Leveling the pickup profile and limiting water flow
Crosslinked polymer compounds
Purpose
The main purposes of injection of crosslinked polymer compositions:
- Reducing the heterogeneity of productive formations;
- Increase reservoir coverage by flooding;
- Reducing the volume of inefficient water injection.
Description
One of the effective technologies for increasing reserve production, increasing flooding coverage and slowing the rate of decline in oil production is the application of crosslinked polymer compositions (CPC) based on water-soluble polyacrylamides.
The use of this technology makes it possible to block the most permeable areas with a polymer gel. Thus, the volume of injected water is redistributed along the thickness and area of the reservoir into previously uncontested or less permeable zones of the reservoir.
Basing on our own and international experience, we can say that the treatment of injection wells using CPC allows us to produce from 500 to 2000 or more tons of oil, depending on the conditions of the deposit and the amount of mobile residual reserves.
Advantages
The use of crosslinked polymer compositions ensures the creation of impermeable screens, which, in turn, enables:
- Reduction of water circulation through the washed highly permeable sublayers;
- Redistribution of filtration flows over the area and section of the treated area of the deposit;
- Involvement of non-drainable mobile stocks in the development process.
Scope of application
The specialists of SNPH JSC develop polymer compositions to meet the needs of a customer, taking into account reservoir conditions, properties of the injected water, available equipment and requirements for the rate of injection of polymer compositions.
The range of SNPH-PM polymers includes more than 100 grades with a wide range of characteristics for various reservoir conditions:
- Medium-temperature polymers are suitable for application in formations with temperatures up to 70°C and water mineralization up to 300 g/l;
- High-temperature polymers are suitable for application in formations with temperatures up to 95°C and mineralization up to 300 g/l.
The line includes polymers of various molecular weights and degrees of hydrolysis – from very low molecular weight to very high molecular weight, from nonionic to polymers with a very high degree of hydrolysis.
Crosslinkers
The use of CPC technology to align the pickup profile involves the use of polymer- crosslinker compositions.
The SNPH-CT crosslinkers make it possible to create the required polymer gel structure in terms of strength and stiffness, which contributes to the effective distribution of the composition in the reservoir. The crosslinking agent is added in the required amount to the polymer composition in order to form a thixotropic structured gel.
The Breaker fluid
Polymer solutions and gels based on polyacrylamide are inert to acid mixtures widely used in oil production processes. In order to eliminate possible complications, such as a significant decrease in pick-up, removal of gel from the borehole, as well as for the purpose of flushing equipment, a special Breaker fluid SNPH-DS was developed. This reagent has various modifications and can work in a wide range of conditions, as well as destroy the most resistant gels or viscous solutions based on polyacrylamide.
Equipment and service
The company SNPH JSC has its own engineering and production facilities, which allows it to design unique equipment that meets customer requirements.
SNPH JSC provides comprehensive service in the fields of its clients.
- Studies of the properties of formations and wells include measurements of the intake capacity of wells; control of pressure drop curves and intake profiles. When pumping polymer compounds, the wellhead pressure is measured.
- A highly qualified team of engineers ensures the continuous operation of the equipment and controls the injection parameters. Monitoring of the injected LPC — crosslinked polymer compositions — allow you to quickly adjust the parameters of the applied technology.
- The mobile laboratory allows the analysis of the quality of injected chemicals directly at the field.
Water flow management technology (OVD) based on WaterAxe reagent
Purpose
WaterAxe is used as a reagent to reduce water production from a productive reservoir with minimal reduction in oil and gas productivity. This reagent completely dissolves in hydrocarbons and forms a gel or precipitate when interacting with water. It is most effective for sandstones – hydrophilic reservoirs, in which it can exhibit blocking properties with high water content in the porous space or as a modifier of phase permeability by reducing water permeability. It is used in combination with hydrophilic agents in hydrophobic reservoirs (carbonates).
Description
WaterAxe reagent is selective. When interacting with water, it creates a durable elastic gel which partially or completely blocks permeable sublayers.
