论文部分内容阅读
气藏剩余压力分布能够直接反映其储量动用情况,采用长岩心多点测压实验装置,选择渗透率分布区间分别为(1.38~1.71)×10~(-3)μm~2、(0.41~0.73)×10~(-3)μm~2、(0.049~0.084)×10~(-3)μm~2的多块砂岩岩心组合形成长度超过50cm的3组长岩心,模拟含水砂岩气藏衰竭开采。实验过程中实时记录气藏边界至气井不同位置处压力剖面变化,研究含水气藏储量动用特征。研究表明:致密砂岩储层产气特征、压力剖面形态、压降过程、废弃时剩余压力分布均与渗透率较高的储层(Ⅰ类)差异显著,明显受渗透率和含水饱和度控制。含水相同(约35%),生产至废弃条件时,Ⅰ类储层的压力剖面整体几乎降为0,而致密砂岩、剩余压力仍维持在原始压力的50%以上,且压力梯度大,表明含水气藏,渗透率越低储量动用越困难,动用均衡性越差;考虑含水,随含水饱和度增加,Ⅰ类储层压力剖面形态及下降过程变化不大;渗透率更低的储层(Ⅱ类)尤其是致密储层(Ⅲ类),其压力剖面形态变化极为显著,含水较高时,压力难以向外波及,储量难以有效动用,且非均衡性极强。
The remaining pressure distribution of gas reservoirs can directly reflect the utilization of reserves. Using the multi-point long-core pressure measuring device, the distribution intervals of selective permeability are (1.38 ~ 1.71) × 10 ~ (-3) μm ~ 2, (0.41 ~ 0.73 ) 3 × 10 ~ (-3) μm ~ 2 and (0.049 ~ 0.084) × 10 ~ (-3) μm ~ 2, forming three sets of long cores with a length of more than 50 cm to simulate the depletion mining of water-bearing sandstone gas reservoirs . During the experiment, the pressure profile at different positions of gas wells along the boundary of the gas reservoir was recorded in real time to study the characteristics of the reserves of the water-bearing gas reservoirs. The results show that gas production characteristics, pressure profile, pressure drop process and residual pressure distribution of the tight sandstone reservoirs are significantly different from those of the higher permeability reservoirs (type Ⅰ), which are obviously controlled by permeability and water saturation. (About 35%), the pressure profile of reservoir type Ⅰ is almost zero when it is produced to the abandoned condition, whereas the tight sandstone still has residual pressure over 50% of the original pressure and large pressure gradient, indicating that the water content In the gas reservoir, the lower the permeability is, the more difficult it is to use the reserves, and the poorer the balance of the use is. Considering the water content, with the increase of the water saturation, the pressure profile and the descending process of the type Ⅰ reservoir have little change. Especially in the tight reservoirs (Ⅲ), the pressure profile has obvious morphological changes. When the water content is high, the pressure is hard to move outwards and the reserves are hard to be effectively used, and the non-equilibrium is extremely strong.