好的方法。

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引用次数: 0

Dynamic simulation of double-cased perforation in deepwater high temperature and high-pressure oil and gas wells 深水高温高压油气井双套管射孔动态模拟

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.05.008

In order to ensure the penetrability of double-cased perforation in offshore oil and gas fields and to maximize the capacity of perforation completion, This study establishes a dynamic model of double-cased perforation using ANSYS/LS-DYNA simulation technology. The combination of critical perforation parameters for double casing is obtained by studying the influencing factors of the jet-forming process, perforation depth, diameter, and stress changes of the inner and outer casing. The single-target perforation experiments under high-temperature and high-pressure (HTHP) conditions and ground full-scale ring target perforation tests are designed to verify the accuracy of numerical simulation results. The reduced factor is adopted as the quantitative measure of perforation depth and diameter for different types of perforation charge under different conditions. The results show that the perforation depth reduction increases with temperature and pressure, and the reduced factor is between 0.67 and 0.87 under HTHP conditions of 130 °C/44 MPa and 137 °C/60 MPa. Comparing the results of the numerical simulation and the full-scale test correction, the maximum error is less than 8.91%, and this numerical simulation has strong reliability. This research provides a basis for a reasonable range of double-cased perforation parameters and their optimal selection.

为确保海上油气田双套管射孔的可穿透性，最大限度地提高射孔完井能力，本研究利用 ANSYS/LS-DYNA 仿真技术建立了双套管射孔动态模型。通过研究射流形成过程、射孔深度、直径、内外套管应力变化等影响因素，得出了双套管关键射孔参数组合。为验证数值模拟结果的准确性，设计了高温高压（HTHP）条件下的单靶射孔试验和地面全尺寸环靶射孔试验。针对不同条件下不同类型的射孔装药，采用减径系数作为射孔深度和直径的量化指标。结果表明，射孔深度减小系数随温度和压力的升高而增大，在 130 °C/44 MPa 和 137 °C/60 MPa 的 HTHP 条件下，减小系数介于 0.67 和 0.87 之间。数值模拟结果与全尺寸试验修正结果比较，最大误差小于 8.91%，数值模拟具有较强的可靠性。该研究为双套管穿孔参数的合理范围及其优化选择提供了依据。

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引用次数: 0

Heat front propagation in shale oil reservoirs during air injection: Experimental and numerical studies 注气过程中页岩油藏中的热锋传播：实验和数值研究

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.06.005

Air injection technique for developing shale oil has gained significant attention. However, the ability of the heat front to consistently propagate within the shale during air injection remains uncertain. To address this, we investigated the heat front propagation within oil–detritus mixtures, shale cores, and fractured shale cores using a self-designed combustion tube (CT) and experimental schemes. By integrating the results obtained from high-pressure differential scanning calorimetry and CT, we developed a comprehensive reaction kinetics model to accurately analyze the main factors influencing the heat front propagation within fractured shale. The findings revealed that in the absence of additional fractures, the heat front failed to propagate within the tight shale. The flow of gases and liquids towards the shale core was impeded, resulting in the formation of a high-pressure zone at the front region of the shale. This pressure buildup significantly hindered air injection, leading to inadequate oxygen supply and the extinguishment of the heat front. However, the study demonstrated the stable propagation of the heat front within the oil–detritus mixtures, indicating the good combustion activity of the shale oil. Furthermore, the heat front successfully propagated within the fractured shale, generating a substantial amount of heat that facilitated the creation of fractures and enhanced gas injection and shale oil flow. It was important to note that after the heat front passed through the shale, the combustion intensity decreased. The simulation results indicated that injecting air into the main fracturing layers of the shale oil reservoir enabled the establishment of a stable heat front. Increasing the reservoir temperature (from 63 to 143 °C) and oxygen concentration in the injected gas (from 11% to 21%) promoted notable heat front propagation and increased the average temperature of the heat front. It was concluded that temperature and oxygen concentration had the most important influence on the heat front propagation, followed by pressure and oil saturation.

