RU2178069C1 - Method of oil deposit development - Google Patents

Abstract

FIELD: oil producing industry, particularly, methods of development of nonuniform oil formation with restriction of water inflow into producing wells and increased oil recovery. SUBSTANCE: method includes injection of aqueous solution of biological surfactant KShAS-M together with biological product and water glass and forcing of reagents through injection well into formation by fresh water; simultaneous injection of aqueous solution of salts, biological surfactant KShAS-M together with biological product and water glass. Biological product is used in the form of product of biotechnological synthesis containing at least 40% of protein. Aqueous solution of salts is used in the form of solution of multivalent metals. EFFECT: higher efficiency of clogging of highly permeable layers and restriction of water inflow into producing wells. 1 tbl, 2 ex

Description

 The invention relates to the oil industry, and in particular to methods for developing a heterogeneous oil reservoir in order to limit water inflow into production wells and increase oil recovery.

 A known method of developing oil fields, including the sequential injection of an aqueous solution of polyacrylamide with sodium silicate and a saline solution containing an aqueous solution of a mixture of calcium chloride and technical lignosulfonate (RF patent 2127802, E 21 B 43/22, 1999).

The closest analogue to the proposed method is a method of developing an oil field, which includes the sequential injection through an injection well of an aqueous solution of a biological surfactant bio-surfactant KSHAS-M, a Simusan biopolymer and liquid glass, forcing the reagents into the formation with a rim - fresh water buffer, then pumping mineralized water - water of this field with a salt content of 140-250 g / dm ³ (RF patent 2136869, Е 21 В 43/22, 09/10/1999).

 The objective of the invention is to increase the efficiency of blocking highly permeable interlayers and limiting water inflow into production wells.

 The problem is solved in that in a method for developing an oil field, which involves injecting an aqueous solution of a biological surfactant bio-surfactant KSHAS-M together with a biological product and liquid glass through an injection well, forcing the reagents into the formation with a fresh water buffer. then the injection of an aqueous solution of salts, bio-surfactant KShAC-M together with a biological product and liquid glass are pumped simultaneously, a biotechnological synthesis product containing at least 40% protein is used as a biological product, and a multivalent metal salt is used as an aqueous solution of salts.

Bio-surfactant KSHAS-M according to TU 9296-015-00479770-2000 is a natural bio-surfactant composition of glycolipid nature, produced by the microorganism culture Pseudomonas aeruginosa S-7. KSHAS-M bio-surfactant solutions have the ability to reduce the surface tension of water to 30 mN / m, as well as high emulsifying activity (liquid paraffins, oil, oils) E ₂₄ to 60-80% (E ₂₄ - emulsion stability for 24 hours). Their main advantage is biodegradability or the ability to completely decompose under natural reservoir conditions, i.e., bio-surfactant technologies are environmentally friendly.

The commodity form of liquid glass according to GOST 13078-81 with a mass fraction of silicon dioxide of 24.6-31.6% and a density of 1.36-1.5 g / cm ³ .

 Biotrin according to TU 9291-001-00479999-95 is a dry product of inactivated biomass. It is not toxic and does not have a cumulative effect.

 BVK (Eprin) according to GOST 28179-89.

Mineralized water - wastewater with a density of at least 1100 kg / m ³ .

 Calcium chloride according to GOST 450-77.

 Magnesium chloride according to GOST 7759-73.

 When injected, the liquid glass provides chemical interaction with the molecules of the rampolipids of the KShAC-M bio-surfactant, protein cells of the biotechnological synthesis product, and multivalent metal ions of mineralized water or multivalent metal salts. As a result of this interaction, a sparingly soluble elastic gel is formed, which effectively reduces the water permeability of the washed zones and increases the coverage of the formation by water flooding. A patch of fresh water between a mixture of bio-surfactants, liquid edema, a biotechnological synthesis product and mineralized water or an aqueous solution of multivalent metal salts controls the depth of penetration of the gel into the formation.

To study the mechanism of behavior of the composite bio-surfactant system KSHAS-M, liquid glass, a product of biotechnological synthesis and a solution of salts of multivalent metals in a porous medium, a model of an inhomogeneous reservoir was used. In physical modeling, the model consists of two hydrodynamically unbound interlayers, which are metal columns filled with a porous medium. Interlayers have a common entrance for pumping liquids. The interlayer length is 0.6 m, diameter 3.0 • 10 ^-2 m. Ground quartz sand served as a porous medium.

