|Theme||Visible||Selectable||Appearance||Zoom Range (now: 0)|
Wang, Lei (Nazarbayev University) | Liu, Mingliang (University of Wyoming) | Altazhanov, Arlybek (Nazarbayev University) | Syzdykov, Bekassyl (Nazarbayev University) | Yan, Jiang (Xinjiang Oilfield) | Meng, Xin (Xinjiang Oilfield) | Jin, Kai (Jiangxi Shale Gas Institute)
Accurate calculation of adsorbed shale gas content is critical for gas reserve evaluation and development. However, gas adsorption and desorption experiments are expensive and time-consuming, while physics-based models and empirical correlations are unable to accurately capture the adsorption characteristics for different shales. Langmuir adsorption is one of the most commonly used model for calculating the adsorbed gas content in shale gas reservoirs. However, most existing correlations for the Langmuir pressure and Langmuir volume in the model are oversimplified based on limited experimental data points. Thus they are not representative of key geological parameters and are far from accurate for prediction in many cases. We developed a variety of machine learning models that are multivariable controlled to quantify shale gas adsorption.
The data-driven method subdivides into two procedures: data compilation and machine learning regression. Over 700 data entries, composed of reservoir temperature (T, °C), total organic carbon (TOC, wt%), vitrinite reflectance (Ro,%), Langmuir pressure, and Langmuir volume are compiled from shale gas plays mainly in USA, Canada, and China. Data have been consistently curated, then machine learning approaches, including multiple linear regression (MLR), support vector machine (SVM), random forest (RF) and artificial neural network (ANN), have been built, trained and tested by partitioning the data into 75%:25%. For SVM, RF and NN models, 1000 simulations were run and averaged for performance comparison.
MLR identifies non-negligible parameters and general trends for shale gas adsorption. Nonetheless, the correlation coefficients from MLR are far from satisfactory. For Langmuir pressure, RF models fit best to the data entries and the other models follow the order of SVM > ANN > MLR. Particularly, RF models show the highest performance stability with the averaged R-squared value of 0.84 and the maximum of 0.87, indicating a very strong relationship constructed for these 213 data entries. For 485 Langmuir volume data entries, RF models also perform best while the other three regression methods are comparable. It should be noted that altering machine learning model structure and parameters could significantly affect the regression results.
Robust and universal machine learning models for estimating adsorbed shale gas content with high confidence level are established, which not only provide more accurate estimation and broader parameter adaptation than physics-based and empirical models, but also circumvent the high-cost and time-consuming deficiency of experimental measurements. These machine learning models can be used to estimate adsorbed gas content for shale plays with limited experimental measurements. Moreover, they can be incorporated into reservoir simulators to improve the simulation performance.
Bailey, Jeffrey R (ExxonMobil Upstream Integrated Solutions Company) | Lathi, Harshit (ExxonMobil Services & Technology Private Ltd.) | Tenny, Matthew J. (ExxonMobil Upstream Integrated Solutions Company) | Payette, Gregory S. (ExxonMobil Upstream Integrated Solutions Company) | Wang, Lei (ExxonMobil Upstream Integrated Solutions Company)
Lateral vibration modeling of certain BHA (bottomhole assembly) designs has shown great sensitivity to the proximity of stabilizer blades. In a previous paper, the BHA chatter vibration mode was presented, including the basic theory and three field examples. In each case, lower drilling rates were associated with higher levels of BHA dynamic dysfunction as determined using a lateral vibration model. One case clearly illustrated a reduction in effective weight applied to the bit, determined using bit dull grade results. This paper will further explore the mechanisms in which BHA dynamic contact forces can act to reduce the effective weight on bit.
The contact forces that push a stabilizer blade to be constrained within a borehole include both static and dynamic components. The dynamic forces are difficult to visualize as they are generated by the BHA in motion, and a well-formulated dynamic model is required to evaluate these forces. In drilling, we simply see the effects as worn and damaged drillstring components.
A frequency-domain BHA lateral vibration model represents lateral vibration flexural waves propagating in the BHA. This model can be used to calculate dynamic side forces acting at stabilizer and LWD tool blade contacts with the borehole for reference excitation forces. These contact forces may be strong functions of rotary speed and BHA contact spacing, and they typically create a non-trivial level of residual drag that impedes getting weight to bit.
