Luo, Xianbo (Tianjin Branch of China National Offshore Oil Company) | Li, Jinyi (Tianjin Branch of China National Offshore Oil Company) | Yang, Dongdong (Tianjin Branch of China National Offshore Oil Company) | Shi, Hongfu (Tianjin Branch of China National Offshore Oil Company)
The relative permeability test (RPT) plays an important part in production prediction, the law of water cut increasing analysis, the research on recovery factor and the reservoir numerical simulation. The residual oil saturation is one of the most significant parameters of RPT. While literature on the quality control of RPT is limited, the experimentalists make qualitative judgments on the rationality of the key data estimate based on their own experience. A new method is presented to predict residual oil saturation of light oil reservoirs.
Zhang, Yiming (CNPC Huabei Oilfield Company) | Tian, Jianzhang (CNPC Huabei Oilfield Company) | Yang, Dexiang (CNPC Huabei Oilfield Company) | Chen, Shuguang (CNPC Huabei Oilfield Company) | Liu, Xing (CNPC Huabei Oilfield Company) | Hou, Fengxiang (CNPC Huabei Oilfield Company) | Tian, Ran (CNPC Huabei Oilfield Company) | Zhang, Chuanbao (CNPC Huabei Oilfield Company)
The study area is located in the Langgu sag of Northern Jizhong depression, Bohai Bay Basin, East China. In order to achieve exploration breakthrough in deep buried hill, key engineering technologies are developed and used to accurately demonstrate important target identification by recognizing new hydrocarbon accumulation patterns resulting from the analysis of multi-stage structure-controlled trap mechanism and the detailed study of controlling factors over high-quality Ordovician reservoirs based on new high-accuracy 3D seismic data. This study reveals a new evolution mechanism of buried hill controlled by structural superposition, experiencing "the uplift from thrusting in Indo-Chinese to early Yanshan epoch, uplifted block faulting into horsts in middle Yanshan epoch, horsts tilting into belt in Eocene, and belt reversion into trap", and thus puts forward a new mechanism for reservoir forming controlled by a superposition of "dolomite, karsting, and faulting". Three types of reservoir development are identified, including "regional layered pore, local block micropore-fracture, and fracture hole pore layer-block composite", and an accumulation pattern in deep buried hill is constructed, characterized by "efficient hydrocarbon supply from gas-type source rock, predominant migration through fractured surface-nonconformity surface, and stratum- and mass-controlled accumulation", which has guided the 40 years' exploration of Ordovician Yangshuiwu buried hill zone and made a great breakthroughs. Novel relevant exploration technologies have been developed, involving high-accuracy imaging, high-precision well logging identification of hydrocarbon reservoir, ultra-high temperature deep drilling and completion, ultra-high temperature carbonate reservoir stimulation, etc, which solve a worldwide problem that has restricted the exploration of the ultra-high temperature buried hill for many years. These technologies make possible the highest daily production of over 100 m3 oil and 0.5 million m3 gas respectively and sustain a high and stable production for a long term, which guarantee the clean energy supply for Beijing-Tianjin-Hebei region.
Wang, Bingjie (CNOOC LTD.-TianJin Bohai Oilfield) | Xu, Changgui (CNOOC LTD.-TianJin Bohai Oilfield) | Wu, Kui (CNOOC LTD.-TianJin Bohai Oilfield) | Zhang, Rucai (CNOOC LTD.-TianJin Bohai Oilfield) | Deng, Jun (CNOOC LTD.-TianJin Bohai Oilfield) | Guo, Naichuan (CNOOC LTD.-TianJin Bohai Oilfield)
A new oil property identification parameter (Pw) is derived which represents the total hydrocarbon generation and pyrolysis hydrocarbon. Using continuous measurement data (Pw) and a series of samplebased attributes from 3D seismic, a strong linear trend is observed. This trend linear is used to calculate heavy oil property data in 3D volume. At the same time, we have got the relationship between reservoir physical and oil properties. Based on this, the core data and geochemical data are used to study the charging of crude oil.
