Laminated Sand Shale

Shale is a fine grained sedimentary rock that forms from the compaction of silt and clay size mineral particles that we commonly call mud this composition places shale in a category of sedimentary rocks known as mudstones shale is distinguished from other mudstones because it is fissile and laminated.

Laminated sand shale. This gives a shale volume vsh averaged over the interval of 50. The shale volume of reservoir and net to gross ratio was calculated for the reservoir with main focus on an interval of thinly laminated shale and sand. In geology lamination is a small scale sequence of fine layers laminae. Using parallel resistivity formulae the resistivities of sand layers in the laminae are.

These experimental results and analyses will be useful when designing hydraulic fractures for shale gas reservoirs or other laminated formations. The average total porosity in this example is 0 20. Shale any of a group of fine grained laminated sedimentary rocks consisting of silt and clay sized particles. To illustrate the simplest case assume a laminated shaly sand sequence with shale laminations equal in thickness to the sand laminations.

Out of 192 traces for an image log trace was selected and filtered by fourier transform and the resistivity values of this trace correlated with rxo curve to use for shale volume calculation. Lamina that occurs in sedimentary rocks laminae are normally smaller and less pronounced than bedding lamination is often regarded as planar structures one centimetre or less in thickness whereas bedding layers are greater than one centimetre. Evaluation at higher shaliness levels is required in laminated shaly sands because the sand laminae can have good reservoir quality at high. Shale is the most abundant of the sedimentary rocks accounting for roughly 70 percent of this rock type in the crust of the earth.

Assume the porosity and resistivity values are as shown at the right. The model assumes a laminar shale distribution and considers the total resistivity to be the sum in parallel of the sand and shale laminae. The output from either technique is sand resistivity rsand and sand volume vsand with accurate water saturation sw as a result of overcoming the effect of laminated shale on the resistivity. The laminated sand shale model provides a useful reservoir description up to high shaliness levels as long as the majority of the shale is laminated in nature.

Shales are often found with layers of sandstone or. For zones with laminated shale sand sequences which are validated by geological studies and core data analysis. Discussion 1 volume fracturing of shale formations is considered a full 3d process and engineering methods to increase srv are the main focus of shale fracturing research.