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Results
Integrated Tubing for Both Steam Injection and Oil Production of Thermal Wells Based on ESP in Offshore Oilfield China
Han, Xiaodong (CNOOC Ltd Tianjin Branch) | Zhou, Fayuan (CNOOC Ltd Tianjin Branch) | Zhang, Hua (CNOOC Ltd Tianjin Branch) | Zhang, Wei (CNOOC Ltd Tianjin Branch) | Liu, Hao (CNOOC Ltd Tianjin Branch) | Wang, Hongyu (CNOOC Ltd Tianjin Branch) | Wang, Qiuxia (CNOOC Ltd Tianjin Branch) | Cui, Junguo (China University of Petroleum)
Abstract Multi-component thermal fluid huff-and-puff pilot has been conducted in Bohai oilfield since 2008. Owing to the limitations of the temperature tolerance of some tools and facilities, the steam injection tubing and production tubing are applied separately during the development. That is, two work-over operations for tubing changes are required in each huff-and-puff cycle, which would increase the cost greatly and lower the development effect. The objective of our present work is to design an integrated tubing with the functions of both steam injection and oil production to decrease the high cost caused by work-over of tubing change. First, we studied the artificial lift method that might be used for lift of fluid with temperature over 250ยฐC e.g., electric submersible pump (ESP in short), gas lift, progressive cavity pump, and sucker-rod pump. Taking into account the degree of technology maturation, applicability in offshore oilfield and its temperature tolerance, the high-temperature electric submersible pump is selected for artificial lift of the integrated tubing. On the basis of the ESP artificial lift, the integrated tubing with a Y-joint is designed. The steam injection string is connected with the main channel of the Y-joint and inserted into the production interval. The ESP is connected to the bypass of the Y-joint which could be used for fluid lifting during the production process. For the realization of the integrated tubing, high temperature tolerance tools such as the subsurface safety valve, and packer are developed. The maximum temperature-telorance value of the improved tools could meet the requirements of realizing the integrated tubing In comparison with the previous techniques, application of the integrated tubing could greatly decrease the cost for thermal production and improve the economic benefit.
- Asia > China > Xinjiang Uyghur Autonomous Region > Junggar Basin > Chunfeng Field (0.99)
- Asia > China > Shandong > North China Basin > Shengli Field (0.99)
- Asia > China > Liaoning > Bohai Basin > Liaohe Basin > Liaohe Field (0.99)
An application of full-waveform inversion to land data using the pseudo-Hessian matrix
Zheng, Yikang (Key Laboratory of Shale Gas and Geoengineering, University of Chinese Academy of Sciences) | Zhang, Wei (BGP Research and Development Center at Houston) | Wang, Yibo (Key Laboratory of Shale Gas and Geoengineering) | Xue, Qingfeng (Key Laboratory of Shale Gas and Geoengineering, University of Chinese Academy of Sciences) | Chang, Xu (Key Laboratory of Shale Gas and Geoengineering)
Abstract Full-waveform inversion (FWI) is used to estimate the near-surface velocity field by minimizing the difference between synthetic and observed data iteratively. We apply this method to a data set collected on land. A multiscale strategy is used to overcome the local minima problem and the cycle-skipping phenomenon. Another obstacle in this application is the slow convergence rate. The inverse Hessian can enhance the poorly blurred gradient in FWI, but obtaining the full Hessian matrix needs intensive computation cost; thus, we have developed an efficient method aimed at the pseudo-Hessian in the time domain. The gradient in our FWI workflow is preconditioned with the obtained pseudo-Hessian and a synthetic example verifies its effectiveness in reducing computational cost. We then apply the workflow on the land data set, and the inverted velocity model is better resolved compared with traveltime tomography. The image and angle gathers we get from the inversion result indicate more detailed information of subsurface structures, which will contribute to the subsequent seismic interpretation.
