PETROLEUM POTENTIAL, THERMAL MATURITY AND THE OIL WINDOW OF OIL SHALES AND COALS IN CENOZOIC RIFT BASINS, CENTRAL AND NORTHERN THAILAND

Oil shales and coals occur in Cenozoic rift basins in central and northern Thailand. Thermally immature outcrops of these rocks may constitute analogues for source rocks which have generated oil in several of these rift basins. A total of 56 oil shale and coal samples were collected from eight different basins and analysed in detail in this study. The samples were analysed for their content of total organic carbon (TOC) and elemental composition. Source rock quality was determined by Rock‐Eval pyrolysis. Reflected light microscopy was used to analyse the organic matter (maceral) composition of the rocks, and the thermal maturity was determined by vitrinite reflectance (VR) measurements. In addition to the 56 samples, VR measurements were carried out in three wells from two oil‐producing basins and VR gradients were constructed. Rock‐Eval screening data from one of the wells is also presented. The oil shales were deposited in freshwater (to brackish) lakes with a high preservation potential (TOC contents up to 44.18 wt%). They contain abundant lamalginite and principally algal‐derived fluorescing amorphous organic matter followed by liptodetrinite and telalginite (Botryococcus‐type). Huminite may be present in subordinate amounts. The coals are completely dominated by huminite and were formed in freshwater mires. VR values from 0.38 to 0.47%R_o show that the exposed coals are thermally immature. VR values from the associated oil shales are suppressed by 0.11 to 0.28%R_o. The oil shales have H/C ratios >1.43, and Hydrogen Index (HI) values are generally >400 mg HC/g TOC and may reach 704 mg HC/ gTOC. In general, the coals have H/C ratios between about 0.80 and 0.90, and the HI values vary considerably from approximately 50 to 300 mg HC/gTOC. The HI_max of the coals, which represent the true source rock potential, range from ～160 to 310 mg HC/g TOC indicating a potential for oil/gas and oil generation. The steep VR curves from the oil‐producing basins reflect high geothermal gradients of ～62°C/km and ～92°C/km. The depth to the top oil window for the oil shales at a VR of ～0.70%R_o is determined to be between ～1100 m and 1800 m depending on the geothermal gradient. The kerogen composition of the oil shales and the high geothermal gradients result in narrow oil windows, possibly spanning only ～300 to 400 m in the warmest basins. The effective oil window of the coals is estimated to start from ～0.82 to 0.98%R_o and burial depths of ～1300 to 1400 m (～92°C/km) and ～2100 to 2300 m (～62°C/km) are necessary for efficient oil expulsion to occur.     

Optimization of downhole pump setting depths in liquid-dominated geothermal systems: A case study on the Balcova-Narlidere field,Turkey

Downhole pumps are being used increasingly more often in low-enthalpy geothermal wells. The depth at which these pumps are installed depends on the physical and chemical characteristics of the geothermal fluid, the production flow rate, and the reservoir pressure and permeability. In this study we have investigated the factors affecting pump setting depths in low-temperature, liquid-dominated geothermal systems and defined the relationship between flow rate and pressure drawdown based on multi-rate test results. The methodology proposed was applied to the Balcova-Narlidere geothermal field, Turkey. It was found that the most important parameters for determining the capacity and setting depth of a downhole pump were flow performance, non-condensable gas concentration, and temperature. The implementation of the methodology is illustrated.     

Physicochemical characteristics and leachability of scale and sludge from Bulalo geothermal system, Philippines

Scale and sludge from Bulalo geothermal field, Philippines, have been characterized by whole rock analysis, radioactivity counting, size analysis, light microscopy, scanning electron microscopy, and X-ray diffraction. Their leachability was assessed by regulatory leaching procedures and by sequential extraction. Both scale and sludge consisted mostly of oxides of Si, Al, and Fe with no radionuclides detected. The scale had 10% S content. Sulfides and silicates were important phases in both samples having size ranges from submicron to 2 mm. Geothermal soils at Bulalo have higher than normal soil levels of As, S, Cu, Cr, Zn, and Pb but regulatory leaching tests indicated that these elements are not released. However, the sequential extraction showed that As, Cu, and Zn were leachable under extreme conditions.     

