High Challenging Tight Oil Development by Integrating Innovative Reservoir Boundary Detection Technology into High Efficiency Horizontal Drilling Campaign in West China

Author(s):  
Jiafeng Zhang ◽  
Chennai Zhi ◽  
Jianxin Zhu ◽  
Yiping Ye ◽  
Tong Li ◽  
...  
2012 ◽  
Vol 430-432 ◽  
pp. 808-811
Author(s):  
Zhi Xin Feng ◽  
Yi Shu Zhai ◽  
De Hua Miao

This paper presents a mold cavity surface subdivision method by using image boundary detection technology to realize high efficiency NC machining. From the new perspective of image processing, the method constructed an optimal cutting direction angle field image in the u-v system of parameters according to the relationship between maximum cutting bandwidth and cutting direction in the theory of iso-scallop height firstly, and then fuzzy c - means clustering method was applied for subdivision surface boundary detection. Experimental results demonstrate good performance of the proposed method in distinguishing and extracting boundary points of surface subdivision.


2021 ◽  
Author(s):  
Jhon Manchola ◽  
Dianys Ballestero ◽  
Jose Villasmil ◽  
Gerson Nava

Abstract Horizontal drilling is part of the development plan for Rubiales field in Colombia, operated by the National Oil Company. By this, different geosteering technologies have been applied during the infill drilling campaign and, it has varied over time. The multi-boundary detection tool has successful results in terms of net sand percent increase, precise location, and cost decrease, related to drilling operations. Some of the challenges for well placement are thin thickness channels with no lateral continuity (deposition environment), oil-water contact closeness, poor correlation with cutting samples, between others. The technology minimizes risks with the real-time resistivity inversion. This process generates a visual representation of the resistivity profile around the wellbore, including geometric definition, dip, and thickness estimation. These inversion results are used to recommend trajectory adjustments while drilling. The complete geosteering experience in Rubiales with the new technology (more than one hundred sixty producing wells so far) has been classified into three main types of wells: lateral sections drilled in continuous sand intervals; lateral variation of resistivity; and wells with a change of prospective zone by channel discontinuity. The implementation success is described by the net sand percentage increasing, around 16% compared with other technologies. The average drilling length was improved by 20% and the number of geological sidetracks concerning previous stages of exploitation reduced by more than 90%, without affecting the drilling rate. These factors, including the update of the sedimentological models, inclusion of new reserves, and the production increase, are part of the optimization plan.


SPE Journal ◽  
2021 ◽  
pp. 1-16
Author(s):  
Lei Li ◽  
Zheng Chen ◽  
Yu-Liang Su ◽  
Li-Yao Fan ◽  
Mei-Rong Tang ◽  
...  

Summary Fracturing is the necessary means of tight oil development, and the most common fracturing fluid is slickwater. However, the Loess Plateau of the Ordos Basin in China is seriously short of water resources. Therefore, the tight oil development in this area by hydraulic fracturing is extremely costly and environmentally unfriendly. In this paper, a new method using supercritical carbon dioxide (CO2) (ScCO2) as the prefracturing energized fluid is applied in hydraulic fracturing. This method can give full play to the dual advantages of ScCO2 characteristics and mixed-water fracturing technology while saving water resources at the same time. On the other hand, this method can reduce reservoir damage, change rock microstructure, and significantly increase oil production, which is a development method with broad application potential. In this work, the main mechanism, the system-energy enhancement, and flowback efficiency of ScCO2 as the prefracturing energized fluid were investigated. First, the microscopic mechanism of ScCO2 was studied, and the effects of ScCO2 on pores and rock minerals were analyzed by nuclear-magnetic-resonance (NMR) test, X-ray-diffraction (XRD) analysis, and scanning-electron-microscope (SEM) experiments. Second, the high-pressurechamber-reaction experiment was conducted to study the interaction mechanism between ScCO2 and live oil under formation conditions, and quantitively describe the change of high-pressure physical properties of live oil after ScCO2 injection. Then, the numerical-simulation method was applied to analyze the distribution and existence state of ScCO2, as well as the changes of live-oil density, viscosity, and composition in different stages during the full-cycle fracturing process. Finally, four injection modes of ScCO2-injection core-laboratory experiments were designed to compare the performance of ScCO2 and slickwater in terms of energy enhancement and flowback efficiency, then optimize the optimal CO2-injection mode and the optimal injection amount of CO2slug. The results show that ScCO2 can dissolve calcite and clay minerals (illite and chlorite) to generate pores with sizes in the range of 0.1 to 10 µm, which is the main reason for the porosity and permeability increases. Besides, the generated secondary clay minerals and dispersion of previously cemented rock particles will block the pores. ScCO2 injection increases the saturation pressure, expansion coefficient, volume coefficient, density, and compressibility of crude oil, which are the main mechanisms of energy increase and oil-production enhancement. After analyzing the four different injection-mode tests, the optimal one is to first inject CO2 and then inject slickwater. The CO2 slug has the optimal value, which is 0.5 pore volume (PV) in this paper. In this paper, the main mechanisms of using ScCO2 as the prefracturing energized fluid are illuminated. Experimental studies have proved the pressure increase, production enhancement, and flowback potential of CO2 prefracturing. The application of this method is of great significance to the protection of water resources and the improvement of the fracturing effect.


