Algeria is the fourth largest producer of crude oil in Africa and a member of OPEC (Organization of the Petroleum Exporting Countries). Production is primarily from the Hassi Messaoud oil field, a Cambrianage, sandstone reservoir in east-central Algeria with estimated in-place reserves of 25 billion bbl.
Discovered in the 1950s, the Hassi Messaoud is subdivided into four formations, Ri, Ra, R2 and R3, with the main producing formation, Ra-Ri, being further split into six intervals, D5, D4, D3, D2, ID, and D1. Porosity values range from 6 to 12% and permeability is between 1 and 100 mD depending on the density of natural fractures, or fissures, which are the primary source of production in this field.
The Hassi Messaoud was initially developed with hydraulically fractured vertical wells and gaslift with gas or water flooding to enhance oil recovery. In the mid-1990s, horizontal wells began to be drilled to develop areas where vertical drilling was unsuccessful. Horizontal wells now account for a quarter of the field’s output; however, several wells are underperforming prompting the decision to perform a pilot study for hydraulic multi-stage fracturing of the lateral wellbore.