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Xinjiang Uyghur Autonomous Region
In recent years, with continuous improvements in ultra-deep oil and gas exploration theory and technology, domestic onshore ultra-deep oil and gas exploration has continued to make breakthroughs, providing an important replacement field for CNPC's upstream business development and large-scale increase of reserves and production. The proven oil and gas reserves in ultra-deep reservoirs in Tarim Basin account for more than 50% of the proven oil and gas in ultra-deep reservoirs in China, and Tarim has become the main field for onshore ultra-deep exploration in China. This is not only due to the innovation of ultra-deep oil and gas geological theory, but also due to the breakthrough of ultra-deep geophysical technology. Tarim ultra deep oil and gas exploration faces many challenges: accurate imaging of steeply ultra-deep structures in complex mountains; better recovery of weak signals; enhanced imaging resolution in the ultra-deep subsalt of large desert areas; ultra-deep imaging in thick loess covered areas and other problems restricts the process and economic development of ultra-deep oil and gas exploration in basin. Therefore, there is an urgent need to study theoretical technologies suitable for ultra-deep geophysical acquisition, weak signal processing and imaging, as well as ultra-deep reservoir prediction and fluid identification under different geological conditions.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > China Government (0.40)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
- North America > United States > Louisiana > China Field (0.95)
General Optimization Framework of Water Huff-n-Puff Based on Embedded Discrete Fracture Model Technology in Fractured Tight Oil Reservoir: A Case Study of Mazhong Reservoir in the Santanghu Basin in China
Xiang, Yangyue (School of Earth Resources, China University of Geosciences, Wuhan) | Wang, Lei (School of Earth Resources, China University of Geosciences, Wuhan (Corresponding author)) | Si, Bao (Tuha Oilfield Company, Petro China, Hami) | Zhu, Yongxian (Tuha Oilfield Company, Petro China, Hami) | Yu, Jiayi (Research Institute of Exploration and Development, Tuha Oilfield Company, Petro China, Hami) | Pan, Zhejun (Key Laboratory of Continental Shale Hydrocarbon Accumulation and Efficient Development, Ministry of Education, Northeast Petroleum University, Daqing)
Summary Water injection huff-n-puff (WHnP) is currently an important technology to improve the recovery of tight reservoirs. On the one hand, this technology can replenish the formation energy, and on the other hand, it can effectively replace the oil in a tight reservoir. In this paper, the effect of WHnP on cumulative oil production and oil increase rate is simulated and analyzed by comparing depleted development and WHnP scenarios, using numerical simulation methods. A field-scale numerical simulation was modeled based on typical fluid, reservoir, and fracture characteristics of Mazhong tight oil, coupled with geomechanical effects, stress sensitivity, and embedded discrete fractures. The result of different WHnP cycles is studied, and the limiting WHnP cycle is determined to be four cycles. The WHnP efficiency is compared for different permeability scales from 0.005 to 1 md, and it is determined that WHnP at a permeability of 0.01 md resulted in the largest production enhancement. Subsequently, sensitivity studies are conducted using an orthogonal experimental design for six uncertain parameters, including the WHnP cycle, production pressure difference, permeability, natural fracture density, hydraulic fracture half-length, and conductivity. The results show that throughput period and permeability are important parameters affecting cumulative oil production, and permeability and natural fracture density are important parameters affecting oil increase rate. In addition, contour plots of permeability and WHnP cycle, hydraulic fracture half-length, and conductivity are generated. Based on these plots, the optimal conditions with better enhanced recovery results in different WHnP scenarios can be easily determined. This study can better solve the problems encountered in WHnP of tight reservoirs and provide a theoretical basis for stable and efficient development.
