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Li X.-L.,Nanjing University of Technology | Li X.-L.,Henan Institute of Engineering | Guo A.-P.,Henan Institute of Engineering | Li S.-L.,Zhongyuan Petroleum Exploration Bureau | And 2 more authors.
Oilfield Chemistry | Year: 2013

Terpolymer of fluid loss reducer for oil well cement was synthesized by acrylamide(AM), 2-acrylamido-2-methyl-propane sulfonic acid(AMPS)and N-vinyl pyrrolidone(NVP). The effects of the monomer concentration, monomer ratio on the fluid loss performance of polymer were investigated. Under the condition of 75°C and 6.9 MPa, the API fluid loss of the cement slurry first decreased and then increased with increasing monomer content, increased with increasing AMPS dosage, and changed slightly with increasing NVP dosage. The optimum reaction condition was obtained as follows: 12% monomer mass fraction, 8.5:1.0:0.5 monomer mole ratio of AM:AMPS:NVP, 70°C reaction temperature, 5 h reaction time, 0.7% initiator and 12 pH value. The fluid loss of cement mortar containing 4.2%(BWOC)polymer at 160°C was of 60 mL with good slurry stability, 14 Bc initial consistency and rapid development of cement stone strength. Source


Wu F.,China University of Petroleum - East China | Jia H.,Yangtze University | Ren Y.,China University of Petroleum - East China | Liu M.,China University of Petroleum - East China | And 2 more authors.
Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science) | Year: 2015

A new ignition technique was proposed for downhole blasting fracturing using high energy propelants, in which a high speed and a low speed propellant are loaded in series with simultaneous ignition in a central tube. The new technique can avoid the problems of the currently ones that use single speed and one-pulse propellant for its instability and ignition-delay. Based on the different deflagration speed equations, the mass and energy conservation equations, a dynamic gas loading model of the multi-pulse deflagration was established, which can be used to simulate the dynamic loading process with different ratios of the propellants. The results show that the packaged propellants work well with the dynamic loading of the combination of the high and low speed propellants, in which a small quantity of the high speed propellant is ignited to generate a high pressure for initializing fractures, and large amounts of the low-speed propellant are ignited for the enlargement and extension of the fractures. It is suggested that, in order to achieve initializing fractures quickly and the protection of the casing, the usage of the high deflagration speed propellant can be reduced, while the quantity of the low deflagration speed propellant can be increased. ©, 2015, Zhongguo Shiyou Daxue Xuebao (Ziran Kexue Ban)/Journal of China University of Petroleum (Edition of Natural Science). All right reserved. Source


Zhen J.-W.,Henan Institute of Engineering | Wang Z.-H.,Henan Institute of Engineering | Lei Z.-M.,Henan Institute of Engineering | Yang J.-J.,Henan Institute of Engineering | And 2 more authors.
Oilfield Chemistry | Year: 2010

The applications, research and development directions of reservoir protection technology and drilling fluid systems which were commonly used in horizontal wells were reviewed, especially for new polymer, oil-based imitation, recyclable foam, weak gelling, clay-free and so on. The horizontal drilling fluids and reservoir protection technology of coal-bed methane, high oil reservoir, fractured reservoir and other special reservoirs were introduced. The technology of removing drilling mud cake and restoring reservoir productivity after the completion in horizontal well was summarized. Finally, several new development directions of horizontal drilling fluid and reservoir protection were proposed. Source


Xu L.,Yangtze University | Zhao L.,Yangtze University | Xu M.B.,Yangtze University | Xu J.,Wuhan University | Wang X.,Zhongyuan Petroleum Exploration Bureau
Applied Mechanics and Materials | Year: 2013

HTHP rheology was investigated for the water-based drilling fluid applied in Yuanba region of Southwest Gas Fields in China. The results showed that under the conditions of temperature up to 180°C and pressure up to 100MPa, the Bingham plastic model is adequate to predict transient rheology at the given HTHP conditions. Effects of temperature on rheology are more dominant than that of pressure, but the latter will enhance at high temperatures and low shear rates. Finally, HTHP viscosity models were established and evaluated for water-based drilling fluid. © (2013) Trans Tech Publications, Switzerland. Source


Wang W.-L.,China Institute of Technology | Hu Q.-A.,Zhongyuan Petroleum Exploration Bureau | Liu H.-W.,Southwest Drilling Company of Zhongyuan Petroleum Exploration Bureau | Zhang W.,China Institute of Technology
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2011

Using the mathematical model of longitudinal vibration of drill string, the characteristics of the axial stress amplitude distribution curve and the maximum axial stress amplitude-frequency curve for drill string were analysed. The impacts of drilling fluid viscosity, bit displacement and shock absorber's installation position on the maximum axial stress amplitude in drill pipe were investigated. The analysis shows that: the axial stress amplitude along the drill string is wavelike distributed and the point of the maximum axial stress amplitude is at the bottom of drill string or in drill pipe; the rotary speed-dependent curve of the maximum axial stress amplitude in drill pipe is in the form of at least one pit, and the speed range should be chosen to locate between the ends of the pits when drilling; the variation trend of the maximum axial stress amplitude in drill pipe with rotary speed is somewhat different from that at the bottom of drill string, and the former but not the latter should be looked as the target for resonance judging and rotary speed optimizing; the maximum axial stress amplitude in drill pipe varies roughly in direct proportion with the bit displacement; the higher the viscosity of drilling fluid is, the smaller the maximum axial stress amplitude in drill pipe is; a shock absorber can change the natural frequency of drill string, and the shock absorber should be fixed close to the bit when drilling with low rotary speed and kept a certain distance apart from the bit when drilling with high rotary speed to protect the drilling tools more effectively; optimizing the make-up of drill string and the rotary speed can prevent drilling tool failure effectively. Source

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