使用地热能的吸收式制冷系统

吸收式制冷系统可以利用低品位的热源来制冷，相对于常见的蒸汽压缩式制冷系统而言在这方面具有优势。我国是一个地热资源很丰富的国家，为了充分利用这一资源，我们有必要对以地热为热源的吸收式制冷系统进行研究。本文着重分析了使用地热资源的溴化锂吸收式制冷系统。     

应用磷灰石裂变径迹研究大民屯凹陷的古地温

为深刻认识辽河盆地古地温特征，利用裂变径迹分析方法，对大民屯凹陷钻井岩心中19块磷灰石样品的裂变径迹年龄和长度做了测试。结果表明，随井深增加，径迹年龄和平均径迹长度有减少、变短的显著趋势，ES3^4地层磷灰石裂变径迹表观年龄比地层年龄年轻得多，说明沉积后曾长时间处于退火带中，退火带古地温为74～130℃，有效加热时间为4l～45Ma，2300～4000m深度地层处于退火过渡带。将径迹长度分布特征与地史、热史模拟结果相结合，认为该区在ES4段末经历一次短时间迅速增温后，ES3^1亚段存在一个区域抬升降温的热事件过程，其后地层稳定下降，沉降幅度小、沉积物较薄，温度增加缓慢，古地温梯度高于今地温梯度，对生、排烃较为有利。     

基于适宜性的西安市水源热泵开发潜力评估

依据适宜性评价,综合考虑水质、回灌率、已运行情况以及环境条件对水源热泵开发的影响,对西安市水源热泵开发利用潜力进行评估。结果表明:西安市适宜性面积占研究区总面积31.52%;将西安市水源热泵开发潜力划分为5类潜力类型区:Ⅰ、Ⅱ类潜力区主要分布于西安市北部,以平原为主,为开发潜力优、良区;Ⅲ类潜力区主要分布于临潼中部、阎良东部、长安南部、户县和周至南部等地,为适度开发潜力区;Ⅳ类潜力区主要分布于蓝田西南、临潼南部以及长安丘陵区,为不宜开发潜力区;Ⅴ类地区为秦岭山地和禁采区,应限制水源热泵的开发利用。研究可确定西安市不同地域的水源热泵开发利用潜力,研究结果可为编制西安市水源热泵开发规划提供参考。     

综合物探方法在地热资源勘查中的应用

地热资源作为一种可再生资源,具有安全、清洁、储量巨大的特点,可用于发电、工业和直接利用等。介绍了地热资源的成因和类型,分析了几种常见地热资源的分布特征,探讨了综合物探方法在地热资源勘探中的应用及前景。     

CSAMT在厦门杏林湾寻找深部地热中的应用

杏林湾地区地热资源丰富、构造复杂,采用CSAMT法对该区进行工作,采用一维反演结果,通过对不同深度卡尼亚电阻率平面图的分析,基本查明测区内各构造的空间分布及特征,经钻孔验证,证实了CSAMT法在寻找深部构造中的可靠性和可行性。     

北京城区典型地热对井地热资源潜力开发研究

地热田对井模式经过10a以上的验证,取得了良好的环境经济效益,但随着出水温度逐年降低,地热资源未来开发远景备受关注。以北京城区122～123对井为例,分析了地热构造条件、热井运行模式,利用相关热储参数和监测数据,计算出目前热能平均开采量为1．03×10^2kJ／a,静态热储量为5．395×10^11d／a,从能量角度出发认为未来仍有近10000a的理论开发潜力。     

浅层地热在皖南古民居中应用前景探讨

本文主要以黟县地区水文和地质资料以及实地调研为依据,提出了井水直接供冷、水源热泵技术、土壤与空气直接换热供冷、农家乐水(地)源热泵系统三联供以及沼气池、太阳能、地源热泵综合应用的五种浅层地热利用在皖南古民居应用的原理以及实现的可能性,对今后皖南地区古民居的可再生能源的利用以及节能提供理论支撑。