Sheng, Xiaofei (Tianjin University) | Shen, Jianguo (Tianjin University) | Shen, Yongjin (Beijing Huahui Shengshi Energy Technology) | Zhu, Liufang (Logging Company of Shengli Petroleum Engineering Co.) | Zang, Defu (Logging Company of Shengli Petroleum Engineering Co.)
Transient electromagnetic (TEM) logging is a promising noncontact method for through-casing formation conductivity measurements. We studied the through-casing TEM logging method based on the processing of TEM logging data measured in a production well. Similar to Doll’s work in borehole induction logging, we presented the expressions of the ‘useful signal’ and the ‘useless signal’ in casedhole logging based on which, the methods of removing the ‘useless signal’ and obtaining the formation conductivity curve are introduced. We analyzed the influence of the casing on the TEM signals, described the characteristics of TEM response signals, and obtained the ‘useful signal’ carrying formation conductivity data. Casedhole formation conductivity curves, which are subsequently compared with the known openhole conductivity log, are obtained by dealing with the ‘useful signal’. We identified the characteristics of casedhole formation conductivity curves, and some problems that need to be considered in their practical application. Due to the influence of the casing, the radial detection depth of the TEM logging tool in a cased hole is small, so the detection result is mainly the equivalent conductivity of the cement ring and formation near the outer casing wall. Although the casedhole conductivity curves are in good agreement with openhole logging results in regular formations, due to the influence of the casing and the changes in the physical environment in the well, complete consistency is unrealistic for these two kinds of curves in all well intervals. Therefore, a thorough analysis is required before practical application. Moreover, the effects of well temperature and casing deformation must be corrected for accordingly.
Qin, Wenting (China University of Petroleum Beijing) | Yuan, Ying (China University of Petroleum Beijing) | Wang, Fei (China University of Petroleum Beijing) | Zhu, Zhouyuan (China University of Petroleum Beijing)
It has been a long tradition, in China, the undergraduate and graduate petroleum engineering courses are taught in Chinese. As the globalization playing an important role in our lives, it has become more and more obvious, in many people's point of view, the education quality provided through those Chinese petroleum universities should also be matched with the international standards, such as ABET criteria.
At 2014, the China University of Petroleum Beijing launched a program called the ABET accreditation preparation program. The primary goal of this program is to prepare the ABET accreditation through the transforming of the traditional Chinese-taught Petroleum Engineering courses into English-taught Petroleum Engineering courses to meet ABET standards. At phase 1 of this program, 2014-2015, only two courses (Reservoir Engineering course and Petrophysics course) were chosen to experiment the new concept. Upon the completion of phase 1, the two courses ranked top 5% among all the courses offered by the Petroleum Engineering Department in terms of its popularity among students. Based on the success of phase 1, at phase 2 (2016-now), additional 4 courses were added into this program. Those 4 courses are: Well Completion Design, Flow in Porous Media, Production Engineering, and Reservoir Simulation.
This paper provides the lesson learned through the 5 years’ experience of setting up the new norm by fundamentally changing the ways of teaching in an environment where native language is not English. The specific details of "Know-how" through the execution of phase1 and phase 2 are presented, analyzed and discussed. The paper addressed the obstacles encountered within the program, the new teaching methods conducted in those classrooms and student's response to those brand-new English taught Petroleum Engineering courses.
The experience obtained through the ABET preparation program at China University of Petroleum Beijing may provide some guidance for those who to pursuit the same goal of seeking international recognition and establishing an international learning environment for their Petroleum Engineering courses.
