塔里木盆地塔河油田奥陶系油气藏储集层特征

塔里木盆地塔河油田已经发现的储量中,88%储藏在奥陶系碳酸盐岩储集层中,其储集空间是相互不连接的与连接的网状溶岩内的孔隙.奥陶系储集层内不同位置的油、气、水特征明显,油田内没有统一的油/水界面,更增加了油气藏的复杂性.经过酸化压裂处理后,获得高产及商业油流的井可达总井数的75.9%.酸化压裂是塔河油田改善储集层内连通性、改造非生产井、提高产量的重要手段,也是其它具有类似储集层油田开发的基本方法.  

基于磷灰石裂变径迹分析数据的时间—温度历史的多元动力学模拟

磷灰石裂变径迹与结晶C轴平行的、与抛光面相交的裂变径迹蚀刻象的最大直径Dpar可以较好地反映磷灰石颗粒的裂变径迹的退火行为。按照Dpar的不同，将同一样品各个磷灰石颗粒的径迹分成几个具有不同动力学性质的成分，然后对这些成分多元动力学成分模拟，使原先“单一”的磷灰石时钟体系变成由若干个独立的热时种构成的体系，这些独立的热时钟分别记录了样品通过不同的温度段的历史，由它们综合而成的历史就更为全面、可靠。本文最后介绍了来自4个盆地的样品的模拟结果。  

低渗复杂断块整体压裂裂缝参数优化设计

低渗复杂断块油藏在进行整体压裂改造时，由于其地应力场分布复杂且井网形式不规则，常规整体压裂产量预测方法不再适用。为此，将油藏数值模拟中的新型网格结构——PEBI网格应用到整体压裂优化设计中，实现了不规则井网条件下任意方位裂缝的模拟，并证实了PEBI网格模拟水力裂缝相对于传统直角网格的优越性。根据濮城油田卫42断块压裂注采井网的实际特点，抽象出适用于复杂断块油藏的3种典型的注采井位关系，并在此基础上进行了裂缝与井网匹配关系和裂缝参数的优化研究。指出：在复杂断块油藏的整体压裂中，注采井位相对角度存在最优值，应根据具体地应力方向进行优化；远离断层区域地应力方向一致，应造长缝，断层附近区域地应力方向容易发生偏转，应重点优化缝长；就特低渗透复杂断块油田而言，注采相对井位、压裂规模对于开发效果的影响要远远大干裂缝导流能力的影响。图10表2参11  

Numerical solution for natural gas production from methane hydrate dissociation

This paper describes a one-dimensional model for natural gas production from the dissociation of methane hydrate in a confined reservoir by a depressurizing well. The approach accounts for the heat released by hydrate dissociation and convection–conduction heat transfer in the gas and hydrate zone. The system of governing equations is solved using a finite-difference scheme. For different well pressures and reservoir temperatures, the gas flow, the pressure and temperatures conditions in the reservoir are simulated. Distributions of temperature and pressure in the hydrate and gas regions and time evolutions of natural gas output also are evaluated. It is shown that the gas production rate is a sensitive function of well pressure. In addition, both heat conduction and convection in the hydrate zone is important. The simulation results are compared with the linearization approach and the shortcomings of the earlier approach are discussed.  

OCEANIC METHANE HYDRATES: A "FRONTIER" GAS RESOURCE

Methane hydrates are ice-like compounds consisting of natural gas (mainly methane) and water, whose crystal structure effectively compresses the methane: each cubic metre of hydrate can yield over 150 cu.m of methane. Hydrates "cement" sediments and impart considerable mechanical strength; they fill porosity and restrict permeability. Both biogenic and thermogenic methane have been recovered from hydrates.
Hydrates occur in permafrost regions (including continental shelves), and are stable in ocean-floor sediments below water depths of about 400 m in the "Hydrate Stability Zone" (HSZ). This is a surface-parallel zone of thermodynamic equilibrium that extends down from the sediment surface to a depth determined by temperature, pressure and local heat flow. Methane and water are stable below the HSZ.
Although the economic recovery of hydrates has taken place in Arctic regions, oceanic hydrates offer far greater potential as an energy resource. A variety of traps for methane gas can be formed by oceanic hydrates. In addition to the gas within the hydrates themselves, simple gas traps in closures beneath the HSZ in the vicinity of bathymetric highs, and complex traps involving both hydrate and structural/stratigraphic components, have been observed.
It has been estimated that at least twice as much combustible carbon occurs associated with methane hydrates as in all other fossil fuels on Earth. The evaluation of methane in, and associated with, oceanic hydrates therefore constitutes a major energy exploration frontier.  

钻井井喷失控井喷流出口速度预测方法研究

失控井喷流出口速度、喷口内压力、喷层产量都是井喷失控处理方案设计、作业施工中重要的基础数据。由于井喷失控井井口环境条件复杂，井喷失控后无法在井口安装测量仪表及在高速喷流中放入参照物，不能直接获取以上数据。文章利用地质、钻井过程获得的地层物性参数和气体动力学方程，探讨井喷失控井天然气喷流在不同井筒流动尺寸及组合的喷流速度预测模型，可应用薄剪切模型或RNG修正的k—ε模型定量描述速度场、温度场、浓度场颁。为井喷失控井处理方案设计、施工作业提供基础数据。  

页岩气赋存形式和初始原地气量(OGIP)预测技术

页岩气有利区或核心区评价的关键是确定页岩初始原地气量(OGIP)的空间分布,页岩气赋存形式介于致密砂岩气与煤层气之间,主要呈3种状态:孔隙中游离气、固体有机质吸附气、油和水中溶解气,温度和压力条件控制3种状态气体的量和相互转化。游离气量主控因素是页岩孔隙度和气体饱和度,吸附气量主控因素是有机质数量和有机质成熟度,溶解气量的主控因素是页岩中残留油的数量。提出了页岩气中游离气量、吸附气量和溶解气量的算法,并在油气系统模拟软件Trinity 3D中实现页岩气OGIP量空间分布计算,以Fort Worth盆地Barnett页岩为例展示了这一技术的实际应用。  

常见黏土矿物电镜扫描微孔隙特征与甲烷吸附性

野外采集的黏土岩的电镜扫描图像分析显示,黏土矿物孔隙分布于颗粒之间和颗粒内部板片自然错断处,前者形态不规则,后者呈楔形或面状缝隙。具层间结构的蒙脱石层内发育纳米级连通孔隙。蒙脱石微孔隙最为发育,伊-蒙混层黏土次之,其粒间孔和层面缝隙为20～100nm,层内连通孔隙小于50nm。高岭石黏土主要发育20～100 nm的粒间孔。伊利石和绿泥石晶体颗粒较大,以微米级孔隙为主。吸附实验所反映的各种黏土矿物甲烷吸附能力与电镜扫描反映的微孔发育程度相吻合,指示泥页岩中的纳米级微孔在一定程度上决定着泥页岩的比表面积和气体储存能力。黏土岩的孔隙发育与岩石成因和成岩演化有关,孔隙大小主要受黏土颗粒大小的控制。