2018 ◽  
Vol 23 (1) ◽  
pp. 115-124 ◽  
Author(s):  
Guo-qiang Xue

Near-source electromagnetic technology has been developed and applied in the exploration of petroleum, metallic ore, coal, and engineering geology due to its high efficiency, high detection accuracy, and deep depth of investigation. In this paper, research and applications of the frequency-domain electromagnetic sounding method (FDEM), wide-field electromagnetic method (WFEM), modified central-loop transient electromagnetic method (TEM), and short-offset grounded-wire TEM (SOTEM) with obvious near-source characteristics, were reviewed and analyzed. From the 1960s to 1990s, the FDEM method and equipment were extensively developed in China. These methods have played important roles in the exploration of coal resources. Based on controlled source audio-frequency magnetotelluric (CSAMT) and FDEM methods, a new method has been developed by deriving a new expression to calculate apparent resistivity. This method, which is referred to as WFEM, has been studied, applied, and received great attention in China. To increase work efficiency and reduce the influence of local transverse anisotropy on the detection processes, a modified central-loop TEM detection technology based on the central loop transient electromagnetic method was developed in China. The advantages of SOTEM in near-source surveys with high resolution and increased depth detection stimulated academic research interest to further develop grounded-wire TEM techniques. [Figure: see text]


2018 ◽  
Author(s):  
Serik Tyran ◽  
Carl Giesemann ◽  
Akimzhan Lukpanov ◽  
Milat Yermekov ◽  
Nariman Abzhanov ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jie Tian ◽  
Hongqi Liu ◽  
Liang Wang ◽  
Liqiang Sima ◽  
Shiqiong Liu ◽  
...  

AbstractThe Da'anzhai Member of the Jurassic Ziliujing formation in central Sichuan is a typical tight-oil reservoir with porosity and permeability less than 2% and 0.1 × 10–3 μm2, respectively. Fractures in this formation are well developed in micro- and nano-scale. However, the factors that control the fracture distribution are unclear. Additionally, the uncomprehensive and ineffective identification and evaluation of fractures in the early stage of tight-oil development makes it difficult to meet the requirements of tight-oil development. In our work, we used cores, thin sections, and a scanning electron microscope (SEM) to study the influence of the microscopic rock composition, including the shelly grains, calcite grains, and clastic grains, on the fracture development. We found that the microscopic composition of shelly grains and calcite grains separately control the development of inter-shelly fractures and shelly fractures, and intergranular fractures, and tectonic fractures. Except for a small number of dissolution fractures found in mudstone, the fractures are not well developed in the formations with clastic grains. According to the characteristics of the development degree of fracture and the resolution of the well-logs, the fractures are divided into large scale, small scale, and micro-scale. By a newly established level-by-level constraints method, we systematically identified the scale, occurrence, filling characteristics, and development degree of fractures in the Da'anzhai member by well-logs. Moreover, a quantitative model is also proposed for identifying the angles and development degree of fractures. The results show that the scale of fractures can be effectively identified by the shapes and values of resistivity logs; the occurrence, development, and filling characteristics of fractures can be semi-quantitatively evaluated by the relative amplitude difference between the matrix resistivity (Rb) and formation resistivity (RT). The results are consistent with the interpretation results by formation micro-resistivity imaging (FMI) log, which further demonstrates that the level-by-level constraint method by conventional well-logs can be used to systematically and effectively predict the fracture characteristics in tight-oil reservoirs.


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