Guo, Qingbin (PetroChina Tarim Oilfield Company) | Qiu, Bin (PetroChina Tarim Oilfield Company) | Zhao, Yuanliang (PetroChina Tarim Oilfield Company) | Fan, Zhaoya (Schlumberger) | Chen, Jichao (Schlumberger) | Han, Yifu (Schlumberger) | Zhang, Tao (Schlumberger) | Li, Kaixuan (Schlumberger) | Yu, Hua (Schlumberger) | Jiang, Lei (Schlumberger) | Wei, Guo (Schlumberger) | Yu, Daiguo (Schlumberger)
The Kuqa foreland thrust belt, as a secondary tectonic unit of the Tarim basin at the front of the Tianshan Mountains, is a foreland basin that formed in the Late Tertiary. The lower Cretaceous Bashijiqike tight sandstone in the basin is an ultralow-permeability and low-porosity reservoir. The Kuqa foreland thrust belt includes Kela, Keshen, Bozi, Zhongqiu, and Alvart blocks. Although these blocks developed under the same sedimentary conditions, the permeability-porosity relationship and wireline log response can be very different among the blocks. Whereas the shallow zone has been had E&P activities for decades, fully understanding the fluid properties, the porosity-permeability relationship, and distribution pattern of gas in the deep to ultradeep zone is of strategic significance and can provide the experience for the exploration of similar gas reservoirs in China and worldwide. The main target zone depth varies from 6000 m to 8000 m, and the formation pressure is near or exceeds 20,000 psi. Compared to a time-consuming and costly drillstem test (DST) operation, the wireline formation test (WFT) is the most efficient and cost-saving method to confirm hydrocarbon presence. However, the success rate of WFT sampling operations in the deep Kuqa formation is less than 50% overall, mostly due to the formation tightness exceeding the capability of the tools. Therefore, development of an optimized WFT suitable to the formation was critical.
More than 30 WFT wells in Kuqa foreland thrust belt were studied to understand the well and formation conditions causing the success or failure of these WFT operations. By doing a statistical analysis of more than 1000 pressure test points, we researched the relationship between mobility and petrophysical logs such as neutron, density, gamma ray, resistivity, P-sonic, etc. Several statistical mathematic methods were applied during this study, including univariate linear regression (ULR), multiple linear regression (MLR), neural network regression analysis (NNA), and decision tree analysis (DTA) methods. A systematic workflow was formed to mine data information, and we delivered a standard chart of the relationship between mobility and the petrophysical logs, an integrated equation based on MLR, and an NNA model that can be applied to WFT feasibility analysis.
These methods can be considered the foundation of artificial intelligence (AI), which can be used in future mobility automatic prediction. This provides a rough estimation of the mobility and sampling success rate and enables WFT optimization to be conducted in advance.
Dong, Xiaohu (China University of Petroleum, Beijing) | Liu, Huiqing (China University of Petroleum, Beijing) | Lu, Ning (China University of Petroleum, Beijing) | Zheng, Aiping (Xinjiang Oilfield Company, CNPC) | Wu, Keliu (China University of Petroleum, Beijing) | Xiao, Qianhua (Chongqing University of Science & Technology) | Wang, Kung (University of Calgary) | Chen, Zhangxin (University of Calgary)
Considering the non-uniform steam conformance of conventional horizontal well, dual-pipe steam injection technique has currently demonstrated technical potential for improving heavy oil recovery. It can delay the occurrence of steam fingering and homogenize the steam injection profile along horizontal wellbore. But in some field tests, it is observed that the results were far greater than such an approach would have justified. In addition, the actual physics are still unclear, and not demonstrated. In this paper, first, we built a cylindrical wellbore physical model to experimentally study steam injection profiles of a single pipe horizontal well and a concentric dual-pipe horizontal well. Thus, the heat and mass transfer behavior of steam along horizontal well with a single-pipe well configuration and a dual-pipe well configuration was addressed. Subsequently, considering the effect of pressure drops and heat loss, a semi-analytical model for the gas-liquid two-phase flow in horizontal wellbore was developed to numerically match the experimental observation. Next, a sensitivity analysis on the physical parameters and operation properties of a steam injection process was conducted. The effect of the injection fluid type was also investigated.
