Layer | Fill | Outline |
---|
Map layers
Theme | Visible | Selectable | Appearance | Zoom Range (now: 0) |
---|
Fill | Stroke |
---|---|
Collaborating Authors
Results
Auto-Identification and Real-Time Warning Method of Multiple Type Events During Multistage Horizontal Well Fracturing
Zhao, Mingze (China University of Petroleum (East China), Qingdao) | Li, Yue (China University of Petroleum (East China), Qingdao) | Liu, Yuyang (PetroChina Research Institute of Petroleum Exploration and Development, Beijing / China National Shale Gas Research & Development (Experiment) Center, Langfang ) | Yuan, Bin (China University of Petroleum (East China), Qingdao) | Meng, Siwei (PetroChina Research Institute of Petroleum Exploration and Development, Beijing, China) | Zhang, Wei (China University of Petroleum (East China), Qingdao) | Liu, He (PetroChina Research Institute of Petroleum Exploration and Development, Beijing, China)
Abstract It is very common to observe various stages and events during multi-stage horizontal well fracturing, and the complex shapes of fracturing curves caused by reservoir heterogeneity and natural fractures development. Accurate-yet-fast identification and real-time warning of diverse events are crucial for high fracturing efficiency. The current human-made methods for identifying fracturing events are time-consuming with low accuracy, and unable to provide real-time warning of various fracturing events. In order to improve the efficiency of fracturing decision-making, this work proposes a new intelligent identification and real-time warning method of multiple types of events during multi-stage fracturing. A new intelligent identification model is developed for "point" fracturing events (i.e., the start/end of fracturing, formation breakdown, and instantaneous shut-in) by integrating the BP neural network with the AttBiLSTM network model. Moreover, the "phase" events (i.e., the pump ball, temporary plugging fracturing, sand plugging, and pre-frac acid treatment) are automatically identified by improved U-net++ network model. Then, a real-time prediction model for flowing pressure is proposed using the AttBiLSTM network model with the warning resolution of 30 seconds. Coupled with the above models, a new workflow is presented to warn the various fracturing events in real time. Practical application of the new method is demonstrated using a real shale gas field example in Southwest China. The new method enhances the precision and efficiency of auto-identification and real-time warning of thousands of various events in the fracturing process, and in particular, compensates for the inability of the current human-made identification method to capture variations of complex fracturing events in high resolution. For a shale gas field example consisting of 20 frac wells with roughly 3×10 time stamps (>200 frac stages), the auto-identification model’s identification accuracy for "point" events can reach more than 97%, the F1 score for the auto-intelligent identification model of the "phase" events is >0.98, the average MIoU is 0.96, and the Cross-Entropy Loss is 0.002; additionally, the Root-Mean-Square-Error of the real-time flowing pressure prediction model is less than 0.003. The primary value of this work is to develop a new data-driven intelligent method, free of human-dependency identification issues, that allows for automatically identify the various events and real-time warn the appearance of any specific events in complex multi-stage fracturing process. This work will be of interest to unconventional oil & gas industry to make more confident decision in well fracturing, and help promote the development of a fully automated real-time fracturing analysis system.
