Discussion on a New Calculation Method for Missing True Formation Thickness - A Case Study from YM32 Area in Northern Tarim Basin

2014 ◽  
Vol 678 ◽  
pp. 98-102
Author(s):  
Xian Ying Luo ◽  
Chuan Rui Dai ◽  
Xiao Fang Yan
Keyword(s):  
Tarim Basin ◽  
Calculation Method ◽  
Geological Conditions ◽  
Important Sense ◽  
Target Layer ◽  
Complete Set ◽  
Boundary Sets ◽  
Northern Tarim Basin ◽  
Direction Distance

The true formation thickness missed in the geologic borehole has important sense for understanding the strata of borehole and position of target layer. Nevertheless, there had not been enough effective technologies and calculation methods to calculate the missing true formation thickness at present. To solve this problem, this paper focuses on mathematical formula combining with the actual geological conditions, collects various useful geologic data and parameters, such as stratigraphic dip, dip direction, distance from drilling well to formation’s pinchout boundary along the dip direction and difference in height between drilling well and pinchout boundary, sets a reasonable calculation method, derives a complete set of new expression to calculate the missing true formation thicknesses. The typical region, YM32 Area in Tarim Basin, was taken as the case study to prove the accuracy and practicability of the calculation method. The result was inspected by the actual data of neighbor boreholes.

The Application in Calculation of the Horizontal Wells’ True Thicknesses – An Example of Penglaiba Formation in the Northern Tarim Basin

2014 ◽  
Vol 1006-1007 ◽  
pp. 101-106
Author(s):  
Xian Ying Luo ◽  
Wei Hong Zou ◽  
Ran Xiong
Keyword(s):  
Tarim Basin ◽  
Oil And Gas ◽  
Horizontal Wells ◽  
Mathematical Methods ◽  
Reservoir Prediction ◽  
Individual Layer ◽  
Gas Drilling ◽  
Geological Conditions ◽  
Geological Situation ◽  
Northern Tarim Basin

Horizontal oil and gas drilling has become one of the most valuable technologies ever introduced in the unconventional drilling especially. Nevertheless, it is complex to calculate the horizontal wells’ true formation thicknesses in the dipping strata. Combined with the actual geological conditions and mathematical methods, a complete set of new formula was derived from the basic data of the strata dips, dip directions and individual layer data to calculate the true formation thicknesses, which could obtain the horizontal wells’ true thicknesses of Penglaiba Formation of Lower Ordovician in the northern Tarim Basin. And the calculation results were accurate. Calculated with this formula, the Penglaiba Formation’s true thickness was given, wells’ relative distributions were located, and the columnar section of Penglaiba Formation was spliced to discover the geological situation subsurface accurately. The columnar section of Penglaiba Formation in the northern Tarim Basin could provide a theoretical basis for reservoir prediction and the distributions in the low permeable beds. This is the key technical method to descript the palaeogeologic map.

scholarly journals Comparison between electrical resistivity tomography and tunnel seismic prediction 303 methods for detecting the water zone ahead of the tunnel face: A case study

2020 ◽  
Vol 12 (1) ◽  
pp. 1094-1104
Author(s):  
Nima Dastanboo ◽  
Xiao-Qing Li ◽  
Hamed Gharibdoost
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Geological Structure ◽  
Rock Properties ◽  
Electrical Tomography ◽  
Tunnel Face ◽  
Resistivity Tomography ◽  
Geological Conditions ◽  
Seismic Prediction

AbstractIn deep tunnels with hydro-geological conditions, it is paramount to investigate the geological structure of the region before excavating a tunnel; otherwise, unanticipated accidents may cause serious damage and delay the project. The purpose of this study is to investigate the geological properties ahead of a tunnel face using electrical resistivity tomography (ERT) and tunnel seismic prediction (TSP) methods. During construction of the Nosoud Tunnel located in western Iran, ERT and TSP 303 methods were employed to predict geological conditions ahead of the tunnel face. In this article, the results of applying these methods are discussed. In this case, we have compared the results of the ERT method with those of the TSP 303 method. This work utilizes seismic methods and electrical tomography as two geophysical techniques are able to detect rock properties ahead of a tunnel face. This study shows that although the results of these two methods are in good agreement with each other, the results of TSP 303 are more accurate and higher quality. Also, we believe that using another geophysical method, in addition to TSP 303, could be helpful in making decisions in support of excavation, especially in complicated geological conditions.

Study on the Calculation Method of Soil-Nailing for High Soil Slope Based on the Logarithmic Spiral Slippery Fracture

2011 ◽  
Vol 261-263 ◽  
pp. 1709-1713
Author(s):  
Meng Yang ◽  
Xiao Min Liu
Keyword(s):  
Mathematical Model ◽  
Stability Analysis ◽  
Engineering Design ◽  
Calculation Method ◽  
Logarithmic Spiral ◽  
Soil Nailing ◽  
Soil Slope ◽  
Mode Pattern ◽  
Shear Function

This paper introduces a new failure mode pattern of soil slope – the logarithmic spiral slippery fracture. A mathematical model for the logarithmic spiral slippery fracture is established, taking the anti-shear function of the soil-nailing into consideration. The shear of soil-nailing, axial force, and the safety coefficients based on the limiting equilibrium method are derived, leading to an accurate stability analysis of the strengthening of soil slope. A case study shows that the anti-shear function of the soil-nailing can be significant and should not be ignored in engineering design.

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