Advanced Materials Research Vols. 734-737

Abstract: The Cambrian dolomite reservoir is an important target in oil and gas exploration. The Penglaiba section in the Keping area is typically examined in studies dealing with the Cambrian dolomite reservoirs of northwestern Tarim Basin. Based on sedimentological, petrographic, and geochemical data, lithofacies and fluids are identified as the major factors that control the dolomite reservoir in the study area. Lithoacies are fundamental to reservoir evolution because they provide suitable channels for dolomitization and dissolution of fluids that, in turn, facilitate the formation of high quality reservoirs. The lithofacies which could form high-quality reservoirs in the study area are: slope slip (collapse) facies, gypsum related facies, and algae dolomite facies. The sources of fluids include seawater, meteoric freshwater, diagenetic/hydrocarbon fluid, and hydrothermal fluid. These fluids lead to dolomitization, penecontemporaneous meteoric dissolution, hypergene dissolution, organic acid dissolution and hydrothermal dissolution that result in secondary porosity, and as such, they have a significant contribution to reservoir evolution.

Abstract: The Aketasi gold deposit, located in Fuyun County,Xinjiang,has some characteristics of subvolcanic-strucural altered type gold deposit. The metallogenic model can be generalized that Beitashan Formation of mid-Devonian was the original mineral source,and then plagiogranite emplace along the deep fracture, activating and extracting the gold element, achieving the first enrichment. The subsequent fault and the hydrothermal activities lead to the secondary enrichment of gold element ,finally form Aketasi gold deposit.The inside and outside contact of plagiogranite rocks,the zone with mercury vapor anomalies and the geochemical anomaly aera of Au Ag are the favorable for gold deposits.

Abstract: Microbialites from Penglaiba section, a well-exposed stratigraphic section in the northwestern area of the Tarim Basin are widely distributed throughout the Lower Qiulitage Formation of the Upper Cambrian. Stromatolites and thrombolites are recognized as the two major components. Thrombolites have two kinds of fabrics under the microscopy based on varying arrangements macroscopically, which are microbial reefs and clotted laminations. The microbial reefs are kind of round and irregular buildups with branched shapes and interconnection as frame, which played the major roles in protecting the other microbial structures against the tides and waves. Based on petrology, stratigraphy and micro-facies combination, depositional environments are indicated for varying water depths and energy. In addition, a model of peleaoenvironments is established in the Lower Qiulitage Formation. Both of thrombolites and stromatolites are associated in the subtidal zone, but in this sedimentary model, thrombolites deposited in the deeper water, in which this facies association is similar to what has happened in Bahamas.

Abstract: Jiyuan Oilfield Luo27 well field chang4+5 reservoir belongs to the typical three low" reservoir, which has tight reservoir, micro-fracture development and strong heterogeneity. After the water flooding development, there are many unusual phenomenons, such as profile absorbing water unevenly, injected water rushing in one direction seriously, block water cut rising rapidly, flooding wells increasing more. For that conventional dynamic adjustment and tracer monitoring are difficult to determine the inflow direction. In order to improve injected water utilization, Luo27 well field chang4+5 reservoir uses PI decision overall profile control technology to improve the injected water utilization, which effectively seals off the high permeability layer and eases the oilfield water cuts increasing speed and finally improves the water flooding recovery ratio.

Abstract: A probabilistic method named discovery process modeling is described for estimating the quantity of undiscovered oil and gas resources in Aral sea area in the North Ustrurt basin. In this model, the pool size distribution was demonstrated, and the numbers and sizes of undiscovered pools were estimated. The most likely remaining plays potential in Area sea area is 3447.2 Billions of standard cubic meters of gas in place. The eastern Jurassic-Cretaceous play bears 2901.5 Billions of standard cubic meters of undiscovered gas in place, and 17 gas pools are yet to be discovered; the paleogene-Neogene play bears 545.7 Billions of standard cubic meters of undiscovered gas in place, and 13 gas pools are yet to be discovered. Based on resources analysis, the Aral sea area is a prospecting exploration area for gas, and the emphasis should be strengthened on the eastern Jurassic-Cretaceous play.