Drilling, as a direct and effective method of opening oil and gas layers, has been widely used. A reasonable combination of drilling tools plays a key role in increasing the rate of mechanical drilling, reducing drilling costs, and reducing downhole accidents. Conventional drilling relies on years of experience of on-site workers and reference to the operation of drilling wells, making use of drilling tools and lacking scientific basis. However, the reservoir situation is erratic, the unknown factors are very numerous, unpredictable, and the difficulty of drilling is increased. Drilling into unknown reservoirs, especially high-temperature and hightemperature risk wells, poses a huge threat to the lives of workers on site. Conventional drilling of known reservoirs will also encounter unknown problems such as drilling distance growth, stuck drilling, drilling tools falling, increased inclination, and deviation from the intended target position, which seriously reduces drilling efficiency, increases operating time, risk and drilling difficulty affected by the reasonable use of the drilling tool combination. With the development and application of computational intelligence, through the accumulation of massive geological property data, reservoir structure data, drilling tool parameters, construction data, drilling fluid parameters and other drilling data, intelligent drilling is used to predict unknown drilling information which can reduce the risk of drilling and improve drilling efficiency. In this paper, the work mode of "data running first, operation post" is used to further strengthen the application of drilling tools combination to improve the rate of mechanical drilling and reduce downhole problems.
Li, Junfei (CNOOC Ltd, Tianjin Branch) | Liu, Xueqi (PetroChina Research Inst. Petroleum Exploration and Development) | Gao, Zhennan (CNOOC Ltd, Tianjin Branch) | Shang, Baobing (CNOOC Ltd, Tianjin Branch) | Xu, Jing (CNOOC Ltd, Tianjin Branch)
After more than 20 years’ development, S oilfield has entered high water cut stage. The layer contradiction is prominent and the water flooding condition is complex, which result in the complex decentralized state of the remaining oil. In order to determine the remaining oil distribution to guide the comprehensive adjustment of the oilfield, the reservoir architecture analysis of delta front was conducted.
Based on the core, seismic data, dense well logging data and production performance data, the reservoir architecture of delta front in Dongying group is characterized with hierarchy process, model guidance and numerical simulation methods. In the paper, the distribution style of interlayers in single mouth bar is discussed. The distribution feature of the remaining oil under the control of interlayers is analyzed.
It shows that multiple main channels form continuous mouth bar complex and single mouth bar develops several accretions. Interlayers in single mouth bar express in two forms: the foreset type along the source direction and the arch type perpendicular to the source direction with a low angle from 0.4° to 1.0°. Along the source direction, remaining oil gathers inside accretions whose injection-production does not correspond under the control of interlayers. And the remaining oil is enriched at the front of accretion. In the vertical source direction, the remaining oil accumulates in the high part of accretions. Under the guidance of remaining oil distribution characteristics controlled by reservoir architecture, one horizontal well was deployed. The average output is more than 100m3/d and the water cut is under 30%, which indicates the effect of this reservoir architecture analysis work.
The successful implementation of the horizontal well demonstrates the vital function of the reservoir architecture research for this kind of mature oilfield. This will also be one promising research direct for the overall adjustment and remaining oil tapping.
Dai, Jianfang (CNOOC(China National Offshore Oil Corporation) Ltd Tianjin Branch, Tianjin, P.R.China) | Wang, Mingchun (CNOOC(China National Offshore Oil Corporation) Ltd Tianjin Branch, Tianjin, P.R.China) | Jiang, Liqun (CNOOC(China National Offshore Oil Corporation) Ltd Tianjin Branch, Tianjin, P.R.China) | Qin, Dehai (CNOOC(China National Offshore Oil Corporation) Ltd Tianjin Branch, Tianjin, P.R.China)
The characterization of volcanic rocks, especially the identification of the bottom interface is the key to reservoir exploration. Based on the veriety of the volcanic rock's response in petrophysical analysis and the difficulty to identify volcanic rock in the profile, we use pre-stack AVO attribute analysis and post-stack amplitudevariations-with frequency (AVF) inversion on the study of volcanic rock type and logging response characteristics to avoid the limitation of single seismic data and single attribute. By using this method, the top and bottom interfaces of volcanic rocks are clear and it provides a strong support for reservoir research and well deployment. Introduction With the continuous deepening of geological understanding, the volcanic rock, once known as the'restricted zone', has become a hot spot for oil exploration, but due to the diversity of volcanic lithofacies, it is difficult to be recognized. In recent years, the use of seismic response characteristics of volcanic rocks, wave impedance inversion, and seismic attribute prediction methods have become important means of describing volcanic rocks.
