Study Of Wall-protecting And Leaking-pluggingincarbonaceousphyllitein A Mining Area Of Gansu Province

The gold belt of Gansu Province is located in the famous Golden Triangle area of “Chuan Shan Gan”Mining Area.Within the mining area,the bedrock stratum generally broken, the Quaternary Systemformation is thick and thedrillability of rockis different,easydeviation,formation leakage,easy to fall.It is necessary to doa comprehensive study of the previous construction practice in the mining areaof long intervalcarbonaceousphyllitestratum,explore and summeup thecharacteristics of carbonaceous phyllite stratumand construction technology.Due to the complex mining bedrock strata,the geological structure in the area generallybroken and looseness, and the interbedded Strata of Soft and Hard Rockfrequently. Carbonaceous phyllite stratum is vrey thick, burialin everydepth,itmight be drilledfrom 50 meters to 1100 meters indepth.Generallyafter run out the surface casing, and thenseldom penetrate this layer. The interbedded Strata of Soft and Hard Rock by Carbonaceous phyllite stratum with Plagiogranite porphyry,silicalite and quartzysandstone.In some horizon,carbon shale phyllite wrapped quartz granite particle breakage,ifthe carbon shale phylliteabsorbed water,then the formation will become soft, dispersed into the drillingliquid.Due to the loss of support,the broken quartz granite block,the collapse occurred and caused more complicated situation in the hole,burying drilling holes,and once occurredthe accident,it is very difficult to deal with.This paper discussed mechanism of the formation easyto fall,when encounter the water,it is easy to dispersible,in-depth explorationof stratigraphic distribution features and construction characteristics.Focuses on the analysis and summary of the construction characteristics of drilling within the mining area of carbonaceous phyllite stratum,Through the optimization of mud formula,to some extent to solve the problem of wall plugging drilling fluid.Bystudy the method of cement grouting and application of the bridge plugmaterials,effectivelyprevent the wall plugging,improvedrilling efficiency and reduce drilling cost.Aiming at the construction problems mentioned above, this paper based on the construction practice, to carry out drilling theory research, this paper carried out research in the following 3 aspects:(1)Carbonaceous phyllitestratum characterization.Theresearch carry out from carbonaceous phyllite characteristics, mechanism of instability and other aspect.By anlysis the study of lithology analysis results, Combined with the characteristics of shale and coal bed, grasp the mechanism of carbonaceous character and it is easy to dispersible when encounter the water,findout the Countermeasures for the site construction,within the mining area complex carbonaceous phyllite stratum construction has certain guiding significance.(2)Study on the countermeasures. By studying the properties of carbon phyllite, optimization the restraining mud formulation,effectively inhibit the formation dispersion, ensure the construction production;design of mud circulating system, using solid control equipment to carry out on-site maintenance of mud, mud performance monitoring in the field, timely adjust and optimize the mud formulation, ensure the mud performance.(3)To carry out the research of plugging technology in mining area.Study on cement water glass plugging process, determine the water cement ratio, optimize work flow; using hemp, vegetable gum, paper, cotton and other bridge plug materials for plugging, andcarry out on-site test.In addition, this subject provides technical reference for construction of find New mines in deep blind stage ofthe mining area.