EOR (ENHANCED OIL RECOVERY)
Due to the unique nature of each oilfield, polymer chemistry must be optimized for field conditions. Injectivity, sweep efficiency, retention, and compatibility with the water and other chemicals have to be studied. In some cases the formulation of polymer with protective additives is necessary to maintain viscosity and to ensure its performance.
SNF has conducted more than 50 oilfield specific studies for customers in the last few years. These include studies of polymer molecular weight, physical form, concentration, inversion systems, as well as functional monomers and polymers with protective additives against iron, oxygen, and, H2S. These studies require close cooperation between SNF and the operator, and involve medium to long-term evaluation of polymer behavior at reservoir conditions. In some cases, this includes SNF expertise in polymer synthesis.
SNF can help in the screening and qualification process in the following areas :
- Polymer synthesis and characterization
- Monomer selection and integration
- Polymer selection
- Filter ratio
- Long-term thermal stability
- Core flooding (for qualification purposes only)
- Mixing and inversion
- Compatibility with production chemicals
SNF produces a range of more than 1,050 products and launches approximately 100 new polymer products each year from laboratory synthesis to full-scale production. Engineering and R&D can move quickly from customer concepts or problems to lab trials to large-scale production. Through integration of the various groups, new product development from laboratory synthesis through the application chain up to the polymer dissolution equipment and surface facilities is accomplished quickly.
Oil Sands tailings
Due to the unique nature of each tailings stream, polymer chemistry must be optimized for the appropriate field conditions. Ionicity, molecular weight, macromolecular structure and chemistry have to be studied. In some cases the use of a dual-polymer treatment may be required for the sake of high clarity released water and strong solid deposits.
SNF has conducted many MFT (mature fine tails) treatment operations over the past 10 years. These studies require close cooperation between SNF and the operator and involve medium to long-term evaluation of polymer behavior against changing field conditions (water salinity, MFT mineralogy …). In some cases, this includes SNF expertise in polymer synthesis.
Primary and secondary bitumen extraction
Addition of caustic is a cheap and common way to improve bitumen recovery by forming natural surfactants, thus facilitating the liberation of bitumen from sand grains and increasing bitumen buoyancy. However, high pH conditions are known to disperse the clays and fines in the resulting tailings, thus making it more difficult for settling to occur.
SNF is developing new chemistries that improve bitumen recovery and froth quality, which has resulted in a series of patent pending new technologies. These additives can be added at different stages of the process and can selectively target components responsible of performances loss: divalents, fines, etc …
With two research centers dedicated to Oil Sands applications (Andrézieux, France and Edmonton, Canada), SNF can help in the screening and qualification processes as follows:
- Polymer synthesis and characterization
- Monomer selection and integration
- Polymer selection
- Quality control (HPLC, GC, viscosity, etc)
- Flocculation tests
- In-line flocculation test rig
- Cake deposit mechanical characterization
- Capillary Suction Time
- Batch Extraction Unit flotation tests
- Denver Extraction Cell
- Dean-Stark toluene extraction
To ensure a proper injection into the reservoir, it is important that polymer dissolution be carried out properly, using equipment that is compatible with the polymer and that works on a continuous basis. In order to optimize the different phases of a project, SNF has developed a wide range of engineering services and polymer flooding equipment thanks to dedicated SNF EOR engineering teams.
During preliminary phases of a polymer flooding project, SNF can develop conceptual studies of facilities to evaluate technical feasibility along with CAPEX budget and project risks (facilities/logistics aspects). Different technical options for polymer storage, dissolution, and injection are studied and compared. Main process principles are described, logistics issues are highlighted, basic costs, and high-level planning are proposed. Typically, the following deliverables are provided by SNF at the end of the study:
- Process description
- Supply chain description
- Process flow diagram (PFD) for polymer storage, preparation and injection
- Preliminary mass balance
- Preliminary equipment list
- Estimated electrical power consumption
- Preliminary general layout and land requirement
- Basic operating & control philosophy
- Preliminary material selection report
- Level 2 schedule for polymer facilities
- Identification of the long lead items
- Proposed SNF vendor list
- Cost estimation of facilities (±30%)
- Comparison of different options and SNF recommended solution
- Injectivity test
During the preliminary phase of a project, SNF is also able to provide very specific polymer injectivity tests and related services to oil companies. The primary goal of an injectivity test is to establish and validate the flow rate and pressure at which the polymer solution can be pumped into the reservoir without fracturing the formation. This test will consolidate the targeted injection viscosity and the polymer selection carried out in the preliminary stage by the SNF laboratory team and oil company reservoir team. SNF’s scope of work for these type of tests includes the supply of standalone polymer injectivity skid tests, the mobilization of a dedicated operating crew (which will operate the unit and run basic viscosity measurements), and supply the polymer chemical to be tested.
