𝗠𝗶𝗴𝗿𝗮𝘁𝗶𝗼𝗻 𝗣𝗮𝘁𝗵𝘄𝗮𝘆𝘀
Types of Migration
1. Primary Migration: Primary migration, also known as expulsion, is the initial movement of hydrocarbons from the source rock into the adjacent permeable carrier beds. This process occurs on a microscopic scale within the pores of the source rock, where hydrocarbons move out of the rock’s matrix into surrounding, more permeable rock layers.
2. Secondary Migration: Secondary migration is the movement of hydrocarbons through carrier beds toward a reservoir rock where they can accumulate. This process usually occurs on a larger, macroscopic scale, moving hydrocarbons through networks of permeable rock layers, faults, and fractures until they reach a structural or stratigraphic trap.
Factors Driving Migration
The movement of hydrocarbons through migration pathways is driven by several forces and conditions:
1. Buoyancy: Buoyancy is the primary driving force for secondary migration. Because oil and gas are less dense than the surrounding water in the subsurface, they tend to rise through permeable pathways toward shallower depths where they can be trapped in reservoirs.
2. Pressure Gradients: Pressure gradients within the subsurface also play a key role in migration. For example, higher pressure zones in source rocks can force hydrocarbons into lower-pressure carrier beds. These gradients can occur due to geological processes such as compaction, tectonic stress, or fluid injection.
3. Capillary Forces: Capillary forces, resulting from the interaction between hydrocarbons and the pore structure of rocks, can influence migration, particularly in finer-grained rocks with smaller pore throats. Capillary forces tend to resist the movement of hydrocarbons, so hydrocarbons require sufficient pressure to overcome these forces during migration.
4. Temperature: High temperatures can reduce the viscosity of hydrocarbons, facilitating migration. Temperature gradients within the subsurface, therefore, impact the rate and ease of hydrocarbon movement.
Types of Migration Pathways
1. Porous and Permeable Rock Layers (Carrier Beds): These are the most common migration pathways. Carrier beds are layers of rock with sufficient porosity and permeability to allow hydrocarbons to flow through them.
2. Faults and Fractures: Faults and fractures can create migration pathways, particularly in regions where rocks are brittle and prone to cracking.
3. Salt Domes and Diapirs: Salt structures, such as salt domes and diapirs, can impact migration pathways by deforming surrounding rock layers and creating fractures or faults that act as conduits.
4. Stratigraphic Boundaries: Certain stratigraphic features, such as unconformities, pinch-outs, or facies changes, can create migration pathways.
Photo refrence, credit :
https://lnkd.in/d6Ydd_m4
Contact Us :
Mail: Reservoir.Solutions.Egypt@gmail.com /res@reservoirsolutions-res.com
Website: reservoirsolutions-res.com
WhatsApp: +201093323215