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Collaborating Authors
Han, Xiaodong
Research and Application of Water Breakthrough Rules in Offshore Edge Water Heavy Oil Reservoirs
Chen, Cunliang (Tianjin Branch of CNOOC, China Co., Ltd) | Yue, Baolin (Tianjin Branch of CNOOC, China Co., Ltd) | Zhang, Junting (Tianjin Branch of CNOOC, China Co., Ltd) | Han, Xiaodong (Tianjin Branch of CNOOC, China Co., Ltd) | Wu, Xiaohui (Tianjin Branch of CNOOC, China Co., Ltd) | Wu, Xuanren (Dragon Stone Energy Ltd)
Abstract LD Oilfield is a heavy oil reservoir with edge water, which oil viscosity is 127~544mPa·s. After 1 to 3 months of production, the water content of the oil well rose rapidly, and the oil production dropped rapidly. Therefore, it is very necessary to carry out research on the water breakthrough rules of edge-water reservoirs. Taking the offshore LD16 oil field as the research object, relevant research has been carried out using numerical simulation technology. First, a multi-layer model is established to study the change pattern of the law of water cut rise by setting different proportions of the reserves of each oil layer. Then a single-layer model was established to study the influence of factors on the water breakthrough time of oil wells, such as average permeability, grade difference, distance from edge water, water multiple, oil production speed, crude oil viscosity and other factors. And the relative range method was used to determine the main controlling factors. On this basis, the orthogonal design method is used to design the simulation plan. According to the simulation results, an empirical formula for predicting the water breakthrough time of edge water reservoirs is established using intelligent algorithms. Research shows that the difference in reserves between layers has an impact on the law of water cut rise. The water cut of oil wells rises more slowly when water cut in the main layer breaks, and the water cut of oil wells rises faster if water cut in the non-main layer breaks. The research results can be used to judge the water break. Compared with oil well profile test data, the agreement rate is as high as 93%. Distance from edge water, oil production speed, grade difference and crude oil viscosity are the main controlling factors that affect the water breakthrough time of LD16 oilfield. Intelligent algorithms can fit formulas well. The prediction result of the empirical formula is consistent with the actual situation of the oil field. Compared with the actual situation, the error rate is only 3.5%. The research results can be used to predict the water breakthrough time of oil wells. The research results have certain guiding significance for improving the development effect of heavy oil edge water reservoirs and will be extended to more oil fields.
- Asia > China (0.69)
- North America > United States > Texas > Harris County > Houston (0.28)
Research and Practice of Steam Huff and Puff Depressurization and Increase Injection Volume Technology for the First Offshore Super Heavy Oil Reservoir in China
Wang, Hongyu (CNOOC Ltd., Tianjin Branch) | Wang, Qiuxia (CNOOC Ltd., Tianjin Branch) | Han, Xiaodong (CNOOC Ltd., Tianjin Branch) | Zhang, Hongwen (CNOOC Ltd., Tianjin Branch) | Liu, Hao (CNOOC Ltd., Tianjin Branch) | Wang, Cheng (CNOOC Ltd., Tianjin Branch) | Zhang, Hua (CNOOC Ltd., Tianjin Branch) | Wang, Zhiyuan (CNOOC Ltd., Tianjin Branch) | Dou, Peng (CNOOC Ltd., Tianjin Branch)
Abstract The surface crude oil viscosity of the first ultra-heavy oil field in Bohai Oilfield is more than 50,00mpa·s, which is unable to be developed under the condition of original formation temperature and requires steam stimulation. In the first period of steam huff and puff well, due to sufficient formation energy, steam injection pressure is high in the process of steam injection. The measures to reduce the steam injection speed are mostly adopted in the field, but it will lead to the problem of large wellbore heat loss and affect the steam stimulation heat injection effect. In this paper, based on the oil characteristics of the first ultra-heavy oil field in Bohai Oilfield, the evaluation of oil soluble surfactant was carried out, and the experimental study of pre-injection of oil soluble surfactant to reduce steam injection pressure was carried out. It has been successfully applied in the development of the first ultra-heavy oil in Bohai oilfield. The results show that the oil soluble surfactant with asphaltene dispersibility has better temperature resistance and viscosity reduction effect, and the viscosity reduction effect is more than 95% before and after aging. Laboratory experiments show that the oil soluble surfactant can reduce the steam displacement resistance of the displacement front and the affected area. When the injection amount of oil soluble surfactant is 0.2PV, the maximum steam injection pressure can be reduced by 22.9% and the steady steam injection pressure by 10.8%. The design treatment radius of oil soluble surfactant is 0.15m, and the field test shows that the steam injection pressure decreases by 1.1MPa during steam injection. After adopting the depressurization and increase injection volume technology, the field injection pressure is effectively reduced, the steam injection effect of ultra-heavy oil is guaranteed, and the technical guarantee for the subsequent development, promotion and application of ultra-heavy oil is provided.