- North America > United States > Texas (0.68)
- Asia > China (0.68)
- Asia > Middle East (0.68)
- Geology > Geological Subdiscipline (0.46)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (0.45)
An Improved Analytic-Hierarchy-Quantitative Pre-Evaluation Method for Post-Fracturing Recoverability in Lamellation-Type Shale Oil Reservoir
Wan, Shuo (China University of Petroleum (East China), Qingdao) | Yuan, Bin (China University of Petroleum (East China), Qingdao) | Liu, He (China National Petroleum Corporation Exploration and Development Research Institute, Beijing) | Meng, Siwei (China National Petroleum Corporation Exploration and Development Research Institute, Beijing) | Lei, Zhendong (China National Petroleum Corporation Exploration and Development Research Institute, Beijing) | Wang, Wendong (China University of Petroleum (East China), Qingdao)
Abstract Recently, a variety model/method to evaluate shale fracability and shale oil mobility have been developed, however, few studies take accounts for the synergic effects of fracability and oil mobility, and provide quantitative pre-evaluation of post-fracturing recoverability in shale oil reservoir. In addition, lamellation-type shale oil reservoir in China is mud-grade pure shale with large amounts of laminae developed, the existing evaluation models could result in great errors. Hence, it is of great value to develop new quantitative pre-evaluation method to more accurately evaluate the post-fracturing recoverability in shale oil reservoir. For this purpose, the various factors affecting lamellation-type shale reservoir fracability and oil mobility are analyzed, of which dataset is obtained by various well logging and core experiments, including ϕe, lamination density, TOC, So, Ro, S1, OSI, αp, BI, Pf and Ds. Followed by, a new improved analytic-hierarchy-model integrating with entropy weight method is developed to determine the influence weights of the above factors. Then a novel quantitative pre-evaluation model is established to forecast the post-fracturing recoverability of shale oil well completed with multi-stage fracturing in shale oil reservoir, and moreover the quantitative pre-evaluation results are verified by the post-fracturing production performance using the unconventional rate-transient analysis (RTA) method. The new analytic-hierarchy-quantitative (AHQ) pre-evaluation method compensates for the inability of that most available methods lack of the synergic effects of fracability and oil mobility. For the target lamellation-type shale oil well in China, the improved AHP results reveal the contribution of the factors affecting shale oil well post-fracturing recoverability: laminae, S1 and OSI contribute by 58.8% in total; while the eight other factors contribute by 41.2%. It is also observed that the lower three layers of the target well have higher post-fracturing recoverability, with average 54% above other layers. Moreover, the AHQ pre-evaluation method is verified by the reservoir/fracture characterization results using RTA method based on on-site well production data within 10% in error. For the first time, both the shale fracability and shale oil mobility are coupled into a new evaluation parameter entitled by post-fracturing recoverability in shale oil reservoir, and the new AHQ pre-evaluation method is developed further. The practical significance of this work is to provide critical technical reference for more accurate pre-evaluation of fracturing production potential and optimization of reservoir development program design in shale oil.
- North America > United States (0.93)
- Asia > China > Shandong Province (0.28)
- Asia > China > Heilongjiang Province (0.28)
- Asia > China > Xinjiang Uyghur Autonomous Region > Santanghu Basin (0.99)
- Asia > China > Xinjiang Uyghur Autonomous Region > Junggar Basin > Lucaogou Formation (0.99)
- Asia > China > Sichuan > Sichuan Basin (0.99)
- (6 more...)
Research and Practice on Enhancing Recovery of Tight Sandstone Gas Reservoirs in Kelasu Gas Field, Tarim Basin
Li, Guoxin (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Tian, Jun (Petrochina Exploration & Production Company) | Duan, Xiaowen (Tarim Oilfield Company, Petrochina) | Yang, Haijun (Petrochina Exploration & Production Company) | Tang, Yongliang (Tarim Oilfield Company, Petrochina) | Bi, Haibin (Tarim Oilfield Company, Petrochina) | Zhang, Cehngze (Petrochina Research Institute of Petroleum Exploration & Development) | Xian, Chenggang (Tarim Oilfield Company, Petrochina) | Liu, He (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing)
