Core sample collecting method with high recovery rate

Abstract

The invention discloses a core sample collecting method with a high recovery rate. The core sample collecting method comprises following steps: geological formation and underground water of a core sample collecting site are identified and monitored respectively, an appropriate drilling mode is reasonably selected, reasonable length of footage per round trip is selected, an aqueous polysaccharide vegetable glue solution is selected as flushing fluid, an appropriate sampler is selected for collecting a core sample in a core sample collecting site with normal-state formation, and the sampler is changed for fractured formation and serious fracture leakage formation in the core sample collecting site. According to the method, a drilling tool of the sampler is appropriately moved when cores areblocked in the core sample collecting process, immediate trip-out operation is performed during invalid drilling of the drilling tool, so that the problem of mutual abrasion of the cores due to long-term lifting motion and forced drilling or reduction of the core recovery rate is reduced because fine-particle cores at the bottom of a drill bit are washed away by the flushing fluid can be solved, and the core recovery rate can be effectively guaranteed.

Description

technical field [0001] The invention relates to the technical field of sample collection, in particular to a method for collecting rock core samples with a high recovery rate. Background technique [0002] Core sampling, also known as core drilling sampling, is a sampling work performed on the core or core obtained by drilling. It is generally divided into two halves along the long axis of the core by manual or mechanical methods according to a certain sampling length. or four parts, and then take half or a quarter of them as samples. The core collection rate refers to the ratio of the total length of the complete rock taken out by drilling plus the broken rock to the return footage, which is an indicator reflecting the drilling quality. The core collection rate It is related to the fractured degree of formation lithology, drilling technology and quality control. [0003] In geological exploration work, the fundamental purpose of core drilling, which consumes a lot of manpo...

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Problems solved by technology

[0004] In view of the above problems, the present invention can avoid long-term lifting and forced drilling by properly moving the drilling tool of the collector when the core encounters resistance during the core sample collection process and immediately pulling out the drill when the drilling tool is ineffective. Drilling leads to inter-grinding of the core or flushing fluid washes away th