To create bound water in a porous medium and initial oil saturation, the models of the layer after preliminary evacuation were saturated with formation water followed by its displacement with oil. The amount of bound water and oil in a porous medium was determined by the volumetric weight method. The experiments were carried out in a constant flow rate of injected fluid (~ 20 cm ³ / h) at 24 ^o C.

 The experimental technique was as follows. First, primary flooding was carried out to a certain oil saturation and stabilization of the filtration characteristics, which occurs after reaching 100% water cut in the production of a highly permeable layer. The degree of water cut of the products extracted from the reservoir as a whole was achieved by selecting the ratio of the permeability of the layers. After downloading the rims, the waterflooding process resumed. The injection efficiency of the compositions was determined by the residual resistance factor and the increase in the oil recovery coefficient compared to conventional water flooding. The results of the study of the process of oil displacement using the method are shown in the table.

 Example 1 (prototype). A rim consisting of a biopolymer and bio-surfactant KSHAS-M is supplied to the reservoir model with a ratio of components 1: 1 in an amount of 0.4 bp. Then the rim of bioreagents is pushed with liquid glass at a ratio of 1: 1: 0.2. A rim of fresh water (0.2 bp) is pumped in and filtration is stopped for 24 hours. Then, filtration with mineralized water is resumed until the pressure drop stabilizes and the samples are completely water-cut. The residual resistance factor is 19.1. Oil recovery growth of 9.7%.

 Example 2 (the proposed method). A rim of fresh water (0.05 p.p.) is pumped into the reservoir model, then simultaneously bio-surfactant KSHAS-M, liquid glass and biotrin 0-3 p.o. The reagents are pushed with fresh water (0.05 p.p.). Next, a solution of calcium chloride of 0.3 p. and stop the filtration "on exposure" 24 hours. Then resume the experiment. The residual resistance factor is 45.4. Oil recovery growth of 21.4%.

An example of a specific implementation of the method in the field. The field is characterized by layered heterogeneity, high injectivity of injection wells (more than 100 m ³ / day). The water content of the extracted products is 90%. The average permeability of 0.13 μm ² . Porosity 0.2-0.24. Formation oil has a viscosity of 1.6 MPa • s. Produced water chloride-calcium type with a small salinity of 16.4 kg / m ³ . The reservoir was opened by one injection and one producing well. Well grid density 25 ha / well.

To implement the method, the injection of wastewater into the injection well is stopped. A rim of fresh water is pumped in an amount of 8 m ³ . Then pumped an aqueous solution of bio-surfactant KSHAS-M in a mixture with liquid glass and biotrin in an amount of 15 m ³ . Reagents push 15 m ^{3 of} fresh water. Next, a solution of calcium chloride is pumped in an amount equal to the volume of the rim of the mixture of bio-surfactant KSHAS-M liquid glass and biotrin. A rim of fresh water 15 m ³ . The well is stopped for 1 day "for reaction". After treatment, the reservoir is further exploited by conventional waterflooding.

 The working volumes of injected reagents are determined depending on the specific injectivity of the wells and the thickness of the formation.

 Processing of the injection well is carried out by the installation of TsA-320M.

 Three months after the treatment of the well, a decrease in water cut in the production of the well from 91 to 79% was observed, and the specific technological effect was 60-70 tons per 1 ton of reagents.

 The proposed method is highly effective for increasing oil recovery at the late stage of development, where alignment of injection well profiles is necessary, isolation of water-washed zones, limitation of water inflow, followed by intensification of oil production from undrained zones of the formation.

Claims (1)

 A method for developing an oil field, including injecting an aqueous solution of a biological surfactant bio-surfactant KSHAS-M together with a bio-product and liquid glass through an injection well, pumping reagents into the formation with a fresh water buffer, then pumping an aqueous solution of salts, characterized in that the bio-surfactant KSHAS-M together with the bioproduct, liquid glass is pumped simultaneously; a biotechnological synthesis product containing at least 40% protein is used as a bioproduct, and as an aqueous solution ora salt - salts of multivalent metals.

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