Development of Deep Rock Stress Tester Based upon Hydraulic Fracturing and Diametrical Core Deformation Analysis

2014 Fiscal Year Final Research Report

• Project/Area Number: 24246147
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Earth system and resources enginnering
• Research Institution: Tohoku University
• Principal Investigator: ITO Takatoshi 東北大学, 流体科学研究所, 教授 (00184664)
• Co-Investigator(Kenkyū-buntansha): SHIMIZU Hiroyuki 東北大学, 流体科学研究所, 助教 (60610178)
• Co-Investigator(Renkei-kenkyūsha): LIN Weiren 海洋研究開発機構, 高知コア研究所, グループリーダー (80371714)
• Research Collaborator: FUNATO Akio , 深田地質研究所, 上席主任研究員 ; NAYUKI Toshinori 大林組, 原子力環境技術部, 主任 ; KATO Kazumasa 海洋研究開発機構, 地球深部探査センター, 技術副主幹
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: 地殻工学 / 地殻応力計測 / 水圧破砕 / BABHY方式 / 大深度

Outline of Final Research Achievements

We are developing new methods based upon hydraulic fracturing (HF), which allow us to measure in-situ stress at few km deep. It is assumed here that a drill string containing a wireline retrievable core barrel assembly has been set in the borehole in advance. The tool is conveyed on a wireline through the drill string, while the outer barrel remains at the bottom of the borehole. This way contributes greatly to avoid the risk of trouble occurring in boreholes such as the tool getting stuck. Then the HF test is carried out in a short hole additionally-drilled at the bottom of the original borehole, which is referred to the baby hole. The core retrieved from the baby hole can be applied to the Diametrical Core Deformation Analysis, DCDA, and we can have additional information on stress state independently of HF. By combining those data obtained from HF and DCDA, we can validate the estimated magnitude and azimuth of the in-situ stresses.

Free Research Field

ジオメカニクス