川东飞仙关组地层压力测井解释方法研究

【作者】 李英；

【导师】 夏宏泉； 张树东；

【作者基本信息】 西南石油学院 ， 地球探测与信息技术， 2003， 硕士

【摘要】 随着油气勘探向深部地层和海洋发展，测井技术在石油工程中的应用越来越重要。尤其是在岩石可钻性预测与钻头选型、地层压力预报、地应力计算以及井壁稳定性评价、泥浆密度安全窗确定等钻井工程问题上。测井技术由于连续性、经济性、可靠性及分辨率高等特点，越来越多地显示了其优越性。本文针对川东北部三叠系地层在钻井过程中遇到的井喷、井漏、井塌和卡钻等工程事故，主要对飞仙关组地层压力的测井解释方法作了大量的深入研究工作。 地层岩性和储层类型识别是测井解释地层压力的地质基础。首先采用NewCRA复杂岩性分析技术对碳酸盐岩地层剖面进行岩性、物性优化解释。其次，在碳酸盐岩储层类型常规识别的基础上，采用分形分维技术，提出了测井曲线分数维（Df）、孔隙结构指数（m）的新算法及其与储层类型之间的关系，有效地进行了碳酸盐岩储层类型的定量识别。 地层压力体系包括上覆岩层压力（P₀）、地层孔隙压力（Pp）、地层破裂压力（FP）和坍塌压力（BP）。等效深度法是目前广泛应用于砂泥岩剖面的地层孔隙压力预测方法。研究认为，此种方法在碳酸盐岩剖面同样适用，关键是建立一套适合于碳酸盐岩剖面选取视泥岩层段的声波时差读值方法和在构建正常压实趋势线时，根据趋势线所计算的泥岩段声波时差值和实测正常压力资料修正该趋势线。应用该方法成功地对川东飞仙关组罗家寨和渡口河构造各井进行了地层孔隙压力预测。 用测井资料可以确定地应力的大小和方向，从而确定地层破裂压力和坍塌压力，并给出合理的泥浆密度，解决井眼力学失稳问题。本文在此综合应用井眼崩落法、人工压裂法和成像测井法以确定地应力的大小和方向，并在分析比较国内外各种地层破裂压力和坍塌压力预测模型优缺点的基础之上，从测井资料中提取多种岩石力学参数，建立了适合于碳酸盐岩地层的破裂压力和坍塌压力预测模型。 室内岩石微可钻性测试是测井预测岩石可钻性的实验基础。本文采用神经网络法与多元回归分析法建立了岩石可钻性测井多参数预测模型及单井地层的连续可钻性级值剖面，同时创造性地推导了地层孔隙压力与岩石可钻性之间的理论关系。 在上述方法理论研究的基础上，结合川东罗家寨和渡口河构造飞仙关组地层的实际情况，编制了一套适合于该研究工区的地层压力测井解释应用程序，并用于罗家4井和渡4井等井的测井资料精细处理中，所计算的地层孔隙压力、坍塌压力和破裂压力与实测资料相符，且所确定的钻井泥浆密度窗得到了实际生产的验证，达到了预期效果。更多还原

【Abstract】 With the development of petroleum exploration toward the deeper formation and the offshore, the application of logging technology in petroleum engineering has been becoming more and more important. Because of the merit of continuity, economical efficiency, reliability and high resolution, the well logging has shown its advantages, especially in some drilling engineering problem, such as the prediction of rock drillability, selecting the drill bit types, prediction of formation pressure, calculation the In-situ stress, evaluating the borehole walls stability and determining the reasonable mud density, and etc. Aiming at the engineering accidents, for example the well spout, well leak, well collapse and the drill blocking during the drill engineering in the T formation in north-east of Sichuan, some farther studies of formation pressure in FeiXianGuan from well-logging information are presented in this dissertation.Stratum lithology and reservoir type recognitions are the geological foundation to explain the formation pressure by using logging data. Firstly, this study uses the NewCRA complex lithology analysis technology to interpret the lithology and physical property of carbonate profile. Secondly, on the basis of general discrimination of carbonate reservoir type, adopts fractal and fractal-dimension technique to bring forward the fractal characteristics of logging curves (Df), new arithmetic of porosity index (m) and their connection to reservoir type, thus discriminates the carbonate reservoir type effectively.The formation pressure system includes the overburden pressure (P0), formation pore pressure (Pp), fracture pressure (FP) and breakout pressure (BP). The most popular method, equivalent-depth method is used to predict the formation pore pressure in sandstore profile. Research indicates that this idea is also applicable for the carbonate. To set up a suit of idea of travel time reading of carbonate interval and use real pressure data to correct it during plotting the normal compaction trend curve are rather important. The method is applied to the prediction of formation pressure in LuoJiaZhai and DuKouHe oilfield successfully.Using logging information can make the size and direction of In-situ stress, and then determine fracture pressure and breakout pressure so can provide the suitable mud density to solve the mechanics instability of borehole. This thesis integrates the borehole collapse model with the artificial fracture and imaging well logging to get the size and direction of In-situ stress, and set up the reasonable prediction model of fracture pressure and breakout pressure for carbonate profile, by making use of the rock mechanics parameters from logginginformation, based on comparing the present various prediction models.Rock drillability test is the foundation of prediction rock drillability from well logging data. This essay adopts the neural network and some parameters regression analysis to set up the some logging parameters prediction model of the rock drillability, then gets the continuous drillability classification value of single well formation. And deduces the theoretic relation of the formation pore pressure and the rock drillability creatively.Based on the above methodological analyses and practical situation of FeiXianGuan interval in the LuoJiaZhai and DuKouHe structure on the east of Sichuan, a set of well log interpretation formation pressure application program is developed. It has been successfully applied to the fine interpretation of LuoJia4 well and Du4 well, and so on. The results of formation pore pressure, fracture pressure and breakout pressure are all accordant with the practical situation. Moreover, the mud density has been validated in practice.更多还原