- Research Report > New Finding (0.55)
- Research Report > Experimental Study (0.55)
- Asia > China > Xinjiang Uyghur Autonomous Region > Tuha Field (0.99)
- Asia > China > Shandong > North China Basin > Shengli Field (0.99)
- Asia > China > Qinghai > Qaidam Basin > Qinghai Field (0.99)
- (3 more...)
Research and Application of the Comprehensive Corrosion Prevention Technology for Offshore Thermal Wells in Bohai Oilfield
Wang, Hongyu (CNOOC Ltd, Tianjin Branch) | Han, Xiaodong (CNOOC Ltd, Tianjin Branch) | Wang, Qiuxia (CNOOC Ltd, Tianjin Branch) | Zhang, Hongwen (CNOOC Ltd, Tianjin Branch) | Liu, Hao (CNOOC Ltd, Tianjin Branch) | Wang, Cheng (CNOOC Ltd, Tianjin Branch) | Zhang, Hua (CNOOC Ltd, Tianjin Branch) | Dou, Peng (CNOOC Ltd, Tianjin Branch) | Wen, Jia (CNOOC Ltd, Tianjin Branch)
Abstract Multi-component thermal fluid stimulation has been conducted in Bohai Oilfield for about ten years and at the early stage of the pilot, the corrosion of the thermal fluid injection tubing is severe with the existence of the oxygen and the carbon dioxide under high temperature conditions, which result in damage of the insulation tubing, increase of the production cost and even unwanted workover. For solving the corrosion problem and extending the working life of the tubing, the corrosion mechanisms is researched and analyzed at the first place. XRD and SEM is applied for analyzing the corrosion product. The results show that the corrosion is mainly caused by the high temperature carbon dioxide and vestigial oxygen. The high fluid flowing velocity and variable inner diameter of the insulation tubing also accelerate the corrosion process. Then, further study of corrosion behavior and corrosion prevention technology are proceeded. Corrosion behavior study is carried out through indoor experiment. The results indicate that steel corrosion rate would reach the maximum value at the temperature of about 80 centigrade. At low temperature range, the corrosion is mainly dominated by CO2, and at high temperature range, the corrosion is mainly dominated by O2. For O2 corrosion at the conditions of about 370 centigrade and 15MPa, if the O2 concentration is below 1000 ppm, the corrosion rate would be lower than 0.076mm/a and when the concentration reaches about 1%, the corrosion rate would rapidly increase to be about 2.38mm/a. Based on the analysis above, high temperature corrosion inhibitor is researched and selected. The inhibition efficiency of the optimized inhibitor could be higher than 90% which could meet the technical requirement for corrosion prevention. For further increasing the efficiency of the corrosion prevention, tubing with higher corrosion resistance is used. For the existence of the CO2 and O2 in the inner tubing during the injection process, the selected corrosion inhibitor is injected before the thermal fluid for forming the protective film at the inner side. And for the annular space, high purity Nitrogen which is higher than 99.9% is injected for lowering its O2 concentration. Till now, the comprehensive corrosion prevention technology has been applied for field test for nearly 30 well times. The corrosion problem has been greatly solved, the corrosion rate is lower than 0.1mm/a and no severe corrosion occurs during the thermal fluid injection process. Its successful application would provide a guidance and technical support for the subsequent offshore thermal exploitation.
