Integrated drilling and completion method for multi-branch hole mining of argillaceous silt hydrate

Abstract

The invention discloses a muddy silt natural gas hydrate multi-branch hole well drilling and completion integrating method, wherein loosening is carried out through one string. Multi-branch holes areformed through the set of string of well drilling and completion, in the drilling process of the different branch holes, a drilling tool assembly does not need to be pulled out from a main well completely, coiled tubing is adopted for hydraulic jet drilling, and after drilling is conducted to the preset depth, gravel is reversely filled directly without pulling out drilling tools. The technological means of combining multi-branch hole gravel filling well completion with large-size main well casing well completion is adopted, the risk of reclosing of the multi-branch holes is prevented, the purposes of stabilizing the main well and preventing a formation from losing stability are achieved, the effect of production increasing through multi-branch hole limited sand control mining can be achieved, well drilling and completion support is provided for a submarine natural gas hydrate multi-branch hole limited sand control mining method, and high practical value and economic value are achieved.

Description

technical field [0001] The invention belongs to the technical field of marine natural gas hydrate resources development engineering, and in particular relates to a one-trip pipe string drilling and completion method specially aimed at the limited sand control mining technology of marine natural gas hydrate multi-branched holes. Background technique [0002] Natural gas hydrate resource is a potential energy source, which has the characteristics of wide distribution and high energy density. Most of the proven natural gas hydrates in my country's sea areas are argillaceous silt type natural gas hydrates. The basic characteristics of this type of reservoir are: (1) The particle size of reservoir sand is extremely low (less than 20 μm in general), and the shale content, especially montmorillonite and kaolinite, is high, and the shale content in some areas exceeds 40%, making sand control difficult; (2) Reservoir permeability Low, poor pressure conductivity, which is extremely unfa...

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Problems solved by technology

[0004] However, this method still needs to be further improved in terms of drilling and completion techniques.

The typical difficulties of the multi-branch hole limited sand control mining method in the drilling and completion stages of muddy silt type gas hydrate reservoirs are as follows: (1) The stability of muddy silt type gas hydrate reservoirs is poor, and the stability and durability of branch holes are poor. During the drilling process of the branch hole, the branch hole formed in the last drilling may have undergone creep compaction; (2) The buried depth of the argillaceous silt type gas hydrate reservoir is shallow and the reservoir is soft, so the sidetracking of the conventional drill pipe Branch hole is very difficult

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