SU827753A1 - Method of preventing deposition of hydrates in gas wells - Google Patents

Description

one

The invention relates to the extraction of natural gas and can be used to prevent the deposition of hydrates in gas wellbores.

A known method for eliminating hydrate deposits involves washing the wellbore with various solvents 1.

The disadvantage of this method is that the wells need to be stopped. In addition, additional equipment is required to flush the well.

A known method of preventing hydrate deposits in the trunks of existing gas wells involves supplying hydrate inhibitors to the well bottom and regenerating it on the surface 2.

The disadvantage of this method is that it requires a large consumption of inhibitors, for separating and regenerating them from the gas stream at the wellhead a separator and a regeneration device are installed. Moreover, a large amount of the inhibitor is lost irreversibly. The disadvantage is also the complexity of servicing the equipment used, the significant capital costs of an additional wellhead.

The purpose of the invention is to simplify the method and reduce operating costs.

This goal is achieved by the fact that the regeneration is carried out directly in the well by maintaining the gas flow rate not exceeding j m / s.

The method is carried out as follows.

A portion of a volatile antihydrate inhibitor, such as methanol, is introduced from the wellhead to the bottom of the well.

gas arriving at the well bottom with a high reservoir temperature is in contact with methanol and is saturated with its vapors. As the flow approaches the section of the trunk covered with hydrates, the temperature of the flow decreases, most of the methanol B conforms to the phase equilibrium of the gas-inhibitor-hydrate system, decomposes the hydrated phase, and the decomposition products - water-methanol solution drains to the bottom.

Claims (2)

Thus, in the course of operation of a well, the mode of which is selected so that the liquid is not discharged from the bottom to the loop, methanol is practically not lost by the well. The condition that no fluid is carried to the plume is reached at gas flow rates in the well not more than 3 m / s. During the decomposition of hydrates, the water flowing through the pipe walls will decrease the concentration of methanol in the bottomhole solution, however, due to the significant temperature difference in the bottom and the section of pipes covered with hydrates, the ratio of water to methanol saturation of the gas changes in favor of methanol as it approaches the hydrated area. Thus, the well site in the interval the downhole-hydrate site is a kind of regeneration column, where the produced natural gas serves as a carrier gas. The process of regeneration of the inhibitor and the elimination of hydrated sediments occurs without outside intervention and does not require continuous monitoring. Claims The method of preventing hydrate deposits in gas wells is to apply a hydrate formation inhibitor to the well bottom and regenerate it, characterized in that, in order to simplify the method and reduce operating costs, regeneration is carried out directly in the well by maintaining the gas flow rate not exceeding 3 m / s. Sources of information taken into account in the examination 1. Yu. P. Korotyev. Exploitation of gas fields. M., "Nedra, 1975, p. 314. 2. Degt roar B. V. and others. Fighting hydrates in the operation of gas wells in the North. M., “Nedra, 1970, p. 52-85 (prototype).