Title:
【発明の名称】待機時間を縮小した液圧ドリリングジャー
Document Type and Number:
Japanese Patent JPH09503258
Kind Code:
A
Abstract:
A reduce waiting time drilling jar 1 includes a mandrel 2, a housing 3 telescopingly positioned about the mandrel 2, and first and second pistons 89, 111 positioned axially between the mandrel 2 and the housing 3. The pistons 89, 111 are spaced longitudinally apart, forming a substantially sealed chamber 88 therebetween. The first piston 89 has a first and second substantially parallel flow passage 94, 200 formed therein and extending longitudinally therethrough to provide first and second flow characteristics. A valve 204 is hydraulically connected to the second flow passage 200. The valve 204 is translatable between first and second operating positions, wherein fluid flows relatively freely through the second flow passage 200 in the first operating position, but is restricted in the second operating position. A pressure relief valve 206 is hydraulically coupled to the substantially sealed chamber 88, and mechanically coupled to the valve 204, wherein movement of the pressure relief valve 206 biases the valve 204 between its first and second operating positions in response to the pressure in the chamber 88 rising above a preselected value.
Inventors:
Evans, Robert Davryu
Application Number:
JP52422094A
Publication Date:
March 31, 1997
Filing Date:
January 05, 1994
Export Citation:
Assignee:
Daily Petroleum Services Corporation
International Classes:
E21B31/113; F16F9/512; F16F9/516; (IPC1-7): E21B31/113
Attorney, Agent or Firm:
Heiyoshi Odashima