The stimulation of mining and injectivity of injection wells using responsereader reagent (RR)

TECHNOLOGY FOR STIMULATION WITH THE USE OF RESPONSEREADER REAGENT PP 


In the process of its development the number of wells is much below its potential. This is due to several reasons, but one of the main issues is the interaction between clay minerals and water. 
The natural permeability of the reservoir remains only till its opening in the drilling process and depends on the physico-chemical and granulometric composition of minerals and formation fluid. But in the process of drilling it enters the filtrate of the washing fluid. The amount and depth of penetration, ceteris paribus, determines the differential pressure (repression) on the layer during its opening. The magnitude of repression, for in-field data can be up to 15...20 MPa. Thus, the drilling mud filtrate penetrates into the formation, causing swelling of clay particles and is retained in a porous medium by capillary forces and displaced from the pore channels can only be when there is significant pressure drops, which makes it difficult to promote the formation fluid to well bottom. With such a high repression of the depth of penetration zone of the filtrate can reach up to 10 meters and more. 
This phenomenon is called hydration. There are two main mechanisms of adsorption of water on clay particles: adsorption of monomolecular layers of water on the flat surface of the crystal lattices of the particles and the osmotic swelling that occurs due to high concentration of ions, held by electrostatic forces near the surface of clay particles. 
In those cases where the clay deposits under the influence of overlying layers of sedimentary rocks are compacted, the clay minerals adsorbed water is squeezed out with the pore water. The remaining amount of water depends on depth, type and volume fraction of clay minerals, presence of exchangeable cations and some other factors. At the opening of formations containing clay deposits, dehydrated clay begins to absorb water, increasing in volume. This phenomenon can cause not only clogging of the channels, but also to destabilize the well bore, which manifests itself in the form of plastic flow of rocks composed predominantly of sodium montmorillonite. 
A slightly different mechanism of action, but calling the same phenomenon can occur when the osmotic swelling of the clays. Its essence consists in the following. Due to the surface dissociation of clay particles and dissolved salts in the rock, between pore water and water interacting with the clay, there are concentration gradients that are introduced into the process of hydration of the osmotic force. Osmotic swelling occurs as a result of the fact that the concentration of cations between clay layers more than their concentration in the bulk aqueous solution. Therefore water is drawn into the interlayer space, causing the distance between the layers is increased and there is a possibility of formation of diffuse parts of double electric layers. 
In addition to the filtrate, the solid phase also penetrates into the formation, which leads to its blockage. It was established experimentally that the permeability of 0.38 to 0.6 µm2...is the largest pore blockage of wellbore zone and makes it very difficult to filtrate after washing and clay particles from the formation into the well during the reverse flow. 

Based on the foregoing, there are three options of chemical exposure on the bottomhole formation zone to increase its permeability. 

1. Dissolution of clay particles. For this purpose various options of acid and pinocytotic treatments aimed at the dissolution of clay particles, however, these compounds act not only on the clay particle, and silicate cements. 

2. The change in the exchange complex. These technologies are designed to prevent peptization clay particles in the formation. For this purpose, aqueous solutions of electrolytes containing the ions K+, NН4+ which prevent clay swelling. The concentration of electrolytes in that solution must exceed the concentration of electrolytes contained in the reservoir water. The best use of such compositions for cleaning wells. 

3. The destruction of clay particles (raspisatsya). Technology responisble aimed at the destruction of clay particles. The technology uses an aqueous solution ammoniagenesis substances, acid and catalyst. The reaction mechanism was the effect on the crystal lattice of the clay particles, while there is a weakening of structural bonds, resulting in the destruction of clay particles, after which the latter is incapable of peptization and seal easily, and are removed from the pore space. 

