Borehole gravity: uses, advantages, and disadvantages
Borehole gravity uses
Borehole gravity is especially effective for the following exploration and production purposes:
Exploration purposes
- Locating nearby salt structures
- Locating distance to nearby structures (e.g., reefs) for step-outs and sidetracks
- Better synthetic seismograms
Production purposes
- Measuring bulk density when radioactive tools are too risky
- Logging cased holes for lithologic changes
- Calculating overburden for hydrofracture jobs
- Monitoring injection fluids
- Monitoring reservoirs during fluid withdrawal
- Exploring for bypassed, behind-casing gas zones
- Evaluating reservoir porosity, especially in carbonate reservoirs where other tools are not as reliable
Borehole gravity advantages
The following characteristics give borehole gravity surveys advantages in certain situations:
- Directly measures bulk density
- Is a deep imaging tool
- Is effective in both cased and uncased wells
- Is unaffected by washouts, hole rugosity, or mud invasion effects
- Can help determine seismic wavelet scale density
- Is a passive measurement, e.g., does not have active radioactive sources
Borehole gravity disadvantages
The following characteristics give borehole gravity surveys disadvantages in certain situations:
- Direction away from the well to distant source cannot be determined without other information
- Engineering limitations of the tool restricts use to certain candidate wells (hole size, low deviation, slow reading)
- Only a few tools presently available for use
- Expensive to operate
See also
External links
| find literature about Borehole gravity: uses, advantages, and disadvantages |
|
|
|
|