Damage Characterization and Production Optimization of the Hassi-Messaoud Field, Algeria

Abstract

Abstract The Hassi-Messaoud Field is a thick sandstone reservoir covering an area of 2000 km2. It is a flattened anticline located on the north of the El-Biod-Hassi-Messaoud elevation. This elevation is formed by a sequence of horsts and grabens contained by faults in a submeridien direction. The faults are in general SSW to NNE oriented and cross all the producing reservoir (Cambro-dovicien). The producing reservoir is located at 3300 m and consists of four distinct formations in addition to a "zone d'alterance"(transition zone). These are subdivided into drains (producing intervals) characterized by distinct properties. Overall, the field is divided into 25 separate zones that differs in their geological and petrophysical properties and are under pressure maintenance by means of water and/or gas injection. Fig. 1 shows the field different zones and a cross section of the Cambro-Ordovicien formation. This paper presents the successful application of a methodology to optimize production and results of matrix acidizing treatments in the Hassi-Messaoud field. The corner stone of the methodology is damage characterization. The damage is analyzed and evaluated per zone. Categories according to damage severity and frequency are presented. Among others these categories include salt deposition; scales deposition including barium sulfate, clays types, fines migration, and asphaltenes. A thorough coverage of the geology, mineralogy, petrophysical properties, formation fluids characteristics, reservoir pressure evolution and pressure maintenance, wells completions and production schemes are presented for the 25 different zones that integrate the heterogeneous Hassi-Messaoud field. Finally, production optimization as a result of applying the methodology on matrix acidizing treatment is presented and quantified by :treatments success ratio;production gain;payout time;decline rates of wells before and after treatment andactual cost per ton of production gained. P. 549