Study And Test For Drilling Pipe’s Resistance Reducing In Submarine Hydrothermal Core Drilling

With the depletion of mineral resources of land, study and development of marine mineral resources’prospecting and mining technology has become an inevitable orientation.Contemporary major marine geological prospecting techniques include:marine communications satellites and high-precision global positioning technology, sonar system and submarine topography mapping system as well as seabed core drilling techniques.Among these prospecting techniques, seabed core drilling is undoubtedly one of the most direct used means of submarine geological survey. The same situation as the world powers, submarine core drilling rig is also an important research project of marine technology in our homeland. And the coring depth of drilling rig had been increased from the initial 0.5m to current 20 m by the efforts of researchers in recent decades.However, with the deepening of coreing depth, the rig’s drilling efficiency has been reduced due to various factors, which has become an obstacle to the development of submarine technology of core drilling on key issues.In response to these challenges,hydrothermal sulfide mining area was chosen as the study environmental background, and high performance composite calcium sulfonate grease have been proposed as a drill lubrication media on the basis of theoretical analysis and experimental study, moreover, a friction measurement device was used to test the grease’s friction reduction performance, and then a few achievements were obtained as follow:comprehensive analysis of the seabed coring rigs operating environment, summarized the submarine core-drilling construction technology; Tested out compound calcium sulfonate grease formulation model, obtained an optimal complex calcium sulfonate grease formula (wc (acetic acid) 2.25%,wp (boric acid) 2.33%,wz (fatty acid) 3.6%, wt (T106) 26.1%)based on BP neural network model and the sample were prepared; developed a high precision drill and core friction measuring device; by analyzing the experimental data, obtained the affect order of the simulation factors on the friction reduction properties of the lubricating grease-the largest submarine pressure, followed by acidity, salinity minimum, and identified the composite calcium sulfonate grease’s lubrication failure time,16h, in the simulated seabed environment; evaluated the effect of the complex calcium sulfonate grease’s friction reduction properties-it can effectively reduce the friction of the drill pipe and the surrounding rock more than 50%, and finally, verified the feasibility of the lubrication used in submarine coring operations.