CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '9135e5e0dfd1fd98',cH: 'JirQLtnrxyro672hVmsYoOLfWH.OxVWtbl868bNP0Ms-1739796572-1.2.1.1-sFpVSq2Z9OUmtr3xZ5krXSYmDQy5r9Gl4vIFqOAamLgQ1zzZ1.vFw6eI1.LV1OA6',cUPMDTk: "\/abstracts\/search?q=underbalanced%20drilling&__cf_chl_tk=nmQe.o5HeGCwmMbOPAqZ_r2IZGvSE5s_9rbtC7x6cBg-1739796572-1.0.1.1-x0KRvn3SGwMIOLLdg3Qiz1icTyd1xqp.dr87quHoK4g",cFPWv: 'b',cITimeS: '1739796572',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/search?q=underbalanced%20drilling&__cf_chl_f_tk=nmQe.o5HeGCwmMbOPAqZ_r2IZGvSE5s_9rbtC7x6cBg-1739796572-1.0.1.1-x0KRvn3SGwMIOLLdg3Qiz1icTyd1xqp.dr87quHoK4g",md: "6NRzb0kNnN0LrrOCHP881_bt19WsrfeRWshddrUOpcM-1739796572-1.2.1.1-fssvkzFzE.8CAttzdw3.I_FqntFhrRAPltNbtktrZaBMCmVFCRndPX51MF8Zzb7HQTtJQbUifGy7oeLqOpCvxFxWWDAovpewRfyxZ2Wzsh9ZUHMm60IbZ1xwRtIaqz5f_4NnGoQ.Px8.ROiIkFIQ950R1kfAPfkXxaAxgPIbcq8vdCLlTl38ZTwyCqwMxM3.jf_1Qmk3fqurn3DidjGi0SoeQSQLL058Jp7P4.TkwhLjVZliJqtwTNbW46k_h.WPRUkxdaXnj3.1u1jK7cAprYiQdK_6pNaAUVkCVGjsjqAGcbgA9HKRJ2GALnqXrX2op3wb.MZTHqV._o3g0qFzd_KnKsNVvGzxvrhGeubAzYza9K2Ym7Vub1Y7FkTn_uNBidYeFUgJWexHoTxg2tD8NyK5m.V7bbAXDB_Y8PoijyDfIc2jDUkCXZmkbxPkFEa3NdTEkk8OwQyQVnU9RvLcZMXDBZvZutKtr5dluyB1TB.rNNFrhQ6HfPex1fkDvTQgOdnDJx2hr66EN28duYys93_TY_2CNHxrITTflMhJfRlUpHwTM29vTqPS9bAh.yG85F4gvlf_DkSuhNbKaCtpJhmiUUXSiP8E290hHtuO3kynoiNHlV5FvMzRhCgtGTsAyt4ILSFkQO3..oKrwT3Kizet8MnbBBXfPzo2TibxmLjiyAZGhIzjf25jWlhf7yHPdNk3pS4FpeNqXLM5aMIHl8RMUqKdGI3sLx0SnohSSObba06X8IgdSSdgIbIiwcwMds83JVgO_DAoigSRx1sa1ZcOMrJGDB_w4sSqGsPdxZ.LzV8kNRr5RVbYMNc0W648ikc_roHhfvg3RjIBkv9oeervkFxPAH7uAkRdK6qOXziqJQTRECh6YmhslMpSsPpOShVcedqwngT4vdis7Kcvk.g3BBa2UEf1exHSYWYNMwGYRg7A96OTP4pwK9nXRTxb98_2g5vyJAYJ.P6g_pZvSDgfAOyin7PLfet_FgkWvoIbWsM_x1AZGJJrdDP00JRwLoUg58niI2nl1ifwd9.XOLYTaqo09CYfYp3B2ka.Jvp4UZgBa8qjqO3EiY9AA926yY2UVzIM8waD2VO2yKnNBwrhgNW63ssdXVTbMGjRlV7iK46cQhlJSlE3b45Kitu11bDAhbX5FG9LCARoa_XwenrlKI19EtZAtJ2xxUtiHfEdcFkvYSIN8l2aTDqEX.6RgF878dhbE_NKlNjs_BKdLu7fyIMGnFMYJpPs4a_nFZcFQitgOFxTRYG4o4YyiKm.y6reaLkkE4_SLntN3v6DSF7k17vcrbLDCSvL9WlCZPkB88yOkfswXTH0sWHB5zxOlVA1MYwgSeu2_xZ0NsUAtvrOLgRwEfFzyyNOV.GqRkMBH0AveXAgRvpfcQGeKYrbeDl1riLXgRXvpAIeLsQObqfyuVz9J0d_Gk7dznT2EBA1EDb_byIOv4maTH4OwucBcq54685i2_semdmDF1ZpPDWtg8yeC2oI1gqAhJfqim1KvjWJxPxM1XSSU.tjZRUZGyYkuRHXs6luti6FlquZUjbfkpTnyfgLZajWppCkSLcuu8Ro9pQpz5Aj0zV5SXV7Xx59DUaqqOtoaDQoDrLdKnsMLNqgQbtwy1EbMsKf1501aDyIYJzLW0_Dfsw25rVEzZh1yIz.4WQ47gn_yi8ExoNwzn1qb9CpAx36WqSGSVNtCVzQ5.g8b3RsC4xrqYoKiiDQfDLagV0e5zeBSpymSXJ1zo3vZziXQBxDZXxDia68Pl4lZbl._FIDf2KHCRJHj5iMX9Zz5kTdBmEq2WsGCnM7W7PIQAnYXzILc9ujDzZjM0we1KqnAIyLTat9SzkXgEoRHmd68jASIErPGpe9Bbes_Q3dMtaFBI0zPB4B.xk55LmBG3JvIH0JRc_W.KoOhHBK.xFXszmmhhHSI8nc7y9kHvaRallQ8O67pwynNvTF49TjzTY.CkX8q1zoamkb",mdrd: "5jNGOuQJShd6dBJL3S21zSlhI2Xi_yNZ3ouyhyXbSDY-1739796572-1.2.1.1-6f2QKSjYLrjNwYUPV2IDRvWGPfTHCTTvVldtvCJwESuks_TRfymobZlUxc6M_Bi7cRheOySIgwqDLrxZx6p.EnGpTSHmJnZF1LX04_vybCg4m1ivjVOQgyBAtJwJfS0fgBzHxI4Vij0modC6y9eiojaqV2tJIBoDN1QZ8oJV.I8vz_8zWY4Mc9WUDyu2F.yMWQYdfxODzyMBuglLjcemTDqe0m2svIM0.Ak1CUIxK2Ha5wFbKti6rWvzkPO9g8jyexx7ILnGh1a77XPexm.UoqX9YinfjzxQ7ob2rUUxMQNTplpt.6p9XYO9XyvRRpE6SWm7jRFa4jaQ2Fi0OqlAuSVmye_y7r4YDQJMG0StlhBvd5j7.atVUHqI21FXoE.EUY_u.S9JJeto_hhoTBz1Gnt6MjoER8yw9LJGUDQ9kXpk39awXv4UJEQrk4a1FU6UDYTcVU9MeberAXxHGTKjsk0RCzWXz76Et8U_xYl1uQpSn.k1PhEHAmfr7cHAM8hj3Upq1wGvlVvEwO28a9GR6NiNDvjWGFU.EMJ2dteL.kp6ZtX9WVUJax8OZvUxBb0PBw1f2IqQQNnfHI_9XIJ2lvTL5yQMnU7v.skEnNpZovavVC4_Zq_xnGbTPRJnqkTOmSrIpm4QwO0eyDfFTqEgeUPNFPX72GEi8TC2OBkidVvUkM0UCKKkruguA.Q3kIiOWW8xmTw46OH.IJWf4YcTbexLgO5LoRjaY8MAdxwNgk3nABsNOJu8s6G.7sH8giStd8Yb2pmg.xxXoyOMxo.Bv.3c_VT6EG4uy4XagF9KYC0wiPRbd66ZszvOkdJDAdgoaWi5RIRuvIWWMuAXMICiifk1b2zCbwBTv1F_TiTfT1Vl7FAGpZBxfeVKj7hb30nx8PNcoxqRGPM65nYaFmOMsU_st2nYkFEM4M.LADurOq5Qahgm5iwBXJ2i3brxTgSL37pzgSGLcNHaXqOPR1SIWAbP5HhZ_iq6jBqZbgWYfakXatxd7TqyzDMAENhGPubaiXLIRizGXq72eTuqQmXiApFiD5T1WcgbkK1V3jytrCo8uS8GQxxIxazx5CiItFmeYd16f1GjyjPL8b_AeS8pjbHjMAb_bILTsvVwSKFLPcoKaBVsJekzqGpBifNwey53LytFwWWp393t9yB5bV_7kumtooFyBZzHp8uSqjW0uNRaJNJLuy.Ns2n2ME3TVMbK3wLMbopJJHGwlBCCPPoUVVmQe0Ht9uujR4JKMmGEkaUbVn17GN_62Xd8jngxYj3AugaP7FKmZJLzDc8FCSymxZ0oSqmW1BkH6dFPf21sTfSv_yAv9SR4VDWMzXYHpIDRyMK4io4nOgMrnun4h.902I4ftzY4KkdMlFuxKAMimvD1Af2j90SBRDkJ1eOHcA..jypr4YV1bXHtCoirgM3Jq5WF7Uwk6.J2lIMy6ZDAORH3wnX8Vf_ykge9boO0dnzq1V0mMKA_3T1535Hh6VDr65o3a4jjWGORuFpgSNbufqGRcj7iNJUe4_Wk5puGgPuXwSGXy0XYney1iWhXkwThZQ9wn08SnK6OMDkGI1qdMUwlchd23igCSQpB0M4bK45z4mcCxO9FsJjecraoBHqoPPSnOAabdZmgsozLkPTE.a5GwIztru8UdrODz_81adM7W4C3hOv5Q4zUAqBZvktOj6u8JlK3vgwKr7SBfG6vx8J1qZmzSdsrHIRClhfGoMFn6qcQz5k2R6aJb6x4jEgDk1rW4nhkMjxeetxBS_SjRvoOln04VFBdcsPUEas2onuXapN0jqIAIwohANhZCPXUVfRheHEwnKLefJ8hW19TSUn3ecHFxMc3v4IIFj_bbWMDWa6rCoXKhNN1yy0v3wVtGI9OJQq1tj0WYqTHgPEiInis5.GV9djW3HOHIxmH90F.FYjP_jUte7.FD0NuNd6hCwYc7nWsqzi1Sn1Bve.HEG6TQ8mHtmk1PpqUOzppIeim"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=9135e5e0dfd1fd98';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/abstracts\/search?q=underbalanced%20drilling&__cf_chl_rt_tk=nmQe.o5HeGCwmMbOPAqZ_r2IZGvSE5s_9rbtC7x6cBg-1739796572-1.0.1.1-x0KRvn3SGwMIOLLdg3Qiz1icTyd1xqp.dr87quHoK4g" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>