Formation Tester Acid Injection for Low-Permeability Stress Testing
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Solution Overview
Problem
Conventional formation testing methods struggle with low permeability geological strata, limited fluid volumes, and high operational costs, especially when injecting acids or proppants, due to the limitations of downhole chambers and downhole pumps.
Innovation Solution
The use of drill pipe supplied fluids, such as acids and proppants, combined with a circulating sub and dual packers, allows for large-volume fluid injection and fracture propagation without relying solely on downhole pumps, enabling efficient stress testing in low permeability conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If downhole chambers are used to carry injection fluids, then the formation tester can be conveyed with drill pipe, but the volume of fluid available for injection is limited to 1-6 gallons per chamber
Solution Approach 1:
Fluids are pre-spotted in the drill pipe before reaching the formation tester location. This allows large volumes of injection fluid to be positioned in advance in the drill pipe, eliminating the volume limitation of downhole chambers while maintaining operational efficiency.
2Productivity
If multiple injection cycles are required over multiple stations, then thorough testing can be performed, but the limited fluid volume in downhole chambers restricts the number of cycles
Solution Approach 1:
Multiple injection cycles are enabled by pre-positioning large volumes of fluid in the drill pipe. The drill pipe acts as a continuous supply source, allowing repeated injection cycles at multiple stations without being constrained by the limited capacity of downhole chambers.
3Reliability
If conventional wireline formation testers are used, then stress testing can be performed, but testing in low permeability situations is limited
Solution Approach 1:
The system combines the drill pipe conveyance method with formation testing capabilities, creating a hybrid approach that copies the successful drill pipe logistics model and applies it to formation testing. This allows the formation tester to benefit from the large fluid carrying capacity of the drill pipe system, enabling reliable testing in low permeability formations where large fluid volumes are needed.
Data Source
AI summary
Embodiments presented provide for formation testing in geological stratum that exhibit low permeability. In embodiments, a drill pipe supplied acid and/or proppant is injected into the low permeability stratum through action of a formation tester, thereby altering the permeability of the geological stratum.