Horizontal wells are used extensively by the oil and gas industry for production from prolific reservoirs. It is also recognized that optimized recovery requires balancing the effect of two natural tendencies of flow into horizontal wells. These are;
Because of friction due to flow along the length of the horizontal section, pressure is higher at the toe of the well compared to its heel. This means that the flow per unit length of the well is higher near the heel, which then leads to faster drainage of reservoir near the heel, and earlier inflow of water and/or gas.
Reservoir permeability heterogeneity causes irregular drainage of the reservoir, which again leads to early production of water/gas through the high permeability parts of the reservoir. Permeability heterogeneity can be due to presence of natural fractures, or, changes in matrix permeability.
Correcting these two effects will lead to more uniform drainage of the reservoir and higher ultimate recovery. Inflow Control Devices (ICD) are tools that are installed within an isolated section of the borehole for flow regulation . Their basic function is to selectively choke and reduce flow. The net effect is higher ultimate oil recovery at lower cost.
While proper use of ICDs is very beneficial for efficient reservoir drainage and economics, its improper use can also be costly by unnecessarily reducing and/or delaying the production of oil, as well as increasing the completion cost. Improperly and indiscriminately placing ICDs throughout the well is expensive and harmful to production. Each well interval requires a different level of choking. Placing the same ICD throughout the well will NOT optimize recovery.
Another important factor is determination of the optimum flow profile in a given horizontal well. All horizontal well segments do not, and should not, flow at the same rate. Attempting to equalize flow along the length of the well is harmful to well productivity and optimized oil recovery.
Proper design of ICDs needs to answer four important questions;
- Which specific well segments require choking. Selection of well intervals that need to be packed off with open hole packers is an important part of ICD design.
- Once the intervals that need choking have been identified, the next step is to determine the optimum level of choking in each interval that will result in uniform reservoir drainage.
- Existing commercially available systems are designed on different engineering principles. Which commercial system is best suited for a specific reservoir condition? The two important considerations in selecting ICDs are system reliability, and ability to provide the desired level of choking.
- How does the modified flow profile meet reservoir production and management objectives
With the above points in mind, we offer two types of services for ICD design.
1. Design software. Our proprietary programs offer the following specific features;
- Special stand-alone design simulator (DCIm.exe) for selection of open hole packer locations, and, the optimum level of choking in each segment of the horizontal well.
- Special stand-alone three phase oil/water/gas simulator (OWGsim.exe) for production forecasting and computation of water/gas break-through time and %oil recovery for various ICD designs
- Performing design computations in formations with non-uniform permeability or flow profile
- Flexibility. Our design software allows changing the vertical location of the well in the reservoir. This provides another level of efficiency for higher production optimization.
- Computation efficiency. It takes only minutes to execute each of the two main simulators. This allows for quick assessment of multiple options and selecting one that best meets reservoir and production objectives.
- User friendliness. The software is designed for ease of use. It takes little time to train technical people to use the software.
- Special customized interfaces. The software can be modified to include designs for specific commercial ICD systems used by the client, and specific features desirable for any reservoir or production environment.
2. ICD design consulting services.
We offer full suite of consulting services related to the design of ICD systems. These include;
- Selection of open hole packer locations based on formation permeability or production profile.
- Computation of optimum choking level for each well interval for best oil recovery
- Recommendation for optimum well location within the pay thickness
- Selection of a commercial system suitable for your well and reservoir
- Computations of oil, gas and water flow rates, average reservoir pressure and recovery factor with time
- Determination of well intervals likely to be the sources for early water or gas break-though
- Determination of the time of water or gas break-through.
- Scenario analysis
- Matching the design with your production and reservoir objectives.
For more information regarding licensing or purchase of this software, or ICD consulting services, please contact us at contact@daneshy.com