Changes

''Pay'' is defined as that part of a reservoir unit from which hydrocarbons can be produced ''at economic rates given a specific production method''. This concept of pay links the physical characteristics of the reservoir (rock properties, fluid saturations, and capillary behavior) to the economic aspects of production (completion method, recovery techniques, and volumetric estimates of reserves). ''Nonpay'' is defined as the part of a reservoir unit that will not produce hydrocarbons at economic rates and includes intrareservoir barriers.

''Pay'' is defined as that part of a reservoir unit from which hydrocarbons can be produced ''at economic rates given a specific production method''. This concept of pay links the physical characteristics of the reservoir (rock properties, fluid saturations, and capillary behavior) to the economic aspects of production (completion method, recovery techniques, and volumetric estimates of reserves). ''Nonpay'' is defined as the part of a reservoir unit that will not produce hydrocarbons at economic rates and includes intrareservoir barriers.

A ''reservoir rock'' is any porous and permeable rock capable of ''potentially'' containing hydrocarbons in its pore system. This statement implies that not all reservoir rocks qualify as pay. In some reservoirs, there may be intermediate pay types or a continuum between pay and nonpay intervals. This situation may include reservoir units that have differing fluid saturations or pore geometries, or that are present at different elevations above the hydrocarbon-water contact.

A ''reservoir rock'' is any porous and permeable rock capable of ''potentially'' containing hydrocarbons in its pore system. This statement implies that not all reservoir rocks qualify as pay. In some reservoirs, there may be intermediate pay types or a continuum between pay and nonpay intervals. This situation may include reservoir units that have differing fluid saturations or pore geometries, or that are present at different elevations above the Basic open hole tools [http://www.glossary.oilfield.slb.com/en/Terms.aspx?LookIn=term%20name&filter=oil-water%20contact hydrocarbon-water contact].

The production methodologies—primary, secondary, and enhanced recovery—affect the definition of pay. For example, beds with limited lateral continuity may qualify as pay under primary production, but may not be waterfloodable at contemplated injector-producer well spacings, thus disqualifying them as pay under secondary production. Thus, there are two separate but related questions regarding pay determination: first, the delineation of [[reservoir quality]] rock, and second, the classification of that part of a reservoir quality interval as pay.

The production methodologies—primary, secondary, and enhanced recovery—affect the definition of pay. For example, beds with limited lateral continuity may qualify as pay under primary production, but may not be waterfloodable at contemplated injector-producer well spacings, thus disqualifying them as pay under secondary production. Thus, there are two separate but related questions regarding pay determination: first, the delineation of [[reservoir quality]] rock, and second, the classification of that part of a reservoir quality interval as pay.