Education Department of AAPG SC ITB Batch 2016
#1 Monthly Lecture Report
Place : Hilmi Panigoro Room, Department of Geological Engineering, ITB
Date : Thursday, February 4th, 2016
Lecturer : Dr. Ir. Dardji Noeradi
Lecture Title : Petroleum Industry and Related Science
The petroleum industry includes the global processes of exploration, extraction, refining, transporting (often by oil tankers and pipelines), and marketing petroleum products. The largest volume products of the industry are fuel oil and gasoline (petrol). Petroleum is vital to many industries, and it’s important to the maintenance of industrial civilization in its current configuration, and thus it’s a critical concern for many nations. Even though many governments in the world nowadays are focus on developing renewable energy resources in order to supply their energy needs, yet petroleum still becomes the largest energy source.
Due to its uncertainty aspects and our little knowledge about the subsurface environment of earth’s crust (where oil mostly found), petroleum industry requires many fields of science to reduce that uncertainty. Oil industry stages can be divided into 3 steps : exploration (to find oil), development (to develop economically) and further development.
Figure 1. 4 levels of petroleum investigation (Mangoon and Dow, 1994)
Sedimentary basin level includes basin analysis, consists of basin formation, basin filling and basin deformation. Those 3 aspects are related to tectonic process, sedimentation and stratigraphy. The formation and deformation of a basin are controlled by tectonic event which influences the basin area, meanwhile basin filling really depends on the sedimentation system that works on it.
Petroleum system analysis consists of generative sub-system (most crucial one), migration sub-system and entrapment sub-system. Generative sub-system is a part that controls the formation of petroleum, there are at least 3 factors which determine whether petroleum can be formed or not, they are richness, kerogene type and maturity. They have strong relation and can be predicted by understanding each sedimentary process, depositional environment and thermal process. In order to understand about the generative sub-system we must have strong concept in geochemical, sedimentology and basin analysis.
Second sub-system, the migration sub-system can be divided into 2: primary migration/expultion (from source to carrier bed) and secondary migration (from kitchen to trap). Knowledge about fluid mechanics is crucial in this sub-system, because we basically have to know about the behaviour of fluid in the subsurface. Concepts like fluid flow in non porous media, capillary pressure concept, maturation-expultion concept, buoyancy concept and pore pressure concept are indeed helpful.
Our last sub-system, entrapment sub-system is a system that controls the accumulation of petroleum after it migrates from the place where it made. The common traps for petroleum are structural and stratigraphic trap (or in some case are both of them). Structural trap is related to basin deformation and quite well-known for its 2 major types: fold and fault related trap. Stratigraphic trap is a trap that created by a combination of various layers of rock.
Play and Prospect Analysis
The word ‘play’ in this term can be interpreted with: a series of related prospect/petroleum zone. Meanwhile, prospect is a potential trap. Prospect generation can be reached by considering these 4 factors: structural mapping, kitchen definiton, migration pathway analysis and prospect ranking. Structural mapping is important in order to get a representative image of the condition below. We can use many methods that actually are related to each other, such as geophysic (structural and stratigraphic approach), well log (reservoir-non reservoir identification and reservoir geometry), stratigraphy (stratigraphic relationship) and structure (structural style and geometry).
Kitchen definition is an understanding about the generative sub-system of petroleum system analysis. Basin modeling (depth and thermal maturity onset), stratigraphy (source rock interval, source rock distribution and possible kerogene type) and structure (structural geometry of the source rock) can be the best methods which we can apply to define our ‘kitchen’ in petroleum system.
Migration pathway of petroleum system can be estimated by considering structural geology (structural geometry of carrier bed and fault seal concept), fluid flow in capillary system (bouyancy and hydrocarbon concept, capillary and pore pressure concept) and stratigraphy (depositional environment and stratigraphic geometry).
Prospect ranking becomes the last and important aspect of play and prospect analysis. It is a final judgement which can be approached by volumetric calculation (making and updating of depth structure, isopach, isoporosity, isosaturation and hydrocarbon pore volume map), risk assesment, ranking and (for the ‘real’ provement) wildcat drilling.