套损井与取心井相似井段识别及其岩石力学参数确定方法

Identification of Similar Intervals of Wells with Casing Failure and Coring Wells and the Determination of their Geomechanical Properties

  • 摘要: 为了确定老油田岩心样本严重匮乏的高套损率区块岩石静态弹性力学参数(静态弹性模量与泊松比),研究了套损井与取心井相似井段识别及其岩石静态弹性力学参数确定方法。对取心井段的岩心进行岩石力学试验,通过分析该井段测井数据与岩石静态弹性力学参数的相关性,提出了基于组合模量确定静态弹性力学参数的模型;通过分析取心井与套损井测井数据的的相关性,提出了识别取心井与套损井岩石力学参数相似井段的判别准则;建立了通过识别套损井与取心井相似井段来确定套损井段岩石静态弹性力学参数的方法(SⅡM)。由试验与计算结果可知:与传统计算模型中动、静态弹性力学参数的相关性相比,考虑有效水平地应力、动态弹性力学参数的组合模量与静态弹性力学参数的相关系数分别提高了10%与20%;取心井与邻近套损井相似井段的识别标准为两井段的声波时差与自然伽马相关系数最大和差值数组标准差最小。研究结果表明,SⅡM方法在高套损率区块多井、多井段静态弹性力学参数的确定中具有较高的适用性与准确性,在现场应用中可取得较好的效果。

     

    Abstract: To determine the static elastic parameters (SEP) (static elastic modulus and Poisson’s ratios) of rock in blocks with high casing damage rates and with limited core samples, an innovative technique has been proposed to identify similar intervals of wells with casing failure and coring wells and to determine the SEP of these intervals. First, the mechanical parameters of cores from coring intervals were tested, then the correlation between logging data and rock mechanical parameters between the similar intervals of the coring well and the casing failure well was analyzed, a model from combined modulus was established to determine static elastic parameters. Then a similar SEP identification criterion was proposed. Mechanical parameters of coring intervals were determined to establish correlations among the logging data and SEPs of rocks in these intervals. Eventually, models for the SEPs based on combined modulus were proposed. By studying correlation among the logging data acquired in the wells with casing failures and coring wells, criteria for similar intervals in wells with casing failure and cored wells were highlighted. By identifying intervals with similar properties in casing failure wells and cored wells, it is possible to determine SEP in intervals of casing failure. Testing and calculation results showed that the combined modulus and SEP with consideration of effective horizontal in-situ stresses may have correlations 10% and 20% higher than those from conventional calculation models. In general, identification criteria for similar intervals in casing failure wells and coring wells can be summarized as the highest correlation between acoustic travel time and GR, and minimum deviation among difference arrays in these two intervals. Research results showed that these techniques have relatively high applicability and accuracy in determination of SEP in multiple wells and intervals in areas with severe casing damage. Satisfactory performance has been observed in field applications of these techniques.

     

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