开发页岩油的空气注入技术受到了广泛关注。然而，在空气注入过程中，热锋在页岩内持续传播的能力仍不确定。为了解决这个问题，我们使用自行设计的燃烧管（CT）和实验方案，研究了热锋在石油-杂质混合物、页岩岩心和断裂页岩岩心内的传播情况。综合高压差示扫描量热法和 CT 的结果，我们建立了一个综合反应动力学模型，以准确分析影响热锋在断裂页岩内传播的主要因素。研究结果表明，在没有额外裂缝的情况下，热锋无法在致密页岩内传播。气体和液体流向页岩核心受到阻碍，导致页岩前沿区域形成高压区。这种压力积聚严重阻碍了空气注入，导致氧气供应不足和热锋熄灭。不过，研究表明，热锋在油-杂质混合物中稳定传播，表明页岩油具有良好的燃烧活性。此外，热锋还成功地在断裂页岩中传播，产生大量热量，促进了断裂的形成，增强了天然气注入和页岩油流动。值得注意的是，热锋穿过页岩后，燃烧强度降低。模拟结果表明，向页岩油藏的主要压裂层注入空气能够建立稳定的热锋。提高储层温度（从 63°C 提高到 143°C）和注入气体中的氧气浓度（从 11% 提高到 21%）可显著促进热锋的传播，并提高热锋的平均温度。结论是，温度和氧气浓度对热锋传播的影响最大，其次是压力和油饱和度。

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引用次数: 0

Differences in hydrocarbon accumulation and controlling factors of slope belt in graben basin: A case study of Pinghu Slope Belt in the Xihu sag of the east China Sea Shelf basin (ECSSB) 海湾盆地斜坡带油气聚集差异及控制因素：东海大陆架盆地（ECSSB）西湖斜坡带平湖斜坡带案例研究

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.06.007

The Pinghu slope belt in the Xihu sag of the East China Sea Shelf Basin (ECSSB) is a crucial hydrocarbon production area in eastern China. However, due to the complex geological conditions, publications have lacked comprehensive research on the spatial-temporal coupling relationships of primary factors that impact hydrocarbon accumulation in the Pinghu slope belt. Furthermore, the hydrocarbon distribution patterns and the controlling factors across different study areas within the same slope belt are not yet fully understood. This study extensively utilized three-dimensional seismic data, well logging data, geochemical analysis, fluorescence analysis, and oil testing and production data to address these issues. Following a “stratification and differentiation” approach, the study identified seven distinct hydrocarbon migration and accumulation units (HMAU) in the Pinghu slope area based on the structural morphology characteristics, hydrocarbon source-reservoir-cap rock patterns, hydrocarbon migration pathways, and hydrocarbon supply range. Detailed analysis was conducted to examine the hydrocarbon distribution patterns and controlling factors within each migration and accumulation unit across different structural units, including high, medium, and low structural components. All data sources support a “southern‒northern sub-area division, eastern‒western sub-belt division, and variations in hydrocarbon accumulation” pattern in the Pinghu slope belt. The degree of hydrocarbon accumulation is controlled by the factors of structural morphology, hydrocarbon generation potential of source rocks, the spatial position of source slopes, fault sealing capacity, and sand body distribution. Furthermore, different coupling patterns of faults and sand bodies play a pivotal role in governing hydrocarbon enrichment systems across various migration and accumulation units. These observations indicate that three hydrocarbon accumulation patterns have been established within the slope belt, including near-source to far-source gentle slope with multiple hydrocarbon kitchens in the XP1−XP4 zones, near-source to middle-source gentle slope with dual-hydrocarbon kitchens in the XP5 zone, and near-source steep slope with a single hydrocarbon kitchen in the XP6−XP7 zones. These findings contribute to enhancing the theoretical system of hydrocarbon accumulation in the slope belt.

东海大陆架盆地（ECSSB）西湖凹陷平湖斜坡带是中国东部重要的油气产区。然而，由于地质条件复杂，出版物缺乏对影响平湖斜坡带油气聚集的主要因素的时空耦合关系的全面研究。此外，对同一斜坡带内不同研究区域的油气分布模式和控制因素也尚未完全了解。本研究广泛利用三维地震数据、测井数据、地球化学分析、荧光分析以及试油和生产数据来解决这些问题。研究采用 "分层分异 "的方法，根据构造形态特征、烃源-储层-盖层岩石模式、烃迁移途径和烃供应范围，确定了平湖斜坡地区七个不同的烃迁移和聚集单元（HMAU）。通过详细分析，研究了不同构造单元（包括高、中、低构造组分）中各迁移和聚集单元内的油气分布模式和控制因素。所有数据均支持平湖斜坡带 "南-北亚区划分、东-西亚带划分、油气聚集变化 "的格局。构造形态、源岩生烃潜力、源坡空间位置、断层封堵能力和砂体分布等因素控制着油气聚集程度。此外，断层和砂体的不同耦合模式在不同迁移和聚集单元的油气富集系统中起着关键作用。这些观测结果表明，斜坡带内已形成三种碳氢化合物富集模式，包括XP1-XP4带的近源至远源缓坡及多个碳氢化合物厨房，XP5带的近源至中源缓坡及双碳氢化合物厨房，以及XP6-XP7带的近源陡坡及单一碳氢化合物厨房。这些发现有助于完善斜坡带碳氢化合物积累的理论体系。

