Home / Journals / CMES / Vol.90, No.1, 2013
Table of Content
  • Open Access

    EDITORIAL

    Preface

    Deli Gao1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, 2013
    Abstract This article has no abstract. More >

  • Open Access

    ARTICLE

    Numerical Analysis of the Gas Injection Rate in Z12V190 Diesel Tail Gas Drilling

    Xuejun Hou1,2, Deli Gao1,3, Zhonghou Shen1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 1-16, 2013, DOI:10.3970/cmes.2013.090.001
    Abstract Diesel tail gas drilling (DTGD) is a type of gas drilling, which uses diesel tail gas (DTG) as a circulating medium. Its cost is slightly higher than that of air drilling, but is cheaper than those of nitrogen drilling and natural gas drilling. When the reservoir is drilled with DTG, just as nitrogen and natural gas, the DTG will prevent the burning and blasting of oil and gas in the bottom hole. In order to reduce costs, the DTG is often used in drilling the reservoir, to prevent the underground explosion. This paper analyzes the composition of the Z12V190 diesel… More >

  • Open Access

    ARTICLE

    The Post-Buckling Behavior of A Tubular String in An Inclined Wellbore

    Deli Gao1, Fengwu Liu1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 17-36, 2013, DOI:10.3970/cmes.2013.090.017
    Abstract A down-hole tubular string in an inclined wellbore, under variable axial and torsional loading, may simultaneously undergo a sinusoidal as well as helical buckling, at different sections. In this paper, the buckling equation for a tubular string, in an inclined wellbore, subjected to axial and torsional loading, is established by an equilibrium method. The analytical solutions for the buckling equations, for sinusoidal and helical configurations of buckled tubular string, are obtained by Galerkin and nonlinear scaling methods. Methods for computing the contact forces between the buckled tubular string and wellbore, are developed. The analytical solutions are in good accordance with… More >

  • Open Access

    ARTICLE

    A New Well Profile for Extended Reach Drilling (ERD)

    Tengfei Sun1, Deli Gao1,2, Hui Zhang1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 37-46, 2013, DOI:10.3970/cmes.2013.090.037
    Abstract Well profile design is one of the critical technologies in extended reach drilling (ERD), because an optimum well profile is an effective means for reducing the torque, drag and cost. This paper proposes a new well profile based on an inverse proportional function, and the new profile design method is analyzed in detail. The new well profile is also compared with other existing well profiles in many aspects such as the hook load, the maximum well curvature, the well length, the torque and so on. The results show that the well profile design based on an inverse proportional curve is… More >

  • Open Access

    ARTICLE

    Research on a Triaxial Rate of Penetration (ROP) Model Related to Unloading in Oil & Gas Drilling

    Hui Zhang1, Deli Gao1,2, Xiaopin Xie1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 47-64, 2013, DOI:10.3970/cmes.2013.090.047
    Abstract In oil & gas drilling engineering, the rock breaking efficiency as well as the trajectory of the Well should be quantitatively and accurately described by an ideal triaxial Rate of Penetration (ROP) model, taking into account the various objective and subjective factors. However, with the existing triaxial ROP models, it is difficult to achieve these goals. The applications of the existing ROP models are limited, especially in under-balanced drilling (air drilling, foam drilling etc.), because the unloading effect (i.e. the effect of the bottom hole differential pressure on the formation force) has been rarely considered. On the basis of a… More >

  • Open Access

    ARTICLE

    An Analysis of the Bottomhole Assembly (BHA) in Directional Drilling, by Considering the Effects of the Axial Displacement

    Zonglu Guo1, Deli Gao1
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 65-76, 2013, DOI:10.3970/cmes.2013.090.065
    Abstract The modeling of the bottomhole assembly (BHA) is an essential problem in directional drilling. Some basic equations for predicting the performance of the BHA are presented in this paper. These equations take into account the effects of the axial displacement. The method of weighted residuals and the Newton-Raphson iterations are used to compute the nonlinear effects of the deformation of the BHA. A computer program is developed for the analysis of the BHA in order to quantitatively predict the performance of the BHA in directional drilling. In addition, a case study is presented to evaluate the effect of the axial… More >

  • Open Access

    ARTICLE

    Study on a Ranging System Based on Dual Solenoid Assemblies, for Determining the Relative Position of Two Adjacent Wells

    Binbin Diao1, Deli Gao1,2
    CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 77-90, 2013, DOI:10.3970/cmes.2013.090.077
    Abstract The measurement of the relative position of two adjacent wells is one of the key technologies in the directional drilling of twin parallel horizontal wells, and the downhole intersection of two adjacent wells. A new electromagnetic ranging system and a guidance method are introduced for determining the relative position of two adjacent wells. The system mainly consists of two solenoid assemblies, improved surveying instrument for measurement while drilling (MWD), and a computational procedure for guidance. Also, the distribution of the magnetic field of each energized solenoid assembly is discussed, by regarding the solenoid assembly as two independent oscillating magnetic dipoles.… More >

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