Yuan, Meng (The Unconventional Natural Gas Institute, China University of Petroleum-Beijing) | Huang, Handong (The Unconventional Natural Gas Institute, China University of Petroleum-Beijing) | Bian, Caiyun (Academy of Chinese Energy Strategy, China University of Petroleum-Beijing)
With the development of the hydrocarbon reservoirs exploration in China, structural reservoir has become unable to meet the needs of oil and gas exploration. Thus, lithologic reservoir becomes the focus of current oil and gas exploration. There are lithologic reservoirs characterized by deposition of narrow channel sand bodies in the middle-shallow formation of Matouying Uplift in the Bohai Bay Basin, China. Seismic data in this area is of good quality but the oil layer is thin, averaging less than 10m. Firstly, we conducted an experiment using seismicfacies-inversion method in a physical model of thin-bed channel sandstone. The inversion resolution is high, so we could identify thin sand bodies and characterize the distribution of channel. Then we also use this method to predicted the thin reservoirs in the Matouying area and successfully portrayed the narrow channel. In order to measure the accuracy of our method in this study area, we chose to compare conventional logging constrained inversion with seismic-facies-control inversion. The results show that our method overcomes the problem of low resolution, and we can precisely describe approximately 5m thick reservoir.
Presentation Date: Wednesday, October 17, 2018
Start Time: 1:50:00 PM
Location: 209A (Anaheim Convention Center)
Presentation Type: Oral
Sun, Xijia (China National Offshore Oil Corporation (CNOOC) Ltd, Tianjin Branch) | Hua, Xiaoli (China National Offshore Oil Corporation (CNOOC) Ltd, Tianjin Branch) | Bian, Lien (China National Offshore Oil Corporation (CNOOC) Ltd, Tianjin Branch) | Liu, Teng (China National Offshore Oil Corporation (CNOOC) Ltd, Tianjin Branch)
The paper creatively applies the research ideas of “Reservoir Architecture�? to the study of volcanic vents for the first time, and the semi-quantitative detailed description of volcanic vents. Research results show volcanic vents are composed of two parts: the upper cone and the lower pipe. In the upper cone, 3 configuration elements, namely bottom surface, top surface and internal fillings, can be identified. With consideration to stratigraphic contact relationship, the top surfaces can be classified into three categories: onlap, dispersion and concordance. The bottom surfaces are predominantly truncated type. The internal fillings include predominantly mass filling and stratoid filling. With consideration to impacts of magmatism on sedimentation, active stages of vents can be analyzed. Eventually, stratigraphic contact relationship and changes in thickness of covering formations can be used as two kinds for standards for timing of volcanic activities. In this way, volcanic activities in 3 stages have been identified. Volcanic activities in Guantao Formation are dominated by fissure eruption with volcanic vent distributed in string configuration along the fault. Due to the double strike-slip conjugate shear of Tanlu Fault in NNE and Zhangpeng Fault in NWW, faulting activities in the Guantao Formation of the study area were quite active. During the period, hot mantle plumes were also active to generate lava eruption events in different stages in the study area. The study may provide valuable references and guidance for oil-gas exploration in volcanic rocks of the east of Shaleitian Uplift.
Presentation Date: Thursday, October 18, 2018
Start Time: 8:30:00 AM
Location: 210A (Anaheim Convention Center)
Presentation Type: Oral
Zhu, Qi (The Fourth Branch Company of CNPC Bohai Drilling Engineering Company Limited) | Wang, Yong (The Fourth Branch Company of CNPC Bohai Drilling Engineering Company Limited) | Zhang, Yongqing (The Fourth Branch Company of CNPC Bohai Drilling Engineering Company Limited) | Sun, Zhihe (Engineering Technology Institute of PetroChina Huabei Oilfield Company) | Wei, Yinghui (The Fourth Branch Company of CNPC Bohai Drilling Engineering Company Limited) | Wang, Runping (The Fourth Branch Company of CNPC Bohai Drilling Engineering Company Limited)
Currently, synthetic additives are widely used in drilling fluid, but these additives have hazards, such as, toxicity, difficult to degradation, leakage and volatilization caused great influence to wellsite environment. Environmentally friendly drilling fluid has been appeared around for decade. However, because of high cost of raw materials, lack of adequate supplement and complexity of modified synthetic process, there has been no widespread industrial application in China. The majority of test wells are straight, but deviated well and highly-deviated well test is seldom reported.
