Testing oil saturation distribution in migration paths using MRI

International audienceMagnetic Resonance Imaging (MRI) method allows to observe the distribution of different fluids in situ in porous media, and to measure oil and water saturation. Although this technique has great advantages compared to others, there remains large space for assessing the method and improving the accuracy of measurement. Using MRI, the oil secondary migration paths are scanned to measure the saturation distribution during the laboratory experiments. The resulting map can be calibrated using a device with the same pore structure as the probed sample and fully saturated with oil. This device is scanned with the probed sample at the same time in order to calibrate the saturation. The Spin-echo multi-slices sequence (SEMS) is adopted for MRI to ensure that the oil saturation in migration paths is accurately measured. The relevant spatial resolution of the mapping is defined according to the concept of REV (representative elementary volume). The oil saturation resulting from data obtained using different image formats are compared and the resulting saturation evaluation is compared to direct bulk saturation measurements. This comparison demonstrates that the calculated MRI oil saturation using DICOM image format is quite accurate, with a relative error less than 2%

Lithofacies logging identification for strongly heterogeneous deep-buried reservoirs based on improved Bayesian inversion: The Lower Jurassic sandstone, Central Junggar Basin, China

The strong heterogeneity characteristics of deep-buried clastic low-permeability reservoirs may lead to great risks in hydrocarbon exploration and development, which makes the accurate identification of reservoir lithofacies crucial for improving the obtained exploration results. Due to the very limited core data acquired from deep drilling, lithofacies logging identification has become the most important method for comprehensively obtaining the rock information of deep-buried reservoirs and is a fundamental task for carrying out reservoir characterization and geological modeling. In this study, a machine learning method is introduced to lithofacies logging identification, to explore an accurate lithofacies identification method for deep fluvial-delta sandstone reservoirs with frequent lithofacies changes. Here Sangonghe Formation in the Central Junggar Basin of China is taken as an example. The K-means-based synthetic minority oversampling technique (K-means SMOTE) is employed to solve the problem regarding the imbalanced lithofacies data categories used to calibrate logging data, and a probabilistic calibration method is introduced to correct the likelihood function. To address the situation in which traditional machine learning methods ignore the geological deposition process, we introduce a depositional prior for controlling the vertical spreading process based on a Markov chain and propose an improved Bayesian inversion process for training on the log data to identify lithofacies. The results of a series of experiments show that, compared with the traditional machine learning method, the new method improves the recognition accuracy by 20%, and the predicted petrographic vertical distribution results are consistent with geological constraints. In addition, SMOTE and probabilistic calibration can effectively handle data imbalance problems so that different categories can be adequately learned. Also the introduction of geological prior has a positive impact on the overall distribution, which significantly improves the accuracy and recall rate of the method. According to this comprehensive analysis, the proposed method greatly enhanced the identification of the lithofacies distributions in the Sangonghe Formation. Therefore, this method can provide a tool for logging lithofacies interpretation of deep and strongly heterogeneous clastic reservoirs in fluvial-delta and other depositional environments

Petroleum Migration and Accumulation: Modeling and Applications

Subsurface hydrocarbon observations at any scale serve as critical clues to understand and reconstruct migration pathways and charge histories through geological time to assess the risk of petroleum exploration targets. Hydrocarbon migration commonly occurred millions of years ago, and the pathways can rarely be observed in wells or in outcrops. Therefore, hydrocarbon migration modeling tools are important to test and quantify the processes and elements, which impact hydrocarbon migration. This paper presents a new method of analyzing migration in superimposed basins, which have experienced multiple stages of basin subsidence and inversion, during which multiple episodes of hydrocarbon generation, migration, and accumulation occurred. The new modeling method first identifies the character of the migration and accumulation units by synthesizing geological factors, such as heterogeneity of carrier beds and reservoirs. Second, hydrocarbon migration is analyzed as a geologic process, for which the invasion-percolation (IP) migration method seems to be most suitable. The IP migration method demonstrates a good relationship between migration driving and resisting forces along pathways and thus can be used to reasonably model hydrocarbon migration processes at any scale of units in a basin. The new migration method provides insights into quantitative methods that can be applied to petroleum system analysis. The new method has been applied to several Chinese basins and has proven to be useful for defining exploration targets and resource assessments in mature, frontier, and, especially, tectonically complex basins. A case study of the Upper Triassic Chang 7 and Chang 8 units in the southern Ordos Basin, central China, is presented to demonstrate a multistage hydrocarbon accumulation unit. Modeling results show that the same pairs of reservoir-seal sets contained different accumulation units in the geological past with different styles of hydrocarbon migration and different accumulation patterns. It can be concluded that the style and character of early hydrocarbon migration have significantly affected the more recent hydrocarbon migration and the present-day distribution of hydrocarbons

