COMPRESSIBILITY OF RESERVOIR ROCKS. COMPACTION OF SEDIMENTS. Porosity is reduced by compaction Porosity reduction is determined by maximum burial depth Principal effects are: Changes in packing Pressure solution Recrystallization Deformation of rock fragments
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Rotation and Closer
(e.g., qtz., feldspar)
Grain, e.g., Shale Rock
Modified from Jonas and McBride, 1977
MECHANICS OF COMPACTION
Overburden pressure, psiRelationship of Original Formation Porosity to Overburden Pressure
Under static conditions, downward overburden force must be balanced by upward forces of the matrix and fluid in pores
As fluids are produced from reservoir, fluid pressure (p) usually decreases while overburden is constant, and:
(a) force on matrix increases ( “net compaction pressure”,
(b) bulk volume decreases, and
(c) pore volume decreases.
Pressure Gradients, Normal Reservoirs:
dpo/dZ = 1.0 psia/ft
dp/dZ = 0.465 psia/ft