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为直观、详细地论述川西新场须二气藏气井产出水状况,文中将气井产出水分为凝析水、地层水、夹层水或残留地层水3个大类。研究发现,构造主体部位的气井在产出地层水之前大多经历过一段较长时间的凝析水产出阶段;之后南北部边水才侵入构造主体;而构造主体的东西部产出夹层水或残留地层水。其主要原因是随着气藏开采,地层能量下降,边部水体沿着南北走向断层入侵到高部位,使得高部位气井大量产水;至于构造主体的东西部,由于远离断层,微裂缝不发育,气井产水量较少。总体而言,由于产出水类型不同,其水化学成分亦存在较大差异,表现为凝析水矿化度低、地层水矿化度高、夹层水或残留地层水的矿化度则介于两者之间。气井产出水化学性质差异性源自水—岩反应环境、流体压力、天然气浓度以及pH值等影响因素的变化。因为随着气井天然气的采出,流体压力下降、天然气浓度降低,盐离子的溶解度亦降低,所以构造主体产出地层水时,其Ca2+浓度较南北边部的要低,水体中出现少量Ca沉淀。
In order to visualize and describe in detail the production status of gas wells in Xuer gas field in Xinchang Xuanchang, the output water of gas well is divided into three categories: condensate water, formation water, interlayer water or residual formation water. The study found that most of the gas wells in the main part of the structure had experienced a long period of condensate production before the production of formation water. Afterwards, the northern and southern marginal water intruded into the main structure, while the western and western parts of the main structure produced interlayer water or residual Formation water. The main reason is that with the exploitation of gas reservoirs and the decrease of formation energy, the water bodies in the margins migrate to the high positions along the north-south strike faults, resulting in a large amount of water production in the high-position gas wells. As for the east-west tectonics, Development, gas well water production less. In general, due to the different types of produced water, the chemical composition of the water is also quite different, showing the low condensate water salinity, formation water salinity, interlayer water or residual formation water salinity Between the two. The difference in the chemical properties of gas produced from wells is due to the change of influencing factors such as water-rock reaction environment, fluid pressure, natural gas concentration and pH value. Because with the recovery of natural gas in gas wells, the pressure of fluid decreases, the concentration of natural gas decreases, and the solubility of salt ions also decreases. Therefore, when the main body produces formation water, its Ca2 + concentration is lower than that of the northern and southern parts and a small amount of Ca precipitate .