In 1993 BEB drilled two of the world's deepest horizontal gas wells in the Zechstein and Rotliegend formations in northern Germany. The aim of the drilling projects was to increase profitability by achieving high production rates. By minimizing the number of production wells and usage of cluster locations, a reduction of field investment and operating costs should be attained.
To achieve the objectives, the projects were planned in a multidisciplinary team. Based on reservoir descriptions, derived from 3D seismic various sensitivity runs were performed. The aim of the runs being to assess vertical permeability distribution and horizontal hole length. The application of advanced drilling and completion techniques resulted in an optimized well design from an economic point of view.
Results of both wells proved that horizontal drilling into these deep reservoirs is technically feasible and economically attractive. A comparison of vertical drilling with horizontal drilling results in a 2 to 3 fold increase in the initial production rates with only a 1.3 to 1.4 times cost increase. Because of the promising results of the horizontal drilling programme in 1993 a further seven new deep horizontal and two reentry wells were drilled in 1994. In future, BEB's standard well design will be horizontal.