摘要
四川盆地东北部地区致密气藏地质特征复杂,开发过程中储量动用率低,效益开发难度大,勘探开发范围难以拓展。以川东北地区五宝场沙溪庙组致密气藏为例,储层物性整体表现为低孔隙度、特低渗透率特征,储层孔隙度仅5.61%,岩心渗透率主要分布在10-4~10-1mD之间,相较于四川盆地内其他沙溪庙组致密气藏更为致密。对此详细分析气藏成藏条件,明确气井的产能主控因素及高产机制,以指导气藏下步的科学高效开发。研究结果表明:(1)气藏是以曲流河—三角洲沉积为主的红色砂泥岩系,具备充足的烃源供给基础,具有相互叠置的储集砂体、沟通烃源岩与储集砂体的断层以及一定规模的封闭盖层,为形成致密岩性气藏提供了有利条件。(2)储层物性及有效厚度仍是决定气井产能的主要因素。(3)裂缝是气井高产的重要因素。首先,气藏高产井主要沿裂缝发育的构造轴部分布;其次,烃源断裂是高产气井发育的关键,即在沟通烃源岩与储集砂体之间的断层附近,发育高产井;第三,通过储层压裂改造实现人工造缝,可在一定程度上提高单井产能。在对致密气藏进行气井产能主控因素研究的基础上,提出了下步寻找裂缝发育有利区及结合纵向多套砂体叠置的特点实施立体综合开发的勘探开发思路。
Tight gas reservoirs in northeastern Sichuan Basin are complex geologically, leading to low producing rate of reserves and difficulties in profitable development and expanding the scope of exploration and development. In this study, the tight gas reservoirs of Shaximiao Formation in Wubaochang were discussed as examples. The reservoirs are generally characterized by low porosity and ultra-low permeability, with the porosity of only 5.61% and the core permeability ranging from 0.0001 mD to 0.1 mD. They are tighter than other tight gas reservoirs of Shaximiao Formation in the basin. The reservoir-forming conditions were analyzed, and the main factors controlling productivity and high-yield mechanisms of gas wells were clearly defined, to guide the subsequent scientific and efficient development. Results show that the reservoirs are a red sand-mudstone system dominated by meandering river–delta sediments, indicating a sufficient hydrocarbon source supply basis. There are superimposed reservoir sand bodies, faults connecting source rocks with reservoir sand bodies, and a certain scale of closed caprocks, which provide favorable conditions for the formation of tight lithologic gas reservoirs. Reservoir physical properties and effective thickness are still the key factors determining the productivity of gas wells. And fracture is the important factor for high production. First of all, high-yield gas wells are mainly deployed along the structural axis where fractures are developed. Secondly, hydrocarbon source faults are crucial to high-yield gas wells, that is, high production can be achieved in the area near the faults connecting source rocks with reservoir sand bodies. Finally, artificial fractures are induced by reservoir fracturing to enhance single-well productivity to a certain extent. Based on the research of the main factors controlling productivity, it is proposed to seek favorable zone for fracture development and implement three-dimensional comprehensive development depending on the characteristics of vert
作者
徐明星
任洪明
胥伟冲
李明秋
张晓丽
杜磊
李咏洲
伍虹莉
Xu Mingxing;Ren Hongming;Xu Weichong;Li Mingqiu;Zhang Xiaoli;Du Lei;Li Yongzhou;Wu Hongli(Northeastern Sichuan Gas District,PetroChina Southwest Oil&Gasfield Company,Dazhou,Sichuan 635000,China;Exploration and Development Research Institute,PetroChina Southwest Oil&Gasfield Company,Chengdu,Sichuan 610041,China)
出处
《天然气勘探与开发》
2022年第4期103-110,共8页
Natural Gas Exploration and Development
关键词
五宝场地区
沙溪庙组
致密气
成藏条件
气井产能
产能控制因素
Wubaochang area
Shaximiao Formation
Tight gas
Reservoir-forming condition
Gas well productivity
Controlling factor of productivity
