Oil recovery increase

Our developments

Introduction

Since 201З, the Group of Companies together with SNF (France), in order to increase the oil recovery ratio, has been implementing polymer flooding technologies for the fields in the last stage of development. To date, three polymer flooding project are successfully implemented and three more are under development. The Group of Companies implements polymer turnkey flooding, including design and estimate documentation, engineering support, analytical works, efficiency assessment, etc.

Alstron

Business profile

During 20 years of operation the Group of Companies has proved to be a reliable partner in the service market of Kazakh and Russian oil and gas industry. Production facilities are located in the majority of  oil and gas producing regions of the Republic of Kazakhstan and the Russian Federation.

Domestic and foreign experience of oil field development shows that one of the most effective methods of enhancing oil recovery is polymer flooding using water-soluble polymers at the fields of the Republic of Kazakhstan. The effectiveness of the technology is confirmed by the results of experimental and industrial tests.

Purpose: reduction of injected water mobility in the form of thickened polymer solutions, partial polymer adsorption on the rock and creation of residual resistance actor, repressuring medium front zoning leveling according to the flooding area and productive formation vertical section, increase of oil recovery factor.

Scope:

• Terrigenic and carbonate revervoirs;
• Oil viscosity: 1 to 10,000 mPa*s;
• Temperature: less 120°(;
• Permeability: not less than 1О mD
• Formation water salinity: not more than 200 g/l.

Method of procedure:

Polymer solution with concentration of 0.03 to 0.2% in amount of 30% to 100% of formation steam volume is injected into formation bank depending on geological structure of deposit and oil viscosity.. The method is to dissolve the polymer in the injected water in order to increase its viscosity, to increase the degree of coverage of the hydrocarbon reservoir by the displacement process.

The resulting viscosity increase as well as the increase in water phase permeability that occurs when some polymers are used, is responsible for the lower ratio of oil to water mobility. Decrease in mobility ratio positively affects displacement ratio and volume coverage ratio.

Well 2-1О Injection Equipment

Polymer solution is prepared and injected using special equipment produced by SNF (France). The polymer preparation and injection line is located in two joined 40’ containers.

Process equipment consists of:

1. Hopper for receiving and feeding polymer to PSU device with capacity up to 1,500 kg of dry polymer.
2. PSU device is designated for pre-wetting, grinding and final mixing with water. It provides up to 15,000 ppm concentration. Its capacity is up to 100 kg/h.
3.  Mother water maturation Unit. It is a 4-section capacity, 4mi. Each section is equipped with electromechanical stirrer.
4. A booster pump for feeding the prepared mother water to the injection unit.
5. Injection unit: two high-pressure injection pumps designed for injection of polymer solution into two wells simultaneously.
6. Nitrogen unit provides continuous nitrogen supply during polymer solution preparation.
7. Section for polymer storage in 25kg bags on pallets. Capacity: 4 t.
8. Switchboard room. It includes power and low voltage equipment, frequency converters, complete EC&I package.
9. Operator room. It is equipped with electrical control panel and HMI (preparation and injection control) system.
10. The plant is equipped with fire and gas detection system.

EXISTING POLYMER FLOODING PROJECTS IMPLEMENTED IN THE REPUBLIC OF KAZAKHSTAN

Within the framework of the program to enhance the oil recovery ratio, the Group of Companies together with SNF (France) implements the following projects in the territory of the Republic of Kazakhstan:

• Industrial introduction of polymer flooding at 4 wells of Nurali field of Kazgermunai JV LTD.
• Evaluation and scientific justification of application of polymers for flooding at Akshabulak field of Kazgermunai JV LTD.
• Industrial introduction of polymer flooding at 6 wells of Zaburunye field, Embamunaigas JSC.
• Evaluation and scientific substantiation of application of polymers for flooding at the fields of Ozenmunaigas JSC.

POLYMER FLOODING IMPLEMENTATION RESULTS

A decrease in water cut (7%) is observed at Nuraly field from 2014 to 2016 during polymer flooding.

Oil production per one ton of polymer: 122.9 t Pilot testing commenced at the field in June, 2014 with injection of polymer solution into 2 wells. In 2016, the project was expanded to injection of polymer solution into 4 wells.

The impact covers the whole formation.

During the operations the following results were achieved:

• Water intrusion reduction: 7%;
• Specific additional oil production 1 t. polymer - 180, bt.

 At  Zaburunye field for the period from December, 2014 through July, 2016, the decrease in water cut (8.1%), oil production per ton of polymer equal to 53.9 t is observed on the production wells of the pilot section 11-55.

Polymer flooding at Zaburunje field commenced in November, 2014 (2 wells).

On the basis of the pilot testing results the following was achieved:

• Water intrusion reduction: 6.5%;
• Specific efficiency: 60t oil per 1 t of the injected polymer.

The pilot testing section was expanded with injection of polymer solution into 6 injection wells.