Conducting Integrated Reservoir Studies in the Quartzite Hamra Reservoir-Tight Oil, Southern Periphery of Hassi-Messaoud Field, Algeria

Abstract

Characterization and analysis of naturally fractured reservoirs is challenging for oil and gas companies around the world. This paper describes how integrated reservoir studies including; geology, seismic, petrophysics, engineering; and geostatistical approaches with multiple realizations of reservoir parameters was used to help understand the risks and quantify the uncertainties for field development in the Hamra Quartzite tight, fractured, oil reservoir in Algeria. The focus is finding the sweet spots, quantifying the hydrocarbon-in-place, and optimizing the field development plans. The reservoir contains fractured quartzite and quartzitic sands with interbedded clays. The reservoir is sub-divided into six reservoir units (1, 2, 3, 4, 5 and 6), that show significant aerial and vertical heterogeneities. The sediments were tightly cemented and in most cases silicified during a series of different diagenetic processes. The tidal and clastic coastal depositional system represents the best fit for the existing characteristics on the described cores. The reservoir is characterized as low porosity and permeability quartiztic sands. These intervals may have been channels for fluid movement, causing subsequent diagenesis, including silicification, and either decreasing or increasing of secondary porosity, associated with micro fractures. One of the most challenging tasks of the reservoir characterization of the quartzitic formation is to deal with complexities associated with the inherent heterogeneity of the rock, uncertainty in influence of natural fractures in some areas, and understating the major efficient parameters in production. Several integration techniques were utilized in order to classify the existing rock types and accordingly distribute rock properties onto the geocellular model. This paper discusses the methods of integrating the results of seismic interpretation and inversion, gemechanical, fracture modelling, petrophysical, and engineering studies to build multiple 3D geological static reservoir model cases of a tight oil quartzitic sand reservoir and how major uncertainties associated with structural modeling, facies identifications and distributions and petrophysical parameter distributions were addressed in an integrated methodology. Ranking the multiple cases is ultimately done to select those necessary for further analysis. Keywords: Quartzite, tight oil, sweet spots, seismic inversion, fracture model, and uncertainty analysis.

AAPG Datapages/Search and Discovery Article #90291 ©2017 AAPG Annual Convention and Exhibition, Houston, Texas, April 2-5, 2017