Hao, Qian (Exploration and Development Research Institute & Science and Technology Department of Changqing Oilfield Company, CNPC) | Wang, Jiping (Exploration and Development Research Institute of Changqing Oilfield Company, CNPC) | Han, Dong (Science and Technology Department of Changqing Oilfield Company, CNPC) | Li, Wuke (Exploration & Development Research Institute of Changqing Oilfield Company, CNPC) | Liang, Changbao (South Sulige Operating Company of Changqing Oilfield Company, CNPC) | Dai, Libin (South Sulige Operating Company of Changqing Oilfield Company, CNPC) | Jia, Yonghui (South Sulige Operating Company of Changqing Oilfield Company, CNPC) | Qi, Congwei (TOTAL) | Zhai, Gaoqiang (TOTAL)
South Sulige operation project is an international cooperation development of tight sand gas field located in the Ordos Basin, Northwest China. The economy of the project relies on technical breakthrough to select good drilling location for getting higher Estimated Ultimate Recovery (EUR) rather than partners continually reducing annual investment and cost saving to survive in the global oil price fluctuations in the long run.
Although a total of 306 wells have been drilled and 1648 Km2 of 3D seismic data have been acquired and processed during the past 3 years, well drilling results were not as good as expected in terms of seismic sand thickness prediction and channel sand / shale discrimination. Seismic data quality indeed improved due to large efforts of the processing, even getting clear seismic images at reservoir level, however, at Upper Permian He8 Formation, the main gas producing target layer, seismic interpretation results are still difficulty to distinguish complicated fluvial depositions of this tight sand gas filed.
On the other hand, existing production data indicate that Absolute Open Flow (AOF) of the super good well which accounts for only 3% of the total drilled wells usually exceed 120×104m3/d, annual production of the super good well could exceed 2500 ×104m3, EUR of the super good well may exceed 2.4×108m3. Compared with the ordinary well, EUR of the super good well is 9.6 times that of the ordinary well. As a result, accurate predicting good drilling location and try to capture more super good wells remains the biggest challenge and the most attractive research direction for this international cooperation project.
Therefore, a different approach joint 3G (Geophysics, Geology, Gas Reservoir) integrated study is carried out by an international joint research team from Paris, France and Xi’an, China. This paper shows a new method of combining sedimentological model from wells results (static data include core description, typical channel E-logs parameters, semi-regional synthesis. dynamic data include AOF, annual production, EUR) with low value of Poisson's Ratio (PR) / amplitude maps which were defined in the study, aiming to identify areas where a given dominant fluvial facies could be predicted.
The paper's objective is to share the integrated study approach to get better understanding of such tight sand reservoir, and the proposed methodology opens new opportunities for predicting good drilling location, increase the probability of capturing more super good wells, lower the project development risk with best practices approach.
Li, Ningjun (Haimo Technologies Group Corp.) | Zheng, Ziqiong (Haimo Technologies Group Corp.) | Guo, Peihua (Haimo Technologies Group Corp.) | Hao, Xipeng (Haimo Technologies Group Corp.) | Chen, Bingwei (Haimo Technologies Group Corp.) | Ren, Yao (Haimo Technologies Group Corp.)
Ordos basin is known for its tight sandstone formations and fracturing has been the most effective approach to improve production[
To successfully treat and reuse flowback fluid in Ordos basin, two major obstacles have to be overcome: First, in the fracturing process, the local common practice is to add the entire designed amount of gel breaker at the end of propant pumping job, to avoid sand plugging and sanding out. This incorrect, but common practice results in incomplete breaking of gel of the frac fluid, which inevitably flows back leading to greatly increased difficulties in flowback fluid treatment. Secondly, organic boron crosslinking agent is widely used as crosslinking agent in the guar fluid system in this area. As boron compounds are extremely difficult to be removed during flowback fluid treatment, proven treatment methods alone cannot make the treated water reusable in making new frac fluids.
