Development Strategy Optimization for Different Kinds of Tight Oil Reservoirs

Abstract

AbstractTight oil has large amount of resources and enormous potential in development. Application of volume fracturing on horizontal wells has a significant impact on tight oil development. But with continuing low oil price, development strategies should be more effective in order to maintain the economic development of tight oil reservoirs. This paper presents a case study of development strategy optimization for different kinds of tight oil reservoirs in China.This paper focuses on MZ tight oil field in China. And reservoir properties and fractures of DAZ reservoir is better developed than that of LGS reservoir of MZ oil field. Based on geological understanding and dynamic characterization on the two formations, two representative sectors of each reservoir are selected. And corresponding geological and numerical simulation sector models are established. Finally, development strategies are optimized through reservoir simulation.The optimized parameters include the length of horizontal section, well spacing, fracture segments spacing, fracture half-length, etc. Sensitivity analysis of all parameters are conducted based on the established simulation models. For DAZ reservoir, the optimized development strategies are: 2000m horizontal well length, 700m well spacing with 300m fracture half-length and 20 fracturing stages. While for LGS reservoir, the optimized development strategies are: 2500m horizontal well length, 800m well spacing with 350m fracture half-length and 22 fracturing stages. Although longer horizontal well and more fracturing stages for LGS reservoir, the predicted average well cumulative oil production within 10 years is still lower than that of DAZ reservoir because of the poorer reservoir quality of LGS reservoir.This paper offers a case study on development strategy optimization for different kinds of tight oil reservoirs. The results have been applied to the two tight oil reservoirs in MZ tight oil field in China with successful results. It also provides a methodology and reference case for engineers and geologists to develop other similar fields.