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Zhang S.,China University of Petroleum - East China | Guan Z.,China University of Petroleum - East China | Wang J.,Drilling Engineering and Technology Company | Shi Y.,China University of Petroleum - East China
Research Journal of Applied Sciences, Engineering and Technology | Year: 2014

This study describes a method of determining the position of adjacent well by analyzing geomagnetic anomalies in the drilling. In the experiment, put a casing in the geomagnetic field respectively to simulate 3 conditions, which are vertical well, deviated well and horizontal well. Study the interference of regional geomagnetic caused by casing, summary the law of the regional geomagnetic field anomalies caused by the adjacent casing. Experimental results show that: magnetic intensity distortion caused by deviated well is similar to that caused by horizontal well, but the distortion is different from vertical well. The scope and amplitude of N and E component magnetic intensity distortion will increase with the increase of casing inclination, meanwhile the scope and amplitude of V component distortion will decrease and the distortion value changes from negative to positive to the southwest of adjacent well. Through the analysis of geomagnetic anomalies, the position of the adjacent wells could be determined.© Maxwell Scientific Organization, 2014. Source

Zhao G.,Drilling Engineering and Technology Company | Guan Z.,China University of Petroleum - East China | Du Z.,Drilling Engineering and Technology Company | Huang M.,Drilling Engineering and Technology Company | Wang W.,Shengda Group Petroleum Engineering and Technology Development Center
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2013

Using acoustic waves to transmit downhole information through the drill-string transmission channel is a promising approach to meet the modern drilling requirements for the high-speed and large-volume transmission of data. Herein, we established a model to analyze acoustic transmission characteristics and examined acoustic characteristics of different drill-string assemblies by means of transmission matrix calculations. The results showed that a distinctive feature of the drill-string transmission channel lies in the existence of passbands and stopbands, in other words, the drill string, serving as a linear comb filter, is a narrow-frequency multi-band communication channel. The transmission performance of a drill string depends considerably on structure dimensions, physical parameters and signal frequencies. Along with the increase of signal frequency and transmission distance, the attenuation rate received increases obviously. In addition, the transmission performance is also co-influenced by the elastic modulus and density of drill-string materials. As for a periodic drill string, when the length of drill pipes increases, the passband center tends to shift to low frequency and both the passband and the stopband become narrower. When the sectional area of joints decreases, the passband widens while the stopband narrows, and the passband center within a band cycle tends to shift to frequencies of the band center. The closer to the band center the passband center is, the greater the offset is. As for a non-periodic drill string, the increase of differences in structure dimensions and physical parameters will change characteristics of the channel frequency domain of the drill string remarkably and reduce the acoustic transmission performance considerably. The signal to noise ratio is the key factor in designing an acoustic signal transmission system within the drill string. In order to realize the acoustic telemetry, the communication frequency of acoustic transmission should be chosen, to the greatest extent, within the low frequency range. Source

Guan Z.,China University of Petroleum - East China | Zhang S.,China University of Petroleum - East China | Wang J.,Drilling Engineering and Technology Company | Shi Y.,China University of Petroleum - East China | And 2 more authors.
Shiyou Xuebao/Acta Petrolei Sinica | Year: 2013

Affected by magnetization of the geomagnetic field, ferromagnetic casing in oil wells can form a magnetic field that results in geomagnetic anomaly in the neighborhood of casing. Thus, the orientation of adjacent wells can be determined by analyzing this geomagnetic anomaly. Through simulation experiments of the abnormal geomagnetic environment caused by casing of three different well types, i. e. vertical, inclined and horizontal wells, researched the impact of casing on the geomagnetic field and summarized regulations of local geomagnetic anomalies. Experimental results show that when adjacent wells are inclined or horizontal ones, the local geomagnetic anomaly caused by them has a similar and wider regional distribution, and anomaly of magnetic tool-face declination caused by them is distributed alike, geomagnetic field is relatively abnormal in the northwest and southeast direction of the well, while anomaly of the magnetic tool-face declination is relatively obvious in the northeast and southwest direction. When the adjacent well is a vertical one, an abnormal region of geomagnetic field and magnetic tool-face declination is relatively smaller and shows a distributional pattern different from those of inclined and horizontal wells, namely in the north-south orientation geomagnetic field is relatively abnormal, while in the east-west orientation magnetic tool-face declination is relatively abnormal. Thus, the location of adjacent wells can be determined jointly according to the abnormal distribution of both the local geomagnetic field intensity and the magnetic tool-face declination. Source

Wang C.,China University of Petroleum - East China | Wang R.,China University of Petroleum - East China | Cheng R.,China National Petroleum Corporation | Chen E.,Drilling Engineering and Technology Company
Advanced Materials Research | Year: 2011

A study on a new lithium salt accelerator was conducted in this paper aiming at the low temperature environment in deepwater cementing. The acceleration mechanism and comprehensive performance of the lithium salt accelerator were thoroughly discussed. Results show that the lithium salt accelerator can accelerate the low-temperature hydration rate of C3S and C2S by speeding up the rupture of protective hydration film and shortening the hydration induction period, and thereby significantly shortens the low-temperature thickening time and the 48-240 Pa transition time for the static gel strength of oil well cement slurry, dramatically improves the compressive strength at low temperatures and shows no effect on the initial consistency of cement slurry. The lithium salt accelerator shows favorable low-temperature early strength accelerating property and has no effect on the types of hydration product, which still remains the same with that of conventional oil well cement, namely the calcium silicate gel, Ca(OH) 2 crystal and a small amount of ettringite AFt crystal. But the micro-structure of the system with the lithium salt accelerator is more compact than that of conventional set cement. Source

Li X.,Drilling Engineering and Technology Company | Chen E.,Drilling Engineering and Technology Company
Drilling Fluid and Completion Fluid | Year: 2013

The low permeability reservoirs of Shengli oilfield has some characteristics of deep buried, bad physical property, severe heterogeneity, low degree of reserve recovery and high development difficulty. Based on theory of Synergistic Effect, the agents of reservoir protection agent AMP and anti-water blocking agent FCS are evaluated, and the low permeability reservoirs drilling fluid system is developed in this paper. The evaluation results show that with the content of AMP 3%, the core plugging rate is more than 90%, after cut by 3.0-3.5 mm in the plugging side, the permeability recovery rate is more than 95%, with the content of FCS 0.3%, the surface tension of filtrate is only 18.5 mN/m, which the two self-developed agents can cooperate with other agents to protect reservoir well. Source

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