- Research Report > New Finding (0.35)
- Research Report > Experimental Study (0.35)
A New-Type Eccentric Christmas Tree for Hollow Rod Electric Heating in Offshore ESP Wells
Fang, Tao (CNOOC Ltd) | Shang, Baobing (CNOOC Ltd) | Han, Xiaodong (CNOOC Ltd) | Zhao, Shunchao (CNOOC Ltd) | Zhou, Yugang (CNOOC Ltd) | Qi, Yadong (CNOOC Ltd) | Hao, Tongchun (China University of Petroleum Beijing)
Abstract The hollow rod electric heating (HREH) technology can greatly increase the temperature of the fluid in wellbore and improve its fluidity, which is widely used in rod pump wells. Bohai offshore oilfields also have urgent application requirements for HREH technology due to the wide distribution of heavy oil and high waxy crude oil. However, more than 90% of the oil wells there are produced by electric submersible pumps (ESPs). None of these christmas trees in use are suitable for ESP wells using HREH technology. Based on the conventional christmas tree with only one main channel, a new type of eccentric christmas tree, with separated main channel and cable channel, is designed. As with the conventional ones, the main channel works as the flow passage of wellbore fluids. And the cable channel is used to run and pull out the heating cable. The eccentric design of the main channel provides the space for the cable channel. The separate cable channel avoids the cable crossing the main channel, so that the master valve of the christmas tree can be opened and closed normally, which contributes to ensuring safe production. In the meanwhile, the christmas tree can also seal the heating cable owing to some special design. This new device has been successfully tested on 6 ESP wells in Bohai Bay. After the installation of the christmas tree, the cable was smoothly run down to the predetermined depth. The construction operation was simple and convenient. There was no oil or gas leakage at wellhead after it was put into use. The wellhead temperature of all these wells reached above 50°C and no wax deposited in tubing any more, verifying its safety and reliability. This new type of safe and reliable christmas tree lays a solid foundation for the popularization and application of HREH technology, especially in those waxy oil wells and heavy oil wells with ESPs.
- Asia > China (0.48)
- North America > Canada > Alberta (0.30)
- Asia > Middle East (0.29)
- North America > United States > Texas (0.28)
Abstract After the reservoir enters the medium-high water-cut period, due to the heterogeneity of the reservoir, the difference of fluid mobility, and the difference in injection and production, large water flow channels are gradually formed in the formation, which result in fixed streamline in the formation, and the inefficient or ineffective water circulation. Ineffective injection water circulation severely inhibits water flooding effect. Conventional tapping measures can’t change the problem of ineffective water circulation. However, the profile control technology changes the flow direction of subsequent injected water by plugging the high permeability layer or large pores, improving the water injection profile, and increasing the formation water retention rate, so as to expand the swept volume. Therefore, profile controlling technology has always been an important method water control and oil stabilization technologies for the reservoirs with thief zones. The success or failure of profile control measures depends to a large extent on thief zones identification and its description, sensitivity analysis of plugging agent performance, scientific and reasonable profile control decision-making and optimization, in addition to selection of candidate wells, optimization of construction parameters, effect prediction and effect evaluation.
- Asia > China (0.69)
- Africa (0.68)
- North America > United States (0.50)
- Asia > Middle East > UAE (0.28)
- Asia > Middle East > Oman > Al Wusta Governorate > South Oman Salt Basin > Nimr Field (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Yian Formation (0.99)
- Asia > China > Heilongjiang > Songliao Basin > Daqing Field > Mingshui Formation (0.99)
Well Control Optimization of Offshore Horizontal Steam Flooding Wells Using Artificial Intelligence Algorithm
Han, Xiaodong (China University of Petroleum-Beijing and CNOOC) | Zhong, Liguo (China University of Petroleum-Beijing) | Wang, Qiuxia (CNOOC Ltd, Tianjin Branch) | Zhang, Wei (CNOOC Ltd, Tianjin Branch) | Zou, Jian (CNOOC Ltd, Tianjin Branch) | Liu, Hao (CNOOC Ltd, Tianjin Branch) | Wang, Hongyu (CNOOC Ltd, Tianjin Branch)
Abstract Maximizing the future economic return of the asset is an important issue in petroleum engineering. For heavy oil reservoir developed with steam flooding, its production cost is much higher than that of conventional production methods. Commonly used parameters optimization method such as single factor analysis and orthogonal test cannot guarantee to obtain global optimal economic benefits. It is necessary and urgent to form a better optimization method to achieve higher profit. A new framework is proposed and presented to optimize well control parameters of both steam injection wells and oil production wells by integrating the reservoir simulator into the optimization algorithms. A net present value (NPV) formula for evaluation of horizontal well steam flooding project is proposed and the optimization objective is to maximize the NPV of production over the life. The generally acknowledged Particle swarm optimization (PSO) is used for solution of the optimization problem. This method has been tested for a typical offshore horizontal well steam flooding project. Results indicate that PSO gives good solutions for this problem and the following conclusions can be obtained. The NPV of the optimized project is improved and larger than the NPV of its initial guess. The control frequency has great influence on the optimal NPV, and the optimal NPV increases with the increase of the control frequency. Steam injection and oil production rates need to be controlled and decreased at the latter stage for mitigating ineffective steam cycle between injection and production wells. The new method has been used for well control optimization of the first offshore horizontal well steam flooding pilot and this method would which will provide powerful technical support for the high efficiency development of the heavy oil resource with steam flooding.
