【摘要】 为了明确有水气藏非均匀水侵的特征,基于水体侵入补给地层能量与封隔储层中天然气的双重作用机制,引入储层非均匀系数(A)与水侵常数(B),分别表征储层物性非均匀程度与外围水体活跃程度,进而建立考虑水封气现象的物质平衡法;在此基础上,绘制有水气藏水侵特征曲线图版,并结合实例气藏进行非均匀水侵模式划分。研究结果表明:(1)基于考虑水封气影响的物质平衡法,绘制的有水气藏水侵特征曲线图版右上、左下区域分别为补给区与封隔区,以A=0、B=2为界限,将补给区划分为强补给区与弱补给区,以A=2、B=2为界限,将封隔区划分为强封隔区与弱封隔区,并对应于强补给、弱补给、弱封隔与强封隔4种水侵模式;(2)对于裂缝性气藏,其储层物性非均匀程度高,水侵后容易形成水封气,该类型气藏的无因次相对拟压力数据位于水侵特征曲线图版的封隔区;(3)储层物性较均匀的气藏,其无因次相对拟压力数据位于水侵特征曲线图版的补给区,水侵对地层能量的补给作用大于水封气对地层能量的削弱作用;(4)随着A增大,储层物性非均匀程度不断增加,水侵特征曲线由右上方向左下方偏移,气藏采收率不断降低,而随着B增大,水侵对地层能量的补给与水封气对地层能量的削弱作用则均减弱,水侵特征曲线分布范围向补给/封隔区分界线收窄,相应气藏采收率区间范围也变窄。更多还原

【Abstract】 In order to clarify the characteristics of non-uniform water invasion in water-bearing gas reservoirs, it is necessary to introduce the non-uniformity coefficient(A) and water invasion constant(B) to characterize the non-uniformity degree of reservoir physical properties and the activity degree of peripheral water, respectively, based on the dual mechanism of water invasion to recharge the formation energy and seal off the gas in the reservoir. Then, the material balance method considering the phenomenon of water sealed gas was established. On this basis, the water invasion characteristic curve chart of water-bearing gas reservoirs was plotted, and the non-uniform water invasion mode was classified based on the example gas reservoir. And the following research results were obtained. First, in the water invasion characteristic curve chart of water-bearing gas reservoirs which is plotted based on the material balance method considering the influence of water sealed gas, the upper right area and the lower left area are defined as recharge area and seal area, respectively. By taking A=0 and B=2 as the boundary, the recharge area is divided into strong recharge area and weak recharge area. By taking A=2 and B=2 as the boundary, the seal area is divided into strong seal area and weak seal area. And correspondingly there are four water invasion modes, i.e., strong recharge, weak recharge, weak seal and strong seal. Second, for fractured gas reservoirs, the non-uniformity degree of reservoir physical properties is high, and water sealed gas can be formed easily after water invasion. The dimensionless relative pseudo-pressure data of this type of gas reservoir is located in the seal area of the water invasion characteristic curve chart. Third, for the gas reservoirs whose reservoir physical properties are relatively uniform, the dimensionless relative pseudo-pressure data is located in the recharge area of the water invasion characteristic curve chart, and the recharge effect of water invasion on formation energy is greater than the weakening effect of water sealed gas on formation energy. Fourth, with the increase of A, the non-uniformity degree of reservoir physical properties increases, the water invasion characteristic curve shifts from the upper right to the lower left, and the recovery factor of gas reservoir decreases continuously. With the increase of B, the recharge effect of water invasion on formation energy and the weakening effect of water sealed gas on formation energy are both weakened, the distribution range of water invasion characteristic curve narrows to the recharge/seal boundary, and the corresponding range of gas reservoir recovery factor also narrows.更多还原