RU2224884C2 - Method for exerting thermochemical influence upon layer extraction area - Google Patents

Abstract

FIELD: oil and gas extracting industry. SUBSTANCE: method for thermochemical treatment of extraction area of layer with asphalt-resin-paraffin laydowns includes consecutive pumping of two compounds into extraction area, for which combustible oxidizing system is used, first compound of which includes ammonium nitrate and water, and second compound of which includes salt of nitrous acid - sodium nitrite and water. First compound additionally includes carbamide and catalyst - nickel nitrate, with following proportion of components in %. Ammoniac saltpeter - 15-65, carbamide - 2-18, nickel nitrate - 0.0005-0.05, water - the rest. Second compound includes said salt in amount of 15-65% and is pumped in amount 1.5- 4 times less, than first compound. Second compound additionally includes 0.0005-0.005% of corrosion inhibitor - hydroxy aldehydes. EFFECT: increased effectiveness of asphalt-resin-paraffin laydowns removal. 2 cl

Description

The method relates to the oil and gas industry, in particular to the processes of thermochemical treatment of the bottom-hole formation zone (PZP) of oil, gas and gas condensate wells with the goal of eliminating the clogging of the pore space with tar and paraffin deposits (paraffin deposits).

A known method of high-energy thermochemical effects on the bottomhole zone [1], which consists in the sequential delivery to the bottom of the well of granular metallic magnesium and hydrochloric acid. Such a system is quite technologically advanced. It is implemented using equipment used in the field for well repair. The positive aspects of this technology are:

- the absence of heat loss in the wellbore, which are typical for methods based on the injection of coolants from the surface;

- unlimited depth of exposure;

- the ability to control the total amount of heat using volumes and concentrations of reacting substances.

The disadvantage of this technology is the need for preliminary fracturing and the use of inert carriers or special containers for the delivery of granular metallic magnesium to the bottom of the well.

The closest analogue is the method of thermochemical treatment of the bottom-hole zone of a reservoir, which is sedimented with paraffin deposits, in which two compounds are sequentially pumped to the bottom of the well, which are a fuel-oxidative system in which the first composition contains ammonium nitrate and water, and the second contains nitrous acid sodium and water [ 2].

The methods of thermochemical impact on the productive formation [1] and [2] do not allow reaching the high temperatures necessary for the conversion of clogging paraffin deposits to lighter hydrocarbons, and even more so their burnout. In addition, the method [2] cannot provide high temperatures and pressures.

The purpose of the proposed method of thermochemical effects on the bottomhole formation zone is to create a two-component system (both components are liquids or suspensions depending on the requirements of the bottomhole treatment zone), the sequential injection of which into the bottom of the well leads to the interaction of the components directly in the perforation interval with the release of a significant amount of heat and a large volume of reaction gases - reaction products, with the provision of increasing the effectiveness of the impact on the PPP.

This goal is achieved by the fact that in the method of thermochemical treatment of the bottom-hole zone of the formation, colded by an ARPD, in which two compounds are sequentially pumped to the bottom of the well, which are a fuel-oxidative system in which the first composition contains ammonium nitrate and water, and the second contains a nitrous salt acids - sodium nitrate and water, the first composition additionally contains urea and a catalyst - nickel nitrate - in the following ratio of components,%: ammonium nitrate 15-65, urea 2-18, az tnokisly nickel 0.0005-0.05, remainder water, and a second composition comprising said salt 15-65%, the second composition is injected in a volume 1.5-4 times smaller than the first. The second composition may additionally contain 0.0005-0.005% corrosion inhibitor - aldehyde alcohols.

Depending on the ratio of these components, the speed and direction of the chemical reaction between the first and second compositions are regulated, thereby reaching temperatures up to 700 - 900 ⁰ С and pressure up to 0.8 MPa. In this case, the conditions for the elimination of paraffin deposits of any density are created. The high pressure of the reaction gases provides additional fracturing and permeability of the reservoir and restoration of well production.

The method is as follows. The first solution containing, wt.%: Ammonium nitrate 15, urea 10, nickel nitrate 0.005, the rest water, the second composition containing sodium nitrate 35 wt.% And the rest water, is pumped to the bottom of the well, which is sedimented with ASPA. The first composition is injected in a volume that allows filling the sump of the well and half the perforation interval. The density of the composition can reach 1.45 g / cm ³ . The second composition is pumped in a volume 2 times smaller than the first. The density of the compositions allows you to displace water (if any) from the sump and the interval of perforation of the well.

Sources of information

1. US patent No. 4615391, MKI ³ E 21 02/21/1986.

2. US patent No. 4482016, E 21 In 43/27, 11/17/1983, 10 S.

Claims (2)

1. The method of thermochemical treatment of the bottom-hole zone of a formation, which is caked with asphalt-tar and paraffin deposits, in which two compounds are sequentially pumped to the bottom of the well, which are a combustible-oxidizing system in which the first composition contains ammonium nitrate and water, and the second contains a nitrous acid salt sodium nitrate and water, characterized in that the first composition additionally contains urea and a catalyst - nickel nitrate in the following ratio of components,%: ammonia RA 15-65, urea 2-18, nickel nitrate 0.0005-0.05, water - the rest, and the second composition contains the indicated salt 15-65%, the second composition is pumped in a volume 1.5-4 times less than first. 2. The method according to claim 1, characterized in that the second composition additionally contains 0.0005-0.005% of a corrosion inhibitor - aldehyde alcohols.