PETROLEUM ENGINEERING

Tedy Muslim Haq

16407170

Institut Teknologi Bandung

Petroleum, oil, and gas are hydrocarbons derived from sedimentary rocks which were deposited in productive region with anoxic (low oxygen) bottom waters. Deep burial resulting in high temperature and pressure converted the organic remains into hydrocarbons. Hydrocarbons can be in gas, liquid, and solid form that depends on the pressure and temperature. Oil hydrocarbons formed in temperature between 180^oF and 295^oF while gas hydrocarbon formed in temperature between 295^oF and 450^oF. Pressure forces the oil and gas from the source rock into water-filled porous and permeable strata above. Because oil and gas are less dense than water, they migrate upwards until their path blocked by and impermeable layer. Oil and gas accumulate, forming a large deposit within the pores of the rocks.

The rocks that has pores filled with oil or gas and blocked by an impermeable layer above and another impermeable layer or water below is called reservoir. There are three kinds of reservoir trap; they are anticlinal, fault, and stratigraphic trap. Reservoir has porosity that is a ratio between the pores volume and the bulk volume. Beside porosity, permeability also has an important role for reservoir quality. Permeability is quantized in miliDarcy unit. Good reservoir has porosity around 15-25% and 10-1000 miliDarcy.

The total amount of oil or gas in the reservoir at initial condition is called original oil-place or original gas-in place. The total amount of oil or gas that can be covered with current technology and at current economic conditions is called reserve. Proved reserves are the quantities of oil or gas from known reservoir which is proven by drilling and expected to be recoverable with current technology and at current economic conditions. Potential reserves are those that may be recoverable in the future with advanced technologies or under different economic conditions.

How much oil or gas can be recovered from the rock is a function of rock properties, type of reservoir, technology, an economics. There are several ways of oil recovery technique; Oil Expansion (2-5%), Solution Gas Drive (10-30%), Gas Cap Drive (20-50%), Water Drive (25-50%), Gravity Segregation (30-70%) and Gas Expansion (70-95%).

Petroleum engineer must to be an expert about reservoir, drilling, formation evaluation, and production engineering. Reservoir engineering is mapping and estimating the initial size of hydrocarbons. It characterizes, describes, predicts and modeling the reservoir. Drilling engineering learns and develops science and technology in communication hole making from surface to a fixed, good, and safe reservoir depth so that is to be a good oil, gas, and geothermal production facility. Drilling rigs can be different, it depends on the kind of place it is been. There are several drilling rigs; land rig, submersible, jackup, semisubmersible and drillship. One of important things in drilling is mud. Mud is being injected while the drilling is in progress. The mud removes cuttings from well, prevents kicks, makes bore hole stable, cools and lubricates bit and downhole tools. The other important thing in drilling is casing. Casing protects bore hole, separates high/low pressure zones, as the basement for wellhead system, reduces frictions of drill string and ensures well completion. Formation evaluation determines about porous and permeable layers (by logging method), calculates productive layer thickness, analyzes rock petrophysics (porosity and saturation) and studies reservoir correlations. Production engineering determines oil and gas production technique to surface, solves the production problem and plans the surface production facility.

Advertisement