石油与天然气地质 ›› 2023, Vol. 44 ›› Issue (2): 350-365.doi: 10.11743/ogg20230208

• 油气地质 • 上一篇    

准噶尔盆地异常压力特征及其对深层-超深层致密储层的影响

孙靖1(), 尤新才1, 薛晶晶1, 曹元婷1, 常秋生1, 陈超2   

  1. 1.中国石油 新疆油田分公司 勘探开发研究院,新疆 克拉玛依 834000
    2.中国石油 青海油田公司 采油三厂,青海 海西 816400
  • 收稿日期:2022-07-25 修回日期:2022-12-08 出版日期:2023-04-01 发布日期:2023-03-17
  • 第一作者简介:孙靖(1982—),男,高级工程师,沉积储层、石油地质综合研究和管理。 E?mail: sun19820804@sina.com
  • 基金项目:
    中国石油天然气股份有限公司“十四五”前瞻性基础性重大科技项目(2021DJ02)

Characteristics of abnormal pressure and its influence on deep and ultra-deep tight reservoirs in the Junggar Basin

Jing SUN1(), Xincai YOU1, Jingjing XUE1, Yuanting CAO1, Qiusheng CHANG1, Chao CHEN2   

  1. 1.Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay, Xinjiang 834000, China
    2.No. 3 Oil Extraction Factory, Qinghai Oil Field Company, PetroChina, Haixi, Qinghai 816400, China
  • Received:2022-07-25 Revised:2022-12-08 Online:2023-04-01 Published:2023-03-17

摘要:

准噶尔盆地深层-超深层领域近年来连续获得发现和突破,储层为非常规致密储层且发育异常高压。为明确异常高压发育特征及其对储层质量的影响,利用已钻重点井完井系统试油测压数据进行统计分析,确定盆地深层-超深层压力分布特征和类型,结合成岩作用类型,明确其对致密储层质量的影响。结果表明:①深层-超深层广泛发育异常高压,剩余压力大,压力系数高,垂向和平面分布范围广;②可划分为一般、中等、强和超强等4个异常高压区,西部和东部区块主要位于一般和中等异常高压区,中部区块主要位于一般和强异常高压区,南部区块从一般到超强异常高压区均有分布;③压力系数垂向演化可分为渐变、突变和多变等3种类型,具有不同成因。异常高压对深层-超深层致密储层影响主要体现在:①通过增强孔隙流体承压能力,减弱岩石骨架颗粒压力,抑制压实作用,使储层保留大量原生粒间孔隙;②通过抑制胶结物的生成和析出,减弱胶结作用,使胶结物体积分数随埋深增加持续下降;③通过抑制有机质演化,延长生、排烃期,延长和扩大有机酸作用的时间和范围,增强溶蚀作用,形成次生孔隙;④通过促进孔隙流体压力积聚,当孔隙流体压力超过上覆地层压力的60 %时,促进非构造裂缝形成。异常高压对盆地深层-超深层致密储层质量的改善和提升发挥了关键作用,是其成为有效储层的控制因素之一。

关键词: 储层变化, 异常高压, 致密储层, 深层, 准噶尔盆地

Abstract:

In recent years, discoveries and breakthroughs have been made successively in exploration of the deep and ultra-deep sequences in the Junggar Basin. The reservoirs found in the sequences are mostly tight with abnormally high pressure. In order to clarify the development characteristics of abnormally high pressure and its impact on reservoir quality, statistical analysis is carried out by using the pressure data obtained through systematic production tests in the key wells to determine the characteristics and types of pressure distribution in deep and ultra-deep layers of the basin, and its impact on the quality of tight reservoirs in combination with diagenesis. The results show that abnormally high pressure is widely developed in the deep and ultra-deep layers where residual pressure and pressure coefficient are high, vertical and lateral distribution of the abnormal pressure are broad. Four abnormally high pressure zones are recognized, i.e., the fairly high, moderately high, very high and super high pressure zones. Blocks in the western and eastern parts are located in the fairly high or moderately high pressure zones, blocks in the central part are located in the fairly high or very high pressure zones, and blocks in the southern part have fairly high, moderately high, very high or super high pressure. The vertical evolution of pressure coefficients can be described as gradual, abrupt and changeable due to different circumstances. The influence of abnormal high pressure on deep and ultra-deep tight reservoirs is mainly reflected in enhanced pressure bearing capacity of pore fluid, which in turn would reduce the pressure of rock skeleton particles, inhibit compaction, and contribute to the preservation of a large number of primary intergranular pores in the reservoirs. The abnormal high pressure also inhibits the formation and precipitation of cement and thus decreases continuously the volume fraction of cement with increasing burial depth, restrains the evolution of organic matter to extend hydrocarbon generation and expulsion period as well as the time and scope of organic acid action, enhances dissolution to form secondary pores, and promotes the accumulation of pore fluid pressure to facilitate the formation of non-structural fractures when the pore fluid pressure exceeds 60 % of overburden pressure. Abnormally high pressure plays a key role in the improvement of the quality of deep and ultra-deep tight reservoirs in the basin, and serves as one of the control factors for reservoirs to become effective.

Key words: reservoir changes, abnormally high pressure, tight reservoir, deep layer, Junggar Basin

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