川西坳陷须五段地层水特征及其产出控制因素

川西坳陷须家河组五段气藏气水关系复杂,地层水矿化度高,均不同程度的产水。通过川西坳陷600多个地层水化学数据的系统分析,探讨了研究区地层水化学特征及其气水产出控制因素。须五段地层水主要为CaCl_2型,少量NaHCO_3型,矿化度较高,平均为68 920.3 mg/L,长期处于高度封闭状态,总体处于交替停滞带,钠氯系数介于钠氯系数介于0.69~0.95,平均为0.8,属于变质的沉积水;脱硫酸系数低,还原彻底,碱交换指数低,地层水不活跃,保存条件较好。地层水开采一定时间后,水型发生转变,Na~+/Mg~(2+)比值降低,气藏开发过程中在岩石变形、水的膨胀以及压差的综合作用下,束缚水转化为可动水进入流动通道并随气体产出,导致地层含水饱和度较高。单井地层水产能与河口坝和水下砂坝厚度百分比、压力和压力系数、断层正相关,与分流河道和浅湖泥厚度百分比负相关。

Formation-water characteristics and the control factor of genetic of the upper Triassic xujiahe formation in the western Sichuan depression

Complex gas and water relations of the fifth memberof Xujiahe Formationof West Sichuan depression, high salinity of formation water and degrees of water. Analysis Bymore than 600 data of xujiahe formation water chemistry, discusses the chemical characteristic of formation water and the controlling factors of gas and water in the study area. Xujiahe Formation the fifth member is mainly in CaCl2type, NaHCO3type is rare,salinity is high, with an average of 68920.3mg/L, Long-term height closed,Generally in alternating stagnation zone, coefficient of sodium and chloride between 0.69~0.95,averagedby 0.8,belong to metamorphic of deposition water; Desulfurization of low acid, reduced completely,Alkali exchange index is low, formation water is not active, preservation is good. After a certain period of producing formation water, water type is changed,Na+/Mg2+ ratios decreased. In the process ofgas reservoir development, rockdeformed, under the condition of swelling and differentialpressure, bound water transform to move water into thechannel and produce with gas, resulting in high water saturationof formation. Single wells waterproduction Capacity showed the the positivecorrelation withmouth bar and mouth bar depth percentage, pressure and pressure coefficient and fault, the negativecorrelation with the thickness of distributary andshallow lacustrine clay percentage.