Artificial Lift System Applications for Thermally Developed Offshore Heavy Oil Reservoirs
Zhang, Hua (Southwest Petroleum University and CNOOC) | Liu, Pingli (Southwest Petroleum University) | Wang, Qiuxia (CNOOC Ltd, Tianjin Branch) | Bai, Jianhua (CNOOC Ltd, Tianjin Branch) | Zhang, Wei (CNOOC Ltd, Tianjin Branch) | Zhang, Hongwen (CNOOC Ltd, Tianjin Branch) | Han, Xiaodong (China University of Petroleum-Beijing and CNOOC)
Abstract The total crude oil resources are approximately 9-11 trillion barrels around the world and the steam based thermal recovery processes are still the most effective methods to enhance heavy oil recovery. Due to the high oil viscosity, high fluid temperature and high fluid volume changes with time, the choice of suitable artificial lift (AL) system is one of the most important techniques in optimizing production from thermally developed heavy oil wells. Notwithstanding the attempt by several studies in the past few decades to understand and develop cutting-edge technologies to optimize the application of artificial lift system in thermally developed heavy oil reservoirs, there remains differing assessments of the best approach, AL type for various kinds of thermal recovery methods. A comprehensive review of artificial lift systems application with specific focus on thermally developed heavy oil reservoirs across the world for offshore oilfields is conducted. The review focuses on the special designed artificial lift system with functions of both steam injection and oil production for offshore oilfield. At the same time, the purpose of this work is to apprise the industry and academic researchers on the various AL optimization approaches that have been used and suggest AL optimization areas where new technologies can be developed for thermally developed heavy oil reservoirs in the future.
- Energy > Oil & Gas > Upstream (1.00)
- Water & Waste Management > Water Management > Lifecycle > Treatment (0.46)
A Robust Artificial Intelligence Method for Predicting Performance of Offshore Oilfield in High Water Cut Period Based on Big Data
Ma, Kuiqian (Tianjin Branch of CNOOC (China) Co., Ltd) | Chen, Cunliang (Tianjin Branch of CNOOC (China) Co., Ltd) | Zhang, Wei (Tianjin Branch of CNOOC (China) Co., Ltd) | Liu, Bin (Tianjin Branch of CNOOC (China) Co., Ltd) | Han, Xiaodong (CNOOC Ltd and China University of Petroleum, Beijing)
Abstract Performance prediction is one of the important contents of oilfield development. It is also an important content affecting investment decision-making, especially for offshore oilfields with large investment. At present, most oilfields in China have entered high water cut stage or even extra high water cut stage, which requires higher prediction accuracy. Water drive curve is an important method for predicting performance. Traditional methods are based on exponential formulas, but these methods have poor adaptability in high water cut period. Because traditional methods deviate from straight line in high water cut period. In this paper, a robust method for predicting performance of offshore oilfield in high water cut period based on big data and artificial intelligence is proposed. Firstly, the reasons for the "upward warping" phenomenon of traditional methods deviating from the straight line are analyzed. It is found that the main reason for the deviation is that the relationship between the relative permeability ratio of oil to water and the water saturation curve no longer conforms to the exponential relationship. So a new percolation characteristic characterization equation with stronger adaptability is proposed, which focuses on the limit of high water flooding development. On this basis, the equation of the new water drive characteristic curve is deduced theoretically, and the dynamic prediction method is established. What's more, the solution of the method is based on large data and AI algorithm. This method has been applied to many high water flooding phase permeability curves, and the coincidence rate is more than 95.6%. The new water drive characteristic curve can better reflect the percolation characteristics of high water cut reservoirs. At the same time, the performance of adjustment wells and measures on the curve of development dynamic image is analyzed. Curve warping indicates that adjustment wells or measures are effective. Field application shows that the prediction error of the new method is less than 6%, which is more in line with the needs of oilfield development. Because of the application of artificial intelligence algorithm, the application is more convenient and saves a lot of time and money. This is a process of self-learning and self-improvement. As the oil field continues over time, each actual data will be recalculated into the database. Then the fitting and correction are carried out, and then the solution is learned again. This method has been applied to several oil fields in Bohai. And the effect is remarkable, which provides a good reference for the development of other oil fields.