Abstract Located in Kelasu Structural Belt in northern Tarim Basin, China, Kelasu Gas Field has mainly pre-salt steep structures in the exploration targets of Cretaceous Bashijiqike and Baxigai Formations. The reservoirs have burial depth ranging from 6000m to 8000m and thickness ranging from 200m to 320m. The formation pressure is 150 MPa and the formation temperature is 190 °C. The reservoirs are typical tight sandstone gas reservoirs with matrix sandstone permeability ranging from 0.001mD to 0.1mD and the porosity ranging from 2% to 8%. The gas reservoirs are very serious in heterogeneity, with fault systems well developed. The distribution of water bodies is complex, and in some of the reservoirs, water invasion occurred fast at the early stage of development, which have serious influence on gas reservoir recovery. Through years of technical study and deepening understanding of geological characteristics and production performance of gas reservoirs, it has been made clear that the main factors affecting the efficient and economic development of the gas reservoirs are structural style, fault system and water body distribution. Laboratory displacement experiments and numerical simulation about differentiated techniques such as well patterns, well types, multi-stage hydraulic fracturing design and implementation, gas production rate have been carried out to explore the applicable measures for enhancement of recovery efficiency of tight sandstone gas reservoir under high temperature and ultra-high-pressure conditions. The research results show that the recovery efficiency of the tight gas reservoir has been increased by 10%-15% because of optimum selection of uniform well distribution or Z-shaped well pattern, developed well types with combination of vertical wells, highly deviated wells and horizontal wells, and temporary soft layers plugging and mechanical hard layered fracture network stimulation technology, implementation of annular pressure control and five-sphere integrated production management and control technology including "barrier maintenance, real-time monitoring, anomaly diagnosis, risk assessment and classification administration" to accelerate the fulfillment of fit-for-purpose wellbore life-cycle management and water prevention and sand control measures, and application of different technical strategies including differential gas production rate, etc.
- Geology > Structural Geology > Tectonics (1.00)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Sandstone (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Fluid Dynamics > Flow in porous media (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Faults and fracture characterization (1.00)
- (2 more...)
In a vertical transversely isotropic (VTI) medium, qP- and qSV- waves are intrinsically coupled as described in elastic wave equations. Therefore, when we perform elastic reverse time migration and imaging processes to qP-waves, qSVwave energy will introduce crosstalk noise to the imaging results. Many authors have proposed to separate qP-waves from elastic waves for better imaging results. As an alternative approach, in this study, we develop a first-order wave propagator of pseudo-pure-qP-wave in 2D heterogeneous VTI media using a staggered-grid scheme. We have performed this algorithm to simulate P-waves propagating in an isotropic medium, VTI media with weak/strong anisotropy and a two-layer VTI model, the synthetic results validate the feasibility of this algorithm.
Experimental Study on the Impact of Supercritical CO2 Soak Pre-Treatment on Re-Fracturing of Shale Oil Reservoirs
Tao, Jiaping (China University of Petroleum) | Meng, Siwei (PetroChina Research Inst Petr Expl & Dev) | Cao, Gang (PetroChina Research Inst Petr Expl & Dev) | Gao, Yang (PetroChina Research Inst Petr Expl & Dev) | Liu, He (PetroChina Research Inst Petr Expl & Dev)
Abstract Initial hydraulic fracturing of shale oil reservoirs has often resulted in disappointing results, with low connected volumes and productivity degradation with depletion. To improve the single well production and oil recovery, re-fracturing techniques have received increased attention, but face the challenges of economy, applicability and feasibility. In this paper, the propagation mechanism during re-fracturing operations is explored through laboratory experiments. Firstly, mechanical analysis and fracturing simulation experiments were performed using the formation cores. After the fracturing simulation experiment, the fractured core was soaked in supercritical CO2 to enhance the re-fracturing effect. Then a re-fracturing simulation experiment was performed to analyze the fracturing propagation mechanism. Meanwhile, some new cores are soaked into supercritical CO2 to explore the changes of mechanical properties under different soak time. The mechanical analysis experiment showed that supercritical CO2 soak has a strong influence on the uniaxial compressive and tensile strength of shale. With an increase of soak time, both the compressive and tensile strength clearly decreased. During the first fracturing operation, fractures propagated only along the horizontal bedding and could not open the rock matrix. After supercritical CO2 soak, re-fracturing could open the horizontal bedding more easily as well as extend to the rock matrix, creating a more complex fractured system, enhancing oil recovery.
