有水气藏气水分布及水区能量

GAS-WATER DISTRIBUTION AND WATER-REGION ENERGY OF WATER-BEARING GAS RESERVOIR

有水气藏中,不同的气水分布模式,决定了水区不同的驱动能量。有水气藏水区能量是由气、水能量叠加组合构成,水体活动性是组合能量的综合体现。圈闭封闭环境下,如果水体量不是足够大,其膨胀量不能使累产气—拟压力关系压降曲线明显偏离无水气藏压降关系线;而圈闭外连通较小的含气区,其膨胀量能够使圈闭内压降关系线明显偏离无水气藏压降关系线。水中溶解气膨胀是增加水体驱动能量和水体活跃性的重要因素。在气水分异不彻底的过渡带气藏,溶解气膨胀驱动地层水侵入气区的作用不可忽视,构造越平缓的气藏,气水分异越不彻底,溶解气膨胀驱动地层水的作用越强,气井生产越容易出水。

In the water region of water-bearing gas reservoir,different flooding energy can be determined by corresponding gas-water distribution.Water-region energy is composed of gas and water energies and water-body activity is the comprehensive expression of the combined energies.Under enclosed environment of trap,if the water-body volume is not large enough,the expansion rate will not obviously deflect drawdown curve of gas production-pseudo pressure relation from the curve of water-free gas reservoir;whereas in gas-bearing region with poor connectivity outside trap,the expansion rate can deflect the drawdown curve inside.Dissolved-gas expansion is the key factor increasing flooding energy and water-body activity.In gas reservoir of transitional zone with incomplete gas-water differentiation,the dissolved-gas expansion plays an important role in driving formation water invading gas region.For gas reservoir with gentle structure,its gas-water differentiation is less complete.And the stronger the driving effect is,the more the water will be produced.