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Optimal technical analysis and pre-development well planning has never been more important in establishing the commercial viability of smaller oil fields. This focus has been exacerbated by recent oil price variation, placing an increased onus on technical teams to make optimal development drilling decisions. This paper outlines a case study of successful technical work undertaken for the further development of the onshore Singleton field, Middle Jurassic carbonate reservoir, UK. The field was discovered in 1989 and production from the field peaked in mid 1990's at c. 1,000 BOPD. Whilst reservoir porosity is fair to good, with some natural fractures evident, matrix permeabilities tend to be low, resulting in low recovery factors. The field had been producing c. 500 BOPD from 6 wells prior to the operator commencing a development study on the field. The aim of this study was to identify a development program that would significantly increase the reserves, recovery factor, and oil production of the Singleton field. The Southern Block of the field was high-graded for the study due to its significant STOIIP. This block has been on production since 1990 with three producers online at the time of study. A simulation study was conducted for the area. Through well test analysis and sector modeling fracture and all other key unknown parameters were estimated. A full field model was built based on a 3D geological model and the derived parameters. These parameters were further adjusted to obtain good matching on production and pressure histories. Based on the simulation results, a production well was targeted to the west area of the block. It was predicted that this additional new well would increase the oil recovery factor by 2%. The effect of fracturing on the oil recovery factor was also investigated with a further increase in recovery factor of c. 2 to 3 % possible based on a range of low to high fracture densities. A new development well was subsequently drilled based on the modeling results. This well came in on prognosis and encountered porous hydrocarbon bearing reservoir section with minor fracture development. The initial well performance has been close to that predicted by the simulation model, with rates and initial reservoir pressure matching the non-fractured simulation prediction case. The simulation modeling helped to improve the geological understanding of the fracture network present in the field. As the well results have demonstrated the viability of the modeling; a number of further development well locations are currently under review to continue the further development of the Singleton oilfield.

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