海相碳酸盐岩地层孔隙压力预测研究

发布时间：2018-06-15 02:17

本文选题：海相碳酸盐岩 + 孔隙压力　；参考：《长江大学》2015年硕士论文

【摘要】：海相碳酸盐岩层系是我国目前和未来油气资源的重要接替区,它所在的地层埋藏深,成孔隙、裂缝、孔洞发育,结构很复杂。对异常高压的预测分为钻前和随钻两个方面。钻前预测主要依靠地震手段,适合于勘探程度较低的区域,但由于深度大、火成岩、盐膏岩的影响和屏蔽作用,导致地震资料品质差,预测精度低；在勘探程度较高的地区,可以通过实测压力数据的统计分析或建立三维压力数据体系来准确预测。随钻预测主要依靠随钻录井技术。由于碎屑岩地层具备连续的沉积压实作用,根据欠压实原理,可通过地震层速度、dc指数等资料对地层孔隙压力进行预测。而碳酸盐岩地层的化学胶结作用大于机械压实作用,其异常高压成因机制及预测方法都不同于碎屑岩地层,因而难度更大。碳酸盐岩地层异常高压预测是真正的世界级难题。其异常高压成因机制及预测方法都不同于碎屑岩地层,因而研究难度很大。如果不能准确预测地层孔隙压力,钻完井等工程设计与施工将缺乏有效基础参数,可能会导致工程施工中复杂故障发生,甚至出现安全事故,大大制约了海相碳酸盐岩油气资源的勘探开发进程。本文在了解相关理论背景,研究状况及发展趋势的基础之上,再结合川东北地区海相碳酸盐岩层易生成异常高压气藏的特点,利用海相碳酸盐岩声波特性规律识别与预测异常高压气层。本文主要研究内容包括四个部分,第一部分为海相碳酸盐岩异常压力成因机制分析,通过相关资料分析得到产生异常高压的机制有液态烃类的热裂解增压作用、天然气自下而上的充注增压作用、构造挤压增压作用和盖层对高压力的保持作用。产生压力下降的机制有地层抬升剥蚀的降温减压作用、TSR反应的泄压作用和构造抬升降压作用。第二部分对海相碳酸盐岩纵波速度进行了理论分析,包括岩石纵波速度方程的建立与推导、岩石骨架与孔隙流体纵波速度的分析。得出了岩石纵波速度由骨架速度项和孔隙流体速度项组成；骨架纵波速度项取决于岩性和孔隙结构,决定了纵波速度的变化趋势,孔隙流体纵波速度项取决于岩石中孔隙压力的大小,导致纵波速度将会出现小幅度波动。并从理论上推导出了孔隙流体对纵波速度的贡献可正、负和0的条件。第三部分通过相关实验论证了引起岩石纵波速度出现小幅度波动的因素主要来源于岩石孔隙压力的大小,孔隙流体对岩石纵波速度的贡献可正、可负和为零的条件。计算出了孔隙流体对岩石纵波速度贡献正负与否的临界压力。为利用岩石声波特性规律预测海相碳酸盐岩地层孔隙压力提供了理论与实验支撑。最后一个研究部分为现场应用与论证部分。利用岩石声波特性规律识别出异常高压气层段所在的深度,并且预测出异常高压力均在临界压力之上,最后根据相关井史资料和各井区的实测压力数据论证了利用声波特性规律预测异常高压的准确性。为海相碳酸盐岩地层孔隙压力预测模型的建立提供了一定的参考价值。
[Abstract]:Marine carbonate rock series is an important replacement area for oil and gas resources in China at present and in the future. Its strata are buried deep, pore formation, crack, hole development and complex structure. The prediction of abnormal high pressure is divided into two aspects: pre drilling and drilling. The pre drilling prediction mainly depends on the seismic section, which is suitable for low exploration area, but it is deep in depth. Large scale, igneous rock and salt and gypsum rock are affected and shielded, which results in poor quality of seismic data and low prediction accuracy. In areas with higher exploration degree, the statistical analysis of measured pressure data or three dimensional pressure data system can be used to predict accurately. In accordance with the principle of under compaction, the pore pressure can be predicted by seismic layer velocity and DC index according to the principle of under compaction. The chemical cementation of carbonate strata is greater than that of mechanical compaction. The formation mechanism of abnormal high pressure and the prediction method are different from the clastic rock formation, thus the difficulty is greater. Carbonate rock formation is different. High pressure prediction is a real world class problem. The cause mechanism and prediction method of abnormal high pressure are different from the clastic rock formation, so it is very difficult to study. If the pore pressure can not be predicted accurately, the engineering design and construction of drilling and completion will lack the effective basic parameters, which may lead to the complicated faults in the construction and even the construction of the engineering. The occurrence of safety accidents has greatly restricted the exploration and development process of marine carbonate oil and gas resources. On the basis of understanding the relevant theoretical background, the research situation and the development trend, the characteristics of the abnormal high-pressure gas reservoirs in the marine carbonate rocks in the northeast of Sichuan Province are easily formed, and the characteristics of the marine carbonate rocks are identified and preformed by the characteristics of the acoustic characteristics of marine carbonate rocks. The main research contents of this paper include four parts. The first part is the analysis of the formation mechanism of the abnormal pressure of marine carbonate rocks. Through the analysis of the related data, the mechanism of abnormal high pressure is the thermal cracking pressurization of liquid hydrocarbon, the pressurization effect of natural gas from the bottom to the top, and the construction of pressurization and supercharging. The mechanism of the formation of the high pressure. The mechanism of the pressure drop is the cooling and decompression effect of stratigraphic uplift and erosion, the pressure relief action of the TSR reaction and the structural lifting and depressurization. The second part analyses the longitudinal wave velocity of the marine carbonate rock, including the establishment and deduction of the velocity equation of the rock longitudinal wave, the rock skeleton and the pore fluid longitudinal. The analysis of wave velocity shows that the longitudinal velocity of the rock is composed of the skeleton velocity term and the pore fluid velocity term. The term of the longitudinal wave velocity of the skeleton depends on the lithology and pore structure, which determines the variation trend of the longitudinal wave velocity. The term of the longitudinal wave velocity of the pore fluid depends on the size of the pore pressure in the rock, resulting in a small amplitude fluctuation in the longitudinal wave velocity. The contribution of the pore fluid to the P-wave velocity is derived theoretically and the positive, negative and 0 conditions are derived. The third part proves that the factors that cause the small amplitude fluctuation of the rock longitudinal wave velocity are mainly derived from the size of the pore pressure of the rock, and the contribution of the pore fluid to the rock longitudinal wave velocity is positive, negative and zero. The critical pressure that the pore fluid contributes positive or negative to the rock longitudinal wave velocity is calculated. The theoretical and experimental support is provided for predicting the pore pressure of the marine carbonate rock formation by using the law of rock acoustic characteristics. The last part is the field application and demonstration part. The abnormal high-pressure gas reservoir is identified by the law of the acoustic wave characteristics of rock. The depth of the section and the prediction of the abnormal high pressure are above the critical pressure. Finally, according to the relevant well history data and the measured pressure data of each well area, the accuracy of predicting abnormal high pressure using sound wave characteristics is demonstrated, which provides a certain reference value for the establishment of pore pressure prediction model for marine carbonate strata.
【学位授予单位】：长江大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】