镇泾地区中侏罗统延安组低幅度圈闭成因类型与评价

Genetic type and evaluation of low amplitude traps of Middle Jurassic Yan′an Formation in Zhenjing area

邹敏 云金表 王濡岳 于岚 伍岳 吉圆圆 成立 何维领 赵刚

中国石化石油勘探开发研究院，北京 102206 中国石化华北油气分公司采油一厂，陕西 咸阳 712000 中国石化上海海洋油气分公司，上海 200120

鄂尔多斯盆地延安组低幅度圈闭广泛发育，但成因类型复杂，成藏富集条件苛刻。为了明确其评价重点、控制勘探风险，文中以镇泾地区延安组低幅度圈闭为例，通过开展平、剖面形态、构造等值线响应、地层厚度变化等特征研究，探讨了低幅度圈闭成因类型及关键控藏要素。结果表明：低幅度圈闭成因以构造作用为主、沉积压实为辅，根据二者在低幅度圈闭主体形成中的作用，分为早期继承型、多期改造型和晚期扭动型3种类型，其中以多期改造型低幅度圈闭为主。早期继承型低幅度圈闭存在构造与砂体的空间不匹配性，评价重点为圈闭主体储层发育情况；多期改造型低幅度圈闭进一步划分为旁侧断裂型和断裂贯穿型2个亚类，关键评价要素分别为横向输导体系与圈闭保存条件；晚期扭动型低幅度圈闭勘探风险较大，需要加强圈闭落实程度和保存条件研究。文中厘清了低幅度圈闭成因类型与评价思路，为镇泾地区延安组滚动勘探评价提供了有力技术支撑。

Low amplitude traps of Yan′an Formation are widely developed in Ordos Basin, but their genetic types are complex, and the reservoir forming factors are sensitive. In order to  to clarify the evaluation focus and control the exploration risk, taking the low amplitude trap of Yan′an formation in Zhenjing area as an example, the genetic types and key reservoir controlling elements are discussed by using various methods such as plane and profile shape, structural isoline response and formation thickness variation. The study shows that the low amplitude traps of Yan′an Formation in Zhenjing area are mainly controlled by tectonism and supplemented by sedimentary compaction. According to the contribution to the forming of main low amplitude trap, the traps can be divided into three types such as early succession, multi?鄄period reformation and late torsion, in which multi?鄄period reformation type is the main type. The early succession traps have the spatial mismatch between the structure and the sand body, and the evaluation should focus on the main reservoir development of traps. Multi?鄄period reformation traps can be divided into lateral fault type and fault penetrating type, the lateral transport system and the trap preservation condition are key evaluation factors of the two types. The exploration risk of late torsion traps is high. It is necessary to make clear the trap confirmation degree and preservation condition. The research results clarify the genetic types and evaluation frame of low amplitude traps, which provides technical support for the rolling exploration evaluation of Yan′an Formation in Zhenjing area.

10.6056/dkyqt202203005