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引用次数: 0

Selection and application of wavelet transform in high-frequency sequence stratigraphy analysis of coarse-grained sediment in rift basin 小波变换在裂谷盆地粗粒沉积物高频层序地层分析中的选择与应用

IF 6 1区工程技术 Q2 ENERGY & FUELS

Petroleum Science

Pub Date : 2024-10-01 DOI: 10.1016/j.petsci.2024.06.020

Ling Li , Zhi-Zhang Wang , Shun-De Yin , Wei-Fang Wang , Zhi-Chao Yu , Wen-Tian Fan , Zhi-Heng Zhang

Wavelet transformation is a widely used method in high-frequency sequence stratigraphic analysis. However, the application is problematic since different wavelets always return the same sequence analysis results. To address this issue, we applied five commonly used wavelets to theoretical sequence models to document some application criteria. Five gradual scale-change sequence models were simplified from the glutenite succession deposition by gravity flows to form the fining-upwards cycle sequences (FUCS) and coarsening-upwards cycle sequences (CUCS). After conducting theoretical sequence model tests, the optimal wavelet (sym4) was selected and successfully used with actual data to identify the sequence boundaries. We also proposed a new method to optimize the scale of continuous wavelet transformation (CWT) for sequence boundary determination. We found that the balloon-like marks in scalograms of db4, sym4, and coif4 wavelet determine, respectively, the fourth-order sequence boundary, the thick succession sequence boundaries in FUCS, and the thick succession sequence in FUCS and CUCS. Comparing the sequence identification results shows that the asymmetric wavelets had an advantage in high-frequency sequence boundary determination and sedimentary cycle discrimination through the amplitude trend of the coefficient, in which the sym4 wavelet is the most effective. In conclusion, the asymmetry of wavelets is the first selection principle, of which asymmetric wavelets are more sensitive to sediment deposition by flood flows. The match of the wavelet between the sequence is the second selection principle, in which the correlation of time-frequency impacts the accuracy of sequence surface localization. However, the waveform of the wavelet is a visual and abstract parameter for sequence boundary detection. The appropriate wavelet for lacustrine sequence analysis is the asymmetric wavelet with a weak number of side lobes. The depositional flows, depositional process, and autogenic are three sedimentary factors that influence the sequence analysis results.

小波变换是一种广泛应用于高频序列地层分析的方法。然而，由于不同的小波总是返回相同的序列分析结果，因此在应用中存在问题。针对这一问题，我们将五种常用的小波应用于理论层序模型，以记录一些应用标准。我们从重力流作用下的糯橄榄岩演替沉积简化出五个渐变尺度序列模型，形成了细化向上循环序列（FUCS）和粗化向上循环序列（CUCS）。在进行了理论序列模型试验后，选出了最优小波（sym4），并成功地与实际数据相结合，确定了序列边界。我们还提出了一种优化连续小波变换（CWT）尺度以确定序列边界的新方法。我们发现，db4、sym4 和 coif4 小波扫描图中的气球状标记分别确定了四阶序列边界、FUCS 中的厚演替序列边界以及 FUCS 和 CUCS 中的厚演替序列。对比序列识别结果表明，非对称小波在高频序列边界判定和沉积周期判别中通过系数的振幅趋势具有优势，其中 sym4 小波的效果最好。总之，小波的非对称性是第一选择原则，其中非对称小波对洪流沉积更为敏感。序列之间的小波匹配是第二个选择原则，其中时频的相关性影响序列表面定位的准确性。然而，小波的波形是序列边界检测的一个直观和抽象的参数。适合于湖泊序列分析的小波是侧裂片数量较少的不对称小波。沉积流、沉积过程和自生是影响序列分析结果的三个沉积因素。

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引用次数: 0