INTERNATIONAL PATENT: CHINA NATIONAL PETROLEUM CORPORATION, 中国石油天然气集团有限公司, CNPC BOHAI DRILLING ENGINEERING COMPANY LIMITED, 中国石油集团渤海钻探工程有限公司 FILES APPLICATION FOR "METHOD FOR FRACTURING DRY HOT ROCK AND METHOD FOR EXTRACTING HEAT FROM DRY HOT ROCK"

GENEVA, June 30 -- CHINA NATIONAL PETROLEUM CORPORATION (9 Dongzhimen North Street,Dongcheng District, Beijing 100007), 中国石油天然气集团有限公司 (中国北京市东城区东直门北大街9号), CNPC BOHAI DRILLING ENGINEERING COMPANY LIMITED (NO. 83, 2nd Avenue, TEDA,Binhai New Area, Tianjin 300457), 中国石油集团渤海钻探工程有限公司 (中国天津市滨海新区经济技术开发区第二大街83...