Estimating the In-situ Stresses at Offshore Area in Central Taiwan Using Well Log Data

• Main Authors: Pei-HuaChao, 趙姵華
• Other Authors: Der-Her Lee
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/7dw723

碩士 === 國立成功大學 === 土木工程學系 === 105 === This study investigates the in-situ stress using the borehole log data from TPCS-M1, CDA-1 and CDA-2. Vertical stresses were obtained by density logs, and its stress gradient is Sv=22.59MPa/km. The formation pore pressures were obtained by the static pore pressure from the repeated formation test, and its stress gradient is Pp=10.0 MPa/km. The minimum horizontal stresses were calculated by the elasticity with additional modifications by tectonic strain. The stress gradient is Sh=15.56MPa/km. Then, the maximum horizontal stresses were obtained by knowing the minimum horizontal stresses. The stress gradient is SH=17.86 MPa/km. The directions of the maximum horizontal stresses from the depth of 1500 to 3000 m can be divided into the following 3 sections by the four-arm caliper tools, which are used in the World Stress Map: 1. The NW-SE for the Toukoshan Formation and Choulan Formation between 1500-2135 m. 2. The E-W for the Chinshui Sale and Kueichulin Formations at the depth of 2135-2450 m. 3. The NE-SW for the Kuanyingshan Sandstone, Talu Shale, and Peiliao Formation at the depth of 2450-3000 m.