The physics of dynamic contact forces are similar in some respects to static contact forces. Superposition of the dynamic modes illustrate that, although an individual component may vanish momentarily, additional modes and phases can constructively combine such that the total force summation does not vanish. The net result is that dynamic forces can generate significant lateral forces that are similar to static contact forces.
Static effects are known to impede application of weight to bit in deviated and horizontal wells, and small ledges can prevent a stabilizer blade from moving forward. Dynamic effects from improper stabilizer placement are potent sources of lateral dysfunction that can have a similar effect. BHA dynamics have the potential to both create borehole irregularities and resist forward motion resulting from contact forces between drilling tools and the borehole.
Gao, Xiang (PetroChina Jidong Oilfield Company) | Wang, Lei (PetroChina Jidong Oilfield Company) | Tian, Jingmeng (PetroChina Jidong Oilfield Company) | Xiao, Guohua (PetroChina Jidong Oilfield Company) | Gao, Feiming (PetroChina Jidong Oilfield Company) | Liu, Xiaoxu (PetroChina Jidong Oilfield Company)
Copyright 2020, International Petroleum Technology Conference This paper was prepared for presentation at the International Petroleum Technology Conference held in Dhahran, Saudi Arabia, 13 - 15 January 2020. This paper was selected for presentation by an IPTC Programme Committee following review of information contained in an abstract submitted by the author(s). Contents of the paper, as presented, have not been reviewed by the International Petroleum Technology Conference and are subject to correction by the author(s). The material, as presented, does not necessarily reflect any position of the International Petroleum Technology Conference, its officers, or members. Papers presented at IPTC are subject to publication review by Sponsor Society Committees of IPTC. Electronic reproduction, distribution, or storage of any part of this paper for commercial purposes without the written consent of the International Petroleum Technology Conference is prohibited. Permission to reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of where and by whom the paper was presented.
Wang, Lei (CNPC Research Institute of Safety & Environment Technology) | Du, Weidong (CNPC Research Institute of Safety & Environment Technology) | Chu, Shengli (CNPC Research Institute of Safety & Environment Technology) | Shi, Mingjie (CNPC Research Institute of Safety & Environment Technology) | Li, Jiayi (CNPC Research Institute of Safety & Environment Technology)
Because of the characteristics of high temperature, high pressure, flammability, explosion and high risk, safety accidents occur frequently in petroleum industry. In order to avoid and prevent safety accidents, it is necessary to promote the construction of safety culture in petroleum industry. With the progress of science and technology, some intelligent technologies (such as artificial intelligence, virtual reality, augmented reality, etc.) have become an indispensable means for the construction of safety culture.
Safety culture has experienced fatalism, empiricism, systematism and essentialism, and its connotation has been constantly enriched and innovated. Essentialism, in the final analysis, emphasizes the prevention and prevention of safety accidents, and holds that safety science and technology is the prerequisite to ensure safe production. Artificial intelligence (
Artificial intelligence is a science that studies the laws of human intelligence activities and can simulate some human behaviors. Intelligent robots that store safety knowledge and safety laws and regulations can publicize and train safety production knowledge and warn unsafe behavior through machine learning and natural language processing.
The interactive three-dimensional dynamic scene of safety production with multi-information fusion can be reconstructed by using virtual reality technology to simulate the interactive three-dimensional dynamic scene of safety production with multi-information fusion, so that employees can immerse in the production site. All links of safety accidents can be vividly displayed in front of employees, so that employees can clarify the causes and consequences of safety accidents.
Augmented reality is a new technology that seamlessly integrates real world information and virtual world information. Therefore, it can overlay the real scene of the oil industry accident scene (such as, fire and explosion, gas leakage, etc.) and response after the accident, display various auxiliary information to the users through the helmet display, and increase the authenticity of the oil industry staff emergency drill.
The application of intelligent technology not only increases the interest of safety culture propaganda, but also enhances the staff's sense of experience in emergency drill. More importantly, it plays an important role in the construction of enterprise safety culture.
