针对深层、超深层和复杂地层等对钻井提速的要求,考虑深层岩体可钻性变化,提出了基于钻头破岩能量与岩石特征自适应匹配的钻井提速技术.在分析钻头破岩过程中扭矩特征的基础上,研制了自适应匹配工具,利用行星齿轮和扭簧结构进行能量存储与释放,钻进岩性均质地层过程中提前蓄能,钻遇砾石层或非均质地层时释放能量进行辅助破岩.通过静力学和动力学性能测试,验证了自适应匹配工具结构的可靠性和实现提速的可行性.自适应匹配工具在深层页岩气井进行了现场试验,结果表明:与使用常规方法的邻井相比,机械钻速提高了 83%,验证了该工具提速的有效性和稳定钻头工作状态的效果.钻头破岩能量与岩石自适应匹配提速技术,为深层、超深层和复杂地层钻井提速提供了理论支撑和新的技术途径.
The 2015 Paris Agreement proposed that the global average temperature rise by the end of the century should be controlled within 2 ℃ above pre-industrial levels. In order to actively respond to climate change, the Chinese government has put forward the goal of “ carbon peaking by 2030 and carbon neutrality by 2060”. However, the economic transformation under low-carbon operation still faces severe challenges. In this regard, based on the carbon market, carbon trading and carbon policy, the status of global CO 2 emissions and the energy transformation measures taken by international oil and gas companies for the dual carbon goal were investigated and analyzed with data mining and artificial intelligence data analysis. Based on the status of carbon emission in China and the practical decarbonization technologies in the oil and gas field, four key recommendations for decarbonization pathways were put forward, including popularizing new low-carbon material and technologies, promoting general carbon market standards, formulating protective policies for green transformation enterprises, and encouraging low-carbon research and development. What’s more, five key areas for the energy transformation of oil companies in China were proposed, which are accelerating low-carbon development and exploration of oil and gas, carrying out carbon footprint full-chain evaluation, promoting intelligent and intensive development of shale gas,expediting research and development of hydrogen energy and CCUS technology. The research results can provide a valuable reference for the achievement of the dual carbon goal and the smooth transformation of oil companies.
深层页岩储层甲烷高温高压条件下的赋存特征是准确评估页岩气储量的关键.首先,基于深层页岩龙马溪组干酪根分子结构单元,构建干酪根不同形状和孔径的纳米孔隙分子模型;然后,采用巨正则蒙特卡洛和分子动力学耦合方法,开展甲烷赋存模拟,分析压力、温度、孔径和孔隙形状对甲烷赋存量的影响规律;最后,研究甲烷微观赋存机理,分析甲烷微观分布特征、甲烷-壁面微观作用特征以及甲烷优先吸附位.研究表明:在深层高压条件下,甲烷过剩吸附量和溶解量受温度影响较小;随温度升高,甲烷绝对吸着量和游离气体量减少;干酪根介孔孔径对甲烷吸附气和溶解气量基本无影响,孔径引起的总气体量变化主要由游离气贡献;与圆管孔相比,狭缝孔中甲烷总气体量更大,但过剩吸附量较少;甲烷分子优先吸附于干酪根结构上的噻吩位点.研究结果为深层页岩气储量评估提供了理论依据.
CO2增能压裂改造效果与生产效果评价受压裂裂缝分布的影响.为明确东营凹陷陆相页岩油CO2 压裂造缝机理,通过试验确定了CO2 浸泡下岩体破裂压力、天然裂缝剪切/张开应力和地应力随时间的变化;在此基础上,考虑CO2 浸泡下的岩石应力参数,采用Pen-Robinson方程刻画CO2 物性参数变化,结合试验和数模方法,形成了基于节点连接方法的CO2 增能压裂裂缝扩展模拟方法,并对东营凹陷某油井进行了实例分析.研究结果表明,CO2 比例对分支缝密度的影响较大,当CO2 比例由 0.1 增加至 0.3 时,分支缝密度增加 117%;应力差主要影响缝长及分支缝密度,水平应力差由 5 Mpa增至 30 Mpa时,缝长度增加了 52%,分支缝密度下降了 13.85%.裂缝形态模拟结果与实际监测结果具有较好的一致性,研究结果可以为陆相页岩油压裂方案的制定提供理论参考.
针对鄂尔多斯盆地页岩油储层压力低、缝网复杂程度低和黄土塬水资源缺乏等问题,以该盆地庆城油田页岩油为研究对象,进行了滑溜水和CO2 压裂物理模拟试验,利用高能CT监测了CO2 压裂裂缝扩展规律,分析了CO2 压裂形成复杂裂缝的可行性;利用油藏数值模拟方法,优化了CO2 注入关键参数,形成了适合庆城油田页岩油的CO2 区域增能体积压裂技术.研究表明:前置CO2 压裂可提高长 7 段页岩油储层裂缝复杂程度,裂缝沿层理弱面扩展并纵向穿层形成缝网;增能理念应由单井段间交替增能向平台整体注入实现井间、段间协同一体增能转变,单井采用全井段注入增能模式,可实现缝控区域全覆盖.庆城油田某平台进行了页岩油CO2 区域增能体积压裂试验,与采用常规体积压裂技术的邻井相比,3 口试验水平井平均压力保持程度提高 1.5 倍,单井平均初期产油量提高 28.6%.研究和现场试验结果表明,CO2 区域增能体积压裂能提高裂缝复杂程度,增加区域地层能量,提高单井产能,可为鄂尔多斯盆地页岩油开发提供技术支持.
