碳酸盐岩气藏气井出水机理分析--以土库曼斯坦阿姆河右岸气田为例

Water producing mechanisms of carbonate reservoirs gas wells: A case study of the Right Bank Field of Amu Darya,Turkmenistan

以土库曼斯坦阿姆河右岸气田为例,系统研究碳酸盐岩气藏气井出水规律及机理。阿姆河右岸碳酸盐岩气藏主要出水来源为凝析水、工程液和地层水,根据单一与混合2种出水来源,分别建立水性-水气比判别法和氯离子守恒判别法,以此甄别出产出地层水的气井。通过建立产水诊断曲线,将气井出水规律划分为"1型"、"2型"和"3型"3种模式。结合储集层静、动态研究成果综合分析认为:"1型"出水模式气井的储集层类型以孔隙(洞)型为主,出水机理为底水沿基质孔隙的锥进;"2型"出水模式气井的储集层类型以裂缝-孔隙型为主,出水机理为底水沿天然裂缝的突进;"3型"出水模式气井的储集层类型以缝洞型为主,出水机理为底水沿大型缝洞的上窜。

The mechanisms of carbonate gas reservoirs were systematically studied with the Right Bank Field of Amu Darya Gas Field, Turkmenistan, as an example. Water produced from the reservoirs has three sources, condensate water, engineering fluids and formation water. The fluid physical property and water-gas ratio （WGR） method for the single component conditions and the chloridion conservation method for the multi-components conditions were established to identify the components contained in the production fluids. A water production diagnosing curve, which refers to the degree of reserve recovery as a function of the water-gas ratio in the log-log coordinate curve, was then established and the formation water producing wells were divided into three patterns, i.e. Type 1, Type 2, and Type 3. Through in-depth studies of the static and dynamic reservoir characteristics of each pattern, the following understandings were attained： The reservoirs of Type 1 are mainly porous, and the water producing mechanism is bottom water coning along matrix pores; the reservoirs of Type 2 are mainly fractured-porous, and the bottom water produces basically through the natural fracture system; the reservoirs of Type 3 are mainly fractured-cavity, and the bottom water produces basically through large-scale fractures and caves.