by Mr. Mohammad Taha
The Brunei Society of Petroleum Engineers will be holding an SPE Evening.
Details are as follows:
Date: Thursday, 18/5/2000
Venue: SKBB, KUALA BELAIT
Time: 7.00 p.m.
Tickets (B$10 for members and B$15 for non-members) are
available from DRO/1/10 (Hj.Salleh).
Don't miss this excellent opportunity!
Abstract
Recent hydrocarbon discoveries in the basement rocks of different parts of the world have demonstrated that fractures can be solely responsible for the making a producing reservoir. Fractured reservoirs are commonly thick, porosity is mainly secondary, distribution of porosity and permeability is irregular, may or may not have a common hydrocarbon/water contact, and vary greatly in production. These reservoirs demonstrate large differences in hydrocarbon storage capacity. The host rock pore structure may or may not contain hydrocarbons, and the reservoir potential may or may not be defined by conventional techniques. Moreover, these reservoirs may or may not drain the juxtaposition hydrocarbon bearing formations.
Effective fracture networks are normally of tectonic origin where different stress sources create different types and distribution of fractures. Fold-related fractures usually differ from fault-related fractures in their explicit relationship to the local stress state. The brittleness and facies of the host rock exert a great control on the density, morphology and extension of fractures.
Evaluating fractures reservoirs requires an integrated effort to properly develop and drain these rocks. Data provided by oriented cores, borehole imagery, open-hole logs, seismic and well testing are extremely important for thoroughly defining, understanding and modeling fractured rocks. Most conventional logs are fracture detectors without the capabilities of calculating hydrocarbon saturation in fractured rocks.
A proper study of fractured reservoirs begins with recognizing the fracture system or systems in terms of geometry, origin, morphology, density, width, trace length and porosity. Fracture porosity in producing fields is very small and rarely exceeds 1%. Estimating the fracture permeability inside the formation and away from the wellbore walls requires additional measurements, such as Stoneley wave analysis, detailed pressure testing, and accurate flow meter information to define which fractured intervals are contributing. Knowing fracture dips and orientations is crucial toward setting successful well trajectories and estimating the rise of water level.
Formation damage by traditional drilling fluids and completion techniques have resulted in generating a pessimistic evaluation of hydrocarbon potential in many reservoirs. Remedies of such damages are extremely difficult and costly. Fractured reservoirs stimulation is another critical operation that normally enhances the productivity of fractured reservoirs. However, it may cause severe damage to the formation by alternating the dynamic system of fractures through associated secondary physical and chemical precipitation. With all the limitations, damage mechanisms and potential for failure, enormous hydrocarbon reserves have been recovered from the naturally fractured reservoirs in many areas of the world.
Biography
Mohamed Taha is Schlumberger’s Reservoir Characterization and Production Enhancement Coordinator for Latin America, and is based in Buenos-Aires. He joined the company in 1984 after gaining wide experience by working for several major oil companies in many regions of the world.
Mohamed obtained a B.SC in geology from Assuit Univeristy, Egypt, in 1967. He has published numerous technical papers, many that describe the contribution of new technology in the areas of exploration and production. He is a member of the Society of Petroleum Engineers, American Association of Petroleum Geologists, the Society of Economic Paleontologists and Mineralogists, and the International Association of Sedimentologists.
Please e-mail comments and
recommendation to SPE Brunei Section
Webmaster
