新场气田须五段地应力特征研究及应用

发布时间：2019-02-26 14:48

【摘要】：新场气田须五段资源量丰富,研究岩石力学参数及地应力,有利于促进气藏的高效开发,确保压裂措施改造增产增效。本次研究针对新场气田须五段地层,系统的进行了岩石力学参数实验,了解新场地区须五段砂岩、泥岩的弹性参数特征以及强度参数特征:(1)新场须五地层砂泥岩变形特征差异明显,砂岩的强度高于泥岩,砂岩以为弹性变形为主,泥岩以塑性变形为主;(2)随着围压的增加,砂岩和泥岩的屈服应力水平均增加,并且砂岩增加的更快,砂岩的屈服应力水平明显大于泥岩,而屈服应变小于泥岩;(3)砂岩的抗压强度、杨氏模量随着围压增加而增加,泊松比较离散,泥岩三者均随围压的增加而增加。围压条件下,砂岩的抗压强度、抗张强度、内聚力、内摩擦角、杨氏模量均高于泥岩,泊松比低于泥岩。以实验测试为基础,建立动静态参数转化关系,利用测井资料针对砂岩、泥岩分别建立了地层岩石抗张强度、抗压强度、内聚力、内摩擦角、弹性模量、泊松比、断裂韧性、脆性指数等岩石力学参数预测模型并建立了岩石力学参数剖面。统计分析研究区岩石力学参数的分布特征。统计分析研究区岩石力学参数的分布特征。按照砂、泥岩分开统计研究区须五段杨氏模量、泊松比、抗压强度的区间分布。依据压实理论,建立了正常的压实曲线,并对地层的孔隙压力预测方法进行了优选,最终选择伊顿法进行区块的孔隙压力的预测,预测结果较为准确,并建立了新场地区须五段的孔隙压力剖面。在此基础上采用声发射实验、差应变测试和压裂资料法分别计算了新场须五地层地应力大小;运用ADS法确定地应力测井解释模型,计算结果较为准确,根据计算结果建立20口井的地应力剖面;根据成像测井、微地震监测等方法确定新场地区须五段地应力方向。研究了新场地区须五段的地应力分布的影响因素,分别从岩石力学性质、岩性、深度以及构造等方面分别探讨:(1)新场气田须五段的岩石力学参数主要影响水平最大、最小主应力,砂岩表现出岩石力学参数与地应力之间的相关性更强。(2)随着深度增加,对砂岩和泥岩垂向应力和水平最小主应力的增加速度相似,而对于最大主应力,在泥岩地层,最大主应力随着深加其增加速度要大于在砂岩地层其增加速度。(3)从构造的角度分析地应力大小方向变化的原因。现今构造部位如构造的高点和翼部,构造形态如断层、褶皱、裂隙等的不同以及构造地势的陡缓如构造的陡翼、倾俯端、鞍部往往产生应力异常带,造成现今地应力特征分布的不同。应用水力压裂法对新场地区须五段进行了的破裂压力的预算,预测结果较为准确。并建立了该区的破裂压力剖面图。通过分析研究新场气田须五段的破裂类型多为KGD形。对工区内的压裂优化分别从地质因素和工程因素两方面分析了影响压裂增产的原因。
[Abstract]:The fifth member of Xinchang gas field is rich in resources. The study of rock mechanical parameters and in-situ stress is beneficial to promote the efficient development of gas reservoir and to ensure that fracturing measures can increase production and increase efficiency. This research is aimed at the strata of Xu5 member in Xinchang gas field, and systematically carries on the rock mechanics parameter experiment to understand the sandstone of Xuwu member in Xinchang area. The characteristics of elastic parameters and strength parameters of mudstone are as follows: (1) the deformation characteristics of sand and mudstone in Xinchang Xuwu formation are obviously different, the strength of sandstone is higher than that of mudstone, the main deformation of sandstone is elastic deformation, and the plastic deformation is dominant of mudstone; (2) with the increase of confining pressure, the yield stress level of both sandstone and mudstone increases, and the sandstone increases faster. The yield stress level of sandstone is obviously larger than that of mudstone, but the yield strain is smaller than that of mudstone; (3) the compressive strength and Young's modulus of sandstone increase with the increase of confining pressure, Poisson's ratio is discrete, and mudstone increases with the increase of confining pressure. Under confining pressure, the compressive strength, tensile strength, cohesion, internal friction angle and Young's modulus of sandstone are higher than that of mudstone, and Poisson's ratio is lower than that of mudstone. Based on the experimental test, the transformation relation of dynamic and static parameters is established. The tensile strength, compressive strength, cohesion force, internal friction angle, elastic modulus, Poisson's ratio and fracture toughness of sandstone and mudstone are established, respectively, according to the logging data, the tensile strength, compressive strength, cohesion force, internal friction angle, elastic modulus, Poisson's ratio and fracture toughness are established respectively. The prediction model of rock mechanics parameters such as brittleness index is established and the rock mechanics parameter profile is established. The distribution characteristics of rock mechanics parameters in the study area were analyzed statistically. The distribution characteristics of rock mechanics parameters in the study area were analyzed statistically. According to sand and mudstone, the interval distributions of Young's modulus, Poisson's ratio and compressive strength in the study area are calculated separately. According to the compaction theory, the normal compaction curve is established, and the prediction method of formation pore pressure is optimized. Finally, the Eaton method is selected to predict the pore pressure of the block, and the prediction result is more accurate. The pore pressure profile of Xuwu section in Xinchang area is established. On this basis, acoustic emission experiment, differential strain test and fracturing data method are used to calculate the ground stress of the five strata in the new field respectively. The ADS method is used to determine the interpretation model of in-situ stress logging, and the calculated results are more accurate. According to the calculated results, the in-situ stress profiles of 20 wells are established, and according to the methods of imaging logging and micro-seismic monitoring, the direction of in-situ stress of five segments in Xinchang area is determined. The influence factors of in-situ stress distribution of Xu5 member in Xinchang area are studied and discussed from the aspects of rock mechanics property, lithology, depth and structure. (1) the main influence level of rock mechanical parameters in Xu5 section of Xinchang gas field is the biggest. The minimum principal stress, the sandstone shows a stronger correlation between rock mechanical parameters and in-situ stress. (2) with the increase of depth, the increase rate of vertical stress and horizontal minimum principal stress of sandstone and mudstone is similar, but for the maximum principal stress, the increase rate of vertical stress and horizontal minimum principal stress of sandstone and mudstone is similar with the increase of depth. In mudstone strata, the maximum principal stress increases faster with the increase of depth than in sandstone. (3) the reason of the change of in-situ stress is analyzed from the point of view of structure. At present, structural positions such as the high point and wing of the structure, the differences of the structural forms such as faults, folds, fissures, etc., and the steep wings of the tectonic terrain, such as the steep wings of the structure, the dipping end, and the saddle tend to produce stress anomaly zones. It causes the difference of the distribution of the in-situ stress characteristics. The hydraulic fracturing method is used to estimate the fracture pressure of the five segments in Xinchang area, and the prediction results are more accurate. The fracture pressure profile of the area is also established. Through the analysis, the fracture type of Xuwu member in Xinchang gas field is mostly KGD shape. In this paper, the factors affecting fracturing production are analyzed from two aspects: geological factors and engineering factors.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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