In the oil and gas industry, understanding the characteristics of underground reservoirs is crucial for successful exploration and production. One powerful tool used to gather this critical information is the Repeat Formation Tester (RFT).
What is an RFT?
An RFT is a specialized downhole instrument designed to repeatedly measure the pressure and fluid properties of a reservoir formation. It's deployed on wireline, typically after a well has been drilled and cased. The RFT operates by isolating a specific zone in the formation and conducting pressure measurements over time. This allows engineers to gather valuable data about:
How does it work?
An RFT consists of a series of components, including:
Once deployed in the well, the RFT is activated, and the packer is inflated to isolate the target zone. Pressure measurements are then taken at regular intervals, allowing engineers to observe pressure changes over time. These measurements provide insights into the reservoir's fluid properties, pressure gradients, and flow characteristics.
Benefits of RFT:
Conclusion:
The Repeat Formation Tester is a valuable tool for oil and gas professionals, offering a detailed understanding of reservoir properties and facilitating informed decisions for successful exploration and production. By leveraging the data obtained from RFTs, engineers can optimize field development, enhance production, and maximize the economic potential of oil and gas reservoirs.
Instructions: Choose the best answer for each question.
1. What is the primary function of a Repeat Formation Tester (RFT)?
a) To measure the temperature of the reservoir formation. b) To inject fluids into the reservoir for stimulation. c) To repeatedly measure pressure and fluid properties of a reservoir formation. d) To identify the presence of hydrocarbons in a well.
c) To repeatedly measure pressure and fluid properties of a reservoir formation.
2. Which of the following components is NOT part of a typical RFT system?
a) Packer b) Pressure gauge c) Sampling system d) Drilling bit
d) Drilling bit
3. What information does an RFT provide that is crucial for production forecasting?
a) Wellbore diameter b) Reservoir pressure c) Drill pipe size d) Cement bond log data
b) Reservoir pressure
4. How does an RFT help mitigate uncertainties in exploration and production decisions?
a) By analyzing the composition of the wellbore fluid b) By determining the depth of the reservoir c) By providing more accurate information about the reservoir properties d) By identifying potential drilling hazards
c) By providing more accurate information about the reservoir properties
5. Which of the following is NOT a benefit of using an RFT?
a) Improved production forecasting b) Enhanced well management c) Reduced uncertainty d) Determining the best location for a new well
d) Determining the best location for a new well
Scenario: An RFT was deployed in a well to measure reservoir pressure. The following pressure readings were obtained at different times:
| Time (hours) | Pressure (psi) | |---|---| | 0 | 3000 | | 2 | 2950 | | 4 | 2900 | | 6 | 2850 | | 8 | 2800 |
Task:
Exercice Correction:
1. The plot should show a linear decline in pressure over time. 2. Average pressure decline rate = (3000 psi - 2800 psi) / 8 hours = 25 psi/hour 3. Estimated pressure after 12 hours = 2800 psi - (25 psi/hour * 4 hours) = 2700 psi