Well Deepening

Jump to: navigation, search

Exploration Technique: Well Deepening

Exploration Technique Information
Exploration Group: Drilling Techniques
Exploration Sub Group: Development Drilling
Parent Exploration Technique: Development Drilling
Information Provided by Technique
Lithology: Drill cuttings are analyzed to determine lithology and mineralogy
Stratigraphic/Structural: Fractures, faults, and geologic formations that the well passes through are identified and mapped.
Hydrological: Identify aquifers, reservoir boundaries, flow rates, fluid pressure, and chemistry
Thermal: Direct temperature measurements from within the reservoir
Well Deepening:
Reentering an existing well and drilling to a deeper reservoir.
Other definitions:Wikipedia Reegle

Well deepening is re-drilling into an already existing well in order to find a deeper more productive reservoir. Sometimes a previously unproductive well can be deepened in order to reach a location with higher flow and temperature.
Use in Geothermal Exploration
Sometimes wells that were initially not planned for utilization such as thermal gradient holes or old mineral exploration holes are re-drilled into and deepened. The advantage to deepening an already existing well is the fact that part of the well is already drilled which the lowers costs and time investment needed compared to starting a brand new well.
Related Techniques

Field Procedures
After a drilling target is determined if there is an existing well at or near the target location well deepening might be considered. Not all wells can be deepened depending on their diameter and how they were drilled and cased. If a well can be deepened it should be cleaned and then drilling procedures would be similar to drilling any other well except the beginning of the well is already completed. See Production Wells

Geothermal production well at Imperial Valley, California. The drilling of production wells, such as this one in southern California, results in one-third to one-half of the cost of a geothermal project. The DOE Geothermal Energy Program pursues the development of technologies that will considerably reduce the cost of drilling these wells.

Best Practices
A well that is going to be deepened should have a large enough diameter required for the new well parameters needed; widening a well would not be practical. Reasons for why the existing well was abandoned should be known before trying to deepen it because there may be lost equipment or collapses down hole that would make deepening it extremely difficult.
Potential Pitfalls
Not practical to widen the diameter of the well so not all wells are suitable for deepening.


    Print PDF