Saturation evaluation of microporous low resistivity carbonate oil pays in Rub Al Khali Basin in the Middle East  

作　　者：WANG Yongjun SUN Yuanhui YANG Siyu WU Shuhong LIU Hui TONG Min LYU Hengyu 

机构地区：[1]State Key Laboratory of Enhanced Oil Recovery,Beijing 100083,China [2]PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China

出　　处：《Petroleum Exploration and Development》2022年第1期94-106,共13页石油勘探与开发（英文版）

基　　金：Supported by the CNPC Scientific Research and Technology Development Project (2019D-4410)。

摘　　要：To solve the problem that it is difficult to identify carbonate low resistivity pays(LRPs) by conventional logging methods in the Rub Al Khali Basin, the Middle East, the variation of fluid distribution and rock conductivity during displacement were analyzed by displacement resistivity experiments simulating the process of reservoir formation and production, together with the data from thin sections, mercury injection and nuclear magnetic resonance experiments. In combination with geological understandings, the genetic mechanisms of LRPs were revealed, then the saturation interpretation model was selected, the variation laws and distribution range of the model parameters were defined, and finally an updated comprehensive saturation interpretation technique for the LRPs has been proposed. In the study area, the LRPs have resistivity values of less than 1 Ω·m, similar to or even slightly lower than that of the water layers. Geological research reveals that the LRPs were developed in low-energy depositional environment and their reservoir spaces are controlled by micro-scale pore throats, with an average radius of less than 0.7 μm, so they are typical microporous LRPs. Different from LRPs of sandstone and mudstone, they have less tortuous conductive paths than conventional reservoirs, and thus lower resistivity value under the same saturation. Archie’s formula is applicable to the saturation interpretation of LRPs with a cementation index value of 1.77-1.93 and a saturation index value of 1.82-2.03 that are 0.2-0.4 lower than conventional reservoirs respectively. By using interpretation parameters determined by classification statistics of petrophysical groups(PGs), oil saturations of the LRPs were calculated at bout 30%-50%,15% higher than the results by conventional methods, and basically consistent with the data of Dean Stark, RST, oil testing and production. The 15 wells of oil testing and production proved that the coincidence rate of saturation interpretation is over 90%and the feasibility of this method

关 键 词：CARBONATE low resistivity pays micropore type reservoir Archie’s formula cementation index saturation index Cretaceous Rub Al Khali Basin 

分 类 号：TE311[石油与天然气工程—油气田开发工程]