Advanced Materials Research Vols. 616-618

Abstract: In order to predict the productivity of vertical well for shallow layer and low permeability reservoirs with horizontal fracture, based on the theory of horizontal fracture distribution and oil seepage in reservoir, establish the reservoir seepage physical model for shallow layer and low permeability reservoirs with horizontal fracture, and derive a novel deliverability equation, considering the effect of reservoir properties, fluid properties, horizontal fracture parameters and working systems. Furthermore, the equation was applied and performed sensitivity analysis to the productivity of a vertical well in Yanchang Chang 6 layer reservoir. Results show that vertical permeability, oil viscosity and the semiminor axis of horizontal fracture have more significant impact on well productivity. With real cases, it is demonstrated the established deliverability equation is simple and practical and meets the engineering accuracy requirements.

Abstract: Oil and gas reservoir evaluation is to evaluate the reserves in large scale or with special significance, and select the block for development. Oil and gas reservoir evaluation program includes a series of technical and economic indicators. Therefore the program optimization of oil and gas reservoir evaluation project is a system with multi-attribute. In order to optimize program comprehensively and systematically, it must establish a multi-level system of technical and economic indicators. Combining with the degree of gray incidence, the paper establishes a multi-level gray comprehensive evaluation model for oil and gas reservoir evaluation project, and applies the model to the practical example. The results show that the model is effective especially for the circumstance of the small sample or the limited amount of data. In addition, the model offers decision makers a new method to select favorable program.

Abstract: In order to simulate heterogeneous reservoir, six parallel homogeneous cores are used to conduct laboratory experiments of polymer flooding after water drive and the indexes of shunt rate, water cut and recovery factor are compared under different alternating injection cycle of polymer flooding stages. The results show that, when the alternating injection cycle is 0.2PV, it can better restrain profile reversal in the process of polymer injection displacement and make profile reversal appear later. Meanwhile it can improve the sucking fluid proportion of low-permeability layer and make overall water cut stay at low point much longer and then get higher recovery factor.

Abstract: L Oilfield construct as a whole for a wide and gentle anticline, the constructor East steep west slow in constructing the eastern part of the main part of the fault development of the western fault is relatively small, types of traps are faulted anticlines. Type of reservoir rock, siltstone and fine sandstone, sandstone and conglomerate, fine-grained sandstone and siltstone; deposition rhythm is rhythm, including a counter-rhythm, uniform rhythm; Cretaceous reservoir deposition mainly delta plain distributaries channel, the deposition of the Jurassic reservoir delta front, subaqueous distributaries channel and mouth bar; cretaceous reservoir average porosity of 19.3%, average permeability of 30 × 10 - 3μm2, in holes, low permeability reservoir sand body has a more serious layer, flat heterogeneity; Jurassic reservoir average porosity 26%, average permeability of 323 × 10-3μm2 to belong to the hole. in permeability reservoir. Water injection to maintain reservoir pressure development, research to determine the reservoir formation pressure to maintain the level of 0.83 times the original pressure, the initial development technology boundaries with more than 1.2 compensates water injection system pressure of 35MPa.

Abstract: In this paper, according to the mechanics balance equation, the law of conservation of mass and the relationship between parameters including coal seam permeability, porosity and volume strain, we build a gas-solid coupling model of hydraulic flushing borehole in the coal roadway floor, and use the model to investigate the relationship between ejected coal amount and effective influence radius. The numerical simulation results indicate that the effective radius of hydraulic flushing borehole increase as the drainage time and the ejected coal amount, and the effective influence radius is 5.8m when the ejected coal mass is 1t/m, which indicate the pressure release and permeability enlarging effect is remarkable.

Abstract: For low permeability and inhomogeneous reservoirs, defective effects such as water content increasing are usually resulted from traditional acidization. The principle of temporary plugging - acidization in Low permeability and inhomogeneous reservoirs, well selection and treatment requirements are introduced in this article. The temporary plugging agent selected from laboratory was used for field experiment. Result shows that: for wells of multiplayer and thin interlayer, temporary plugging – acidization technique can acidify the formation by the subsequence from high to low permeability, thus significantly increase the effectiveness of acidization, decrease the requirement of treatment operation and save the cost of production; the price of selected temporary plugging agent is comparative low, and the field process can be easily realized without affecting the progress of traditional acidization which has a good practicability and value to extend and apply.

Abstract: Hydraulic fracturing is one of the main stimulations, however, it is effected by various factors. This paper considers the influence of net thickness, permeability, flow pressure, water cut, injector—producer distance, cumulative injection-production ratio, sand input intensity, pad fluid volume, sand ratio. Applying the expert system to establish the predictive knowledge base, dividing various effect factors into four grades, and giving the different membership functions according to different grade. The 76% prediction results of established expert system are the same as actual results, and 20.5% are close to the actual results. The results show that the established expert system has the guidance action on the layer selection of fracturing and the fracturing design.

Abstract: The principle of preparation of PFASS by using gangue was introduced in this paper. By examining indicators such as COD, SS and chrominance, the best dose and operating time were evaluated for waste water from Changing oil field. It was showed from the experiment that: PFASS produced from the technology mentioned in this paper had a good effect on the waste water in oil field; using PFASS produced from gangue to treat field water is a good way to fight against waste by waste.

Abstract: To investigate hydrocarbon potential of the evaporites, some deep wells such as Haoke-1 well and Fengshen-2 well were intensively cored, tested by TOC, Rock-Eval, and chromatography and mass spectrometry and evaluated using geochemistry of biomarker and hydrocarbon generation. High content of gammacerane and low Pr/Ph was exhibited in the evaporite system compared to the non-evaporite system. Different response of biomarkers parameters for the different sedimentary systems was exhibited, such as C₁₉/(C₁₉+C₂₃) terpanes, C₂₉/(C₂₇+C₂₈+C₂₉) steranes, C₂₄/C₂₃ and C₂₂/C₂₁ tricyclic terpane. The evaporites and mud stones have the capacity to generate and expel hydrocarbons. The tested samples were mostly typeⅠand typeⅡ1 of organic matter, and their original generating capacity can reach 40 mg/g rock and 20 mg/g rock respectively. The efficiency of hydrocarbon expulsion reached 60%, but the distribution of organic matter and its generative potential was highly variable. In general, the mudstones show greater generative potential than the evaporites. High maturity severely reduced the capacity of their rocks to generate and expel petroleum.

Abstract: An improved lime-sintering process was developed to produce alumina from low-grade diasporic bauxite in this paper. Both clinkers sintered by the real bauxite and simulated bauxite at 1350 °C when the molar ratio of CaO to Al₂O₃ decreased to 1.4 were produced, the alumina leaching rates of which reached over 90% in sodium carbonate liquor. The main phases in the clinkers after sintering are 12CaO•7Al₂O₃, γ-2CaO•SiO₂ and 2CaO•Fe₂O₃. Addition of alkali can decrease the C/A ratio and get a high alumina leaching rate of clinker.