Advanced Materials Research Vols. 616-618

Abstract: New geochemistry, Nd–Sr–Pb isotopes and U–Pb zircon data from the Jinfosi Biotite granite provide important constraints on the evolution of the crust in this part of the North Qilian, NW China. The Jinfosi Biotite granite have the following properties: SiO2 > 65%, A/CNK(Molar Al2O3/(CaO + Na2O + K2O) ratios generally > 1.1, Na2O generally < 3.2%, Sm/Nd values between 0.17 and 0.27, and high Rb/Sr values. A chondrite-normalized rare earth element (REE) pattern shows negative Eu anomalies and depletion in heavy REEs. 143Nd/144Nd values are relatively low, and values of εNd(t) and εSr(t) are indicative of continental lithosphere. (87Sr/86Sr)i values are between 0.69952 and 0.70962, corresponding to continental crust mixed with a minor component of mantle material. Values of 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb are 18.9–19.0, 15.59–15.85, and 38.00–and 39.00, respectively, corresponding to S-type collision-related granites. The Jinfosi Biotite granite yield a SHRIMP zircon U–Pb age of 416.7 ± 4.1 Ma. R1–R2 and Rb versus (Yb + Nb) discrimination diagrams indicate that the Jinfosi biotite granite was produced during continental collision following closure of the paleo-North Qilian Ocean.

Abstract: Based on the analysis and testing data of rocks, the basic geologic characteristics of Suganhu depression is discussed. It is concluded that the 200m thickness dark mudstone of inshore shallow lake face in the middle–lower Jurassic stratum is the only source rock of this region. It has the characteristics of high abundance of organic matter and in high mature stage. And the type of organic matter is Ⅱ2.The reservoir properties is controlled by the influences of both the sedimentation and the diagenesis and belong to the low porosity and low permeability ones. The mudstone of Upper Jurassic is the local cap, the ones of braided river face and braided river delta face which existed in the up-middle of the middle Jurassic can be qualified as sealing bed between the sand bodies. Paleocene–eocene mudstone is the regional cap rock. The ability of upper Jurassic sealing bed is good because of the low porosity and permeability and high break pressure. The regional cap rock has the characteristics of big thickness and large area. Both the local and regional cap rock had been able to seal the petroleum and gas before the time of hydrocarbon accumulation of middle Jurassic. In general, Mesozoic formed reservoir–cap combination with the features of lower–generation and upper–reservoir, upper–cap.

Abstract: The energy situation of China has been very tough. Our country’s oil is heavily dependent on imports and lack of oil and gas reserve. The shortage of oil and gas resource has become an important factor which restricts our national economy health and sustainable development. Guided by the theory of petroleum system, we analyzed the Mesozoic-Palaeozoic marine strata hydrocarbon accumulation elements and conditions of the sourthern depression in Southern Yellow Sea Basin and concluded the hydrocarbon accumulation pattern in order to find the reserving oil and gas. There are seven source-reservoir-cap assemblages. Different tectonic units experienced different tectonic evolution history. The source rock of Lower Palaeozoic, Upper Palaeozoic and Lower Triassic have experienced four, three and two hydrocarbon generation stages separately in the depression. But the source rock of Lower Palaeozoic and Upper Palaeozoic in the salient have only experienced two and one hydrocarbon generation stages separately. Hydrocarbon generated by Mesozoic-Palaeozoic source rock migrated to the traps by fault, crack and unconformity. Lithologic trap, broad anticlinal trap and fault-lithologic trap are the main types in the study area. By the analysis of Mesozoic-Palaeozoic marine hydrocarbon accumulation in the sourthern depresssion, we concluded two accumulation patterns which are the original lithologic reservoir in the Mesozoic-Palaeozoic marine strata and fault-lithologic reservoir in the Mesozoic-Cenozoic terrestrial strata. These results will help to predict the oil and gas resources.

