Sweet spot identification and optimization of Chang8 tight reservoir in Fuxian Oilfield
There are problems such as unstable drilling ratio and high water cut of reservoir when expanding the new area of Chang8 tight reservoir in Fuxian Oilfield.The reason is insufficient research on sweet spot identification and optimization.In order to identify and optimize the sweet spots of Chang8 tight reservoir in Fuxian Oilfield more accurately,This paper summarized the previous evaluation methods of tight oil sweet spots to promote the better development of Chang 8 tight reservoir in Fuxian Oilfield.The main controlling factors of the sweet spots of Chang8 tight oil reservoir in Fuxian Oilfield were studied from four aspects:source rock thicknesses,reservoir sand body thicknesses,reservoir physical properties,and structures.The sweet spots of Chang8 tight reservoir in Fuxian Oilfield were identified and optimized by introducing the comprehensive evaluation coefficient F of the reservoir and adopting the superposition coefficient method.The achievements were as follows:1)The test production of Chang8 tight reservoir in Fuxian Oilfield increases first and then decreases when the source rock thickness increases and reaches the peak when the source rock thickness is up to 90 m;the test production gradually increases when the thickness of the reservoir sand body increase;the test production significantly increase when the porosity and permeability of reservoir increase but not controlled by the structure;2)The comprehensive evaluation coefficient F of Chang8 tight reservoir in Fuxian Oilfield are greater than 64.2,between 48.9 and 64.2 and between 33.7～48.9,and they belong to Class I,Class Ⅱ and Class Ⅲ sweet spot areas,respectively;3)Ten exploration wells were deployed in optimized Class Ⅱ sweet spot areas of Chang8 tight reservoir in Fuxian Oilfield,and the industrial oil flow were obtained 7 wells,with a success rate of 70％and significant effect.The research results have good popularization and application value for identifying sweet spot and optimizing similar tight reservoirs.
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