Optimal Reservoir Modelling Improves Development Decision Making for a Fractured UK Onshore Oil Field - A Case Study (SPE-130105)

摘要

Optimal well planning is very important in establishing the 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, Middle Jurassic carbonate reservoir, UK. . The field was discovered in 1989 and production peaked in mid 1990s at c. 1,000 BOPD. Whilst reservoir porosity is good, matrix permeabilities tend to be low, resulting in low recovery. The field had been producing from 6 wells at 500 BOPD prior to the development study. The aim of the study was a development programme that could significantly increase reserves and oil production of the field. The Southern Block of the field was chosen due to its significant STOIIP. Through well test analysis and sector modelling fracture parameters and all other key unknown parameters were estimated. A full field model was based on a 3D geological model and derived parameters. These parameters were further adjusted to obtain good matching on production and pressure histories. Based on these results a production well was targeted to the block west area. This new well would increase the oil recovery factor by 2%. A further increase to 3% depending upon the fracture density was predicted. A new well was subsequently drilled. The initial well performance is close to that predicted by simulation, with rates and initial reservoir pressure matching the non-fractured simulation case. The simulation modelling helped to improve the geological understanding of the fracture network in the field. As the well results have demonstrated the viability of the modelling; a number of further development well locations are currently under review to continue the further development of the Singleton oilfield.