- Research Report > New Finding (0.48)
- Research Report > Experimental Study (0.34)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
- Geology > Geological Subdiscipline > Economic Geology > Petroleum Geology (0.42)
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Disposal/Injection (0.35)
Effect of Grain Size Distribution on Pore Size Distribution Characteristics in a Conglomerate Reservoir from an Alluvial Fan Via Artificial Rock Approach
Gao, Wenbin (State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) | Li, Yiqiang (College of Petroleum Engineering, China University of Petroleum (Beijing) (Corresponding author)) | Kong, Debin (College of Petroleum Engineering, China University of Petroleum (Beijing)) | Luan, Huoxin (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing)) | Chen, Xin (School of Civil and Resources Engineering, University of Science and Technology Beijing) | Qi, Huan (Research Institute of Experimental and Testing, Xinjiang Oilfield Branch Company, PetroChina) | Tang, Xiang (College of Petroleum Engineering, China University of Petroleum (Beijing))
Summary Conglomerate is characterized by a multiscale grain stacking structure and various pore size distribution modes (PSDMs), significantly affecting multiphase fluid movement and transport in porous media. The multimodal structure and complicated PSDM are related to grain size distribution. However, the relationship between grain size distribution and pore structure characteristics remains unclear, which makes it hard to investigate using natural rocks affected by a single factor. Herein, a newly developed full-pore-scale artificial rock approach was used in this work to provide the ideal samples for experimental research. A bimodal distribution model was adopted to characterize the grain size distribution features quantitatively. Furthermore, the relationship between lithofacies, permeability, and PSDM was analyzed. The results demonstrate that grain size distribution includes coarse grain distribution (CGD) and fine grain distribution (FGD). As the average value of FGD increases, the permeability of conglomerate and sandstone have different decreasing trends. The increases in the grain size difference between CGD and FGD can decrease the most frequent and average pore radius, while the PSDM of conglomerate transforms from a steep peak shape to a hill shape. Furthermore, PSDM relates to permeability and lithofacies in an alluvial fan environment. The maximum permeability of sandstone with PSDM of hill shape is about 40 md while that of conglomerate is about 70 md. The grain and pore size distribution of artificial rocks is highly similar to that of natural rocks compared with natural rocks within the alluvial fan of Karamay conglomerate reservoirs. The findings are significant for robust determination in reservoir evaluation and development.
- Research Report > New Finding (0.68)
- Research Report > Experimental Study (0.68)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 338 > Block 16/1 > Edvard Grieg Field > ร sgard Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 338 > Block 16/1 > Edvard Grieg Field > Skagerrak Formation (0.99)
- Europe > Norway > North Sea > Central North Sea > Utsira High > PL 338 > Block 16/1 > Edvard Grieg Field > Hegre Formation (0.99)
- (4 more...)
Analyzing Wellbore Breakout in Deep Shale Oil Reservoirs of Western China Using Poro-Elastic Dynamics
Yang, Shuai (PetroChina Research Institute of Petroleum Exploration & Development, China) | Liu, Yingbiao (PetroChina Xinjiang Oilfield, China) | Meng, Xiangyan (PetroChina Xinjiang Oilfield, China) | Ding, Kun (PetroChina Xinjiang Oilfield, China)
Abstract The deep shale oil reservoir in the Junggar Basin of China is facing challenges due to elevated deviatory stress conditions and extensively developed fracture features, which increase the risk of wellbore breakout during drilling. This paper presents a poro-elastic dynamic based mechanical model to characterize the wellbore stress response and breakout features for deep shale oil reservoirs. Different from the conventional method, this proposed model includes the fluid-solid coupling and the effects of fluid and solid inertia. The Mohr-Coulomb failure criterion is applied to evaluate shale matrix failure and the weak-plane failure criterion is applied to evaluate the failure of shale bedding/fracture plane in this model. Rock mechanical properties and permeability anisotropy is also considered in this model. Then, a set of deep well parameters were taken as the examples to calculate the near-borehole stress field. The failure behaviors were also analyzed and compared with the pore-elastic static model. The results show that compared with the poro-elastic static model that does not consider inertia, the poro-elastic dynamic model can reflect the dynamic response characteristics of pressure and stress around the wellbore after excavation. Static models tend to underestimate the severity of wellbore instability, while dynamic models are more accurate in predicting borehole breakout. The study on the factors affecting the wellbore breakout shows that Biot coefficient, in-situ stress difference, fracture parameters and bottomhole pressure have a great influence, while the elastic modulus and matrix permeability have minor influence on the wellbore breakout. This model offers insights into the dynamic mechanisms underlying wellbore instability in deep shale oil reservoirs, serving as a valuable tool for accurately predicting breakout pressure, optimizing drilling mud density, and ensuring wellbore stability.