Wang, Lei (Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) | Yang, Chunhe (Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) | Guo, Yintong (Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) | Chang, Xin (Institute of Rock and Soil Mechanics, Chinese Academy of Sciences) | Xiao, Jialin (Research Institute of Petroleum Engineering / Jianghan Oilfield Company) | Song, Yafen (Hubei Business College)
ABSTRACT: Large-scale multistage hydraulic fracturing is a high risk for the problem of sustained casing pressure in shale gas well, which could severely threaten long-term safe production. In this paper, triaxial compression test for cement stone was conducted at high temperature, the mechanical parameter and deforming feature were acquired. Then, triaxial cyclic loading test was performed, the mechanical response mechanism of cement stone under alternating load was revealed. Moreover, based on test datum, a multi-step elasto-plastic calculation model was established for casing-cement sheath-formation system, and the critical equivalent plastic strain was used to judge whether cement sheath interface might fail or not. Finally, a typical shale gas well from south-eastern China with sustained casing pressure was calculated, and its sealing failure mechanism was illuminated. Results showed that (1) at high temperature, cement stone showed the feature of strain hardening after passing through its yielding stress; (2) hysteresis and strain accumulation were two remarkable features during cyclic loading; (3) cement sheath at shallow stratum could suffer tensile failure while in deep formation might suffer interface bonding failure. Research findings would be of theoretical and practical value for the prevention of sustained casing pressure in shale gas well.
Shale gas reservoir, featured in low porosity and low permeability, is usually exploited by horizontal drilling and staged hydraulic fracturing (Fisher et al., 2004; Mayerhofer et al., 2010; Dohmen et al., 2014; Zhang and Yin, 2014; Lin and Ma, 2015; Zhou et al., 2016). During the large-scale staged hydraulic fracturing, casing pressure would grow up and down by a large margin, exerting highrisk for cement sheath sealing failure. In south-western China, where several shale gas fields are located, the phenomenon of sustained casing pressure (SCP) was widespread after hydraulic fracturing, severally threatening the long-term safe production of shale gas well. For instance, Fuling field was the first demonstration plot of shale gas exploration in China. By the end of 2015, a total of 166 wells were fractured successfully, among which 132 wells experienced SCP problems (Xi et al., 2018). Weiyuan Field, another shale gas demonstration plot, also occurred SCP in a number of wells (Tao and Chen, 2017).
The cooperative control of multiple marine surface vehicles has been receiving considerable attention over the past few years. The main challenge is to design stabilizing controllers to make a group of surface vehicles track predefined paths within a desired formation. In the literature, the problem is addressed through three approaches, namely behavior-based method, virtual structure method, and leader-follower method. This paper presents a novel leader-follower formation control strategy for underactuated surface vehicles. A numerical simulator is developed based on Robot operating system (ROS). The formation control method is designed based on line-of sight (LOS) guidance law. The constant parameter in the design of the look-ahead distance is replaced by a dynamic parameter, which ensures quick convergence speed of the follower vehicles to the desired position. Then an adaptive LOS bearing angle is proposed to effectively reduce and eliminate the chattering near the equilibrium point. Meanwhile the approach angle is designed considering time delay of the control system and the curvature of the leader’s path. The method can be applied to both straight-line and curved-line paths. The tracking errors of the closed-loop system are used to design the formation controller through feedback linearizing, and the system is proved to be uniformly globally exponentially stable based on Lyapunov stability theory. Simulation and comparison results are given to illustrate the effectiveness of the proposed method.
During the past few decades, the cooperative control of multiple underactuated surface vessels (USVs) has gained much more research because of its high maneuverability, intelligentialization and robustness compared with a single vehicle (Yin, S., Yang, H., & Kaynak, O., 2017). USVs are widely applied in marine industry for various applications such as ocean exploration, research, rescue and search, oil harvesting and so on. Due to the complex marine environment, the missions are difficult for us, such as searching for Malaysia Airlines MH370 disappeared in south China sea, however a group of vessels under the cooperative control can be an efficient way in such searching missions (Sun, Z., Zhang, G., Lu, Y., & Zhang, W., 2018). When performing these tasks, path planning, path-following, trajectory tracking and formation keeping of surface vessels are all necessary and fundamental for a cooperative mission. Among these, the formation control has attracted more attention by researchers.