Experimental results indicated that under the same steam injection condition, an application of the dual-pipe well configuration can significantly enhance the oil drainage volume by about 35% than the single-pipe well configuration. During the experiments, both a temperature distribution and liquid production along the horizontal wellbore were obtained. A bimodal temperature distribution can be observed for the dual-pipe well configuration. From this proposed model, an excellent agreement can be found between the simulation results and the experimental data. Because of the effect of variable-mass flowing behavior and pressure drops, the wellbore segment closed to the steam outflow point can have a higher heating radius than that far from the steam outflow point. From the results of sensitivity analysis, permeability heterogeneity and steam injection parameters have a tremendous impact on the steam injection profile along wellbore. Compared with a pure steam injection process, the co-injection of steam and NCG (non-condensable gas) can improve the effective heating wellbore length by over 25%. Furthermore, this model is also applied to predict the steam conformance of an actual horizontal well in Liaohe oilfield. This paper presents some information regarding the heat and mass transfer of a dual-pipe horizontal well, as well as imparts some of the lessons learned from its field operation. It plays an important role for the performance evaluation and remaining reserve prediction in a dual-pipe thermal recovery project.
For most of the mature fields, the oil well operation and maintenance expenditures continue to put financial pressure on the operators in the low oil price period. Digital oilfields and artificial intelligent technology are the major areas invested to fight for declining oil production and increasing cost. This paper provides a novel artificial intelligent method to monitoring and diagnose the sucker-rod pumping wells using deep learning algorithms.
Traditional method using load and displacement sensors to measure the dynamometer card needs large investment on the equipment installation and maintenance. We build a general model that generates the dynamometer card from electrical parameter using state-of-art deep learning algorithms. The deep learning algorithms can analyze the relationships between the electrical data and corresponding dynamometer card in different conditions, which is very hard for human being to detect. In addition, we build another automated diagnosis deep learning model from thousands of dynamometer cards labeled with different classifications.
We have already tested these newly developed artificial intelligent models on hundreds of sucker rod pumped wells in different oilfields in PetroChina. The field test results show that the dynamometer cards generated from electrical data have above 90% similarity compared to the real dynamometer, which meet the requirement for well diagnosis. The card generation model is stable and prevents the disturbance of hostile environment change and sensor failures. The automated diagnosis model also proved to be a good substitute to the conventional software, with above 95% prediction accuracy. The automated diagnosis model reduces the liability and uncertainty of traditional diagnosis software and can integrated with the former dynamometer card generation model to fulfill well monitoring and diagnosis automatically without any physical model based calculations.
These models developed with artificial intelligent technology will be important components in the "Intelligent Fields". They can also be embedded in the IIoT edge computing machines for automatic diagnosis and control. For ultra-low production wells and the newly producing wells utilized this method, operator can save expenditure and human resources tremendously.
Dai, Zong (CNOOC Limited Shenzhen) | Li, Hailong (CNOOC Limited Shenzhen) | Tang, Fang (CNOOC Limited Shenzhen) | Luo, Donghong (CNOOC Limited Shenzhen) | Wang, Yahui (CNOOC Limited Shenzhen) | Yan, Zhenghe (CNOOC Limited Shenzhen)
A new method of digital core construction and analysis for unconsolidated sandstone is presented in this paper to solve the problem for friable cores. Results are compared with conventional experimental techniques and routine digital core construction methods.
The new method procedures: Firstly, rocks are full-closure cored from unconsolidated formation and frozen; multi-scale (meter/millimeter/micron) CT scanning for core samples with original formation fluids, and the core heterogeneity has been analyzed. Then, skeleton and pore space of samples are segmented with the watershed algorithm. Finally, pore network model is extracted with maximum sphere method. After building the digital core, petrophysical parameters and fluid flowing characteristic are simulated.
Compared with conventional experimental method, samples preparation is convenient under lower requirements of the size and shape. Without cleaning, the distortion of experimental parameters are avoided due to damages to the original pore structure of friable core samples, especially for unconsolidated samples. Compared with conventional digital core construction, the focused scanning mode is used for micron scanning, without catching the smaller samples. The new method not only simplifies the preparation of conventional core analysis that reduces the difficulty of sample preparation of unconsolidated sandstone natural core, but also guarantees the quality of core analysis data.