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline > Geomechanics (1.00)
Genesis, Distribution, and Characterization of a Paleokarst Subsurface River System in the Tahe Area, Tarim Basin, Western China
Lyu, Xinrui (School of Energy Resources, China University of Geosciences (Beijing)) | Ju, Binshan (Petroleum Exploration and Production Research Institute, SINOPEC) | Wu, Xingwei (School of Energy Resources, China University of Geosciences (Beijing) (corresponding author)) | Xiao, Fengying (Petroleum Exploration and Production Research Institute, SINOPEC)
Summary Subsurface river systems constitute one of three major paleokarst types that make up Ordovician reservoirs in the Tahe area of the Tarim Basin. The total length of the river system is approximately 400 km, and the reserves associated with this karst type are more than 200 million tons. However, it is manifested that 47% of drilled wells have not encountered river paleokarst, while 50% of wells that have encountered river paleokarst are fully filled due to the poor understanding of the paleokarst of this region, resulting in a significant variation of production capacities. In this study, we propose a detailed data integration approach with outcrops, drilling, logging, seismic profiles, and dynamic data to delineate the complex paleokarst river system in the Tahe area. The karst geological theory with reservoir characterization is combined in particular. The workflow of clarifying the main controlling factors, architecture types, and development distribution modes of the subsurface river system is established. Fill material type, sequence of fill structure, and fill controlling factors are also revealed. A quantitative characterization method of the subsurface rivers is established adopting predictions based on seismic data and high-resolution geostatistical and geological modeling. The Ordovician reservoirs in the Tahe area comprise three paleokarst river systems with different characteristics. Karst paleogeomorphology is the main control over the overall flow direction and plane distribution of the subsurface rivers. Changes in the surface of the phreatic zone are crucial in controlling the vertical layers and scale of the rivers. The combined action of faults plays a decisive role in controlling the anastomosing pattern of the rivers. Single-branch channels, reticulated channels, and structural corridors in single-layer or multilayer styles are the main subsurface river types. Trunk channels, branch channels, hall caves, and inlets/outlets are dominant structures in the architecture of the river system. Sand-mud, breccia, and chemically precipitated materials are the most common fill types. Three typical sequences of fill structure and four spatial combination modes exist in the subsurface river system. The morphology and fill characteristics of rivers are predictable using seismic attributes, such as frequency division energy, frequency division inversion, and coherent energy gradient. 3D models are constructed by multivariate control multipoint geostatistical method, which can characterize the strong heterogeneity characteristics of subsurface river systems. This complex paleokarst system enables remarkable results for the adjustment of the reservoir development plan through quantitative characterization.
- Asia > China > Xinjiang Uyghur Autonomous Region (1.00)
- North America > United States > Texas (0.67)
- North America > United States > Texas > Fort Worth Basin > Northwest Field (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin > Tahe Field (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin > Tabei Field (0.99)
- (2 more...)
