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Acid mine drainage (AMD) is difficult to treat due to its physicochemical characteristics, such as high pH and high heavy metal concentrations, so it causes great harm to the environment and human health. If acid mine drainage is discharged arbitrarily without treatment, it will lead to a series of environmental problems and cause long-term environmental pollution. In this paper, the source and hazards of acid mine drainage are introduced in detail. And the principle, the mechanism, the application, and basic information of the current primary technology of the treatment for acid mine drainage are comprehensively introduced and summarized. The summarized treatment technologies for acid mine drainage mainly include neutralization, sulfidization, constructed wetland method, adsorption method, microbiological method, ion exchange method, membrane technology, and microbial fuel cell technology. Also, the primary technology of treatment for acid mine drainage is systematically compared and evaluated. Moreover, some suggestions on the development direction of water treatment technology in the future are put forward. This paper provides a scientific reference for scientific and technical works to treat acid mine drainage.

Based on the productivity equation of coalbed methane (CBM) well, considering the impact of coal reservoir reformability on gas well productivity, the main production layer optimization index in the “three-step method” of optimal combination of production layers is corrected, and then the CBM production layer potential index is introduced to evaluate favorable areas for commingled multi-coal seam production. Through analysis of the key parameters of coal reservoirs affecting the CBM productivity index, a development unit division method for areas with multi-coal seams is established, and a quantitative grading index system is proposed. On this basis, the evaluation process of CBM development favorable area is developed: the mature 3-D modeling technology is used to characterize the reservoir physical properties of multi-coal seams in full-scale; the production layer potential index of each grid is calculated, and the production layer potential index contour under single-layer or commingled multi-layer production are plotted; according to the distribution of the contour of production layer potential index, the quantitative index of CBM development unit is adopted to outline the grade I, II, III coal reservoir distribution areas, and thus to pick out the favorable development areas. The practical application in the Yuwang block of Laochang in Yunnan proved that the favorable area evaluation process proposed can effectively overcome the defects of selecting favorable development areas only relying on evaluation results of a major coal seam pay, and enhance the accuracy of the evaluation results, meeting the requirements of selecting favorable areas for multi-coal seam commingled CBM production. Key words: coalbed methane, reservoir physical property, joint mining, production layer potential index, development unit division, quantitative index, favorable area evaluation

The Shahejie Formation in Huimin Sag is an important crude oil/natural gas reservoir stratum. The results show that (1) in the study area, the Sr/Ba value of Shahejie Formation ES4, ES3, and ES2 in Huimin Sag is 0.55–0.58, showing that these were freshwater-brackish water environment with a continental deposition; the average Sr/Ba value of the first member of Shahejie Formation (ES1) is 1.88, showing that it was a salt water environment. (2) B element method of paleo-salinity analysis shows that in ancient times, the salinity of ES1 was the highest; ES2 and ES4 had basically the same salinity that were lower than that of ES1; the third formation of Shahejie Formation(ES3) had the lowest salinity. (3) Analysis of values of Fe/Mn, Mg/Ca, and paleoclimate index C shows that the Shahejie Formation had generally a semi-dry climate. (4) Based on the analysis of the paleoenvironment, combined with the description of the cores, a sedimentary evolution model is built: ES4 was a debris flow fan-shaped river delta sediment in a shallow lake environment; ES3 was a delta-deep water fan-shaped system in a semi-deep-deep lake environment; ES2 was a delta system in semi-shallow lake environment; ES1 is the semi-shallow lake environment, the main sedimentary facies is the shore shallow lake facies.

