Geology, geography and global energy

Scientific and Technical Journal

Liquidation of wells by thermal impact on plastic rocks

2015. №4, pp. 115-120

Skokov V.V. - Leading Engineer, Ltd "Gazprom Mining Astrakhan", 61a Savushkin st., Astrakhan, 414056, Russian Federation,

The main objective of elimination is increase of safety of the wells which executed the appointment. In the course of elimination of wells of one of the major problems assurance tightness of a design of wells and space between rock is. Emergence not of tightness can be caused by many reasons, including: low efficiency of the applied technologies of fastening of wells; lack of the bridging materials capable to provide long-term tightness of cement between columns and rock; frequent pressure testings of an operational column and cement bridges; Acid treatments of productive horizon; aging of a cement stone temporally; influence of hostile environment (hydrogen sulfide, etc.). Negative influence on fastening of upsetting columns (destruction of cement between columns and rock) is rendered by frequent start-up of a well in operation and its closing, inevitable at operation. During the work of well upsetting columns get warm that leads to thermal expansion both on length of columns, and in the diameter, and at a stop there is the return - cooling and narrowing of columns. Besides, negative impact on timbering of a well render the constant vibration field arising at the movement of a gas-liquid stream from productive layer to the mouth, seismic influence of Earth's crust and abnormal geodynamic processes. All this leads to deformation and cracking of a cement stone, emergence of the channels promoting a filtration of fluids (gas, oil, water, a brine) from layers with in layers with smaller pressure. There are cross-flows, intercolumned pressure and microgriffins round the mouth of a well. In this article is considered the question of influence of temperature on durability of plastic breeds (salt). Set a proportional dependence of the rate of salts flowing deformation shaft wells. The possibility of improving the technology of well abandonment through the use of thermal effects on the bottom zone in the range of the notch of the casing (columns).

Key words: боковое горное давление, текучесть солей, пластичность пород, термическое воздействие, призабойная зона, физико-механические свойства, критическая температура, ликвидация скважины, прочность, вырезка обсадной колонны, lateral mountain pressure, plasticity