AAPG ASUSC . انزل بالبريمة PROSPECT GENERATION . PETROLEUM GEOLOGY SESSION

Conventional vs. unconventional oil And thermal heavy oil recovery methods

Conventional oil is the product of the organic matter in deep layers subjected to temperature and pressure and migrated from its source rock towards shallower beds before it was trapped by an

impermeable bed (seal). It can be easily (and cheaply) extracted from the ground using the traditional methods of drilling (Vertical wells and the oil will rises without any additional stimulation).

On the other hand, unconventional oil is any oil produced by any method other than traditional drilling. It is heavy and highly viscous. It fails to migrate from its source rock to porous and permeable reservoirs. Additional stimulation (hydraulic fracturing) is needed to be produced. Many types of source rocks can produce unconventional oil and gas such as shale gas, coal beds or low quality reservoirs (tight gas).

Methods of extraction . Heating of reservoir by soaking the reservoir with injected steam. This is called cyclic steam injection. Or heating the oil electrically, possibly powered by a nuclear reactor . . Freezing the ground at a distance from the well.

SAGD Steam assisted gravity drainage . Two horizontal wells are drilled . Injected steam forms a ‘’steam chamber’’ . Steam and gases rise filling the void left by oil . The condensed water and crude oil or bitumen is recovered to the surface by pumps

CSS Cyclic Steam Stimulation Stage 1. high pressure steam injected Stage 2. Major portion of reservoir is thoroughly saturated Stage 3. production phase (when production phase declines another cycle of steam injection begins)