Technology and processes were developed to manage four key factors that affect the performance of guar frac fluid configured with treated flowback fluid: a) Metal ions, b) Bacteria, c) Breaking agent, d) Crosslinker. Mobile units developed in association with treatment processes and agents also help avoid secondary pollution from the transportation of fresh and flowback fluid. In 2017 and first quarter of 2018, more than 15,000 cubic meters of flowback fluid have been successfully treated and reused. One third of the treated water was guar frac fluid and was reused in making new frac fluid, reducing the need for fresh water significantly. Fracturing service company conducted tests on the treated water and found that the performance of the fluid configured with the treated water completely satisfy the requirements of the SY/T6376-2008 "General Technical Requirements for Fracture Fluid" and SY/T 5523-2016 "Oilfield Water Analysis Method" standard. Frac fluid configured with the treated water was successfully applied to the stimulation jobs of horizontal wells, resulting in double savings to the operators: purchase of fresh water and transportation of flowback fluid (to treatment centers) and fresh water, also avoided secondary environmental impacts such road safety hazard and fluid seepage.
With the treatment and reuse of flowback fluid, savings up to 8% of total frac costs per well were observed which could lead to 100+ million RMB within 2018 alone. Most importantly, the technology can effectively relieve environmental pressure and reduce the need of fresh water which is a scarce in this area.
Chen, Changzhao (State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology) | Li, Xingchun (China University of Petroleum) | Wu, Baichun (State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology) | Zhang, Kunfeng (State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology) | Song, Quanwei (State Key Laboratory of Petroleum Pollution Control, CNPC Research Institute of Safety and Environmental Technology)
The world has seen a peak in unconventional gas development in recent years. Based on the practice of unconventional gas field development domestic in China and abroad, it is risky that the reinjection water may contaminate groundwater in local or adjacent areas during reinjected fluid migration. Ensuring environmental safety of the reinjection is a multi-disciplinary system project. This paper carries out the analysis and shares the experience of China's practice based on the actual cases from the following aspects. 1) The screening of the well location and the formation of the reinjection. 2) The drilling and cementing construction of the reinjection well, which considers the factors such as cementing quality and cement height and casing material. 3) The estimation of the total reinjection capacity, and the factors such as porosity and permeability of the geologic trap and reservoir fracture pressure is considered. 4) The monitoring of well and migration of reinjection fluids. Further environmental risk study of produced water reinjection is presented in this paper, on both sandstone formation of tight sand gas field and carbonate karst formation of shale gas field in China's typical unconventional gas development areas, using laboratory geochemistry experiments and large area geophysical test to obtain seismic data.
Zaini, Muhamad Zaki (Schlumberger) | Du, Kuifu (Schlumberger) | Zhu, Ming (Schlumberger) | Feng, Li Jun (Schlumberger) | Yang, Hai Hua (Schlumberger) | Wei, Lin (Schlumberger) | Liu, Yi (Schlumberger)
Yanbei Project is a tight unconventional gas development that covers a vast area of 2,341 km2 in the Ordos basin – the largest gas producing basin in China. The paper outlines the innovative technologies applied, major achievements and the integrated approach used to successfully develop this large-scale gas greenfield of highly heterogeneous fluvial thin sands with very complicated surface terrains and resources overlaying issues (coal mines and water reservoirs). The project scope calls for drilling and fracturing 784 wells in the full field development in two phases. Phase 1 includes construction of 7 hubs, central processing facilities (CPF), and 360 km of pipelines on a complex hilly topography and aims to deliver production of 1.4 bcm/year. Phase 2 will ramp up to a higher rate. The horizontal well with multi-stage fracture development concept was introduced for the first time in the project and has significantly improved both single well productivity and project economics. More than 20 different technologies, ranging from subsurface, drilling, logging, completion, stimulation, production and facilities, have been applied each of which has been carefully assessed to ensure its value to the project. The advanced 2D seismic technologies have enabled the project to successfully reprocess and interpret a complicated 2D seismic dataset that is heavily distorted by the hilly terrains. The integration of the 2D seismic interpretation with a variety of subsurface and drilling datasets have enhanced the understanding of reservoir characterization and sandbody architectures hence significantly reduce geological risks in drilling horizontal wells in such a complex fluvial system. The drilling and surface engineering work have dealt with a variety of different challenges such as well pad acquisitions, conflicting with coal mines & surface water reservoir areas along with local community issues. One of the key success factors for the project is the integration of the industry's worldwide expertise of technologies, procedures and HSE standards coupled with the local experience, which has ensured an innovative and fit-for-purpose technology-driven solution in planning and execution of the project. The paper describes the main geological and engineering challenges and outlines an integrated approach in applying extensive but selected technologies to resolve those challenges.
