Occurrence state and production mechanism of bound water in tight gas reservoirs in western Sichuan depression
-
摘要: 致密砂岩储层微观孔隙结构复杂,普遍存在束缚水,其分布规律、赋存状态及流动机理对储层含气性和微观渗流影响较大。通过选取川西坳陷不同类型气藏的岩样,开展半渗透隔板法实验分析,揭示微观孔隙结构与束缚水赋存状态、产出机理的内在联系。研究结果表明:①不同类型储层具有不同的束缚水饱和度分布特征,微观孔隙结构是影响束缚水饱和度的内因。孔隙半径较大,但片状或缩颈状喉道发育,孔喉分选性差且微细孔喉较多,原始地层水易被捕集在孔喉尺寸急剧变化处或微细孔喉中,导致束缚水饱和度偏高;而孔隙缩小型、管束状喉道较发育,孔喉分选性较好,微细孔喉较少或者孔喉体积比小,束缚水饱和度相对较低。②部分高值束缚水在较大压力梯度的作用或可动水的诱导下,水可转化为临界水,最终成为可动水参与流动,随天然气产出。结论认为,开发初期应控制生产压差,一旦原始束缚水开始参与流动,将加剧气井产水和开发中后期井筒积液。Abstract: The micro pore structure of tight sandstone reservoir is complex, and bound water exists generally. Its distribution, occurrence and flow mechanism have great influence on gas bearing property and micro seepage. By selecting rock samples of different types of gas reservoirs in western Sichuan depression, the experimental analysis of semi permeable partition method is carried out to reveal the internal relationship between micro pore structure and occurrence state and production mechanism of bound water. The results show that: ①Different types of reservoirs have different distribution characteristics of irreducible water saturation, and the micro pore structure is the internal factor affecting the irreducible water saturation. When the pore radius is large, but the flaky or necked throat is developed, the pore throat separation is poor and there are many micro pores and throats. The original formation water is easy to be trapped in the places where the pore throat size changes rapidly or in the micro pore throat, resulting in high irreducible water saturation. While, as for the shrinkage pores, the tube bundle throats are relatively developed, the pore throat separation is good, the micro pore throat is less or the pore throat volume ratio is small, and the irreducible water saturation is relatively low. ②Under the action of large pressure gradient or the induction of movable water, part of high value bound water can be transformed into critical water, and finally become movable water to participate in the flow and produce with natural gas. It is concluded that the production pressure difference should be controlled in the initial stage of development. Once the original bound water begins to participate in the flow, the water production and wellbore effusion in the middle and later stages of development will be intensified.
-
张岩,陈昱林.川西坳陷新场气田蓬二段气藏储层物性特征新认识[J].天然气技术与经济,2020,14(1):32-38. 段永明,张岩,刘成川,等.川西致密砂岩气藏开发实践与认识[J].天然气地球科学,2016,27(7):1352-1359. 朱华银,徐轩,安来志,等.致密气藏孔隙水赋存状态与流动性实验[J].石油学报,2016,37(2):230-236. 王启颖,张岩.川西致密砂岩气藏有效砂体分布特征与形成机理[J]. 地球科学前沿, 2018, 8(6):1096-1103. 刘成川,张岩,詹国卫,等.川西洛带气田上侏罗统遂宁组有效砂体特征与形成机理[J].天然气技术与经济, 2019,13(5):30-35. 刘成川,刘莉萍,王启颖,等.川西地区雷口坡组第四段复杂气水分布多重控制因素[J].成都理工大学学报(自然科学版),2020,47(2):159-168. 高辉.红河油田长8致密砂岩储层微观孔隙结构及可动流体饱和度特征研究[J]. 石油地质与工程, 2018, 32(5):44-47. 贾家磊.致密砂岩双重介质储层可动流体影响因素分析——以鄂尔多斯盆地泾河长8段为例[J].石油地质与工程,2018,32(2):61-65. 吴一雄,胡向阳,杨东,等.一种基于毛细管压力资料获取岩心束缚水饱和度的新方法[J].地质科技情报, 2018,37(5):100-105. 吕金龙,卢祥国,王威,等.裂缝对致密储层渗流能力影响实验研究[J].特种油气藏,2019,26(2):141-146. 岳文正,陶果,赵克超.用核磁共振及岩石物理实验求地层束缚水饱和度及平均孔隙半径[J].测井技术, 2002, 26(1):22-25. 程大勇, 李彦来, 房娜, 等.聚驱相对渗透率曲线变化规律实验研究[J].油气藏评价与开发, 2019, 9(2):56-59. -

计量
- 文章访问数: 305
- HTML全文浏览量: 21
- PDF下载量: 40
- 被引次数: 0