He, Huacheng (Shanghai Jiao Tong University) | Wang, Lei (Shanghai Jiao Tong University) | Xu, Shengwen (Shanghai Jiao Tong University) | Li, Bo (Shanghai Jiao Tong University) | Zhang, Jian (School of Naval Architecture and Ocean Engineering / Jiangsu University of Science and Technology)
For dynamic positioning systems, a three degree-of-freedom motion control in the horizontal plane has usually been regarded as adequate for practical applications. However, for marine structures with small water-plane area and low metacentric height, an unintentional coupling phenomena between the vertical plane and the horizontal plane will be induced by the thruster actions. In order to effectively mitigate the thruster induced roll and pitch motion, a fixed damping controller is first applied for the dynamic positioning of a semi-submersible platform in head seas. Then a novel adaptive fuzzy damping controller is further proposed to improve the pitch mitigating effects. The fuzzy controller takes the low-frequency pitch angle and pitch rate as input, and outputs the time varying damping control coefficient through fuzzy inference. Comparisons are made between the fixed damping controller and the proposed fuzzy damping controller. The simulation results reveal that the adaptive damping controller has outstanding performance in both horizontal and vertical motions.
The increasing demand for oil and gas in recent years has led to marine operations in harsher and deeper waters. As a result, marine vessels are usually required to be positioned at a special location with high accuracy, which leads to the widespread use of dynamic positioning system (DPS). A dynamically positioned (DP) vessel is defined as a vessel that maintains its position and heading (fixed location or pre-determined track) exclusively by means of active thrusters (Sprensen, 2011).
In the traditional design of dynamic positioning systems, it has been adequate to only consider the three degree-of-freedom (DOF) motion in the horizontal plane (surge, sway and yaw). However, for certain marine structures with a small water-plane area and low metacentric height, which results in relatively low hydrostatic restoring force compared to the inertia forces, an unintentional coupling phenomenon between the vertical plane and the horizontal plane through the thruster action can be invoked. This is usually found in semi-submersible platforms, which typically have natural periods in roll and pitch in the range of 35-65s (Sørensen and Strand, 1998). The thruster induced roll and pitch motion may lead to limited operating condition and discomfort of the crew. Therefore, special control strategy should be derived to suppress the unintentional coupling effects.
Wang, Yiting (School of Naval Architecture / Shanghai Jiao Tong University) | Wang, Xuefeng (School of Naval Architecture / Shanghai Jiao Tong University) | Xu, Shengwen (School of Naval Architecture / Shanghai Jiao Tong University) | Wang, Lei (School of Naval Architecture / Shanghai Jiao Tong University)
Very large floating structures (VLFS) are deemed to be one of the alternative ways relieving the land pressure of the coastal cities. However, the precise prediction of the hydrodynamics of floating structures over variable bathymetry still is a big challenge for engineers and researchers. This paper experimentally investigates the seabed effects on the hydrodynamic responses of a single module (SMOD) of a semi-submersible type VLFS. An artificial seabed model, based on the practical seabed topography of the supposed operation area, was installed on the bottom of the ocean basin. The natural periods and damping coefficients were measured by the free decay tests in different sea floor conditions. It was found that natural periods are significantly influenced by the average water depth, while the seabed topography has no noticeable influence. For damping coefficients, the water depth slightly affects the roll and pitch while the roll damping coefficient is significantly influenced for different seabed conditons. Response Amplitude Operators (RAOs) of the SMOD in different water depths and different seabed condtions were obtained by the white-noise wave tests. Numerical simulations were also performed by conventional diffraction-radiation code. The comparison results indicate that the multi-slope seabed affects the specific motion modes (sway) when the frequency < 0.7 rad/s. The seabed effect is enlarged when the water depth decreases. Motion responses of the SMOD over multislope seabed in irregular waves were experimentally and numerically investigated. The comparison results show that numerical simulations with damping modification may still slightly under-predict the motion responses due to the neglect of the multi-slope seabed effects, which would cause the amplification of the sway motions.