ABSTRACT The first-arrival traveltime tomography is an important approach for solving the near-surface imaging problem, from which results are needed to calculate statics. The method involves inverting massive traveltime picks and therefore may require heavy computation. We apply mathematics methods of Sample Average Approximation (SAA) and Stochastic Approximation (SA) to improve the efficiency of traveltime tomography. SAA and SA are the two approaches to enhance the computational efficiency theoretically, which are realized by selecting a small portion of data randomly to perform the inversion as opposed to all data and that leads to a consequence of saving the computational memory or the computational time cost at the same time. We adapt the SAA and the SA methods in the first-arrival traveltime tomography and compare the inverted results and the computational cost with the standard approach. Both SAA and SA give satisfying approximated solutions, and save computational cost in different aspects. To obtain the same imaging results as the one inverted by the standard approach, one just need run 3-5 iterations of full data inversion. We evaluate the performance of this method by synthetic and real data tests. As our tests, the advantage of the SAA method is main reflected in the view of computational memory, which can save about 95% cost. However, by applying the SA method, the cost of both computational memory and time can be saved at about 95% and 75%, respectively. Presentation Date: Monday, October 17, 2016 Start Time: 1:00:00 PM Location: 150 Presentation Type: ORAL
ABSTRACT The event locations are essential quantities in microseismic monitoring for mapping hydraulic fractures. For downhole monitoring, the accuracy of the event locations depends on the accuracy of the P-wave polarization angle, which consequently depends on the accuracy of sensor orientation. Sensor orientation angle is generally determined by known location events such as perforation or drop-ball event, which is characterized by low signal-to-noise ratio (SNR). The accuracy of sensor orientation can be verified by the waveform coherence for various events after applying sensor orientation. In this study, we develop a new method utilizing both perforation/drop-ball event and high SNR microseismic events at unknown locations to derive orientation angles. In this approach, the waveform coherence of unknown events is directly used in the determination of sensor orientation angle. We use both synthetic data and real data to demonstrate the feasibility and reliability of the new method, which is more accurate than the traditional approach using drop-ball event alone. Presentation Date: Wednesday, October 19, 2016 Start Time: 4:15:00 PM Location: 144/145 Presentation Type: ORAL
ABSTRACT In this paper we introduce a new finite-difference scheme for 2D frequency-domain acoustic wave modeling on irregular grids. It is developed from the average-derivative optimal nine-point scheme (ADM). The ADM scheme breaks the limitation on directional sampling intervals but can't be implemented on non-uniform grids. Our new scheme overcomes this restriction and is more generalized than the ADM scheme. It can be proved that the ADM scheme is a particular case of our new scheme. A simple two-layer model is tested for verifying the feasibility and efficiency of our new scheme. Presentation Date: Tuesday, October 18, 2016 Start Time: 3:45:00 PM Location: 161 Presentation Type: ORAL
ABSTRACT A dynamic lattice method (DLM) is developed to simulate seismic wave propagation in transversely isotropic (TI) media with tilted symmetry axis (TTI media). Basing on a particle lattice model, this method calculates the micro-mechanical interactions between particles in the lattice instead of solving the wave equation. Seismic waves in continua are approximated by the dynamics of these particles and the elastic properties of the continuum are represented by properties of the particle lattice. Our research reveals the theoretical connections between the TI medium and the particle lattice model. We have applied this method to elastic wave simulation in TI media with free surface topography and reverse-time migration on a TI model to test its usefulness in elastic wave simulation for TI media. Presentation Date: Wednesday, October 19, 2016 Start Time: 11:35:00 AM Location: 150 Presentation Type: ORAL
ABSTRACT Here we introduce a new method for 5D seismic data interpolation that is based on low rank radial function interpolation. Being different from traditional methods that exploit the sparsity of data in Fourier/Curvelet/TauP domain, and use an iterative subtraction approach to fit the data, our method uses the linear combination of a set of radial functions to fully represent the seismic data. The advantages of this method are: first, our method guarantees full representation of the original data thus no "information loss" which iterative approach cannot achieve; second, our method is not based on Fourier transfer thus result does not have artifacts caused by Gibbs phenomenon; Finally, the implementation of this method involves only matrix operation thus can be easily parallelized and migrated to GPU or FPGA devices. We use a model data example and a field data example to demonstrate the quality and effectiveness of our method. Presentation Date: Tuesday, October 18, 2016 Start Time: 2:15:00 PM Location: 148 Presentation Type: ORAL
ABSTRACT The double-difference (DD) location method has long been applied for locating a cluster of earthquakes with data recorded at surface seismic stations. This method has also been used for locating microseismic events with multiple monitoring wells during hydraulic fracturing. We first extended the approach for locating a cluster of microseismic events with data recorded from a single well. To do this, we have reduced the 3D location problem to 2D by projecting all of the events onto a vertical () plane, with a vertical -axis and a horizontal -axis representing the distance to the monitoring well, considering the symmetric character of the 1D velocity model and the vertical monitoring well. We then performed a 2D location inversion and projected the results back to 3D using the event azimuths, which were determined from a separate analysis of the initial P-wave polarizations. However, although the DD method could determine relative locations of events reasonably well, it yielded poor absolute locations. We have developed a cross DD (CDD) approach using the cross traveltime difference between the P-wave arrival of one event and the S-wave arrival of another event for inversion instead of the arrival-time differences of the same phases as in the DD method. The CDD method contains more information on absolute locations than the DD method, resulting in a much more stable absolute location determination. The synthetic and field data tests indicated that the CDD method could improve the accuracy of relative and absolute event locations in microseismic clusters.