Dynamics of Hydrocarbon Migration: Quantitative Dynamics Studies and Applications

This Book Presents the Authors\u27 Research Findings on the Dynamics of Oil Migration, Research Methodologies, Insights and Applications in Petroliferous Basins. It Studies the Behaviors of Oil Migration in Porous Media through Physical Experiments and Numerical Simulations, Explores the Mechanism of Oil Migration and Effects of Migration Process, and Then Establishes a Migration Modeling Method by Coupling the Source, Driving Forces and Carriers. the New Method Can Be Used to Estimate the Amount of Migrated Hydrocarbons and Then Predict the Location of Possible Hydrocarbon Accumulations in Different Parts of a Basin. This Approach is Useful for Resources Assessment and Prediction of the Distribution of Hydrocarbon Accumulations. an Example Utilizing This Methodology is Presented to Study the Dynamics of Migration and Accumulation Processes in the Southern Slope of Dongying Depression in Bohai Bay Basin in China. the Book Appeals to Scientists and Professionals Working on Petroleum Prospecting as Well as Faculty and Students in Petroleum Geology

The complete chloroplast genome of a medical herb, Gentianopsis paludosa (Hook. f.) Ma (Gentianaceae), from Qinghai-Tibet Plateau in China

Gentianopsis paludosa (Hook. f.) Ma (Gentianaceae) is one of the genuine medicinal materials in Qinghai-Tibet Plateau, China. Here we report the first chloroplast (cp) genome of G. paludosa using Illumina NovaSeq 6000 platform. The length of its complete cp genome is 151,568 bp, containing four sub-regions; a large single copy region (LSC) of 82,834 bp and a small single copy region (SSC) of 17,928 bp are separated by a pair of inverted repeat regions (IRs) of 25,403bp. The complete cp genome of G. paludosa contains 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of the cp genome is 37.8%. The phylogenetic analysis, based on 23 cp genomes, suggested that G. paludosa is closely related to G. grandis (H. Smith) Ma and Swertia species

The complete chloroplast genome of a medical herb, Rheum lhasaense (Polygonaceae), from Qinghai-Tibet Plateau in China

Rheum lhasaense (Polygonaceae) is one of the genuine medicinal herbs in Qinghai-Tibet Plateau, China. Here we report the first chloroplast (cp) genome of R. lhasaense using Illumina NovaSeq 6000 platform. The length of its complete cp genome is 161,820 bp, containing four sub-regions. A large single copy region (LSC) of 87,086 bp and a small single copy region (SSC) of 12,814 bp are separated by a pair of inverted repeat regions (IRs) of 30,960 bp. The complete cp genome of R. lhasaense contains 130 genes, including 85 protein-coding genes, 37 tRNA genes, and 8 rRNA genes. The overall GC content of the cp genome is 37.4%. The phylogenetic analysis, based on 28 cp genomes, suggested that R. lhasaense is closely related to R. acuminatum and R. pumilum

Diagenetic Heterogeneity of Deep Sandstones and Its Relationship to Oil Emplacement: A Case Study from the Middle Jurassic Toutunhe Formation in the Fukang Sag, Central Junggar Basin (NW China)

The Middle Jurassic Toutunhe Formation at depths of approximately 4000–6000 m has increasingly come into focus as a current deep reservoir target in the central Junggar Basin (NW China). Based on petrography, SEM, stable isotopes, and fluid inclusion analyses, the goals of this study were to investigate the effect of depositional lithofacies on sandstone diagenetic heterogeneity and to examine the relationship between diagenetic evolution and oil charge within a heterogeneous reservoir. Grain size controls the overall abundance of cement and porosity and reservoir properties through its effect on ductile lithic sand grains and hence on mechanical compaction. Early diagenetic calcite cement is an exception to this trend. Ductile lithic-rich, very fine-grained sandstones featured compaction of easily deformed, clay-rich grains, resulting in a very rapid loss of porosity during burial. In contrast, dissolution and cementation occurred as well as ductile compaction in the fine-grained sandstones. Two episodes of oil charge occurred in the relatively coarser-grained sandstone lithofacies. Diagenesis progressed alternately with oil emplacement, and some diagenetic alterations and oil charge occurred simultaneously. Ductile lithic-rich, highly compacted sandstones and tightly calcite-cemented sandstones can create permeability barriers embedded in permeable reservoir sandstones, probably resulting in heterogeneous flow

