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 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.
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.
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
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.
Not practical to widen the diameter of the well so not all wells are suitable for deepening.