关键词: 三叠系, 延长组, 下组合, 储层特征, 鄂尔多斯盆地

Abstract:

The gas reservoir with abnormal pressure is characterized by high pressure and large productivity, so, it is very important to evaluate the deliverability. Meanwhile, the water breakthrough often occurs in the gas well under certain unreasonable working systems, which reduces the productivity significantly. Thus, it is vital to confirm the reasonable working system on the base of accurate prediction of the productivity of gas well with abnormal pressure. Considering stress sensitivity, non-Darcy flow, pulsation effect and water producing of gas well, this paper deduced a trinomial equation for water producing gas well with abnormal pressure. On the basic of the multiple linear regression and intersection method, absolute open flow capacity was determined and the correctness of result was demonstrated by the case analysis. The effects of permeability sensitivity coefficient and water/gas mass ratio on the gas well productivity were quantitatively analyzed. Calculation results show that: the effect of permeability sensitivity coefficient on gas well productivity is greater than that of producing water; for the gas well with large productivity, the effect of pulsating flow on the absolute open flow of gas well should not be overlooked. This study has significance for the exploitation of abnormal pressure reservoir.

Key words:  Triassic, Yanchang Formation, lower assemblage, reservoir characteristics, Ordos Basin