CROUCH, SYRIE, WALTER BAUMGARTNER, ERIC HOULLEBERGHS, ALEXON KHOR, ALAN SCHULTZ, and JOHANNES WALZEBUCK, Nederlandse Aardolie Maatschappij, Velsen, Netherlands

ABSTRACT: Development of a Tight Gas Reservoir by a Multiple-Fracced Horizontal Well: Ameland-204, Netherlands

The poor productivity of tight Permian gas reservoirs is a major constraint on economic field development in the Dutch offshore sector. In a number of fields, economic production from Rotliegendes reservoirs could not be achieved with conventional development techniques due to very low flow rates of less than 200,000 cu m/d. A case history is shown from the Ameland field in the Dutch North Friesland area. The flanks of this layered Rotliegende reservoir can in general be classified as "porous but tight." The geological causes are (1) a poor sand facies development, and (2) pervasive clay mineral impairment, affecting the pore connectivity, leaving behind untapped reserves. It was decided to improve this reservoir performance by applying multiple-fracced horizontal well technology.

The project was approached in a fully integrated manner, involving the petroleum engineering and drilling departments. The key problems addressed were (1) verification of sufficient GIIP, (2) analysis of reservoir architecture, and (3) modeling of productivity improvement by multiple-fraccing technology. The success of the project was confirmed when the multiple-fracced well succeeded in achieving economic production rates (transient) in the range of 1.9 x 10{6} cu m/d at 150 bar drawdown, from a tight Rotliegende gas reservoir. The experience gained and the positive results show that multiple fraccing of horizontal wells is applicable to other tight gas reservoirs and could raise them from uneconomic prospects to potentially profitable developments.

AAPG Search and Discovery Article #90990©1993 AAPG International Conference and Exhibition, The Hague, Netherlands, October 17-20, 1993.