海洋天然气水合物探测及取样钻具研制

Development of Marine Gas-Hydrate Detection and Drilling Sampler

在海洋天然气水合物资源调查评价过程中,通常先采用地球物理方法来探测海底拟反射层(BSR),然后根据BSR的位置来判断水合物的分布范围和埋藏深度。但在钻井取样过程中发现BSR并不能完全准确地反映水合物的埋藏深度,为此项目组研发了一种绳索打捞式的组合钻具,在钻井过程中不仅能够使用随钻测量钻具探测地层电阻率来确定地层是否有水合物,而且还能通过绳索打捞方式更换取样钻具,完成水合物地层的取样。通过设计、试制和室内测试,验证了水合物探测及取样钻具方案是可行的,为后续的野外试验奠定了基础。

Some geophysical methods are used to detect the bottom simulating reflector （BSR） in investigation of marine gas hydrate resources, and then the distribution scope and depth of gas hydrate is identified according to the position of BSR. But drilling samples demonstrate that BSR can not entirely and accurately reflect the depth of gas hydrate. A new type of combined wireline drilling tool has been developed, which can not only use logging-while-drilling tools to detect formation resistivity to determine whether gas hydrate exists in the formation, but can also be switched to wire-line core samplers to take cores by use of the wire-line fishing system. Through design, trial-manufacture and laboratory tests, the feasibility of the gas-hydrate detection and drilling sampler has been verified, which lays a foundation for the subsequent field experiments.