PILOT AND FULL-FIELD EQUIPMENT
As soon as the polymer selection and the injection parameters have been validated, the next step of the polymer flooding project is to go through continuous injection pilot-test or directly to full-field development. This is the core business of our SNF EOR engineering department. We can propose either skid mounted units (for pilot or small size full-field projects) built in SNF partners’ workshops or turn-key systems and preparation plants (for large pilot or full-field projects), where equipment are delivered and assembled onsite.
BASIC AND DETAILED DESIGN
In order to efficiently manufacture the skid-mounted injection units or field-erected plants, design work is conducted with cooperation between SNF engineers and the customer. For each project, SNF is able to mobilize a dedicated team of highly skilled engineers and designers with strong experience in polymer flooding projects, and covering most of the disciplines in such projects. These disciplines include: process, mechanical, piping, electrical instrumentation, control and automation, as well as chemistry.
During this project development phase, specific attention is focused on health, safety, and environmental issues through risk analysis sessions, ergonomic reviews, etc…, in accordance with customer policies.
Based on our extended experience in polymer flooding, SNF defines, selects, and implements equipment based on efficiency and durability that has been proven on past experiences and site field conditions. Due to the polymer shearing sensitivity, specific attention is paid to the equipment that handles the polymer solution, such as low-pressure transfer pumps, tank agitators, high-pressure injection pumps and static mixers. Design and selection of equipment will also be engineered to minimize oxygen ingress in the system, which leads to the presence of contaminants (Iron, H2S), and therefore, polymer degradation.
In addition, in case where the of use of powder-grade polymers imply significant inconvenience by having to rely on conventional dissolution system (i.e., eductors), SNF has designed and patented specific polymer dissolution equipment, called the FLOQUIP™ PSU. This equipment has quickly become a standard in EOR applications in the USA and Canada and has also been used in other projects around the world.
MANUFACTURING AND FABRICATION
To limit costly activities in the field, SNF develops and fabricates units for equipment mounted on stand-alone structures (either closed or opened). These structures are then shipped and installed onsite. Manufacturing and welding is able to be carried out following different construction standards including ASME, API, and DIN.
If construction and installation activities are necessary to be carried out at the customer site, SNF utilizes local construction companies with knowledge of that country’s applicable rules and oil consortium or company-specific requirements, as well as all accreditations required to perform the work in the field.
TRAINING, COMMISSIONING, AND OPERATIONS
After completion of onsite construction, SNF mobilizes its dedicated commissioning team. This team, composed of engineers and technicians with different skills, is able to perform all commissioning steps and start-up of the facilities in accordance with company specifications. In addition to installation and start-up, the team collects polymer solution samples and appropriate parameters are analyzed (yield viscosity, filter ratio, etc…) in order to optimize the process parameters of the system. Parallel to these start-up activities, SNF conducts specific theoretical and practical training sessions for the appropriate company teams such as operations, maintenance, and laboratory.
As soon as facility start-up has been completed, target performance parameters validated, and smooth operation of the unit is occurring, the system is handed over to the company according to contract conditions. However, as an added service, SNF is able to provide support/supervision of the operations, or provisions for full-plant operations and maintenance through a specified period agreed upon between the customer and SNF.
Once SNF has completed the engineering/design, fabrication of equipment, and delivery of the equipment for a specific oilfield project, a dedicated commissioning team is mobilized to the project site. This team will consist of engineers and technicians with different skills and abilities to perform all commissioning steps and start-up of the facilities in accordance with company specifications. In addition to the installation start-up, the team collects polymer solution samples and main parameters are analyzed in order to optimize the process parameters of the system. In parallel to these start-up activities, training is conducted by SNF personnel tailored to the specific needs and requirements of each oilfield project, involving various customer departments such as operations, maintenance, and laboratory.