石油学报 ›› 2012, Vol. 33 ›› Issue (4): 533-540.DOI: 10.7623/syxb201204001

• 地质勘探 •    下一篇

新疆北部石炭系火山岩风化壳油气地质条件

侯连华 邹才能 刘 磊 文百红 吴晓智 卫延召 毛治国   

  1. 中国石油勘探开发研究院 北京 100083
  • 收稿日期:2012-01-27 修回日期:2012-05-26 出版日期:2012-07-25 发布日期:2012-08-01
  • 通讯作者: 侯连华
  • 作者简介:侯连华,男,1970年7月生,1992年毕业于中国石油大学(华东),2003年获中国石油大学(北京)博士学位,现为中国石油勘探开发研究院高级工程师,主要从事岩性地层油气藏、非常规油气地质、综合勘探等研究工作。
  • 基金资助:

    国家重大科技专项“岩性地层油气藏成藏规律、关键技术及目标评价”(2011ZX05001)资助。

Geologic essential elements for hydrocarbon accumulation within Carboniferous volcanic weathered crusts in northern Xinjiang, China

HOU Lianhua ZOU Caineng LIU Lei WEN Baihong WU Xiaozhi WEI Yanzhao MAO Zhiguo   

  • Received:2012-01-27 Revised:2012-05-26 Online:2012-07-25 Published:2012-08-01

摘要:

新疆北部晚石炭世处于陆—陆碰撞后的构造松弛环境,发育多个火山岩与沉积岩“间互式”充填、广泛分布的裂谷或裂陷槽,火山岩以中基性岩为主,原始物性较差。石炭纪末整体抬升遭受剥蚀,风化淋蚀形成火山岩风化壳,岩性和风化程度控制风化壳储层质量,各种岩性火山岩经长时间强风化均可形成有利储层。受断裂改善、溶蚀环境、产生裂缝等影响,风化壳储层物性更好、有效储层发育深度更大,近、远断裂区有效储层距不整合顶面埋深分别可达1100 m、550 m,孔隙度最大值分别为32%、24%。现今残留凹陷控制烃源岩分布,受火山岩强非均质储层控制,油气围绕有效烃源岩区近源成藏,石炭系上覆泥岩盖层是有效保存条件,与古构造吻合较好的现今构造高部位和斜坡区是油气运聚指向区,断裂控制油气富集。该认识改变了“石炭系为盆地基底、不具备油气生成条件”的观点,扩大了勘探领域,指导了克拉美丽气田、牛东油田等油气田的发现,对类似地区油气勘探具有重要的理论和现实指导意义。

关键词: 新疆北部, 石炭系, 火山岩风化壳, 油气地质条件, 残留凹陷, 油气藏

Abstract:

In Late Carboniferous, there occurred a tectonic-slack environment after a continent-continent collision in northern Xinjiang, under which developed various and widespread rifts or rifted troughs filled alternately by volcanic and sedimentary rocks. These volcanic rocks are primarily composed of intermediate and basic rocks with poor original properties, and a volcanic weathered crust was formed due to the uplift, erosion, weathering and leaching of strata at the end of the Carboniferous period. Generally, lithology and weathering degree control the reservoir quality of weathered crusts and all kinds of volcanic rocks could be altered to form a favorable reservoir because of long-term intensive weathering. Affected by erosion and fracture caused by faults, physical properties of the weathered crust became better and its pay zones developed even more deeply. For example, the burial depth of pay zones to the top surface of the unconformity is 1100 m and 550 m, respectively, depending on the nearest or farthest distance to faulted areas, and the maximum porosity for them is 32% and 24%, respectively. The distribution of source rocks is controlled by presently remnant depressions, hydrocarbons defined by strongly heterogeneous volcanic reservoirs have accumulated around the neighborhood of effective source rocks. The overlying mudstone is an effective cap rock and the currently structural high and slope consistent well with paleo-structures act as intended zones for hydrocarbons to migrate and accumulate, consequently, oil/gas accumulations are controlled by faults. The above acquirement has changed the conventional view that Carboniferous rocks in Xinjiang were only the basin’s bedrock, not qualified for hydrocarbon accumulations. This research enlarged the exploration sphere in the study area and directed discoveries of the Karat-Meili gas field and Niudong oil field, thus, it is of theoretical and practical significance in oil/gas exploration of similar geologic regions.

Key words: northern Xinjiang, Carboniferous, volcanic weathered crust, geologic condition for hydrocarbon, remnant depression, hydrocarbon accumulation