Seismic spatially variant noise suppression method in the Tarim Basin based on FFDNet and transfer learning
Yan, Tingshang (China University of Petroleum (East China)) | Dai, Yongshou (China University of Petroleum (East China)) | Wan, Yong (China University of Petroleum (East China)) | Sun, Weifeng (China University of Petroleum (East China)) | Han, Haoyu (China University of Petroleum (East China))
Abstract Due to a complex geologic structure and ultradeep reservoir location, noise distribution of prestack seismic data in the Tarim Basin is nonuniform. However, most of the current seismic random noise suppression methods lack the flexibility to deal with spatially variant random noise. To address this issue, we have developed an intelligent denoising method for seismic spatially variant random noise and applied it in the Tarim Basin. On the basis of denoising convolutional neural network (DnCNN), we add an extra channel to the input and introduce a tunable noise level map as input. The noise level map has the same dimensions as the input noisy seismic data, and each element in the noise level map corresponds to a denoising level. By adjusting the noise level map, a single model can handle noise with different levels as well as spatially variant noise. Due to the lack of labeled field data in the Tarim Basin, we introduce a transfer learning scheme that transfers features of effective signals learned from synthetic data to the denoiser for field data. The network learns the general and invariant features of an effective signal from a large number of easily obtained synthetic data and then learns the real effective signal characteristics from a small amount of approximately clean field data in the target area by fine-tuning. The processing results of synthetic and field data demonstrate that, compared with f-x deconvolution, dictionary learning, and DnCNN, our method exhibits high effectiveness in suppressing spatially variant random noise and preserves effective signals better.
The controls of strike-slip faults on fracture systems: Insights from 3D seismic data in the central Tarim Basin, northwest China
Liu, Jun (SINOPEC Northwest Oil Field Company) | Gong, Wei (SINOPEC Northwest Oil Field Company) | Wang, Peng (SINOPEC Northwest Oil Field Company) | Yang, Yingjun (Beijing Tianan Ruida Technology Development Co., Ltd) | You, Jun (Beijing Tianan Ruida Technology Development Co., Ltd)
Abstract The central Tarim Basin has gained wide attention for its petroleum reserves, especially the recent commercial discovery of carbonate reservoirs of the Ordovician age in the Shunbei oil and gas field. A systematic analysis is conducted based on 3D seismic interpretation in the central Tarim Basin. The results indicate the presence of several major strike-slip faults and associated fracture systems. The characteristics of major strike-slip faults indicate a lower positive or negative flower structure in the Lower-Middle Ordovician and faults with a normal sense of movement in the Upper Ordovician due to the regional stress field. The major strike-slip faults commonly cause fractures in multiple scales. The fracture systems in different segments of major strike-slip faults contain significant differences in characteristics. In addition, two models are established with regard to strike-slip fault-associated fracture systems in a compressional setting and an extensional setting. The development of fracture systems varies to a large extent in relation to the scales of a strike-slip fractured zone. The fracture systems in a small-scale shear zone or strike-slip fractured zone usually develop along the fracture plane. In contrast, the fracture systems in a large-scale strike-slip fractured zone commonly develop along the fault zone on both sides.
