Application Study Of Foamed Plant Gum In Large Fracture Formation

In this paper introduce that drilling fluid leakage seriously and the hardly come back from the bottom of the borehole, when drilling in large fracture formation, which induced a serious of accidents such as sticking> burying drilling and burning of bit, which resulted in a large number of drilling footage scrapped. In order to overcome the technical problem, foamed plant gum was applied in coal geological exploration for the first time in hunan province.First it has done research in the composition and basic properties of foam fluid even in the basic characteristics of the foam drilling fluid. Secondly, it has also done research in the physical properties,chemical composition and influence of plant gum which has to the character of drilling fluid. Finally, based on the theory of the foam fluid and plant gum, it has also took the stability and rheological property of foamed plant gum drilling fluid in research from laboratory test to production practice.The basic characteristics of plant gum was studied through laboratory tests, with it the adaptive plant gum was determined, and the influence that the plant gum had to foam fluid was also studied.The accidents encountered in the process of drilling was studied and summarized through characters and cause of large fracture and karst cave formation. Combining with specific coal exploration of actual circumstance in Changsha city of Ningxiang county and the experience of designing foam generator in the past, it has designed a set of simple,convenient foam generator which was applied to field test. It has also designed a set of circuit device according to the experimental sites and equipment conditions.Through the field practice showed that the foam plants gum could succeed in solving fluid leakage problem in large fracture and karst cave formation, and it guarantee the quality of borehole with the powerful ability to carry rock powder, which could be taken as an example to the similar project.