【摘要】：中間主應(yīng)力σ_2對巖石強(qiáng)度具有顯著影響,在井壁穩(wěn)定性研究中需考慮σ_2效應(yīng)。常用中間主應(yīng)力強(qiáng)度準(zhǔn)則有統(tǒng)一強(qiáng)度理論(UST)、Mogi-Coulomb(MG-C)準(zhǔn)則、Drucker-Prager(D-P)準(zhǔn)則、修正Lade準(zhǔn)則、三維Hoek-Brown(H-B)準(zhǔn)則和修正Wiebols-Cook(W-C)準(zhǔn)則等6種。文中對比分析了上述6種強(qiáng)度準(zhǔn)則在σ_1-σ_2平面內(nèi)的曲線,并進(jìn)行了井壁穩(wěn)定分析。結(jié)果表明:在σ_1-σ_2平面內(nèi),除UST準(zhǔn)則為雙折線形式外,其他準(zhǔn)則均為非線性形式;D-P準(zhǔn)則所預(yù)測強(qiáng)度最高,其他準(zhǔn)則預(yù)測結(jié)果相近。在當(dāng)量坍塌壓力計算中,UST準(zhǔn)則(b≠0)、MG-C準(zhǔn)則、修正Lade準(zhǔn)則、三維H-B準(zhǔn)則和修正W-C準(zhǔn)則計算結(jié)果相接近,D-P準(zhǔn)則所計算當(dāng)量鉆井液密度最低。對于安全鉆井方位,UST準(zhǔn)則下安全井壁穩(wěn)定分布區(qū)域隨著參數(shù)b值升高而逐漸減小;D-P準(zhǔn)則下井壁穩(wěn)定分布區(qū)域最高;MG-C準(zhǔn)則、修正Lade準(zhǔn)則、三維H-B準(zhǔn)則和修正W-C準(zhǔn)則所給出的井壁穩(wěn)定分布區(qū)域相近。對比分析后,在井壁穩(wěn)定性研究中推薦使用MG-C準(zhǔn)則。該準(zhǔn)則不僅反映了σ_2對巖石強(qiáng)度的影響,且形式簡單,便于在實(shí)際工程中應(yīng)用。
[Abstract]:The intermediate principal stress 蟽 _ 2 has a significant influence on the rock strength, and the 蟽 _ 2 effect should be considered in the study of wellbore stability. There are six kinds of intermediate principal stress strength criteria: unified strength theory (UST), Mogi-Coulomb (MG-C) criterion, Drucker-Prager (D-P) criterion, modified Lade criterion, three-dimensional Hoek-Brown (H-B) criterion and modified Wiebols-Cook (W-C) criterion. In this paper, the curves of the above six strength criteria in the 蟽 _ 1- 蟽 _ 2 plane are compared and analyzed. The results show that in the 蟽 _ 1- 蟽 _ 2 plane, all the criteria are nonlinear except for the UST criterion, and the D-P criterion has the highest predicted intensity and the other criteria are similar. In the calculation of equivalent collapse pressure, UST criterion (b 鈮，

本文編號：2275811