- Geophysics > Seismic Surveying > Surface Seismic Acquisition (1.00)
- Geophysics > Seismic Surveying > Seismic Processing (0.71)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
- Asia > China > Bohai Basin (0.99)
Fluid Identification with Multiple Nonelectrical Methods in Ultradeep Tight Gas Reservoir, A Case Study from Tarim Basin
Hu, Jianfeng (PetroChina Tarim Oilfield Company) | Zhao, Yuanliang (PetroChina Tarim Oilfield Company) | Shuai, Shichen (PetroChina Tarim Oilfield Company) | Ge, Shengquan (PetroChina Tarim Oilfield Company) | Cai, Liang (SLB) | Wang, Wei (SLB) | Wu, Jinlong (SLB) | Zhao, Xianran (SLB)
Abstract The complex geology of fold-and-thrust belt led to significant difficulties with the engineering aspects of drilling, logging, completion, and testing. The Bashijiqike Formation and Baxigai Formation feature a tight sandstone reservoir that exists below a salt layer with high pressure and high downhole temperature. Reservoir characterization is indispensable in the development of this Cretaceous structural fractured tight sandstone reservoir formation. Fluid identification is a key tool used to locate the sweet spot with high producibility for further development. Resistivity is the most common and straight-forward method. However, because of the mixed effect from pore structure, formation sedimentary dips, far-end fractures, and the influence of the surrounding rocks etc., gas and water cannot easily be identified based on the resistivity difference. Compressional coefficient and Poisson's ratio is without obvious cross-over effect because of the compaction effect on rock sonic waves. Under these circumstances, new methods based on other nonelectrical technologies are used. Nonelectrical means for fluid identification including T1โT2 based on 2D NMR measurement, and the spectroscopy related sigma and chlorine element method were successfully applied in this region. The 2D NMR measurements provide porosity and permeability information for T2 based analysis. When used in conjunction with T1 based measurement, the fluid identification through different T1โT2 response provides an advantage for distinguishing hydrocarbon and water, especially for gas. Since relaxation due to diffusion only applies to T2 and never to T1, given the typical magnetic field gradients of the logging tool, the oil and gas signal can easily be distinguished from the T1/T2 ratio. The continuous measurement enables the separation and quantitation of different fluids that exist in the pore system for the entire interval of the targeted reservoir. Formation water salinity is contributed by the NACL present in the fluid in this area. Advanced spectroscopy data provides chlorine measurements minus this effect in a mud system. The chlorine from the formation is calculated in this way. Formation water can be derived to further identify the main contributor of the fluid inside the pore system. Case studies are presented from this ultradeep tight gas reservoir that solved the fluid identification issue when resistivity cannot directly distinguish fluid type. The result matched the well with the test, which provided a novel solution to finalize the sweet spot interval for the targeted reservoir.
- North America > United States (0.69)
- Asia > China > Xinjiang Uyghur Autonomous Region (0.41)
- Europe > Norway > Norwegian Sea (0.25)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Geology > Structural Geology > Tectonics > Compressional Tectonics > Fold and Thrust Belt (0.74)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tarim Basin (0.99)
- North America > United States > Louisiana > China Field (0.95)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Tight gas (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Exploration, development, structural geology (1.00)
- Reservoir Description and Dynamics > Formation Evaluation & Management > Open hole/cased hole log analysis (1.00)
Mechanism of Wellbore Collapse for Carboniferous, Ordovician and Cambrian Strata in Southwestern Tarim of China
Sheng, Yong (Tarim Oil Field Company, Petro China, China) | Zhu, Jinzhi (Tarim Oil Field Company, Petro China, China) | Lu, Haiying (Tarim Oil Field Company, Petro China, China) | Bai, Bing (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, China) | Zhang, Zexv (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, China) | Chen, Mian (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, China) | Lu, Yunhu (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, China)
ABSTRACT: Samples corresponding to severe wellbore collapse in Carboniferous, Ordovician and Cambrian strata were collected from oil field company according to drilling and logging data. In this study, X-ray diffraction, hydration inhibition (linear swelling, dispersion and cation exchange capacity) tests and SEM experiments were conducted on representative samples. With the combination of caving analysis, the mechanisms of wellbore collapse were investigated for specific strata in Southwestern Tarim. The results showed that in Carboniferous strata, wellbore collapse was the comprehensive results of mudstone hydration and the existence of weak planes. In Ordovician strata, it could be concluded that the existed natural fractures providing drilling fluid flow path was the dominant factor inducing the wellbore instability. In Cambrian strata, the results showed the salt dissolution was the main reason of borehole collapse. INTRODUCTION The Southwestern Tarim Basin of China is an important region for achieving high oil recovery in the future. Currently, the borehole instability phenomenon is frequently encountered in Carboniferous, Ordovician and Cambrian strata when exploratory wells are drilled. In these strata, the lithology and stress conditions are complex, drilling fluid could not effectively maintain wellbore stability due to the lack of knowledge about collapse mechanism. Thus, it is necessary to investigate the mechanism of wellbore collapse in these strata to achieve effective and economic further drilling in Southwestern Tarim of China. During the process of qualitative analysis for wellbore collapse, mineral composition, hydration ability and microstructure characteristics are indicators of the reason for wellbore collapse (e.g. DeNinno et al. 2016, Mohammed et al. 2019 and Sandra et al. 2012). Meanwhile, the analysis of cavings shape is also an important indicator to illustrate the mechanism of wellbore collapse (e.g. Anjanava et al. 2020 and Jose et al. 2019). In this research, X-ray diffraction, hydration tests and scanning electron microscope experiments were performed to investigate the hydration ability and microstructure of representative lithology in Carboniferous, Ordovician and Cambrian strata. With the combination of cavings shape, the mechanisms of wellbore collapse were studied.