Yao, yongjun (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Yuan, quan (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Cai, junjun (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Zhu, jianying (China National Offshore Oil Corporation) | Gan, xiaofei (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Ruan, jifu (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Hu, guoheng (Southwest Oil&Gas Ltd, PetroChina and staff engineer) | Zhao, xuanzhi (Southwest Oil&Gas Ltd, PetroChina and staff engineer)
The Xujiahe gas reservoir in the central Sichuan is a large tight sandstone gas reservoir with low porosity, low to ultra-low permeability, strong heterogeneity, and poor reservoir connectivity. The estimated reserve is about 200 billion cubic meters of gas. More than 870 wells had been drilled since the discoveries in 1956 and 440 wells are producing. However, nearly all wells produced at financial marginal. The production declined at an unpleasant rate. Water flooding occurred unpredictably due to diverse aquifers. It's been challenging for engineers to establish reasonable production rates and to prolong the stabilized production time(SPT).
In our study, a three-step method was used to scrunize the primary factors affecting the stable production. The first step is to perform a principal component analysis; The second step is to do a cluster analysis; The tlast step is to conduct a comprehensive geological evaluation. 102 wells data was used in the principal component analysis, the cluster analysis and the comprehensive analysis of geological characteristics. The main control factors were found and, at the same time quantified to the relationship between the main control factors and the SPT.
The analysis results show that the parameters such as absolute open flow(AOF), productivity index, gas production rate, dynamic reserves, permeability and water saturation. The main control factor for naturally Fracture wells and Fracture wells is AOF, for pore-type wells is gas production rate. The stable production capacity of the former wells with AOF >20×104m3 /d is poor, and the SPT of wells with AOF <20×104m3 /d is long; the latter wells with AOF > 4×104m3 /d has poor stable production capacity, while well with AOF <20×104m3 /d has a long SPT. The higher the productivity index, the shorter SPT, the shorter SPT for wells with gas production rate> 3 %, and the longer SPT for wells with gas production rate< 3 %. Fracture wells play a positive role in SPT and reserves production, while pore-type wells are difficult to produce reserves. Low permeability tight reservoirs (< 0.1 MD) require a large pressure differential to reach a certain gas production. High permeability reservoir (> 1 MD) has strong gas phase seepage capacity and can achieve higher production under a lower pressure differential. Water saturation has a great influence on gas phase seepage in low permeability tight reservoirs. At the same gas production rate, the SPT and cumulative gas production decrease with increasing water saturation. The larger the water saturation, the larger the remaining reserves. If the WGR >10m3 / 104m3, the SPT is shorter, and if the WGR is less than 3m3 / 104m3, and the SPT is relatively longer.