- North America > United States (0.69)
- Asia (0.47)
- Geology > Rock Type > Sedimentary Rock > Clastic Rock > Mudrock > Shale (1.00)
- Geology > Geological Subdiscipline (0.85)
Intelligent analysis of pore structure for oil reservoir based on conditional GAN
Ren, Yili (Research Institute of Petroleum Exploration & Development) | Liu, He (Research Institute of Petroleum Exploration & Development) | Luo, Lu (Research Institute of Petroleum Exploration & Development) | Liang, Jia (Research Institute of Petroleum Exploration & Development) | Gao, Yan (Research Institute of Petroleum Exploration & Development)
Reservoir pore structure is an important factor to control reservoir physical properties and productivity, and also an important basis for reservoir characterization. Core slice image is an important method of pore structure analysis. At present, the analysis of core slice image mainly depends on the traditional image processing technology, and uses expert experience as an assistant. This method can only process a single image one by one. It has a long analysis period, a slow speed, and no effective use of the historical data that has been analyzed. In this paper, a large number of core slice images are collected, and the pore structure analysis model is constructed by Conditional GAN network. When a core slice image is input into the model, it can automatically give the corresponding pore structure distribution map. In this way, the intelligent analysis of reservoir pore structure is realized by the method of deep learning. At the same time, we put forward C-IoU, C-MSE evaluation indexes, which effectively solve the difficulty of model evaluation in the application of Conditional GAN. Presentation Date: Monday, October 12, 2020 Session Start Time: 1:50 PM Presentation Time: 2:15 PM Location: Poster Station 1 Presentation Type: Poster
An Uneven Acid Injection Technology for Long-Lateral Horizontal Wells in Complex Carbonate Reservoirs: Simulation, Optimisation and Practice
Zou, Honglan (Petrochina Research Institute of Petroleum Exploration & Development) | Cui, Mingyue (Petrochina Research Institute of Petroleum Exploration & Development) | Liu, He (Petrochina Research Institute of Petroleum Exploration & Development) | Liang, Chong (Petrochina Research Institute of Petroleum Exploration & Development) | Liu, Pingli (Southwest Petroleum University) | Xue, Heng (China Zhenghua Oil Co.,Ltd) | Wang, Peishan (PetroChina Southwest Oil and gas field branch)
Abstract Focusing on the characteristics of long horizontal interval (>800m) and strong heterogeneity of complex carbonate reservoir, this paper puts forward a high efficiency uneven acid distribution technology, consequently solving the problems of high large scale and financially-challenged acidizing result. It takes the damage profile in productivity established stage or liquid production profile in the stable production stage for horizontal wells as the designed core, and selects optimal injecting point and interval in the long-interval horizontal well to maximize stimulation effect with minimal acid. This paper establishes an integrated mathematical model for the quantitative analysis of non-uniform damage of horizontal well simulated acidizing diverting and the acid-etched wormholes propagation for complicated carbonate reservoir. Besides, the matching technological methods and strategies, such as whole or local selective acid injection using coil tubing, inert liquid injection in the annulus, and the secondary segmented acidizing displacement, were presented. This technology has been applied in the AHDEB and HALFAYA oilfield, completing 296 wells acidizing treatments. The results demonstrated that the average acidizing volume decreased from 500-900m to 150m and production significantly increased.
