Informatics Publishing Limited

Chunsheng Wang ¹, Xiaohu Wang ¹, Jie Zheng ¹, Xu Wang ¹

Affiliations
1 College of Petroleum Engineering, Northeast Petroleum University, Daqing, Heilongjiang, 163318., CN

Abstract

In the later period of water distribution to increase output of oilfield, it is difficult for the measuring and adjusting apparatus going down in the lubricator when the wellhead pressure reaches to some value, in separate zone injection testing. For this reason, we analyzed its reasons through theoretical derivation and experiments. According to the basic theory of statics of fluid mechanics, we derive and set the mathematical model among the static pressure differential of measuring and adjusting apparatus and the main factors such as wellhead pressure, cable diameter, etc. Indoor experiments and field testing jointly, we set the relationship of wellhead pressure affect the friction between the packing and the cables. The result: down resistance of measuring and adjusting apparatus in lubricator is linear with wellhead pressure and it is square with cable diameter, friction force between the packing and the cables have no big change while the wellhead pressure changes. Through the study of firing resistance, we can calculate the additional weight needed accurately when measuring and adjusting apparatus in lubricator fire and down, and provide theoretical basis for optimizing running parameters and heightening testing efficiency.

Keywords

Injector, Lubricator, Measuring and Adjusting Apparatus, Down Resistance, Additional Weight

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Xiaohua Qin ¹, Dongsheng Liu ², Qianghui Song ³, Runze Wu ¹, Xu Wang ¹

Affiliations
1 Department of Civil Engineering, Logistical Engineering University, Chongqing-401311, CN
2 Chongqing Bureau of Geology and Minerals Exploration, Chongqing-400071, CN
3 Chongqing Key Laboratory of Geomechanics & Geoenvironmental Protection, Chongqing-401311, CN

Abstract

Landslide is a major natural disaster, and large number of landslide disasters show that rainfall infiltration is a main factor to induce instability for unsaturated soil slope. To explore the failure mechanism of soil slope under extreme rainfall, the influence of rainfall infiltration for soil slope’s saturation, pore water pressure and displacement are analyzed based on fluid-structure coupling and theory of unsaturated soil mechanics under different extreme rainfall conditions. The results show that: (1) It has same rainfall discharge and rainfall duration for the four kinds of rainfall patterns, but they have different space-time effect on soil slope’s saturation, pore water pressure and displacement. (2) The rainfall pattern has large impact on slope’s displacement, and gradually increasing rainfall has most effective for slope’s displacement than other rainfall patterns after rainfall last 48 h, followed by first increasing and then decreasing rainfall after the first type, the third is gradually decreasing rainfall, and the least is stability rainfall. (3) Different rainfall patterns have different danger points during rainfall, but it occurs at the time that when rainfall intensity up to the maximum. According to the paper, gradually decreasing rainfall has most impact on slope’s stability at early-term of rainfall, first increasing and then decreasing rainfall has most impact on slope’s stability at medium-term of rainfall, and gradually increasing rainfall has most impact at last-term of rainfall.

Keywords

Soil Slope, Failure Mechanism, Extreme Rainfall, Fluid-Structure Coupling, Stability.

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