- North America > United States > South Dakota > Williston Basin > Bakken Shale Formation (0.98)
- North America > United States > North Dakota > Williston Basin > Bakken Shale Formation (0.98)
- North America > United States > Montana > Williston Basin > Bakken Shale Formation (0.98)
Research on Overland Shifting and Marine Transportation of large-scale Topside
Zeng, Ji (Shanghai Maritime University) | Zhang, Wei (Shanghai Waigaoqiao Shipbuilding CO., LTD) | Wang, Yuhan (Shanghai Waigaoqiao Shipbuilding CO., LTD) | Cheng, Lei (Shanghai Waigaoqiao Shipbuilding CO., LTD) | Yin, Yan (Shanghai Waigaoqiao Shipbuilding CO., LTD) | Wang, Chao (Shanghai Waigaoqiao Shipbuilding CO., LTD)
Abstract It is of great importance to move the large-scale topside safely onto a barge for load-out and carry out marine transportation for float-over installation. Taking a semisubmersible production platform as an example, structural strength of the topside was analyzed in three overland shifting plans of self-propelled modular transporters, sliding rail and track. The track plan is comparatively reasonable. Moreover, motion response of the system for the topside and barge during the marine transportation was studied. Roll, pitch, heave and sway motion of the composed system should be paid more attention for safe transportation. Introduction With the continuous exploitation of offshore oil and gas resources, various types of offshore platforms are developed with a trend towards large-scale, integrated installations (Xu, Yang and Li, 2012). A semisubmersible production platform is composed of topside and lower structure. The overall weight of the platform structure has increased, leading to the increase of platform installation difficulty. The topside and the lower structure are generally installed at sea separately. Offshore installation methods of topsides mainly include traditional lifting method and emerging float-over method (Wang, 2013). Traditional lifting methods can be divided into block lifting and floating crane methods. For large-scale offshore platforms, it takes too much time to use the block lifting method. The capacity of a floating crane is so limited that the whole topside cannot be lifted. Compared to the traditional lifting method, the float-over method has the features of short time installation duration and large lifting capacity, especially suitable for large-scale platform offshore installation. Taking a large-scale deepwater semisubmersible production platform as an object of study, three overland shifting plans of the topside were discussed with emphasis on self-propelled modular transporters, sliding rail and track in this paper. Moreover, based on the three-dimensional potential flow theory, motion response of the system for topside and barge during the marine transportation was studied. The short-term motion response of the composed system in irregular wave was forecast.
A Novel Terminal Sliding Mode Control for the Navigation of An Under-actuated UUV
Liu, Gang (Huazhong University of Science and Technology) | Xu, Guohua (Huazhong University of Science and Technology) | Chen, Ying (Huazhong University of Science and Technology) | Zhang, Wei (Wuhan Second Ship Design and Research Institute) | Wang, Guanxue (Huazhong University of Science and Technology) | Li, Fengyuan (Huazhong University of Science and Technology)
Abstract In this paper, we present a self-developed under-actuated Unmanned Underwater Vehicle (Hereinafter abbreviated as UUV). After analyzing the motion and actuating characteristics of the UUV, the maneuvering motion models are established in the horizontal plane and vertical plane separately. Considering the model parameter uncertainties and unknown environmental disturbances, the course and depth automatic operating controllers of UUV are designed respectively on the basis of the sliding mode variable structure control algorithm to overcome these problems. The stability of the presented control laws is proved in the sense of the Lyapunov stability theory. Simulations performed on the under-actuated UUV demonstrate the effectiveness of the proposed method. Introduction In recent years, people pay more and more attention to the UUVs due to their important applications value in the fields of marine environment surveying and mapping, objective searching and other ocean scientific research. In order to realize the satisfactory and steady characteristics of navigation when the UUV is carrying out the sailing tasks in the complex ocean environment, the automatic motion control system must be robust and insensitive against the influence of system uncertainty. In addition, owing to the nonlinear characteristics of the UUV motion system, traditional linear control algorithms can not meet the performance requirements in the practical experiments. Therefore, it is meaningful to design an adaptive and robust control system for the under-actuated UUV to reduce the impact of hydrodynamic parameters uncertainties and unknown environmental disturbances. With the development of nonlinear control theory, the nonlinear control methods for unmanned underwater vehicles have also been extensively studied in a large number of published literatures. In Gianluca et al (2001) and Yeow et al (2009), two kind of adaptive control laws are proposed for autonomous underwater vehicle (AUV), which have the advantages of simplicity and ease of implementation. On the basis of the neural networks (NNs) control approach, some research results were presented for tracking control of under-actuated autonomous underwater vehicles with model uncertainties; see for example (Pepijn, 2005 and Bong, 2014). However, there are no generic analytical methods to prove convergence of online learning for NNs. Besides, Ma and Cui (2006) designed a robust path-following control method for a nonlinear and under-actuated AUV based upon a fuzzy hybrid control strategy. In summary, a good application perspective of the nonlinear control theory for the underwater vehicle has been certified through all of the above researches.