Gas in Place

Gas in place, abbreviated as GIP, is the total quantity of natural gas contained in a subsurface reservoir.  It includes all the gas within the rock formations of the reservoir, regardless of whether it is technically or economically recoverable.  Understanding and accurately estimating the reservoir gas in place is vital for efficient reservoir management and the planning of gas field development.

GIP is generally categorized as

Original Gas in Place (OGIP)  -  This is the total amount of gas present in the reservoir before any production starts.

Remaining Gas in Place (RGIP)  -  This refers to the amount of gas left in the reservoir after some production has occurred.

 

Gas in Place formula  43,560 = conversion factor from acre-ft to \(ft^3\)
\( GIP \;=\;  \dfrac{43560 \; A \cdot h \cdot n \cdot (1 - W_s )}{B_g }\)     (Gas in Place) \( A \;=\;  \dfrac{GIP \cdot B_g }{ 43560 \; h \cdot n \cdot (1 - W_s )}   \) \( h \;=\; \dfrac{GIP cdot B_g }{ 43560 \; A \cdot n \cdot (1 - W_s )}   \) \( n \;=\;  \dfrac{GIP \cdot B_g }{ 43560 \; A \cdot h \cdot (1 - W_s )}   \) \( W_s \;=\;  1 -  \dfrac{GIP \cdot B_g }{ 43560 \; A \cdot h \cdot n }   \) \( B_g \;=\;  \dfrac{43560 \; A \cdot h \cdot n \; (1 - W_s )  }{GIP}    \)
Symbol	English	Metric
\( GIP \) = Gas in Place	\(bbl\)	-
\( A \) = Reservoir Area, acres from map data	\(acre\)	-
\( h \) = Reservoir Thickness	\(ft\)	-
\( n \) = Porosity	\(dimensionless\)	-
\( W_s \) = Water Saturation	\(dimensionless\)	-
\( B_g \) = Gas Formation Volume Factor (cubic feet of gas at standard conditions per cubic foot of gas at reservoir conditions)	\(bbl\;/\;ft^3\)	-