Application of temporary and shielding plugging technology to improve well logging responses for tight sandstone gas reservoir

Tight gas bearing sands are vulnerable to the damage from drilling fluids due to its characteristics of low porosity and permeability,low initial water saturation and natural fractures.Owing to the water phase trap damage caused by drilling and completion fluids invasion,the logging data do not reflect the real characteristic of gas reservoirs,which results in weak or no well log response and response and gas formation miss.A thin and strong filter cake without permeability is formed by using the temporary and shielding plugging technology favorable for guarding against solids phase invasion and reducing formation damage.This paper regards the Tabamiao tight sandstone gas reservoir in the north of Ordos Basin as the research subject and analyzes the conventional logging data separately obtained from laboratory evaluation and field application of shielding and temporary plugging drilling-completion fluid,showing that the temporary and shielding plugging technology can improve the filter cake quality and the roughness of well diameter and borehole face,provide a good condition for well data acquisition,enhance well logging responses to gas zone and the logging test capacity to gas saturation,and is beneficial to the discovery of high gas production formation.The capillary imbibition experiment reveals that the water phase trap damage cause the high gas production formation-Box 2+3-not to be found before applying the temporary and shielding plugging technology.