摘要
海上低渗气藏受到钻杆地层测试(DST)费用高、难度大以及测井渗透率精度不够的影响,故针对基于电缆地层测试(MDT)压降流度计算低渗气藏有效渗透率的方法展开研究。实际储层中多为气水两相渗流,因此在分析低渗气藏钻井滤液侵入机理和不同渗透率差异性研究的基础上,分为单相纯气储层与气水两相储层,提出基于MDT压降流度结合岩心相渗实验驱替规律计算地层有效渗透率的方法。将该方法获取的有效渗透率与测井渗透率和DST测试渗透率分别建立转换关系式,即可将测井渗透率对标到DST渗透率,用于产能预测。通过实例对比分析,相对于DST测试渗透率,该方法得到的有效渗透率误差,单相纯气储层为3.1%、3.7%,气水两相储层为9.1%,验证了该方法的可行性,为低渗气藏有效渗透率的计算提供了一种新的思路和方法。通过建立X区域渗透率关系图,相关系数较高,验证了可将该方法获得的地层有效渗透率作为渗透率转换值,从而降低了低渗储层有效渗透率获得成本。
Offshore low permeability gas reservoirs are affected by the high cost and difficulty of drill stem testing(DST)and the low permeability logging accuracy,so the method for calculating the effective permeability in low permeability gas reservoirs based on the pressure drop mobility measured by wireline formation testing(MDT)is studied.Most of the actual reservoirs are gas-water two-phase flow.Based on analyzing the invasion mechanism of drilling filtrate and studying the difference of different permeability in the low permeability gas reservoirs,it is divided into single-phase pure gas reservoirs and gas-water two-phase reservoirs,and a method is proposed to calculate the effective permeability of formation based on MDT pressure drop mobility combined with displacement law of core relative permeability experiment.The conversion relationship between the effective permeability obtained by this method and the well logging permeability and DST test permeability is respectively established,and the well logging permeability can be benchmarked to the DST permeability for productivity prediction.Through comparative analysis of examples,compared with the permeability measured by DST,the effective permeability error obtained by this method is 3.1%and 3.7%for single-phase pure gas reservoirs and 9.1%for gas-water two-phase reservoirs,which verifies the feasibility of this method and provides a new idea and method for the calculation of effective permeability in the low permeability gas reservoir.The permeability relationship diagram in region X is established with high correlation coefficient,which verifies that the effective formation permeability obtained by this method can be used as the conversion value of the permeability,thereby reducing the cost of obtaining effective permeability of the low permeability reservoirs.
作者
宋帅钰
王梦琳
李慧敏
李剑
Song Shuaiyu;Wang Menglin;Li Huimin;Li Jian(School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an Shaanxi 710065;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi'an Shaanxi 710065)
出处
《中外能源》
CAS
2023年第8期63-67,共5页
Sino-Global Energy
关键词
有效渗透率
MDT测试
压降流度
岩心相渗
渗透率转换
低渗气藏
effective permeability
MDT test
pressure drop mobility
core relative permeability
permeability conversion
low permeability gas reservoir