The applications of very large floating structures (VLFSs) in nearshore region are expected to be a resonable way to relieve the land pressure of the well-developed coastal cites by many researchers and engineers (Suzuki, 2005; Lamas-pardo et al., 2015). A multi-modular semisubmersible type VLFS can be viewed as several modules connected by flexible connectors. Each individual module is treated as a rigid body, of which hydrodynamic responses can be calculated by many commercial diffraction-radiation softwares such as WAMIT (Lee, 1995), HydroStar (Bureau-Veritas, 2007) and so on. The water depth conditions of these codes are normally constant. However, for the coastal region whose water depth is variable, the hydrodynamics of the floating structure may be significantly affected: the incident wave may show some complicated phenomenon when the wave propagates from deep sea to nearshore, such as dispersion, reflection and friction on seabed; the wave excitation and radiation loads on the offshore structures may be different from those over constant water depth. These codes may not have sufficient accuracy for predicting the wave loads.
Luan, Guohua (CNPC Research Institute of Safety&Environment Technology) | Chu, Shengli (CNPC Research Institute of Safety&Environment Technology) | Li, Xin (CNPC Research Institute of Safety&Environment Technology) | Wang, Lei (CNPC Research Institute of Safety&Environment Technology)
Since 2005, more than 250 oil spill accidents have occurred in coastal areas and rivers in China, and the risk of oil spill accidents is higher. When oil spill is occurring, it will harm the river water and even normal life of nearby residents. As such, the challenges faced in responding to oil spill of inland river water crossing pipeline merit wider discussion. The Yellow River is a very important river in China and is a high risk area for oil spill due to the leakage of crude oil in across pipeline. Based on the hydrodynamic model, 12 kinds of oil spill scenarios are simulated by MIKE21 OilSpill module, and the influence of wind, water and leakage position on the oil spill drift and diffusion pattern is analyzed. According to the simulation results and the river’s own characteristics, nine Key Sections of Emergency Disposal (KSED) in high-risk waters are obtained, and effective emergency response time of different critical sections which are given to provide technical support for oil spill emergency preparedness work. Results show that the influence of different water phases and leakage location on spill velocity is relatively large. The diffusion velocity of oil spill in flood season is much higher than that in dry season. When leakage point is in the middle position, oil spill velocity is the fastest, followed by the south bank and the North bank. The influence of wind period on the diffusion rate of oil spill is relatively weak, which has a certain effect on the shape of oil spill contaminated zone. When strong wind, flood season and middle position leakage occur, oil spill diffuses fastest with water flow drift, and oil spill emergency disposal is most difficult. According to the need of oil spill emergency preparedness, the easily accessible sluice and bridge structures are selected as the KSED treatment in the length of the river reach studied. The time to reach the KSED of the spillway front is calculated by simulation. Because of the accuracy of the simulation results of this model on key sections of emergency disposal and effective emergency disposal time, Lanzhou Petrochemical Company successfully handled a large-scale oil spill practice. These successful oil spill simulation technology and practice cases about responding to oil spill prove its feasibility. The accuracy of KSED and effective emergency disposal time will be able to provide a new promising responding method to control oil spill pollution.
Chu, Hongyang (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Liao, Xinwei (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Gao, Zhanwu (Changqing Oil Field, PetroChina) | Wang, Lei (CNCP Research Institute of Safety&Environment Technology, Beijing) | Yuan, Zhou (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing) | Zou, Jiandong (State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum, Beijing)
In this paper, we adopted a novel semi-analytical method to calculate the carbon geosequestration capacity of shale reservoir. Our methodology has the ability to calculate carbon geosequestration capacity of shales by considering Knudsen diffusion, molecular diffusion, Langmuir's adsorption, and stress-sensitivity of the permeability. Our model is more in line with the actual situations, allowing us to accurately estimate the carbon storage capacity by capturing the transient pressure solutions of the injection well. Additionally, the model verification in this paper shows that the error is 3%, indicating the reliability of the model. Sensitive analysis presents that the CO2 geosequestration capacity is proportional to fracture half-length and fracture conductivity. The change in the property for hydraulic fractures only affects the early period of the CO2 geosequestration process. For the adsorption coefficient, with the increase of the adsorption coefficient, the CO2 geosequestration capacity also become greater. This phenomenon has become more apparent with the continuous progress of the CO2 storage process.