A series of indoor evaluation and field applications were carried out in process of modifying low cost additives to the environmentally friendly treatment agents. HTHP aging and filtration experiment to verify temperature resistance; adding sodium chloride to verify anti-salt properties; adding bentonite and cuttings recycling experiment to verify inhibition performance of slurry and mud shale; friction resistance experiment verifies that lubrication capacity meets deviated well and highly-deviated well operations; core flow experiment to verify reservoir protection performance; heavy metal, biochemical oxygen demand, chemical oxygen demand, biological toxicity analysis experiment to verify influence of the system on environment.
Ability of temperature resist 120 °C, anti-salt ability reaches saturation and recovery of cuttings is more than 85%. Environmental performance of the drilling fluid system is ideal, EC50 value is 1.61×105, no biological toxicity, BOD5/CODcr is 0.11, easy biodegradation. Field application for morethan 30 wells, with beyond 20 deviated wells and highly-deviation angle more than 50 ° wells are 10.
The new types downhole tools for speeding-up and controlling hole size, rotary impactor and wellbore cleaner, were used to improve mechanical penetration rate (ROP) and wellbore cleaning. After employing the environment system, the drilling fluid does not need to be transshipped and processed directly in wellsite, and well fields are restored. Drilling fluid disposal process saves the cost of artificial working, transportation and environmental management. This drilling fluid system is first applied on-site in North China, which fills the blanks and provids reliable technical support and reference examples for the subsequent replacement of drilling fluid systems used now in North China.
Erpeng, Guo (Research Institute of Petroleum Explortaion & Development, CNPC) | Yongrong, Gao (Research Institute of Petroleum Explortaion & Development, CNPC) | Youwei, Jiang (Research Institute of Petroleum Explortaion & Development, CNPC) | Yunjun, Zhang (Research Institute of Petroleum Explortaion & Development, CNPC) | Zhigang, Chen (Changqing Oilfield, CNPC) | Yao, Wei (Development Management Department, Liaohe Oilfield CNPC)
Thermal recovery process is widely adopted in exploitation of heavy oil reservoirs. But for extra-heavy oil reservoirs with bottom water and depth more than 800m, effective recovery is not achieved with steam injection. SAGD (Steam assisted Gravity Drainage) process is tested in such reservoirs but showed poor performance because of high reservoir pressure and bottom water. This paper proposed a new approach which is utilizing super critical hydrocarbon gas to replace most part of steam during steam injection and SAGD process for exploitation of such reservoirs.
Calculations of heat distribution along the steam injection tube were carried out. The solubility of supercritical hydrocarbon gas in heavy oil was tested with PVT apparatus. Also the viscosity reduction effect of super critical gas is also tested. SAGD simulation with high mole percent of gas injection was carried out with theoritical model. Different operation strategy including pure steam, supercritical CO2 and steam co-injection, wet gas and steam co-injection was compared with numerical simulation.
The main theory of this approach is that injected gas can greatly decrease partial pressure of steam hence reduce the heat loss and drawdown of quality during injection. The results shows that the heat loss can be decreased by 40% in steam injection tubing. At super critical conditions, solubility of gas in heavy oil is almost 100m3/m3. Viscosity of heavy oil saturated with gas will be lower than 200mPa.s at 150℃which is 80% less than that without gas. The viscosity is already low enough for drainage process. High pressure SAGD experiment shows that temperature decreases gradually from the inner part to the out range of steam chamber when injected mole percent of gas is 20%. This means the decrease of steam saturation pressure related to partial pressure of steam because injected gas will take the corresponding pressure in steam chamber. The recovery process shows high recovery factor which is similar to SAGD process. And steam oil ratio is 0.8~1.2 which is much lower than any existing pure steam injection SAGD process. Simulation results shows that during the operation process bottom water will not flux into steam chamber after the balance between reservoir and bottom water was achieved.
This paper provides an effective approach to exploit the heavy oil reserves with great depth which is meaningful for reducing the steam consumption and operation cost for oil industry.