Anatomy of a Lacustrine Stratigraphic Sequence within the Fourth Member of the Eocene Shahejie Formation Along the Steep Margin of the Dongying Depression, Eastern China

A comprehensive study on rift stratigraphy requires a solid understanding of sequence architecture along the steep margins of rift basins. This study analyzes an Eocene lacustrine sequence along the steep margin of the Dongying depression in eastern China through integrated core, well-log, and three-dimensional seismic analyses. The lacustrine sequence is bounded by unconformities and their correlative conformities at the base and top and consists of three systems tracts, namely an early expansion systems tract (EEST), late expansion-early contraction systems tract (LEECST), and late contraction systems tract (LCST),which record a lake expansion-contraction cycle. These systems tracts differ in thickness and development of depositional systems. The EEST is the thickest and contains well-developed marginal and basinal fan systems with an overall retrogradational stacking pattern. The well-developed fan systems are the most striking features within the sequence. The LEECST is the most widespread and contains dominantly profundal-sublittoral deposits. The LCST is the thinnest, with poorly developed fan systems, and is characterized by significant erosion by fluvial incision. The variable thickness and development of depositional systems in the three systems tracts are the responses to the interplay of sediment supply and accommodation space. Accommodation space establishes the framework for sedimentary infill, and sedimentsupply determines spatial distribution and temporal evolution of depositional systems within each systems tract. This study provides a lake expansion-contraction scheme to divide a lacustrine stratigraphic sequence into systems tracts and highlights the feasibility of applying this approach in studying sequence stratigraphy along the steep margin of a lacustrine rift basin. The results also provide understandings for the development, distribution, and evolution of depositional systems and their controlling factors along the steep margin of other rift basins in the world

Elucidating the material basis and potential mechanisms of Myricaria germanica acting on rheumatoid arthritis by UPLC-Q-TOF-MS /MS and network pharmacology

Objective: This study used the UPLC-Q-TOF-MS/MS technique, network pharmacology, and molecular docking technology to elucidate the molecular mechanism of action of Myricaria germanica against rheumatoid arthritis. Methods: The UPLC-Q-TOF MS/MS technique and Swiss Target Prediction databases were used to select active compounds for Myricaria germanica and to predict relevant targets, respectively. The targets of rheumatoid arthritis were obtained from the TTD and GeneCards databases. Constructing protein interaction networks utilizing the String database, GO functional enrichment analysis, and KEGG pathway enrichment analysis of target genes utilizing the DAVID database, constructing ''component-potential target-pathway'' networks utilizing Cytoscape 3.9.1 software, and finally performing molecular docking utilizing Autodock Vina and other software. Results: Myricaria germanica screened 47 chemical components and 302 component targets, obtaining 4017 disease targets, and 32 intersection targets of chemical component targets and disease targets using the Veen diagram. PPI results demonstrate the greatest impact on TNF, VEGFA, ALB, etc. The GO enrichment analysis of 32 targets associated with rheumatoid arthritis reveals that all of these targets are associated with 129 biological processes, including the process of collagen degeneration and the positive regulation of the RNA polymerase II promoter. KEGG enrichment analysis reveals that 87 signaling pathways are involved in these rheumatoid arthritis-related targets, with the IL-17, Relaxin, and TNF signaling pathways being the most significant. As deduced from the network diagram of ingredient-potential target-pathway, the key ingredients for the treatment of rheumatoid arthritis in Myricaria germanica are Apigenin, Quillaic Acid, and Isorhamnetin, and the associated targets are MMP9, PTGS2, and TNF, with a binding energy of less than -4.25 kcal/mol. Conclusion: Myricaria germanica may act on potential core targets such as TNF, PTGS2, and MMP9 through key active ingredients such as Apigenin, Quillaic Acid, and Isorhamnetin to regulate signaling pathways such as IL-17, TNF, and Relaxin to exert therapeutic effects on rheumatoid arthritis