The Dainan formation reservoirs in Shaobo area, Gaoyou sag, Southern China, sedimented mass conglomerates dominated by lacustrine slope apron system which fended by multiple flood channels with massive terrigenous clasts. In the early days, offshore fan-shaped sediments in the Shaobo area of the Gaoyou Sag were considered to be the main sedimentary system. However, a new lacustrine sedimentary model is presented in this paper. By careful core description and interpretation, four facies unions are recognized: (1) Facies union 1: Downslope clastic pathways that composed of massive conglomerates up to 6-25m thick, alternating with brown-dark gray mudstone and the etching structures can be often observed; (2) Facies union 2: Debris-flow Lobe is composed of massive conglomarates, matrix-supported to clast-supported polymictic conglomerates up to 10-50m thick; (3) Facies union 3: Underwater distributary channel is composed of trough cross-stratified sandstone, horizontally stratified sandstone and ripple cross-stratified fine to medium-grained sandstone, up to 5-20m thick; (4) Facies union 4: mudstone is dominates by thick grey black mudstone interbeding thin sandstone, the etching features are rare and bedding is typically parallel. In our study area, the traction current deposits constitute the producing petroleum reservoirs, and the conglomerates deposits are poor reservoirs. The sedimentary model may be applicable to other fault depression for predicting reservoir distribution.

The Chang 6 reservoir in Hulangmao area is a lithologic reservoir controlled by Zhidan Jingbian delta depositional system in Northern Shanxi Province. The oil reservoir has entered the middle-high-water-cut stage. The reservoir is characterized by low porosity and low permeability, with strong heterogeneity and great development difficulty. Therefore, it is necessary to further study the distribution of remaining oil through fine single sand body division and correlation，so as to improve the level of the reservoir development. Based on the theory of high-resolution sequence stratigraphy, according to the characteristics of mudstone marker bed and logging combinations, the sedimentary cycles are studied by using the techniques of maximum entropy spectrum and wavelet transform, and the cycle characteristics of different levels are clarified. Chang 6 member is divided into 3 fourth-level cycles, 6 fifth-level cycles (small levels), 13 sixth-order cycles (single level), and 21 seventh-order cycles (single sand body). Based on the stratigraphic correlation analysis model of sand body equal thickness, channel down-cutting, lateral phase transformation and splitting of superimposed sand body, and combined with the core and logging characteristics of the target area, the correlation framework of single sand layer in the whole area is established.

With the ability to provide complete profiles of pseudocolor image formation, IL (imaging logging) measures directionally, thereby offering a possible alternative to drilling and coring. This paper, relying mainly on IL information but also referring to formation dip angle logging information, details sandstone lamina dips and identifies sedimentary body dips, and sums up a practical palaeo-provenance direction judgment method using heavy mineral data analysis. By identifying a fine sandstone reservoir through an IL lithological model, a bedding model and a rhyme model, a 1D pseudoresistivity curve (named the 'IL rhythm curve') is, according to IL image analysis, extracted to assist in the interpretation of sedimentary microfacies and to establish an IL single-well facies analysis profile, overcoming an observance difficulty of IL in silty sandstone regions and intuitively displaying whole-horizon sedimentary evolution. As for a glutenite formation, calibrating IL information by rock cores, a single-well facies sequence of IL is established by identifying the Bouma sequence, high-density turbidity succession, the middle fan braided channel, the outer fan mudstone and other microfacies sequences, finely dividing the sedimentary facies sequence about sedimentary stage.

Considering that available data in Li32 block is limited, log phase method and core analysis were used to divide sedimentary facies and sequence, the former is principal, and two short-term cycles, five middle term cycles, and fifteen short-term cycles were divided. Combined seismic interpretation with fault point and fault rod, the instantaneous phase profile explained small fault more clearly and accurately. The sever faults were analyzed, and integrated structure was constructed. Lithofacies in cored wells were observed; the grain-size probability curves mainly are suspension and jumping transport; grain size is mainly for the siltstone and fine sandstone; the color of mud in the second segment of Shahejie formation (ES2) is mainly gray–green, gray to dark gray, these reflect that sediment environment is delta front, which included underwater distributary channel, mouth bar, distal bar, and so on. Well data and structural maps were integrated to build 3D structure model and sedimentary microfacies model of Li32 reservoirs using stochastic simulations with geometry data. The integrated 3D geological model is a valuable tool of reflecting geologic body with great reality and can accurately represent and describe the complex reservoir heterogeneity.