控压钻井测控理论及关键问题研究

The focus of oil and gas resources exploitation has turned to deep zone, deep water, difficult producing reserves and exhausted oil fields. Complex problems occur frequently in drilling operation as a result of narrow density window and abnormal formation pressure. MPD technology is one of the most effective means to solve these problems. Currently, operators combine downhole pressure measurements and mud logging to interpret the MPD problems. But the interpretation and control speed are lagged due to the low mud pulse transmission rate and long lag time (up to 1-2 hours in deep well). This study proposes new ideas of real-time downhole condition analysis including synchronous measurement of double points, real-time short-distance wireless data transmission and in-situ downhole conditions interpretation. Modern measurement technology and control theory are used to design double points multi-parameter downhole measurement device while drilling and extract feature information of downhole conditions. Multi-parameter data fusion and pressure systems interpretation model in downhole complex conditions are established. The wellbore flow and pressure variation law during the complex conditions of MPD is revealed. Through the theoretical studies of ground - wellbore - formation coupled flow system and indoor simulation experiments, a high precision, high stability, fast response control models and control algorithms is established. Finally, this study forms a new set of theories and methods of MPD, which integrates measurement, interpretation and fine control as a whole and lays the foundation for fine pressure managed drilling technology.

油气资源开采的重点已向深部、深海、难动用储量和老油田改造转移。由于窄密度窗口以及井下压力异常等问题导致的复杂事故频发，控压钻井技术是解决这些问题的最有效手段之一。目前的控压钻井采用井下压力测量与地面解释相结合的方式进行工况判别，受制于泥浆脉冲传输速率和迟到时间（深井达1-2小时），导致工况识别与控制滞后。本研究提出基于井下双点同步测量、短程数据无线实时传输、工况直接识别的井下实时分析的新思想。利用现代测控理论和技术，设计双测点多参数井下随钻测量装置，提取井下复杂工况的特征信息；建立井下复杂工况下多参数数据融合与压力系统解释模型，揭示控压钻井复杂工况下井筒流动、压力变化规律；通过地面-井筒-地层耦合流动系统的理论研究和室内模拟实验、建立高精度、高稳定性的快速响应控制模型和控制算法；形成一套新的集测量、解释、精细控制为一体的控压钻井理论和方法，为精细控压钻井技术的应用奠定基础。

油气资源开采的重点已向深部、深海、难动用储量和老油田改造转移。由于窄密度窗口以及井下压力异常等问题导致的复杂事故频发，控压钻井技术是解决这些问题的最有效手段之一。目前的控压钻井采用井下压力测量与地面解释相结合的方式进行工况判别，受制于泥浆脉冲传输速率和迟到时间（深井达1-2小时），导致工况识别与控制滞后。本研究提出基于井下双点同步测量、短程数据无线实时传输、工况直接识别的井下实时分析的新思想。利用现代测控理论和技术，设计双测点多参数井下随钻测量装置，提取井下复杂工况的特征信息；建立井下复杂工况下多参数数据融合与压力系统解释模型，揭示控压钻井复杂工况下井筒流动、压力变化规律；通过地面-井筒-地层耦合流动系统的理论研究和室内模拟实验、建立高精度、高稳定性的快速响应控制模型和控制算法；形成一套新的集测量、解释、精细控制为一体的控压钻井理论和方法，为精细控压钻井技术的应用奠定基础。研究结果表明，双测点多参数井下随钻测量装置，能够测量井下钻压、扭矩、环空内外介电常数、环空内外压力、钻柱三轴振动及井底钻具转速，井下智能分析芯片能够根据这些参数，快速准确识别出井下复杂工况，同时基于卡尔曼滤波的地面辅助判别分析软件，能够实时反演出井底气侵发生的位置、井下气侵量、井下漏失发生的位置及井下漏失量等关键参数，当井下复杂事故发生时，地面串并联复合节流管汇能够迅速准确地自动对井口施加回压，阻止事故的进一步恶化，保障钻井过程安全快速进行。