The new method is successfully applied and results are compared in field of South China Sea. The results from different methods with consolidated samples analysis, such as porosity, permeability and parameters of relative permeability, show the relative errors are less than 10%. The results from unconsolidated samples analysis with conventional experimental method show obvious errors: permeability of some samples are more than 15 Darcy, the relative permeability curve is obviously not consistent with the actual field performance. While results from unconsolidated samples analysis with the new method show good agreement with actual field performance.
This method can accurately test the petrophysical parameters of unconsolidated sandstone, reduce the experimental errors caused by conventional methods and shorten the experimental schedule. It could be applied to core analysis of similar formation.
Wellbore integrity was a thorny issue in China since hundreds of thousands of wells needed to be repaired annually, leading to cost increase and production delay. This problem became more excruciating in the long horizontal wellbore considering the high risk of downhole tools stuck. So far casing damage in the horizontal wellbore was either chemically plugged or separated by bridge plug, posing huge threat to the reservoir and future operations. Solid expandable tubular was a rising star in the downhole workover programme, its application in the horizontal wellbore would further enrich our technical warehouse to enhance the wellbore integrity.
In this paper, the challenges of horizontal wellbore workover operations were presented; the expandable technology was introduced and then innovated the adapt to the challenges, finally its field operation was described and relevant summaries of lessons were demonstrated.
The results indicated that as the number of horizontal well increased dramatically, problems such as casing damage, sand plugging occurred more frequently, downhole tools usually needed additional force to forward in the horizontal part to finish well logging or other activities, casing integrity was necessary to prevent the stuck of downhole tools.
Solid expandable tubular was a field proven technology, in order to overcome issues like tripping in process, expansion hurdles in the irregular well trajectory, the structure of solid expandable tubular was optimized radically. First the material of tubular was changed to achieve N80 steel grade after expansion, the OD of tubular was adjusted to maximize the annulus space between the casing and the tubular. Second the thread was restructured the further enhance its strength. Finally the rubber outside the tubular was innovated to prevent being worn out as much as possible during its friction with the horizontal wellbore. Field operation was carried out in west China, 18m length of expandable tubular was deliver into the end of 327m horizontal wellbore, expansion process was started and 41MPa expansion force was recorded.
This paper served to enrich our capabilities to deal with workover operation in the horizontal wellbore, its content helped better understand the principle, procedure and potential of this enable technology.
Note from the TWA Student Focus Section Editors: In this new "Student Chapter Spotlight" series, we aim to highlight the activities of SPE student chapters from around the world. We hope that these student chapter profiles will inspire the SPE community across the globe. If you are interested in featuring your chapter in this series, please contact us at email@example.com. Since its establishment in 2006, the Northeast Petroleum University Student Chapter of the Society of Petroleum Engineers (NEPU-SPE) experienced significant growth, from having a handful of members to a well-structured student organization led by core leadership and multiple committees. The NEPU-SPE chapter hosts academic exchanges and activities and various international conferences, which actively promote inquiry, involvement, and innovation in cutting-edge petroleum science and technology.
This course discusses the fundamental sand control considerations involved in completing a well and introduces the various sand control techniques commonly used across the industry, including standalone screens, gravel packs, high rate water packs and frac-packs. It requires only a basic understanding of oilfield operations and is intended for drilling, completion and production personnel with some sand control experience who are looking to gain a better understanding of each technique’s advantages, limitations and application window for use in their upcoming completions.
Participants in the World Petroleum Congress (WPC) Youth Forum, the first in WPC's 71-year history, hailed it a success. It was held 17–20 October 2004 at the Beijing Intl. Convention Center, and more than 540 delegates, all under 35 years of age, participated in the program. In addition, 56 observers from 17 WPC member countries and 102 other participants took part as specially invited delegates. Participating in the opening ceremony and other forum activities were WPC officials, members of Chinese Natl.