- South America > Brazil > Campos Basin (0.99)
- Asia > Middle East > Iraq > Maysan Governorate > Arabian Basin > Widyan Basin > Mesopotamian Basin > Halfaya Field > Mishrif Formation (0.99)
- Asia > China > Sichuan > Sichuan Basin > Southwest Field > Longwangmiao Formation (0.99)
Abstract The development of a new low-carbon operation mode of artificial lift in high-water-cut oilfields, is significant for reducing energy consumption, improving operation efficiency and lowering production costs of oilfields. The annual electric consumption of the oilfield is increasing year by year. In 2016, the total electric consumption exceeded 35 billion kWh, of which the mechanical production system accounts for 57%. The rodless artificial lift eliminates the use of the sucker rod, and reduces the installed motor power over 50%. The electric consumption is greatly decreased, while tremendous gain is seen in the system efficiency. Moreover, the application performance is especially good for low-production wells. Under such circumstances, the operation cost of the oilfield declines. The current rodless artificial lift is basically based on two types of pumps, namely submersible plunger pump and submersible direct-drive screw pump. The submersible plunger pump lifts liquid via vertical reciprocation of the moving body driven by the motor, with daily electric consumption of an individual well decreasing by 46%, from 133.4 kWh to 72.5 kWh. The reduced annual electric cost per well is RMB 14,000, and the annual single-well carbon emission falls by 17.5 tons. As for the submersible direct-drive screw pump, the rotation of the pump is directly motivated by the downhole submersible motor, through which the downhole liquid is elevated to the surface. The daily electric consumption of an individual well decreases by 38.4%, from 224kWh to 138kWh, contributing to the annual electric cost reduction per well of RMB 13,600 and annual carbon emission decline per well of 17.1 tons. The application of the two types of rodless artificial lift has taken initial shape. The submersible plunger pump has been applied to over 200 wells, and the submersible direct-drive screw pump, over 60 wells. The new low-carbon operation mode of artificial lift is critical for the energy saving, efficiency improvement and consequent cost reduction of oilfields, particularly in cases of the industry downturn triggered by low oil prices.
- Energy > Oil & Gas > Upstream (1.00)
- Government > Regional Government > Asia Government > China Government (0.31)
- Asia > China > Shanxi > Ordos Basin > Changqing Field (0.99)
- Asia > China > Shandong > North China Basin > Shengli Field (0.99)
- Asia > China > Shaanxi > Ordos Basin > Changqing Field (0.99)
- (7 more...)
A Comprehensive Approach for the Performance of the Re-Fracturing Horizontal Well in Tight Oil: Coupling Fluid Flow, Geomechanics and Fracture Propagation
Lei, Zhengdong (The Research Institute of Petroleum Exploration and Development) | Wu, Shuhong (The Research Institute of Petroleum Exploration and Development) | An, Xiaoping (Exploration and Development Research Institute of Petro China Changqing Oilfield Company) | Zhu, Shengju (Exploration and Development Research Institute of Petro China Changqing Oilfield Company) | Zhu, Zhouyuan (China University of Petroleum) | Hu, Die (China University of Petroleum) | Liu, He (China University of Petroleum)
Abstract Multi-stage fractured horizontal wells have been successfully implemented in tight oil reservoirs. It is often observed that oil production declines rapidly in unconventional reservoirs. Consequently, re-fracturing may be necessary to improve/enhance oil production and ultimate recovery. However, many challenges exist in optimizing re-fracturing treatment designs, due to lack of accurate quantification of depletion-induced pressure and local stress changes around the fractures. We propose a workflow here to study and optimize re-fracturing job to increase reserves utilization level and energy level. We present a comprehensive approach that integrates discrete-fracture, geomechanics, and multi-well production simulation models. First, the approach couples the simulated 3D reservoir pressure with a geomechanical finite-element model (FEM) to quantify the changes in the magnitude and azimuth of the in-situ stresses from the development process. Second, the altered stress field is utilized as the input for modeling the new fracture system created by the re-fracturing treatment. In addition, the finite element method is used in the calculation in the coupled reservoir flow and geomechanics model. And a unique full 3D unstructured mesh generation method effectively is adopted to simulate the longitudinal propagation of fracture. The synthetic cases of interference between wells due to stresses and fracture design are also investigated in this work. Furthermore, a systematic sensitivity study is performed for the effects of re-fracturing mode, formation pressure and matrix permeability. The model prediction agrees well with the observed pressure response and microseismic event results. Results show that quantification of stress field changes during reservoir depletion provides new insights for the design and evaluation of re-fracturing treatments to enhance field development. There is a critical time in the well life that protection refracture could help pressurize the formation directly by increasing the pore pressure through the fluid injection, and indirectly by mechanical dilation of existing fractures, respectively. The dynamic changes captured timely in the stress field are invaluable to guide the optimization of re-fracturing mode for reducing the stress shadow effect. The dynamic change in the pressure field can be utilized to optimize the fracturing fluid volume, which can increase the volume of the fracture transformation and supply formation energy. This comprehensive approach is demonstrated to be very practical and effective in enhancing oil recovery, achieving satisfactory re-fracturing results. The paper presents a novel approach in calculating stress changes and dynamic fracture propagation during the development of tight oil reservoirs. This work provides better understanding on the propagation of new fractures as well as old fractures during re-fracturing process, which serves as a great potential solution to improved oil recovery in tight oil reservoirs.
