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  = 5-29

  | topg    = 5-64

  | topg    = 5-29

  | 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

! Estimated

! Estimated

|-

|-

| *  Using RFT (repeat formation tester) data *  Using reservoir bottom-hole pressure buildup tests *  Using DST shut-in pressures

|  

 

*  Using [[Wireline formation testers|RFT (repeat formation tester)]] data  

| *  Calculating hydrostatic pressures from measured water density or salinity *  Estimating hydrostatic pressures from fluid density using R_w (formation water resistivity) *  Using the weight of drilling mud *  Using the rule-of-thumb pressure gradient, 0.465 psi/ft

*  Using reservoir bottom-hole pressure buildup tests  

 

*  Using DST shut-in pressures

*  Calculating hydrostatic pressures from measured water density or salinity  

*  Estimating hydrostatic pressures from fluid density using R_w (formation water resistivity)  

*  Using the weight of drilling mud  

*  Using the rule-of-thumb pressure gradient, 0.465 psi/ft

|}

|}

==Accuracy of measured pressures==

==Accuracy of measured pressures==

RFTs, DSTs, and bottom-hole pressure buildup tests measure formation fluid pressures. Pressure gauge accuracy is a critical factor in all three tests, but the BHP measurement is generally more precise due to the greater time taken for the test. Generally two types of gauges measure pressures: strain and quartz. The table below shows the accuracy and precision of both types.

RFTs, DSTs, and bottom-hole pressure buildup tests measure formation fluid pressures. Pressure gauge accuracy is a critical factor in all three tests, but the BHP measurement is generally more precise due to the greater time taken for the test. Generally two types of gauges measure pressures: strain and [[quartz]]. The table below shows the accuracy and precision of both types.

{| class = "wikitable"

{| class = "wikitable"

| Strain Gauge

| Strain Gauge

| 0.18

| 0.18

|

| < 1 psi

 

|-

|-

| Quartz Gauge

| Quartz Gauge

[[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]]