Zhao, Le (China University of Petroleum, Beijing) | Zhang, Hong (China University of Petroleum, Beijing) | Tu, Yulin (SINOPEC Research Institute of Petroleum Engineering) | Duan, Qingquan (China University of Petroleum, Beijing)
Le Zhao and Hong Zhang, China University of Petroleum, Beijing; Yulin Tu, SINOPEC Research Institute of Petroleum Engineering; and Qingquan Duan, China University of Petroleum, Beijing Summary The application of an expandable profile liner (EPL) for leakage plugging in a directional section of deep and ultradeep wells is still at the exploratory stage. EPL that can meet the plugging and strength requirements. The internal-pressure-limit test, crushing test, overall string-sealing experiment, and mechanical shaping experiment are performed, and the optimal welding procedure is developed. After the hydraulic-expansion and mechanical shaping process, the EPL is found to meet the design size and construction requirements. Simulating the trip-in and the expansion process at different reaming-wellbore diameters, with a comprehensive consideration of the expansion requirements and ensuring that the adhesion force effectively seals the EPL against the wellbore, it is better to set the diameter of the reaming wellbore to 6.889 in. Introduction Severe drilling-fluid leakage is an important unfavorable factor that hinders safe, fast, and economical drilling in petroleum-drilling engineering (Abdrakhmanov et al. 1995; Metcalfe 2002; Takhautdinov et al. 2002, 2003; Abdrakhmanov et al. 2006). Unlike vertical wells, the wellbore stability of a directional well varies from the changes of the deviation angle and the azimuth, and therefore research on wellbore stability of the directional well will encounter enormous challenges. Plugging construction is much more difficult to apply to the directional section of deep and ultradeep wells to reconcile the demands of reservoir protection under complex geological conditions, raising higher requirements for effective leakage plugging.
Wang, J. (Beijing Research Institute of Uranium Geology) | Chen, L. (Beijing Research Institute of Uranium Geology) | Zhao, H. G. (Beijing Research Institute of Uranium Geology) | Zhao, X. G. (Beijing Research Institute of Uranium Geology)
With the rapid development of nuclear power in China, the disposal of high-level radioactive waste (HLW) has become an important issue for nuclear safety and environmental protection. Deep geological disposal is internationally accepted as a feasible and safe way to dispose of HLW, and underground research laboratories (URLs) play an important role in the development of HLW repositories. This paper introduces the overall planning and the latest progress for China’s URL. On the basis of the proposed strategy to build an area-specific URL in combination with a comprehensive evaluation of the site selection results obtained during the last 33 years, the Xinchang site in the Beishan area, located in Gansu Province of northwestern China, has been determined as the final site for China’s first URL in granite. In the process of characterizing the Xinchang URL site, a series of investigations, including borehole drilling, geological mapping, geophysical surveying, hydraulic testing and in-situ stress measurements, have been conducted. The investigation results indicate that the geological, hydrogeological and engineering geological conditions of the Xinchang site are very suitable for URL construction. According to the achievements of the characterization of the URL site, a preliminary design of the URL with a maximum depth of 560 m is proposed.
Safe disposal of high-level radioactive waste (HLW) is a challenging task for the sustainable development of nuclear energy and environmental protection. Geological disposal is considered as a feasible and safe option for the long-term management of HLW worldwide, and many countries have considered building deep geological repositories (DGRs) in which to dispose of spent fuel or vitrified HLW. In order to investigate the suitability of geological rock formations for hosting DGRs, to develop and test disposal concepts and technologies, to gain knowledge about multi-field coupled processes in geological and engineered barriers, and finally to assess and demonstrate the long-term performance and safety of DGRs, a number of underground research laboratories (URLs) have been constructed around the world (Kickmaier and McKinley, 1997; NEA, 2001; Wang, 2007).
URLs can generally be divided into generic URLs and site-specific URLs. Generic URLs are facilities developed for research and testing purposes at a site that will not be used for waste disposal while site-specific URLs are facilities developed as a potential site for waste disposal and a precursor to the development of a repository at the site (NEA, 2001; Ahn and Apted, 2010). In the past few decades, generic URLs have been developed within pre-existing underground excavations, such as mines and tunnels; e.g., the Grimsel Test Site and Mont Terri road tunnel in Switzerland and the Tournemire facility in France. There are also purpose-built generic URLs in specific rock types, such as the Äspӧ Hard Rock Laboratory in granite in Sweden and the Whiteshell URL in granite in Canada. The site-specific URL may be constructed either adjacent to or within the proposed repository location. Site-specific URLs include the ONKALO URL in granite in Finland, the Meuse/Haute Marne URL in claystone in France (Delay et al., 2010), the Gorleben URL in salt in Germany, and the ESF in volcanic tuff in the United States (NEA, 2001).