Successful Application of Rigless Fully Retrievable ESP System in Bohai Offshore Oilfield, China
Shang, Baobing (CNOOC Ltd., Tianjin Branch) | Li, Junfei (CNOOC Ltd., Tianjin Branch) | Fang, Tao (CNOOC Ltd., Tianjin Branch) | Yu, Fahao (CNOOC Ltd., Tianjin Branch) | Han, Xiaodong (China University of Petroleum, Beijing and CNOOC Ltd., Tianjin Branch)
Abstract In bohai offshore oilfield, about 98% oil wells produce with electric submersible pump (ESP). For the common ESP system, workover is needed to replace the failed pump about every 4 years, resulting in significant operation cost and production lost. To solve this problem, a new type of rigless fully retrievable electric submersible pump (RFR-ESP) is developed and applied in bohai oilfield. This paper mainly introduces the technical details of the used RFR-ESP system, and the real application effects in typical wells. This new system consists of downhole permanent part and retrievable part, with the power cable clamed externally along with the tubing. The core of the system is a specially designed wet connector system. Through this connector, any ESP manufacture's equipment can be used. For this technology, the retrieval of ESP can be finished by standard oilfield wireline operation, and no rig workover is required any more. Till now, two different systems suitable for 7″ tubing and 5-1/2″ tubing have been developed in order to meet the yield of different wells. Bohai oilfield installed the first RFR-ESP in 2013. Up to now, 6 wells have applied this technology, including one water source well and five oil wells. The longest running time of the ESP is about 2000 days, and it is still in service now. The maximum liquid production is about 2800m/d. For this new system, the workover time of ESP replacement reduces from 10 days to about 2 days comparing to the traditional rig workover process, and the number of the workover operators reduces from 30 to about 10. All of these are helpful to reduce the workover cost and the production lost. Besides, several problems encountered in the wells, such as power cable failure provides valuable field experience for the promoted application in bohai offshore oilfield. The successful application of this technology indicates that it has the potential to lower ESP operating costs, and even improve the artificial lift status of offshore oilfield. What's more, this new system is expected to be used in unmanned platform, thus no workover boat is needed any more, which will drastically cut down the development cost.
- Asia > China (1.00)
- North America > United States > Louisiana (0.34)
- Asia > Middle East > UAE > Abu Dhabi Emirate > Abu Dhabi (0.15)
A New Artificial Intelligence Method to Predict Water Flooding Performance in Layered Reservoir
Chen, Cunliang (Tianjin Branch of CNOOC China Co., Ltd) | Han, Xiaodong (CNOOC Ltd and China University of Petroleum, Beijing) | Zhang, Wei (Tianjin Branch of CNOOC China Co., Ltd) | Zhang, Yanhui (Tianjin Branch of CNOOC China Co., Ltd) | Zhou, Fengjun (Tianjin Branch of CNOOC China Co., Ltd)
Abstract The ultimate goal of oilfield development is to maximize the investment benefits. The reservoir performance prediction is directly related to oilfield investment and management. The traditional strategy based on numerical simulation has been widely used with the disadvantages of long run time and much information needed. It is necessary to form a fast and convenient method for the oil production prediction, especially for layered reservoir. A new method is proposed to predict the development indexes of multi-layer reservoirs based on the injection-production data. The new method maintains the objectivity of the data and demonstrates the superiority of the intelligent algorithm. The layered reservoir is regarded as a series of single layer reservoirs on the vertical direction. Considering the starting pressure gradient of non-Newtonian fluid flow and the variation of water content in the oil production index, the injection-production response model for single-layer reservoirs is established. Based on that, a composite model for the multi-layer reservoir is established. For model solution, particle swarm optimization is applied for optimization of the new model. A heterogeneous multi-layer model was established for validation of the new method. The results obtained from the new proposed model are in consistent with the numerical simulation results. It saves a lot of computing time with the incorporation of the artificial intelligence methods. It showed that this technique is valid and effective to predict oil performance in layered reservoir. These examples showed that the application of big data and artificial intelligence method is of great significance, which not only shortens the working time, but also obtains relatively higher accuracy. Based on the objective data of the oil field and the artificial intelligence algorithm, the prediction of oil field development data can be realized. This technique has been used in nearly 100 wells of Bohai oilfields. The results showed in this paper reveals that it is possible to estimate the production performance of the water flooding reservoirs.
- Asia > China (0.71)
- North America > United States > Texas (0.69)