- Asia > Middle East (0.94)
- Asia > China > Xinjiang Uyghur Autonomous Region (0.24)
- Phanerozoic > Paleozoic > Ordovician (1.00)
- Phanerozoic > Paleozoic > Cambrian (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock (0.59)
- Geology > Mineral > Silicate > Phyllosilicate (0.50)
A Post-Stack Seismic Sparse Dictionary Learning Inversion Method Based on Logging Data - A Case Study of the Tarim Basin
Chen, Long (PetroChina Tarim Oilfield Company, China) | Zhang, Xin (College of Petroleum Engineering, China University of Petroleum Beijing, China) | Zhao, Li (PetroChina Tarim Oilfield Company, China) | Zhou, Bao (PetroChina Tarim Oilfield Company, China) | Han, Yutian (PetroChina Tarim Oilfield Company, China) | Ding, Yan (CNPC Engineering Technology R&D Co., Ltd., China) | Lu, Yunhu (College of Petroleum Engineering, China University of Petroleum Beijing, China)
ABSTRACT: Highly accurate seismic inversion results help refine geomechanical modeling. In this paper, a post-stack seismic sparse dictionary learning inversion method based on logging data is proposed. First, feature functions are extracted from the logging data. Then, a dictionary is learned adaptively from known observations. This dictionary is composed of a series of feature functions, using which the parametric model can be effectively characterized. This method effectively avoids the problem of single mathematical model assumptions. Finally, the post-stack wave impedance inversion data are solved, and the separation of wave impedance data is performed using the correlation between the velocity data and the density data. This method can effectively improve the resolution of seismic inversion results by extracting a priori information from logging data. It is found that the root-mean-square error of the sparse dictionary learning method is reduced by 9.075% compared to the Tikhonov method. INTRODUCTION Due to the lack of drilled well data in the undeveloped area of the field, the only available information is seismic data. The seismic data effectively reflects the rich stratigraphic characteristics such as lithology, tectonics, and physical properties in the study area. However, the seismic data need to be analyzed and converted through a series of processing to obtain velocity data and density data of the study area which can be used as input data for geomechanical models. Currently, there are several methods of using seismic data to obtain the basic input data for geomechanical models. In conventional studies, the Dix formula is generally used to calculate the layer velocity as a basic geomechanical data (Dix, 1955; Gholami et al, 2019). The method is mainly based on the stacked velocity obtained from the raw seismic data. After dip and phase correction, the stacked velocity is converted to layer velocity. This method is simple and applicable. However, the accuracy depends on the stratigraphic position and the accuracy of the stacked velocity. In particular, the accuracy of this method is not high when the dip angle of the stratum and the lateral variation of the velocity are large.
- Asia > China > Xinjiang Uyghur Autonomous Region (0.41)
- North America > Canada > Alberta > Stettler County No. 6 (0.24)
- North America > Canada > Alberta > Starland County (0.24)
- (2 more...)
- Geophysics > Seismic Surveying > Seismic Processing > Seismic Migration (1.00)
- Geophysics > Seismic Surveying > Seismic Modeling > Velocity Modeling > Seismic Inversion (1.00)