Reservoir potential of carbonate rocks in the Kutai Basin region,East Kalimantan,Indonesia

Fifteen percent of the exploration wells drilled in the Kutai Basin region were targeted for stratigraphic play-types. Carbonate reservoirs comprise almost 70% of the objectives in these stratigraphic plays. There was need for a better understanding of the carbonate reservoir potential in the region. Accordingly, this study was carried out. The distribution, depositional environment as well as factors controlling the quality of carbonate reservoirs are reviewed and analyzed. Carbonate reservoirs in the study area can be found sparsely throughout the Kutai Basin. Carbonates range in age from Oligocene (Bebulu limestone) to Late Miocene (Dian limestone). The main constituents of these carbonate build-ups are platy-corals, encrusting red algae and larger benthonic foraminifera. Most of the carbonates were deposited in a shallow marine environment (inner to middle shelf) during rises in relative sea level. Highstand system tracts are characterized by well-developed carbonate facies-belts. The carbonate build-ups generally occur as isolated bedded mounds, from a few feet up to 1000 ft in thickness. The preservation of primary porosity is generally poor due to diagenetic processes during burial history, particularly the infilling of pores by non-ferroan calcite cement. The development of secondary porosity is limited, due to the retardation of subsurface fluid flow by non-permeable layers, and the absence of solution effects due to sub-aerial exposure and karstification. Preserved porosities are mainly present as vugs, best developed in coarse-grained shelf-margin facies, which may not have subsequently been completely filled by calcite cement. Early hydrocarbon migration may retard the diagenetic processes and preserve the primary carbonate porosity.     

民用蜂窝煤燃烧排放颗粒物的化学组成和稳定碳同位素特征

本文选用了镜质组反射率在0.77%-1.88%之间5 种不同成熟度的煤, 将其制成民用蜂窝煤球, 研究民用蜂窝煤燃烧排放颗粒物（PM）的化学组成, 包括元素（C、N、O、S）、有机碳（OC）、元素碳（EC）和水溶性无机离子（WSII）, 稳定碳同位素组成特征和质量吸收效率值（MAE）, 并讨论了它们与煤成熟度之间的关系.结果表明, 5 种原煤C、N、O、S 元素组成差别不大, 但是燃烧后排放的PM 化学组成差别比较大.无烟煤燃烧排放的PM 粒径分布呈双峰结构, 峰值分别在0.09 μm 和0.25 μm; 而烟煤PM 的峰值为0.58 μm.无烟煤排放PM 的颗粒数远小于烟煤.PM、OC 和EC 的排放受煤成熟度的影响非常大, 无烟煤排放的量最小, 分别为2.21 g/kg、0.22 g/kg 和0.004 g/kg; 成熟度最低的烟煤排放量最大, 分别为70.3 g/kg 、46.1 g/kg 和2.42 g/kg.PM、OC 和EC 的排放因子与煤的成熟度成幂指数关系.EC 的MAE 在0.17-21.9 m^2/g 之间, 与煤成熟度呈指数相关关系.燃煤WSII 的平均排放因子为801 mg/kg, WSII 当中含量最高的是NH4^＋ 和24SO4^2- , 平均分别占WSII总量的23.5%和44.4%.燃煤排放PM 的δ^13C 变化范围为–24.5‰-–22.8‰, 平均值为–23.6‰.以上研究有助于人们从原煤性质的角度去考察民用燃煤对人类健康和气候变化的影响, 并为大气污染源解析提供一些科学依据.