RU2156353C1 - Method of treatment of bottom-hole zone of oil producing well - Google Patents

Abstract

FIELD: oil producing industry. SUBSTANCE: claimed method consists in that bottom-hole is treated and downhole equipment is cleaned from paraffin accumulations with help of microorganism in aqueous of nutrient and adaptogen in form of sodium acetate. Process is carried out in conditions optimal for microorganisms activity. Used in process is DESTROIL biological. After treatment, intensive drainage of formation is performed with help of implosive and swabbing devices. Compositions of nonionic surfactants are used for hydrophobization of porous channels of bottom-hole producing formation zone before perforation operations. EFFECT: intensified microbiological treatment of bottom-hole formation zone high oil recovery factor. 3 cl, 1 tbl

Description

 The invention relates to the oil industry, in particular to methods for treating an oil reservoir using microorganisms and chemicals in order to increase oil recovery and restore productivity of the bottom-hole zone of the oil reservoir.

 Known methods of dealing with asphalt-resin-paraffin deposits (AFS) in the downhole and in the bottomhole formation zone (BHP) by injecting various solvents into the well, for example, based on toluene, turpentine, hydroxyethylated alkyl phenol and gas gasoline / 1 /, gasoline, kerosene, ligroin diesel fuel in combination with machining / 2 /. Methods / 1 / and / 2 / involve the use of expensive and flammable reagents.

 There is also a method of increasing oil recovery by pumping chemicals into it, for example surface-active substances (surfactants) / 3 /. However, the use of these methods is constrained due to the high cost of the reagents and lack of effectiveness.

 Closest to the proposed is a method of processing an oil reservoir using microorganisms / 4 /. The method provides for the injection into the formation of solutions of chemicals, for example surfactants, which contribute to improving the conditions for injection of reagents into the formation and easier removal of spent reaction products and contaminants of the formation, and then a suspension of hydrocarbon-oxidizing microorganisms that provide microbiological effects in the zone of the productive formation. After this, technological exposure is carried out to act on the formation, and then intensive formation drainage is carried out with the help of implosion and swab devices to remove mudding products and plugging agents / 4 /.

 The disadvantage of this method is the insufficiently high efficiency associated with the relatively low oil laundering properties of the resulting oil-displacing agents - products of microbiological degradation of part of the reservoir hydrocarbons, the lack of impact on the bottom-hole point of production wells.

 The aim of the proposed method is to increase the efficiency of the formation treatment using microorganisms by actively stimulating the bottom-hole zone of producing wells.

 The technical result of the invention is to increase oil recovery, restoration of the productivity of its bottom-hole zone due to the combined use of chemicals (surfactants) and hydrocarbon-oxidizing microorganisms with a wide functional orientation and under conditions conducive to a more rapid survival of microorganisms in the formation and activation of their vital functions.

The task is achieved by a method of treating the bottom-hole zone of oil wells, including injecting into the formation solutions of chemicals and biomass slurries of hydrocarbon-oxidizing microorganisms (UOM), technological shutter speed of the well and subsequent intensive drainage of the reservoir to remove the mud products and plugging agents, in which the hydrocarbon-oxidizing microorganisms (UOM) use Destroil biological product and its suspension with the content of microorganism cells of at least 10 ⁹ -1 is pumped into the formation 0 ¹² cells / l and when an adaptogen is added to the suspension - sodium acetate salt at a concentration of 0.05-0.2%.

 Usually, when injected into the reservoir, nitrogen and phosphorus salts are introduced into the suspension of microorganisms (UOM). In the described method, it is proposed to introduce diammophos or urea in an amount of 0.05-0.3% into the suspension of UOM.

 At the same time, nonionic hydrocarbon-based surfactants are pumped into the bottom-hole zone of the reservoir.

 The difference between the method is the use of a suspension of the Destroil bio-drug (TU 9291-006-05803071-96), which turned out to be the most compatible with the chemical agents injected into the formation, in particular non-ionic hydrocarbon-based surfactants.

 The microbial suspension used in the method is a community of hydrocarbon-oxidizing microorganisms in the aquatic environment. To improve the adaptability of microorganisms to borehole conditions, an adaptogen salt of sodium acetate is used at a concentration in suspension of 0.05 to 0.2%. This provides a faster survival of microorganisms in the reservoir.

 It was found that the hydrocarbon-oxidizing microorganisms used in this method not only produce products of microbiological degradation of part of the reservoir hydrocarbons, thereby increasing the amount and volume of oil-displacing agents, but also contribute to biodegradation and the prevention of asphalt-resin-paraffin deposits (ASPO) on the surface of tubing (tubing) ) On the surface of the tubing and the existing thin layer of ARPD, a biofilm is formed from UOM and their vital products, which are hydrophilic in nature and thereby slow down the process of further paraffin deposition.

As shown by laboratory and field studies, the use of nonionic and composite surfactants (nonionic surfactants AF ₉ -6 and AF ₉ -12, ML-72, ML-80 (TU-84-509-1-82), AF ₉ -6-12 (TU-38.507. -63-171-91) does not inhibit the activity of hydrocarbon-oxidizing microorganisms, leads to an increase in the overall effect, contributes to a better washing of oil from the reservoir and more effective cleaning of the bottom-hole zone. as a result of a reservoir fire, microorganisms can penetrate previously unreached areas of the reservoir. persons carry out as follows.

