Multi-fractured horizontal wells have become one of the most common technologies for developing unconventional oil and gas reservoirs.Compared with shale gas reservoirs,coalbed methane reservoirs have more complex production characteristics,as the two phases of gas and water are generally existed in it.Few studies have been conducted in coalbed methane reservoir,especially on gas-water two-phase flow.In this paper,by obtaining the production rate and bottomhole pressure of a single well,a comprehensive work flow has been developed to obtain the formation parameters and hydraulic-fracture properties.The studies show that the flow regime of multi-fractured horizontal wells in under-saturated coalbed methane reservoirs can be divided into five stages.In single-phase water stage,the formation parameters can be obtained by coupling the Wattenbarger type-curve method and Compound linear flow type-curve method.In gas-water two-phase flow,the noise points should be removed before analysis so as to diminish the influence of the application of superposition time which will exhibit irregular distribution in the square-root of time method.To demonstrate the feasibility and practicability of the developed work flow,an actual coalbed methane reservoir has been analyzed.The consistent assessment results for field cases validate the proposed method.The method presented in this paper can provide basis for rate-transient analysis of fractured wells in coalbed methane reservoirs.
关键词
欠饱和煤层气/多级压裂水平井/不稳定产量分析/单相水阶段/气水两相阶段
Key words
Under-saturated coalbed methane reservoir/Multi-fractured horizontal well/Rate transient analysis/Single-phase flow of water/Multi-phase flow of gas and water
维普
万方数据