Kap 2.

Field discovery, field evaluation, field development, field production, field abandonment

✓ A seismic survey involves sending acoustic energy into the ground by producing a shock wave (seismic wave 80 Hz).

✓ The seismic wave travels into the earth, and the reflected sound is captured and converted into an electrical impulse.

✓ The electrical impulse-captured by geophones are transmitted to be processed in high-performance computers.

Stratigraphic Traps Structural traps

1. Anticline Traps

2. Fault Traps

3. Salt domes Traps

✓ The movement of hydrocarbons out of their source rock. ✓ Migration typically occurs from a structurally low area to a higher area in the subsurface because of the relative buoyancy of hydrocarbons in comparison to the surrounding rock.

Permeability and porosity

• Deep an impermeable rock

• Fracturing require more water

X-tree or Blowout Preventer (BOP) valve

Hydro-fracturing

It is a steal pipe assembled and inserted into a recently drilled section of a borehole and typically held into place with cement.

✓ Conductor casing: It is the initial stable structural foundation for a well.

✓ Surface casing: o It protects fresh-water aquifers onshore o It provides minimal pressure integrity, and thus enables a diverter or perhaps even a blowout preventer (BOP) to be mounted.

✓ Intermediate casing (optional) Intermediate casing is set to isolate: o Unstable hole sections o Lost-circulation zones o Low-pressure zones Production casing

Cementing is the displacement of cement slurry down the casing, tubing or drill pipe to a pre-specified point in the well

✓ To bond and support the casing.

✓ To protect the casing from corrosion or erosion.

✓ To restrict fluid movements.

✓ To protect the casing from shock loads during drilling of next zone.

it is a high viscous slurry consists primarily of water or non-aqueous fluid mixed with

o barite (BaSO4)

o bentonite clays

✓ Cooling by reducing friction and heat.

✓ Lubrication of the pipe and the bit.

✓ Carrying out the drill cuttings.

✓ To prevent circulation loses.

✓ To suppress high formation pressures and prevent blowouts

Conventional vertical Drilling: To extract the oil from a single reservoir

Conventional Horizontal Drilling: Oil and natural gas can be extracted from a wider area with fewer wells and less surface excavation. This technology only can be useful in certain locations.

Multilateral Drilling Sometimes oil and natural gas reservoir are located in separate layers. Multilateral drilling allows the extraction of hydrocarbons from several reservoirs with one well drilling. This dramatically increases productivity and reduce drilling costs. Complex path drilling: To avoid geological obstacles Hydraulic fracturing: To extract natural gas from shale rock. The process involves horizontal drilling and the injection of water, sand and chemicals at high pressures to fracture the sale rock and release hydrocarbons.

Kick, loss of circulation and pipe stuck

”Fracing” is a way of opening-up or ”loosening” a reservoir by applying high hydraulic pressure (often in combination with special solvents) and then fill the open spaces with a porous material like sand. This creates improved flow paths for oil, gas, water etc out of the reservoir and into the well (creating ”artificial porosity”

Jack-up has a floating hull with retractable legs which can be jacked down to the seabed.

Semi-submersible is not bottom-supported, but it is designed to float. It can be moved from place to another.

Drillships are used to drill the well in deep water. It can move between locations at high speed compared to semi-submersible rigs.

Conventional rigs ✓ Small land rigs ✓ Medium land rigs ✓ Large land rigs

Mobile Rigs Portable

Drilling fluids used inside the wellbore to lubricate, cool the drilling bit, and to remove the fragments.

Drilling formation:

Freshwater

Hydrocarbons

Other geological formation