海相碳酸盐岩地层水对油气的响应特征——以塔中北斜坡奥陶系为例

Responses of Marine Carbonate Formation Water to Oil and Gas——Taking Ordovician of Tazhong Northern Slope as an Example

海相碳酸盐岩地层水与碎屑岩地层水化学特征、作用及对油气的响应不尽相同。对塔中奥陶系地层水及油气性质的研究表明奥陶系地层水以（K＋＋Na＋）、C1一为主要离子成分，以CaCl2水型为主，矿化度集中在（70～200）×10^3mg／L之间，pH值与储存类型相关；碳酸盐岩地层水对油气的响应主要体现在三个方面：钠氯系数、脱硫系数、矿化度等综合反映油气的保存条件，矿化度升高方向指示油气运移方向，矿化度、出水量、油气性质差异反映成藏过程中的油气分异现象。根据出水量和出水特征，可将塔中奥陶系地层水划分成凝析水、断层水、边（底）水和封存水4种类型，不同类型地层水反映成藏特征不同。

Marine carbonate formation water and clastic rock formation water are different in chemical charac- teristics, function and response to oil and gas. The chemistry of Ordovician formation water in the Northern Slope, Tazhong Low Rise, Central Uplift,Tarim Basin were studied, showed that this water with （K＋ ＋ Na＋ ）and Cl- as main ion composition was mostly of CaC12 type with salinity ranging from （70 -200） × 10^3 mg/L and its pH value was associated with reservoir type. Ordovician formation water provided the material basis of migration dynamics for the carbonate oil and gas reservoirs and reformed the reservoir beds. The response of marine carbonate formation water to oil and gas was mainly in three aspects： rNa ＋/rCl-, desulfurization and salinitly, reflecting the preserva- tion conditions of oil and gas. Increase of salinity indicated oil and gas migration direction. Difference in salinity, water yield and oil and gas properties reflecting differential accumulation of oil and gas. According to water yield and watering characteristics, Ordovician formation water can be divided into four types, condensate water, fault-re- lated water, side （bottom） water and pent-up water, and different types of formation water reflected different char- acteristics of oil and gas accumulation.