Sand Control Application in Mediterranean Sea Pliocene Gas Reservoirs-Case Study

Abstract In the last ten years a lot of gas fields were discovered in Egypt at Mediterranean Sea area, the most reservoirs of these fields were discovered in the Pliocene age and described as a unconsolidated sand reservoirs. Some of these reservoirs located in shallow water and others located in deep water (Water depth for these reservoirs ranging from 400 to 1100m). Several options were evaluated to prevent sand from being produced with the gas with particular emphasis on the fact that some of these reservoirs are subsea and having an expected lifetime of close to 20 years. Intervention into the wells to fix and repair a problem will be costly and have to be considered against maintaining deliverability to protect a Gas Sales Agreement. Hence, finding a method that would prevent sand from being produced over the field life time span was the challenge. Comprehensive sand analysis of available sand samples were conducted for the discovered reservoirs and as the sand is friable, several operational methods were evaluated:Cased Hole Gravel Packing (CHGP)Frac-PackExpandable ScreenConsolidation (Chemical)Stand-Alone Screen solutionOpen Hole Gravel Packing (OHGP) This paper describes the sand control technology and its success for some of these discovered reservoirs. Also the paper high light on the offshore sand control completion operations conducted for these reservoirs and the lesson learned from these operations for the future development in Egypt. Introduction In the last ten years a lot of gas fields were discovered in Egypt at Mediterranean Sea area, the most reservoirs of these fields were discovered in the Pliocene age and described as a unconsolidated sand reservoirs. The reservoirs of Hapy (Gupco), Rosetta (Rashpetco), Darfeel and Nours (Petrobel) Fields located in shallow water and the reservoirs of Scarab/Saffron and Simian/Seina (Rashpetco) fields located in deep water (Water depth for these reservoirs ranging from 400 to 1100m). Darfeel field considered the first field completed in the pliocene age (April 1997). Scarab Saffron represents a significant milestone for the Egyptian Oil and Gas industry, as it is the first advanced subsea development (April 2003) Fig 1. Several options were evaluated to prevent sand from being produced with the gas with particular emphasis on the fact that some of these reservoirs are subsea and having an expected lifetime of close to 20 years. Intervention into the wells to fix and repair a problem will be costly and have to be considered against maintaining deliverability to protect a Gas Sales Agreement. Completion operations have shown a significant learning curve and best in class performance resulting in the final of normal and subsea completions (for Example, estimated saving of over $20mm for Scarab/Saffron Field in the overall drilling and completion costs against the overall project budget. Causes and Effects of Sand Production The conditions which can cause sand production and the probable condition of the formation outside of the casing after sand is produced can be determined by the factors that affect the beginning of sand production.