电阻率测井泥浆侵入影响校正方法研究——以鄂尔多斯盆地天然气储层为例

Slurry invasion correction in resistivity logging - Case study of natural gas reservoir in Ordos basin

中国石油化工股份有限公司石油勘探开发研究院南京石油物探研究所 江苏 南京 210014

Nanjing Institute of Geophysical Prospecting for Petroleum, SINOPEC, Nanjing 210014,China

地层压力低导致泥浆侵入深度加大,电阻率测井响应受到泥浆侵入的影响不能真正反映地层的电阻率特性。在天然气高产的储层段,深、浅电阻率测井应该有的差异被弱化,使得电阻率测井识别与评价天然气储层的应用受到制约。为此,依据电阻率测井的基本原理及泥浆侵入对双侧向测井的影响机理,研究了鄂尔多斯盆地天然气储层电阻率测井的响应特征及其在应用中存在的问题,探讨了仪器结构参数、地层视电阻率、真电阻率、泥浆侵入深度之间的关系,给出了电阻率测井泥浆侵入影响的校正方法及泥浆侵入深度的计算方法;选择了有代表性的几口井(A15井,A16井,AK2井)对方法进行了验证,改进了该地区天然气储层的识别与评价方法。

A low formation pressure may result in an increase of invasion depth of slurry. Affected by slurry invasion, the resistivity log response can't truly reflect the attributes of strata's resistivity. In the reservoir with a high gas output, the difference between the deep resistivity log and shallow one will be weakened, which restraints the application of resistivity logs in recognizing and evaluating gas reservoir. So according to the basic principle of resistivity log and affection mechanism of slurry invasion on dual lateral log, resistivity log response characteristics and problems existing in application are studied. The relationship between instrument structure parameter and apparent resistivity record value, real formation resistivity and mud invasion depth is researched, which gives both the correction method for slurry invasion and the calculation method for the invasion depth in resistivity log, several representative wells are selected to verify the method, which improves the recognition and e-valuation methods of natural gas reservoir in this area.