Tar mats and residual oil distribution in a giant oil field offshore Abu Dhabi
Tar mats and residual oil distribution in a giant oil field offshore Abu Dhabi
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阿布扎比近海巨型油田的焦油垫和残油分布
DOI：
10.1016/j.petrol.2006.12.009
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发表时间：
2007
影响因子：
--
通讯作者：
J. Chautru
中科院分区：
文献类型：
--
作者：
B. Carpentier;H. Arab;E. Pluchery;J. Chautru
本文介绍了地球化学数据（岩石评价分析、SARA成分）与电缆测井解释相结合，如何识别阿布扎比海上大油田主储层沥青的分布和连续性。将新的地球化学数据与石油公司ZADCO提供的数据和现场信息相结合，可以识别出该油田主储层中两种类型的富沥青层：一种是对应于高电阻率、高含油饱和度的富沥青主储层，称为“焦油垫”；另一种是对应于低含油饱和度层，可归类为“重质剩余油”。在横向和纵向分布方面，沥青垫位于现今构造的顶部，位于储层单元的底部，位于致密灰岩之上，起着垂直渗透屏障的作用。沥青垫似乎独立于现今的OWC，与生物降解过程无关。稠油剩余油主要分布在油田的东北部和东南部，靠近油田接触面，但除了1)西部泄漏点区域和2)西北部发现流动油和水直接接触区域外，油田周围也存在稠油剩余油。构造演化研究表明，在达曼时代（始新世）开始了场的倾斜。构造的倾斜导致西部构造闭合减小，随后部分原困油泄漏。这种地质情景的数值模拟得出的流体（水、可动油和剩余油）分布与目前在该油田观测到的非常接近。该模型可以预测研究储层内残余稠油的延伸和分布，并可用于更好地确定最佳生产方案。残馀稠油对流体循环的影响很难评价，这取决于沥青在孔隙网络中的分布。
This paper describes how geochemical data (Rock Eval analysis, SARA composition) combined with wireline log interpretation allows for the recognition of the distribution and continuity of bitumens in a main reservoir of an offshore giant field in Abu Dhabi. The integration of new geochemical data with data and field information provided by the oil company ZADCO allows for the recognition of two types of bitumen rich levels in the main reservoir of the field: a) one corresponding to bitumen rich main reservoir intervals associated with high resistivity and high oil saturation, these intervals can be called “tar mats”, b) the other corresponding to low oil saturated intervals, and can be classified as “heavy residual oil”. In terms of lateral and vertical distribution, the tar mats are found at the crestal area of the Present-day structure and are located at the base of the reservoir unit above a tight limestone which plays a role of being a vertical permeability barrier. The tar mats seem to be independent of the Present-day OWC and are not related to biodegradation processes. The heavy residual oil is mainly located in the Northeast and the Southeast parts of the field and close to the OWC but it is also present all around the field except 1) in the west, in the area of the spill point and 2) in the Northwest area where direct contact between mobile oil and water is detected. Study of the structural evolution demonstrates that a tilting of the field began at Dammam age time (Eocene). The tilting of the structure led to a reduction of the structural closure in the West followed by the leakage of part of the originally trapped oil. Numerical modeling of such a geological scenario leads to a distribution of fluids (water, movable oil and residual oil) very close to the one observed at Present-day time in the field. This modeling allows a prediction of the extension and distribution of the residual heavy oil within the studied reservoir and can be used to better define an optimal production scheme. The effects of the residual heavy oils on the fluid circulation are difficult to evaluate, depending on the distribution of the bitumen in the pore network.