Specifics of drilling wells in the abnormally-high-pressure rock beds in the oil-and-gas fields of Eastern Siberia

Abstract

Eastern Siberia is Russia’s most promising region as a potential high-capacity oil-and-gas source of the country. Its territory includes large provinces that are promising in terms of oil and gas reserves. Opening-out of the oil and gas deposits is restrained by the deposits’ complex geological structure hindering the hole-making. This includes: saliferous deposits, abnormally high rock pressure in the intervals containing highly mineralized waters, unstable caving-in clay rocks, etc. Many of these problems can be solved using highly-mineralized Siberian brines occurring all over the Siberian craton, one of the largest world’s hydro-mineral provinces. The paper deals with the research on the preparation of weighted and hydrogel-magnesium drilling muds based on the salt from the Znamensk deposit brine. The muds have been processed with Flo-Vis Plus biopolymer and Flo-Trol starch that have a wide-range resistance to high mineralization. The mud weighting has been done with barite and hematite. Based on the Znamensk deposit brine, hydrogel-magnesium drilling muds have been prepared. The research shows that the fluid-loss reducing agents (i.e. Sul-facell and Camcell) should be infused as a 5% solution because they are fixed in the hydrogels when in a dry state. Samples 7 and 8 are not recommended as stabilizers because the solutions have high filtration and viscosity values. The use of the brine helps to prevent cavernosity and salt-bearing rocks’ solubility as well as to prevent the complications connected with the brine recrystallization in the reservoirs and on the surface of the drill tool.