中国南方海相页岩气超压机制及选区指标研究

在页岩气勘探开发选区的过程中,首先要寻找含气量较高的地区作为开发区块,含气量高的地区其资源丰度高,在同样的增产改造规模下单井EUR也较高,经济性也好。由于页岩含气量等于吸附气加上游离气,再加上溶解气,游离气、吸附气和溶解气都与压力系数关系密切。在美国开展页岩气地质选区过程中,由于地质条件稳定,认为超压对于页岩气田没有那么重要,正常压力、甚至欠压都可以实现开发,因此美国页岩气地质选区指标中没有压力系数的概念,并没有将超压作为一个关键指标。但是由于中国与北美地质成藏背景不同,北美页岩气主要位于环加拿大克拉通盆地,背景非常稳定,而我国是由多个地块拼接而成,构造复杂,同时页岩形成的时代较久,因此,我国与北美地质条件最大的差别为页岩成熟度高低和构造运动的强弱。因为我国海相成熟度高,导致孔隙压实,孔隙度降低;我国构造运动相对活跃,断裂发育,保存条件相对差。对于高成熟、低孔隙度的页岩,要达到同样的含气量需要较大的地层压力系数,这样单井最终可采储量才能达到经济极限,才能实现商业开发。我国南方分布有丰富的海相页岩气,具有厚度大、分布稳定的特点,普遍经历了高成熟演化和强烈地质构造运动。在油气生成过程中由于排烃作用的发生形成了广泛发育超低含水饱和度的特征,超低含水饱和度存在为形成超压富集区创造了条件,这种超压核心区是南方海相页岩气近期主要的勘探目标。扬子地区已经发现的超压页岩气田的增压机制主要包括构造抬升型增压、水热型增压、黏土矿物脱水型增压、生烃型增压。焦石坝海相页岩气田主要为构造型增压所形成的超压页岩气田,长宁页岩气田主要为生烃增压型页岩气田。页岩气选区指标应该是核心区/富集区优选指标,指标取值依据必须与超压气田地质特征参数匹配才有意义。北美地区页岩气地质选区需要考虑埋深、页岩厚度、TOC含量、含气量、硅质矿物含量。由于北美地质条件简单、成熟度适中,在低压、欠压条件下可实现商业化,但在高成熟、断裂发育背景下,地层压力系数尤其重要,应该考虑地层层压力系数。因此,本文认为页岩气地质选区中,除了考虑页岩埋深（1 500~4 500m）、页岩厚度（〉30m）、总有机碳含量（〉2%）、硅质矿物含量（〉30%）等基本参数外,应把地层压力系数大于1.3以上作为我国南方海相页岩气选区的重要指标之一,才能体现我国南方海相页岩气特点,同时提高页岩气选区的准确性和科学性。

输油管道首站停泵时低压区超压分析及对策

某成品油管道首站在停输时,泵机组停运过程中储罐区、给油泵区等低压区偶发超压现象。针对这一异常工况,排查各输油主泵运行状态,结合站场工艺流程设计,分析泵机组启停控制逻辑,找出了停泵后低压区超压原因并提出了解决措施,整改后低压区没有再出现超压现象。

中国南方古老海相页岩气超压富集特征及勘探开发意义

我国南方古生界龙马溪组和筇竹寺组海相页岩埋藏较深,经历了复杂的构造改造历史,成熟度很高,这对页岩含气性具有重要的影响,改变了页岩的储集能力和含气饱和度。为查明南方海相页岩气成藏特征和富集规律,通过开展成藏演化分析、流体包裹体研究后认为,中国南方地区喜马拉雅期构造运动对页岩气的成藏具有关键影响,主要体现在地层压力系数出现异常,形成超低含水饱和度现象和超压核心区。最后,认为我国南方古老海相页岩在高成熟阶段能够形成大量的天然气,导致页岩广泛发育超低含水饱和度现象。构造抬升和超低含水饱和度导致我国南方构造相对稳定区发育超压页岩气富集区,是主要的勘探目标,在超压核心区广泛存在超压页岩气藏,控压生产方式能提高页岩气井的稳定产量。

