基于v_p/v_s定量计算碳酸盐岩储层参数方法探讨

On Quantitative Calculation Method of Carbonate Reservoir Parameters Based on v_p/v_s

川东北YB气田以长兴组气藏为主要目的层的天然气井具有高温、高压、高含硫的特点,井身结构复杂,测井难度及风险极大。目的层测井项目通常仅包括自然伽马、声波、电阻率等,有限的测井资料给储层参数的准确计算带来很大困难。通过纵、横波时差提取,以及纵横波速度比(vp/vs)与储层岩性、物性、含气性的关系研究,发现vp/vs与白云石含量等具有很好的相关性;利用vp/vs岩性识别原理,建立对vp/vs含气性影响校正模型,提出了基于vp/vs定量计算碳酸盐岩储层参数的新方法。经应用检验,该方法计算的储层参数准确性较高。通过含气性校正前后的vp/vs重叠区域可定性指示地层含气性。

The gas well with Changxing group gas reservoir as the main target layer of YB gas field in northeast Sichuan has the characteristics of high temperature, high pressure and high sulfur, together with logging difficulty and risk due to complex well body track and structure. Because logging projects of targeted layer usually include only the natural gamma ray log, acoustic log and resistivity log, it is very difficult to calculate the reservoir parameters. In this article, through the extraction of the P-wave and S-wave time difference, the study on the relationship between the vp/vs, reservoir lithology, physical properties and gas-bearing, we found that Vp/Vs and dolomite content have good correlation. Moreover, using the principle of vp/ vs identification of lithology, relationship to eliminate the influence of gas content on the Vp/Vs is established, and a new method for calculating reservoir parameters based on Vp/Vs is proposed. Practical application shows the high accuracy of reservoir parameters calculated by this method. At the same time, through the vp/vs overlap before and after the gas-bearing correction can indicates gas-bearing reservoir in the case of limited log data, this paper provides a method for visual indication of gas-bearing reservoirs.