Cui, Weixiang (Petrochina Research Institute of Petroleum Exploration and Development) | Zou, Honglan (Petrochina Research Institute of Petroleum Exploration and Development) | Wang, Chunpeng (Petrochina Research Institute of Petroleum Exploration and Development) | Yang, Jiang (Xi'an Shiyou University) | Yan, Jun (Petrochina Research Institute of Petroleum Exploration and Development)
This paper studied a new fracturing fluid based on a supramolecular complex between associative polymer and viscoelastic surfactant (VES). The combination of VES and associative polymer synergistically enhances the viscosity several times more than that of the individual components alone. The fluid system was optimized by experimental design. The microstructure of wormlike micelle and complex formation was verified by electron microscopy. The proppant transport test in a large-scale fracture simulator showed good proppant suspension ability. After fracturing, the nano- surfactant molecule in the liquid have a high surface energy, which can play a good oil displacement effect in the crack.
The fluid has 50% lower formation damage than that of conventional guar. The fluid was prepared with less additives and formed gel instantly, which can be mixed on the fly in the field. The gel can be completely broken with almost no residue. By flooding and [
Supramolecular fracturing fluid provides a new fracturing system with less formation damage to fracturing operation. This paper will be beneficial to all engineers and technologists who are currently working at tight gas stimulation applications.
Conventional deterministic inversion can only predict thick sand layers qualitatively or semi-quantitatively because of the limitation in resolution of seismic data. With the development of gas exploration and exploitation, the problems of the gas sand with “deepness, thinness, lowness and heterogeneity�? are increasingly prominent. Quantitative forecasting of reservoir distribution is the key to high efficient development and production enhancement. With the multi-dimensional petrophysical parameters analysis, this paper analyzes the relationship between geophysical parameters and physical property of gas reservoir and determines the sensitive parameters of gas-bearing layers. This technique can reduce the ambiguity of reservoir prediction by using single elastic parameter. In order to predict the thin reservoir, the high quality pre-stack gather data is obtained by using the OVT processing. Combining the advantages of pre-stack inversion and stochastic modeling, pre-stack geostatistics inversion can well predict the spatial distribution of thin reservoir. Under the constraint of geological statistical inversion, the spatial characteristics of gas reservoirs can be quantitatively described by using three-dimensional geologic modeling which is carried out by sequential gaussian simulation. By applying this method, good drilling effect is achieved in Su*-2 block of Sulige gas field in China. The ratio of successful wells has been increased to 86.7% and two wells proposed have achieved more than one million high yield. One of the wells, well-4, even gets a record yield in the Sulige gas field. This method is an effective quantitative description of seismic in low permeability tight sandstone gas reservoirs.
Presentation Date: Tuesday, October 16, 2018
Start Time: 1:50:00 PM
Location: Poster Station 6
Presentation Type: Poster
PETRONAS FLNG SATU (PFLNG1) is a floating liquefied natural gas facility producing 1.2 million tonnes per annum (mtpa) of LNG, on a facility that is 365m long, and 60m wide, making it among the largest offshore facility ever built. The PFLNG1 project is the first of its kind in the world and is the first deployment of PETRONASâ€™ Floating Liquefied Natural Gas (FLNG) technology, consolidating the traditional offshore to onshore LNG infrastructure into a single facility. This will see a giant floating facility capable of extracting, liquefying and storing LNG at sea, before it is exported to customers around the globe. The FLNG journey has come a long way since 2006, with many technological options explored to monetise and unlock the potential of small and stranded gas fields. Moving an LNG production to an offshore setting poses a demanding set of challenges â€“ as every element of a conventional LNG facility needs to fit into an area roughly one quarter the size in the open seas whilst maintaining safety and increased flexibility to LNG production and delivery. The keynote address describes the breakthrough features of PFLNG1 â€“ the worldâ€™s first floating LNG facility; and the pioneering innovation that it brings to the LNG industry.