石油与天然气地质 ›› 2022, Vol. 43 ›› Issue (6): 1505-1514.doi: 10.11743/ogg20220619

• 方法技术 • 上一篇    

深层碳酸盐岩储层溶洞垮塌物理模拟及分布预测

吕心瑞1(), 邬兴威1, 孙建芳1, 夏东领1, 李彦普2, 丁炎志3, 王斌3   

  1. 1.中国石化 石油勘探开发研究院, 北京 102206
    2.中国石油 大港油田分公司 第一采油厂, 天津 300280
    3.山东大学 岩土与结构工程中心, 山东 济南 250061
  • 收稿日期:2021-04-18 修回日期:2022-09-19 出版日期:2022-12-01 发布日期:2022-11-21
  • 第一作者简介:吕心瑞(1983—),男,高级工程师,油气田开发工程。 E-mail:lvxr.syky@sinopec.com
  • 基金项目:
    国家科技重大专项(ZX201605014-002);中国石化科技攻关项目(P20016)

Physical simulation and distribution prediction of karst cave collapsing in deep carbonate reservoirs

Xinrui Lyu1(), Xingwei Wu1, Jianfang Sun1, Dongling Xia1, Yanpu Li2, Yanzhi Ding3, Bin Wang3   

  1. 1.Petroleum Exploration and Production Research Institute,SINOPEC,Beijing 102206,China
    2.No. 1 Oil Production Plant,Dagang Oilfield Company,PetroChina,TianJin 300280,China
    3.Geotechnical and Structural Engineering Center,Shandong University,Jinan,Shandong 250061,China
  • Received:2021-04-18 Revised:2022-09-19 Online:2022-12-01 Published:2022-11-21

摘要:

大型古岩溶洞穴是深层碳酸盐岩储层的重要储集空间类型,钻井揭示溶洞大多存在不同程度的垮塌角砾充填,对溶洞垮塌机制、垮塌模式及分布规律的认识直接影响此类油藏的高效开发。依据相似性理论,以塔河油田奥陶系储层大型溶洞为工程背景,利用融蜡成腔方法制作未充填、砂泥充填和水充填3类球型溶洞,开展溶洞垮塌的地质力学物理模型试验,揭示不同充填类型溶洞的垮塌机制,分析垮塌形态及破坏范围,建立溶洞垮塌体模式,根据其地震反射特征,探索不同类型溶洞垮塌体地震预测方法。结果表明:物理模型试验适用于塔河地区深层应力作用下溶洞垮塌研究,弥补了传统方法在直观、真实方面的不足;揭示了溶洞垮塌机制主要为压实破坏和剪切破坏,溶洞顶板及周边原岩垮落,并出现剪切滑移破坏带,范围为2~3倍洞径;砂泥充填溶洞稳定性大于水充填溶洞的稳定性,未充填溶洞稳定性最差;建立了2类溶洞垮塌模式,Ⅰ类垮塌模式主要受上覆重力影响,Ⅱ类垮塌模式主要受剪切应力影响,二者地震反射特征存在局部差异,综合有色反演、分频能量、GR反演及相干能量梯度等地震属性能够实现2类溶洞垮塌体的预测,研究区不同类型垮塌体分布预测结果与油井产能具有较好对应关系。

关键词: 溶洞垮塌, 物理模拟, 垮塌模式, 垮塌预测, 深层碳酸盐岩储层, 塔河油田

Abstract:

Large paleokarst caves constitute important storage space in deep carbonate reservoirs. Drilling data reveal that many such caves are filled to some extent by collapsed breccia. A better understanding of their collapse mechanisms, modes and distribution would be helpful in the highly efficient development of such reservoirs. This study applies the similarity theory to the making of unfilled, sand/mud-filled and water-filled spherical caves using the molten wax cavity method to simulate the large karst caves in the Ordovician carbonate reservoirs for geomechanical physical model test of karst cave collapsing. Collapse modes are established based on the revealed collapse mechanism, morphology and damage zone of simulated karst caves of different filling types and the possibility of seismic prediction is also explored based on the seismic reflection characteristics of the collapsed karst caves during the tests. The results demonstrate the effectiveness of using physical model test to analyze the karst cave collapsing in deep carbonate reservoirs under in-situ stress in the Tahe area. Being more visualized and real than traditional methods, the test reveals that compaction and shearing are the main causes of cave collapsing, during which the roof and surrounding rock of the cave sink in, with a shear-slip damage zone of 2 to 3 times larger than the cave diameter. The sand/mud-filled cave is shown to be more stable than the water-filled cave, and the unfilled cave is the least stable. Two cave collapse modes are established: Type Ⅰ being mainly affected by overlying gravity and type Ⅱ by shear stress. Their seismic reflections show local differences. If combined properly with colored inversion and GR inversion as well as seismic attribute like frequency division energy and coherent energy gradient, and etc., the reflection differences can be used to map the two types of collapsed karst caves. The prediction of collapsed karst caves shows a good correspondence with oil well productivity.

Key words: karst cave collapse, physical simulation, collapse mode, collapse prediction, deep carbonate reservoirs, Tahe oilfield

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