Abstract: A big tendency in oil industry is underestimating the heterogeneity of the reservoir and overestimating the connectivity, which results in overly optimistic estimates of the capacity. With the development of seismic attributes, we could pick up hidden reservoir lithology and physical property information from the actual seismic data, strengthen seismic data application in actual work, to ensure the objectivity of the results. In this paper, the channel sand body distribution in south eighth district of oilfield Saertu is predicted through seismic data root-mean-square amplitude and frequency division to identify sand body boundaries, predict the distribution area channel sand body characteristics successfully, which consistent with the sedimentary facies distribution. The result proves that seismic attribute analysis has good practicability in channel sand body prediction and sedimentary facies description.

Abstract: Ongniud Banner is located in the northern margin of the North China platform, possessing binary attribute of the greenville period orogenic belt and North China block. The authors reclassify geological unit through the rock stratigraphic correlation and isotope chronology. Achaean strata is mainly composed of quartz schist, chlorite schist, amphibole schist, and the rocks have been highly metamorphosed into the green schist facies, and its single particle zircon U-Pb age is 2645 ±86Ma, so it is assigned to North China block. Proterozoic strata is mainly composed of metamorphic complex including chlorite schist, marble, basalt, amphibolite, plagiogranite and olivine pyroxenolite, and its single particle zircon U-Pb age is 1620±160Ma, so it is assigned to Greenville period orogenic belt. According to 1:50000 stream sediment geochemical elementary assemblage characteristics, the authors discuss the metallogenic endowment and minerogenetic series of geological unit in research area.

Abstract: Time-space-source dynamic controlling sand theory emphasized the size, supply and distribution of the source changes with time and space. Based on this theory, ramp-type, half-graben type and slots, grooves parallel-type sand control modes were established at Surennuoer oil field. According to the attribute maps and the sandstone thickness maps, the sand scope of nantun group can be determined, after identified the sand control point by using the fault throw statistic and 3D visualization technology. Sedimentary facies and the single well integrated histogram were used to verify the accuracy of the sand body divided. The results showed that: the sand control scope divide very accurately,and the sand control scope dovetail nicely with turbidite fan, braided channel and other sand-rich sedimentary facies.

Abstract: Shale gas is one of unconventional natural gas reservoirs,with forming pattern of self-generating and self-preserving. The research indicates that the distribution characteristics of shale gas content is influenced by the factors of the depth,the structure shape,the total carbon organic and the physical property of shale reservoir. The shale gas is on dynamic balance among the adsorbed gas, the free gas and the dissolved gas. By the exploration and development of shale gas,we obtained important theoretical understanding that there exists a parabola model relation between the shale gas content and the depth of shale reservoir,which is called L-W model of enriched accumulation belts of shale depth. Theory and practice studies show that the synclinal layer is the main structural factors controlling the enrichment of shale gas. Therefore,in the background of stronger geological tectonic movements in our country, finding weak tectonic area such as the synclinal layer formation occurrence,is the exploration direction for determination of favorable target areas of shale gas.

Abstract: Based on the division and correlation of sand groups in Heidimiao, synthesizing the information of 3D seism data, drilling data, logging data and core data, well ties profile, sandstone contrast diagram and oil reservoir profile are drawn in this article in a way of combining the data of logging and seism. Furthermore, spatial distribution rules of sandlayer in Heidimiao oillayer are expected to be analyzed in this article through the data of stratum thickness, sandstone thickness, the thickness ratio of sandstone to stratum, and porosity isogram. The rules are described as: the Heidimiao oil layer is thick in east and north but thin in the west and south as a whole. Little sandstone is found in H3 (Nen 2) but that is highly developed in H2 (Nen 3) and H1 (Nen 4) in which lenticular sandlayer can also be found. Sandstones in each oil group are developed with varying thickness, great depth difference and complex lateral connectivity. What’s more, sandstones in the research area manifest a decline in layers and thickness from east to west. The thinner and smaller-scale sandstones in the west have weak lateral connectivity but strong control of oil and water distribution, which results in the formation of concealed lithological reservoir uncontrolled by geological structure.