- Asia > China (1.00)
- North America > United States > Texas (0.96)
- North America > United States > California > San Francisco County > San Francisco (0.28)
- North America > United States > Texas > West Gulf Coast Tertiary Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Sabinas - Rio Grande Basin > Eagle Ford Shale Formation (0.99)
- North America > United States > Texas > Maverick Basin > Eagle Ford Shale Formation (0.99)
- (10 more...)
- Well Drilling > Drilling Operations > Directional drilling (1.00)
- Well Completion > Hydraulic Fracturing > Re-fracturing (1.00)
- Reservoir Description and Dynamics > Unconventional and Complex Reservoirs > Naturally-fractured reservoirs (1.00)
- Reservoir Description and Dynamics > Reservoir Characterization > Reservoir geomechanics (1.00)
Research and Application of Ultra-Short Radius Flexible Sealed Coring Technology in Re-Development of Matured Fields
Liu, He (RIPED, CNPC) | Zhang, Shaolin (RIPED, CNPC) | Sun, Qiang (RIPED, CNPC) | Li, Tao (RIPED, CNPC) | Ming, Eryang (RIPED, CNPC) | Huang, Shouzhi (RIPED, CNPC) | Han, Weiye (RIPED, CNPC) | Chen, Qiang (RIPED, CNPC) | Li, Yiliang (RIPED, CNPC) | Pei, Xiaohan (RIPED, CNPC)
Abstract After long-term water-flooding, many of the matured fields in China have experienced changes in the physical properties of reservoirs. Moreover, the inefficient cycle of water flooding in the reservoirs is serious, and the heterogeneity of reservoirs causes difficulty to determine the distribution of remaining oil. It is impossible to reflect the real situation of the stratum only by simulation analysis with the numerical simulation software. To core in a specific location through coring technology and analyze the core can not only re-conduct a more accurate evaluation of the stratum, but also can modify relevant data of existing models to improve the simulation accuracy. But the current technology can’t conduct coring operations near wellbore and in deep parts. Therefore, based on the ultra-short radius sidetracking technology, this paper aims to develop ultra-short radius flexible sealed coring technology to achieve coring outside the casing. Compared with the ultra-short radius sidetracking technology, the ultra-short radius flexible sealed coring technology has, in addition to the windowing, deflecting, and horizontal drilling tools, the core tools of this technology, that is, the flexible sealed coring tool. The tool is mainly composed of a flexible outer cylinder and a highly elastic titanium alloy inner cylinder. The flexible outer cylinder is connected by a multi-section of flexible units that can be bent up to 5°. And a special coring bit is connected to the front of the tool. The maximum length of the core taken in a single coring process is 1.1 meters; the core diameter is up to 40mm. By using this technology, the minimum horizontal distance of the core position and the borehole wall is 0.8 meter, and the maximum horizontal distance can be up to 100 meters. At present, the technology has been successfully applied to more than 10 wells, and the average core recovery rate has reached 90%, which provides valuable data for the geological departments and is of great significance for re-developing matured fields. This technology can obtain the core from outside of the casing and near wellbore, and offers a more accurate evaluation on changes of physical properties of the reservoirs, providing the basis for adjusting the subsequent water flooding development plans.
- Asia > China (0.49)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.15)