Complex Challenges of fluid flow in Wellbores
Fluid flow in wellbores can be extremely complex, especially where changes in temperature and pressure along the wellbore cause large changes in the oil viscosity, the volume fraction of gas, and possibly phase changes between water and steam.
The characteristics of the fluid determine what flow regime dominates in the production tubing, which affects the frictional flow losses and pressure drop along the tubing. These flow effects can impact the efficiency and run life of artificial lift systems and the overall productivity of the well.
Similar flow and heat transfer analyses assess the performance in wells injecting complex fluids such as steam, mixtures of steam, solvents, and non-condensable gases, as well as in CO2 and acid gas storage wells.
Flow Control Devices
SAGD wells utilize Flow Control Devices (FCDs) to improve flow conformance. Operators deploy FCDs in the long horizontal sections of SAGD injection wells to ensure even steam injection into the reservoir along the entire well length. FCD’s also control inflow in the SAGD production well preventing steam from short-circuiting through high permeability pathways between the injector and producer.
Dealing with Solids
Solids transportation in a wellbore plays an important role in drilling operations by removing drill cuttings and is also necessary when sand enters the wellbore with the produced fluid. While the first priority involves designing the production system to transport the solids from the wellbore without causing erosion, it is also crucial to address how to remedy upset conditions where either excessive solids influx or reduced flow conditions cause solids to settle in the wellbore.
C-FER Yourself – Helping Understand Wellbore Hydraulics
Testing
- Testing the performance of downhole flow control devices (FCDs). FCD testing includes characterizing the pressure drop and flow rate through the device under high temperature conditions with mixtures of oil, water, steam and non-condensable gas (NCG). Erosion tests are also used to evaluate how extended exposure to produced fluids carrying solids could affect the flow characteristics of these devices.
- Building full-scale custom wellbore tests to investigate operational conditions and issues. For example, a full-scale drilling simulator was built to develop best practices for freeing drilling bottomhole assemblies (BHAs) that are impacted by drill cuttings accumulation in the well annulus.
- Testing the insulative properties of vacuum insulated tubing (VIT) and other insulated tubing products to determine how they can improve steam injection performance in SAGD wells. Similar analyses can be used to evaluate the benefits of insulated production tubing in retaining heat in geothermal wells.
- Developing and testing technologies and processes to assist with removing water from gas wells, thus avoiding water loading.
Modelling
- Performing wellbore thermo-hydraulic modelling of the entire well to ensure that the flow control devices and associated tubulars are sized correctly.
- Modeling the transient steam injection behaviour in SAGD wells during start up. This requires consideration of heat loss to the surrounding formations and changes in the liquid portion of the steam (steam quality) as the steam heats up the wellbore and flows into the formation.
Concept Development
- Developing a concept for CHOPS operations where the produced sand is not produced to surface by flowing the sand-laden produced fluid into a small salt cavern immediately below the oil reservoir. The sand settles in the cavern where it is permanently stored, and clean produced oil and water can be pumped from the cavern.
Explore Our Laboratory
Laboratory
Overview
Explore our laboratory
equipment overview
Load Frames Overview
A variety of large-scale servo-hydraulic load frames to simulate complex loading scenarios representative of field conditions.
Deep Well Simulator
Develop and test a wide range of systems and products under precisely simulated downhole service conditions.
In-flow Control device Characterization Loop
Test hydraulic performance of FCDs under real-world thermal operating conditions.
In-flow Control Device (ICD) Erosion Apparatus
Simulate different erosive operating scenarios in SAGD.
Pressure Testing Equipment
Learn about the capacity of our large capacity pressure systems.
Contributor
Brian Wagg, MSc, PEng.
Director, Testing Services
With over 35 years with C-FER, Brian Wagg’s current focus is on applying C-FER’s analytical and full-scale testing capabilities to projects in clean energy including CCUS, hydrogen, geothermal and small modular nuclear reactors.
