Changes

==Selective depletion by diffusion==

==Selective depletion by diffusion==

Studies of source and reservoir contacts show that diffusion of dissolved hydrocarbons selectively depletes the more soluble compounds from the edges of [[[[source rock]]s]] into adjacent sands. The extracts found in sands resemble condensates or light oils, while the extracts found on the edges of depleted source rocks look less mature and somewhat biodegraded compared to the less depleted center of the source rocks. Diffusion selectively depletes the more soluble compounds in reservoirs. Although light hydrocarbons are expected to be transported only tens of meters into a shale capping a reservoir, significant quantities of light hydrocarbons can diffuse into this section of overlying seal.

Studies of source and reservoir contacts show that diffusion of dissolved hydrocarbons selectively depletes the more soluble compounds from the edges of [[[[source rock]]s]] into adjacent sands. The extracts found in sands resemble condensates or light oils, while the extracts found on the edges of depleted source rocks look less mature and somewhat [http://www.oiltracers.com/services/exploration-geochemistry/oil-biodegradation.aspx biodegraded] compared to the less depleted center of the source rocks. Diffusion selectively depletes the more soluble compounds in reservoirs. Although light hydrocarbons are expected to be transported only tens of meters into a shale capping a reservoir, significant quantities of light hydrocarbons can diffuse into this section of overlying seal.

==Micelles==

==Micelles==