 In the field, preparatory and research work is carried out related to the determination of the parameters of the formation, its injectivity and pressure testing of the production string. If necessary, work is carried out to clean the production casing from ASPO by injecting an organic solvent in the volume of the well and holding the well at rest for the duration of the response, depending on the type of solvent used (at least 24 hours).

Underground equipment then rises through the column and tubing (tubing) is pumped calculated amount of hydrocarbon solution with a concentration of 0.1- 1.0% surfactant (AF ₉ Neonol -6 or ML-80) and is forced into the formation.

 After this, the tubing rises, and the well is prepared for perforation according to the requirements of perforating and blasting operations. The formation is shot in the perforation interval with an intensity of up to 10 holes per 1 p / meter in order to increase the perfection of the degree of opening the formation.

Then, on the surface in special containers, the necessary volumes of the microbiological solution are prepared in fresh water or industrial water with the addition of an adaptogen - sodium acetic acid 0.05-0.3% and nutrients, for example, diammophos concentration of 0.05-0.1%, there add the calculated amount of surfactant (Neonol AF ₉ -12 or ML-80) with 0.1-1.0% concentration from the calculation
V = πR ² hm,
where V is the volume of the solution in m ³ ;
R is the radius of the formation covered by the bottom-hole zone, in m, the value of which is taken based on the reservoir properties of the formation and the multiplicity of treatment (1.5 + 3.5) m,
h - perforated formation thickness in m:
m - porosity in dol.ed.

The treatment composition is brought to the receiving downhole pump and is forced into the PPP aqueous surfactant with 0.1-1.0% (AF ₉ Neofloor -6 or ML-80) in a volume of tubing.

 After that, the well is closed for microbiological processes for 1 ... 3 days. In this case, the previously injected hydrocarbon solution serves as an additional feed for the UOM, and the surfactant has a positive effect on the desorption and disaggregation of paraffin deposits.

Further, depending on the type of well and the type of equipment used to clean the formation of mud products and plugging agents, the method is carried out in two versions:
1. An implosion device is lowered into the well to the middle of the interval of the treated formation. By increasing the pressure at the mouth, the membrane is ruptured or the inlet valve of the implosion chamber opens from the control panel of the actuator (depending on the type of implosion device), resulting in a deep depression on the formation. The implosive effect is carried out pointwise, after 0.5 m of the thickness of the reservoir, but not less than 3 times, while an aqueous surfactant solution with a 0.1% surfactant concentration (Neonol AF ₉ -6 or ML-80) is used as a fracturing fluid.

 2. A tubing with a non-return valve and a swab device is lowered into the well to a depth agreed with the geological service of the enterprise-customer, and the well is swabbed. Structurally swab devices can be arranged in different ways. The main structural element of the swab is a plunger pair with a valve device at the bottom. As the swab rises, the liquid above it is transported upward, while simultaneously creating a depression effect on the perforated formations. Depending on the flow rate of the well, development is carried out until the formation fluid is obtained or the well flow rate can be determined.

 The treatment is completed by lowering the underground equipment and putting the well into operation.

 The technical and economic advantage of the proposed method lies in the fact that it allows you to enhance the microbiological effect on the bottomhole zone of the oil reservoir in the right direction without a significant increase in the cost of reagents.

 The effectiveness of the proposed and well-known methods of stimulation of wells is determined by the additional oil production in accordance with the approved industry regulatory documents and guidelines.

 Table 1 presents data on the technological efficiency of the known (basic) methods for processing bottom-hole zones of wells that have been tested in the oil fields of Tatarstan. These methods or their components and principles of stimulation are included in the proposed integrated method of stimulation of the oil reservoir using microorganisms and physico-mechanical methods of exposure, which due to the synergistic effect and new technological solutions should have higher technological efficiency compared to known methods of stimulation wells.

Sources of information:
1. USSR copyright certificate 1562433.

 2. RZH "Mining", 1990, 5G389.

 3. Copyright certificate of the USSR 1511375.

 4. RF patent 2129658.

Claims (3)

1. A method of treating the bottom-hole zone of oil wells, including injecting into the formation solutions of chemicals to a suspension of biomass of hydrocarbon-oxidizing microorganisms, technological shutter speed of the well, followed by intensive drainage of the formation to remove the mud products and plugging agents, characterized in that the suspension of microorganisms of the biologic preparation is pumped into the formation , with a cell content of at least 10 ⁹ - 10 ¹² cells / l and with the addition of an adaptogen - sodium acetate salt at a concentration of 0.05 - 0.2%.  2. The method according to claim 1, characterized in that diammophos or urea is introduced into a suspension of microorganisms in an amount of 0.05-0.3%.  3. The method according to claims 1 and 2, characterized in that non-ionic hydrocarbon-based nonionic surfactants are pumped into the bottomhole zone of the reservoir.

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