Changes

  | part    = Critical elements of the petroleum system

  | part    = Critical elements of the petroleum system

  | chapter = Formation fluid pressure and its application

  | chapter = Formation fluid pressure and its application

  | frompg  = 5-1

  | frompg  = 5-33

  | topg    = 5-64

  | topg    = 5-35

  | author  = Edward A. Beaumont, Forrest Fiedler

  | author  = Edward A. Beaumont, Forrest Fiedler

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch05/ch05.htm

==Operating an RFT survey==

==Operating an RFT survey==

The table below explains how to operate an RFT survey (see Gunter & Moore<ref name=ch05r9>Gunter, J., M., Moore, C., V., 1987, Improved use of wireline testers for reservoir evaluation: Journal of Petroleum Technology, p. 635–644.</ref>).

The list below explains how to operate an RFT survey (see Gunter & Moore<ref name=ch05r9>Gunter, J., M., Moore, C., V., 1987, Improved use of wireline testers for reservoir evaluation: Journal of Petroleum Technology, p. 635–644.</ref>).

# Use well logs to pick permeable zones for formation pressure measurements. Look for an invasion profile.

# Plot mud hydrostatic and formation pressure at the well site to recognize anomalies or tool errors and to optimize station coverage.

# Occasionally repeat formation pressure measurements at the same depth to check for consistency.

# Repeat at some of the same depths for multiple surveys to help normalize the different surveys.

| 1 || Use well logs to pick permeable zones for formation pressure measurements. Look for an invasion profile.

# Sample both water- and hydrocarbon-bearing intervals to establish both the water and hydrocarbon pressure gradients.

# Plot pressures at the same scale as well logs to aid in interpretation.

| 2 || Plot mud hydrostatic and formation pressure at the well site to recognize anomalies or tool errors and to optimize station coverage.

| 3 || Occasionally repeat formation pressure measurements at the same depth to check for consistency.

| 4 || Repeat at some of the same depths for multiple surveys to help normalize the different surveys.

| 5 || Sample both water- and hydrocarbon-bearing intervals to establish both the water and hydrocarbon pressure gradients.

| 6 || Plot pressures at the same scale as well logs to aid in interpretation.

==Controlling RFT quality==

==Controlling RFT quality==

The table below describes how to control RFT quality. For details, see Gunter & Moore.<ref name=ch05r9 />

The list below describes how to control RFT quality. For details, see Gunter & Moore.<ref name=ch05r9 />

# Inspect the tool and check calibration before going in the hole.

# Run quartz and strain gauges simultaneously. Record both readings independently. Normalize to one another after completing the survey.

# Maintain a slight overflow of mud to keep the level in the borehole constant during the survey and to prevent mud hydrostatic pressure errors.

# Take mud hydrostatic pressures while descending into the hole to give the instruments time to equilibrate to changing temperature and pressure and to provide a mud hydrostatic pressure profile.

| 1 || Inspect the tool and check calibration before going in the hole.

# Check for tool errors by calculating mud hydrostatic pressures at different depths from mud weight; check them against measured mud hydrostatic pressures at the same depths.

| 2 || Run quartz and strain gauges simultaneously. Record both readings independently. Normalize to one another after completing the survey.

| 3 || Maintain a slight overflow of mud to keep the level in the borehole constant during the survey and to prevent mud hydrostatic pressure errors.

| 4 || Take mud hydrostatic pressures while descending into the hole to give the instruments time to equilibrate to changing temperature and pressure and to provide a mud hydrostatic pressure profile.

| 5 || Check for tool errors by calculating mud hydrostatic pressures at different depths from mud weight; check them against measured mud hydrostatic pressures at the same depths.

==See also==

==See also==

[[Category:Critical elements of the petroleum system]]  

[[Category:Critical elements of the petroleum system]]  

[[Category:Formation fluid pressure and its application]]

[[Category:Formation fluid pressure and its application]]