Abstract: The subtle reservoir has become an important exploration target within the Bohai Bay Basin, especially in the Qikou sag. In order to guide subtle reservoirs exploration in offshore area geological analysis to Sha’nan structural belt is carried out in this paper. Qikou sag has large thickness, high abundance, ideal type hydrocarbon source rock. By unconformity recognition technique and paleotectonic analysis technique, results show that tectonic uplift had provided sedimentary source to the depression around it after Es1. By 3-D seismic interpretation technique and Seismic facies analysis, the sedimentary facies was confirmed. Geological analysis results show that sand bar, subaqueous fan is developed around it in Ed3. With the new geological analysis data sedimentary model of Sha’nan structural belt has been built in this paper. The sand bar and subaqueous fans showed a good reservoir potential, which are advantageous to oil accumulations. The southern part of Sha’nan structural belt has good hydrocarbon exploration potential.

Abstract: Studing the identification methods of sedimentary microfacies by the implement of self-organizing neural network model. Picking up the geometrical characteristic parameters and image characteristic parameters of the logging curves. Establishing the relationship of sedimentary microfacies patterns and well logging curves shapes by characteristic parameters. Developing the Sedimentary microfacies patterns identification system and applying it to 1000 wells of the southern area of Daqing Changyuan, the recognition rate can reach 90%, it can prove the validity of the method.

Abstract: Gejiu tin ore deposit is a famous tin-polymetallic deposit in the world because of its enormous metal reserves. Besides tin, there are copper, lead, zinc, silver, iron, sulphur, tungsten, bismuth, indium and rare earth elements. It was believed that there mainly are skarn-type tin deposit, stratiform tin deposit and basalt-type copper deposit in Gejiu tin orefield. The stratiform tin deposit are distributed in Lutangba, Malage and Huangmaoshan, which are hosted by carbonate rocks of Gejiu formation in Middle Triassic Series. 40Ar-39Ar dating of cassiterite from the sratiform tin deposit in Lutangba yields plateau age of 202.18±2.35Ma and isochron age of 206.81±3.23 Ma respectively. The ages are obviously older than those of the ore of the skarn type deposit of the Yanshanian epoch．The mineralization is the seabed exhalative hydrothermal sedimentary mineralization of the Indosinia epoch.

Abstract: By applying the data of drilling core, well logging and 3D seismics and studying the sequence framework, sedimentary microfacies and shallow gas distribution law, it shows that the Heidimiao Reservoir is vertically divided into a long-term, 4 intermediate-term and 25 short-term base-level cycles. Heidimiao Reservoir is of the gentle river controlled sedimentary system of delta front The main microfacies are underwater distributary channels, mouth bars and distal bars. Shallow gas is vertically distributed in the reservoir sandbody at the period of intermidiate hemicycles of late decrease or early rise in long-term hemicycles of the early fall. It is reasonable match of distribution discipline of single sandbody, gas source faults and structure that is the dominated factor for shallow gas plane accumulation. Based on the study above, 90 gas traps are depicted by applying the gas-water interpretation templates.

Abstract: Recently, many strong magnitude earthquakes and volcanoes have taken place on earth, which reveals that the Earth perhaps in its active period of tectonic movement currently. The heat flow will increase during the active period of tectonic movement, and it can provide meltwater to lubricate the basal layer of the West Antarctic Ice Sheet, which can leads to the sea-level rise.

Abstract: In the light of the principle and method of sequence stratigraphy, the sequence stratigraphic framework of Badaowan formation in the Dishuiquan area was established. The results show that the sequence of Badaowan formation is one and half, including 5 system tracts. The whole experiences the process of retrogradation, progradation and then retrogradation again. There develop three types of sedimentary facies such as braided river, braided river delta and lakes, five types of sedimentary subfacies and 10 types of sedimentary microfacies. Most of JSQ1 sequence lowstand system tract is braided rivers, the lacustrine transgressive system tract mainly develops shore-shallow lacustrine sediment and most of highstand system tract is braided river delta; lowstand systems tract of JSQ2 sequence mainly develops braided river delta, most of the lacustrine transgressive system tract is shore-shallow lacustrine sediments.