Advantages
Application of crosslinked polymer compositions ensures the creation of impenetrable screens, which, in turn, allow:
- Strong adhesion in the bottomhole zone of the formation;
- Water-binding reagent, completely inert and soluble in hydrocarbons;
- Inert to acids;
- Short period of well downtime and operation without complications;
- Simple application process;
- Reduction of the permeability of washed areas and maintaining permeability in oil-saturated areas;
- Viscoelastic composition. It does not break down with high depressions;
- The chemical composition penetrates into the depth of the formation from 1 meter or more;
- Suitable for formations with a temperature of 10°C and without upper threshold limit.
The reaction is initiated by interaction with water/ interstratial water
Scope of application
- Vertical, directional, horizontal wells (including after hydraulic fracturing). Oil, gas, gas condensate wells, UGS wells;
- Reservoir temperature: up to 1500 C;
- Thickness of the formation: not limited;
- Ambient temperature: up to -600 C;
- Reservoir type: sandstones / carbonates;
- Water content of products: up to 100 %;
- Mineralization of reservoir water: up to 300 g/l;
- Type of flooding: breakthrough of the injected water, plantar, cone formation, column overflow, leakage of electrical equipment, etc.
Sedimentation compositions
Purpose
Selective isolation and limitation of reservoir water inflow by sequential injection of the SNPH-8909 grade B modifier and an aqueous solution of the multifunctional reagent SNPH-SG grade B1 by reducing the filtration and capacitance characteristics of water-saturated intervals and involving low-permeability oil-saturated zones.
Description
When the modifier SNPH-8909 grade B interacts with an aqueous solution of the multifunctional reagent SNPH-SG grade B1, sedimentation-resistant systems are formed blocking the flow of reservoir water into the well. Due to the selectivity of processing and reduction of associated water production, the inflow profile of the extracted liquid is changing.
Scope of application
Producing and injection wells, which open carbonate or terrigenous formations at reservoir temperatures up to 100 ° C, characterized by high watercut (more than 80%).
Emulsion compositions
SNPH-9633
Purpose
The SNPH-9633 reagent is used for processing wells with reservoir temperatures no higher than 60 ° C and is available in several grades, depending on the purposes and conditions of use;
The SNPH-9640 reagent is intended for use at reservoir temperatures of 60-105 °C.
The technology is based on blocking the water-saturated zones of the reservoir with highly viscous emulsion systems of the reverse type, formed during injection of the reagent. Emulsions that occur in the washed-out zones of the reservoir are resistant to water erosion and are destroyed upon contact with oil. The reagent significantly reduces water permeability and does not impair the permeability of oil-saturated sublayers. It has a hydrophobic effect and is able to dissolve and disperse AFS heavy oil deposits and lower the viscosity of oil. This ensures high selectivity of the method.
Description
Producing wells
– technology of water management is designed to reduce the watercut of extracted products (selective isolation) and increase in oil production.
Injection wells are a technology for influencing a reservoir in order to equalize the intake profile and regulate filtration flows.
Advantages
- Low solidification temperature (below minus 55°C);
- The reagent does not contribute to the swelling of clays;
- Capable of binding large amounts of water;
- Promotes the dissolution and dispersion of AFS;
- Injection is not accompanied by foaming;
- Standard oilfield equipment is used;
- The reagent is supplied in commercial form.
SNPH-9777
Purpose
The SNPH-9777 emulsifier is designed to produce invert emulsions used for:
— killing oil and gas wells;
— as a basic reagent for the preparation of process fluids used in the processes of enhanced oil recovery and for major well repairs;
— during the development of oil and gas condensate fields at any stage of flooding in order to increase oil recovery, before acidification for temporary isolation of highly productive flooded sublayers, which allows a targeted effect on a low-productivity reservoir.
Description
The killing liquid is an invert emulsion:
- Dispersion medium – a hydrocarbon solution of the Emulsifier SNPH-9777,
- The dispersed phase is water mineralized with various salts.
The viscosity and density of the killing fluid is regulated by the phase ratio and the degree of water mineralization.
Dependence of dynamic viscosity on the amount of dispersed phase in the emulsion
Initial data: emulsifier SNPH-9777, water – CaCl2 (density 1.358 g/mp)