Application responsereader reagent PP 

Clay represent finely dispersed and relatively stable mineral compounds of the group of hydrous aluminium silicates or layered layered tape structure. They are based on the octahedral grid, which form octahedra, articulated to the side edges. In the center of the octahedron Al(O,Oh)6 is a cation Аl3+. The tops of the octahedron are occupied by oxygen or hydroxide ions. In other words, the crystal lattice of clay minerals formed by the combination of silica and oxygen-hydroxide-aluminum layers. Accordingly, by removing or linking atom Аl3+, the equilibrium in the crystal lattice of the clay particle is broken and splits it into its component parts. 

Technology responisble aimed at the destruction of clay particles. 

The reaction mechanism is the impact on the crystal lattice of the clay particles, while there is a weakening of structural bonds, resulting in the destruction of clay particles, after which the latter is incapable of peptization compaction and easily from the pore space. 

Intensification of the production in OOO "Kubangazprom" 
Work on the intensification of inflow to the wells of OOO "Kubangazprom" began to take place since February 2006. For stimulation technology was used, developed in INNOYL, OOO: raspisatsya bottomhole formation zone with application of responsereader reagent PP. 
Before beginning work on a natural core material, studies have been conducted different acid compositions to determine their effectiveness. Studies were conducted on various compositions, including hydrochloric acid and glyoxylate. 

On the basis of the experiments were made the following conclusions: 

1. Of the proposed compositions based on inorganic acids and alkalis is best demonstrated compositions based on hydrochloric acid and glyoxylate. These compounds are traditionally used in the oil and gas industry under the name of glyoxylate. Relatively high performance in the application of these compositions can be explained by the fact that they do not destroy the structure of clay particles and dissolved clay and silicate of education, creating channels, but the duration of treatment should not exceed 4 hours to avoid generowania of the reaction products. These formulations can be used for processing of borehole zone of the formation, increasing its permeability, followed by the deeply penetrating treatments with application of organic acids. 

2. The use of alkaline reagents in clogged reservoirs is not valid due to the strong hydration of clays by increasing the inter-planar distances in the clay particles. 

3. The use of aqueous solutions of sulfide lye and sodium bisulphite produced no results. 

4. The most effective proved to on the basis of responsereader reagent PP in clogged layers with a developed system of cracks that was shown in the experiment (Fig.1) when in an artificially created fractured models after pumping responsereader composition of PP increased permeability of 8.64 times. In field conditions, such cracks can be created by the periodic creation of the maximum pressure, followed by a sharp reset (hydrocarbone). 

5. In the simulation conditions, the mudding of a bottomhole zone of the reservoir drilling fluid, a composition based on responsereader reagent PP, also showed its high efficiency, the permeability of the sample after the mudding mud followed by pumping an aqueous solution of the reagent responsereader RR rose 5.84 times (Fig. 2). Conduct this experiment suggests that during the development of wells came from drilling the application of this technology will be quite effective. After experiments on core material have been conducted field work at the wells Koshekhablskoye, Markov and 

Krilonskogo fields 
On Koshekhablskoye field was carried out injection of 10% saline solution responsereader reagent PP in the amount of 15m3 / shutter response-within 48 hours. The result of this work the rate of gas production increased from 4.2 m 3/day up to 12 m 3/day. For the Markov field was carried out processing on the 3 wells pumped at 7m3 7% solution responsereader reagent PP delayed response 24 hours. The average increase of flow rate was from 2 to 7 times. On Krasilovka field was carried out treatment on 4 wells pumped through 4m3 5% solution responsereader reagent PP delayed response 24 hours. The average increase in yield was 1.5 to 2.5 times. For more up-fifty-treated wells amounted to 4.19 million m3 of gas to the amount of 5.95 million rubles. In an experiment to compare the effectiveness of technology on 1 well was carried out by means of hydrochloric acid treatment, which has not produced results. 

Conclusions: 

1. Technology responisble with the use of responsereader reagent PP showed high efficiency at minimum cost, since its implementation, in most cases, were not required to attract the crews KRS or PRS. 

2. In the implementation of this technology requires the use of liquid acids, which allows you to refuse the use of containers for storage of acids and acid units. 

3. The ability to carry within the field responsiveui reagent RR conventional vehicles and provide storage at any indoor venues.

 
 
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