异常压力封存箱中压力消散的速率

本文介绍了一种改进的描述封存箱内通过达西流动而导致异常压力消散的解析解。该解析解一般是由前人在所述限制条件下提出的：①一个厚的封存箱和一层薄的阻挡层和②一层厚的阻挡层和一个薄的封存箱。业已证明，在分析油气藏时包括流体可压缩性是很重要的。前人在该领域的工作仅仅包括了本体岩石的可压缩性，而忽略了流体的可压缩性的影响。该解被用于典型的油气藏规模上压力封存箱和盆地规模上的超压地区。业已表明，在典型的油气藏封存箱中的压力梯度在数小时或数天左右将回到静水压力梯度，而异常压力则很可能在几万到几十万年内方能消散。因此，任何在发现时与其邻近地区具有不同压力的油气封存箱在生产期间都可以被认为是一个独立单元。然而，盆地规模的异常压力可能要花数千万年乃至数亿年才能消散。因此，没有必要引入零渗透率盖层或毛管压力盖层来解释地质时期异常压力的存在。

南方海相页岩气超压特征及主要选区指标研究

针对我国南方海相高成熟、强改造的地质背景,结合国内典型的超压页岩气田的特征分析,系统开展页岩气超压特征、成藏机制研究,认为增压机制主要包括构造增压、水热增压、黏土矿物脱水增压及生烃增压,焦石坝页岩气田为典型的构造增压型超压页岩气田,长宁页岩气田为典型的生烃增压型超压页岩气田。认为针对我国南方整体较为复杂的构造特点,应该把地层压力系数作为一项重要指标纳入页岩气地质选区指标体系,可以充分体现我国南方海相页岩气成藏的特征,同时提高页岩气地质选区的准确性。

Fabrication and Simulation of an AlGaAs/GaAs Ultra-Thin Base NDR HBT

A novel mesa ultra-thin base AlGaAs/GaAs HBT is designed and fabricated with wet chemical selective etch technique and monitor electrode technique. It has a particular and obvious voltage-controlled NDR whose PVCR is larger than 120. By use of device simulation,the cause of NDR is that increasing collector voltage makes the ultrathin base reach through and the device transforms from a bipolar state to a bulk barrier state. In addition, the simulated cutoff frequency is about 60-80GHz.

Test and application of hydraulic expansion bolts in a roadway under goaf with ultra-close separation

The roof of a roadway under goal with ultra-close separation consists of thin rock strata and rocks caving in upper goal. Influenced by the mining of the upper coal seam, the roof is loose and broken, and its integ- rity is poor. Resin anchored bolts cannot provide an effective anchoring force in such roof conditions. By conducting free expansion tests and field pull-out tests on a hydraulic expansion bolt, this study has ana- lyzed the influencing factors and laws of radial expansion and anchoring force changes in the rod body. This has revealed the anchoring mechanism of such bolts, and has obtained reasonable water injection pressures and suitable drilling diameters （which are 20-25 MPa and 32-35 mm respectively） for the hydraulic expansion bolt （cR28 mm） used in these tests. Based on pull-out tests at different interlayer spacing, the applicability of hydraulic expansion bolts had been verified for controlling the roof of road- ways under goal with ultra-close distance. Combined with the deformation and failure characteristics of the test roadway roof, this paper proposes a united roof-control technology based on the use of hydraulic expansion bolts and advancing intubation for the roof. Engineering practice indicated that the roof of the test roadway did not generate leaking and caving phenomenon, and the amount of roof deformation was controlled to within 150 mm. Maintenance of the roadway roof has been improved significantly, which ensures safe mining in coal seams with ultra-close separation.

Correlation between Rimjingang belt and Dabie-Sulu orogenic belt

The Dabie-Sulu orogenic belt in central-eastern China is considered as a high-pressure and ultrahighpressure metamorphic belt that demensions are comparatively large,and formed as a result of the collision of Sino-Korean and Yangtze cratons in eastern China. After continuous discoveries of high-pressure and ultra-high pressure metamorphic assemblages in the Dabie-Sulu area,the issue of the Dabie-Sulu orogenic belt extending eastward to the Korean Peninsula has been paid attentions widely. The discoveries of eclogites in the Hongsoeng area,the middle-western Korean Peninsula gives rise to the debate on the tectonic affiliations of the southern massifs. Although the Rimjingang belt in the Korean peninsula has been well investigated,the relation and comparative study to the Dabie-Sulu orogenic belt are lacking of detail work. In this paper,on the basis of informations and results of our previous works,some new contrastive considerations on the correlation between the Dabie-Sulu orogenic belt in central-eastern China and Rimjingang belt in the Korean Peninsula have are provided.