Unconventional gas includes tight sandstone gas, shale coalbed methane, and natural hydrate. With huge reserves, unconventional has become the most important resource successor after end of “Easy Oil era.” The drilling fluid is an indispensable wellbore working for with multiple functions. polymer (PDF) common, longest developed, diverse type. advantages easily controlled rheology, convenient o...

Ice coring of temperate and polythermal glaciers demonstrates some limitations of most electromechanical (EM) and thermal electric (TE) drills. Most TE drills are heavy, require a heavy power system, work slowly and cannot operate in boreholes going through the cold–temperate ice transition. Antifreeze thermal electric drills (ATED) are capable of operating in polar ice caps, polythermal and te...

[1] Knowledge of frictional resistance along faults is important for understanding the mechanics of earthquakes and faulting. The clearest in situ measure of fault friction potentially comes from temperature measurements in boreholes crossing fault zones within a few years of rupture. However, large temperature signals from frictional heating on faults have not been observed. Unambiguously inte...

This paper analyzed the characteristics of managed pressure drilling (MPD) technology and impact of wellhead back pressure on the wellbore annulus pressure profile, and found that the application of this technology provides room for improvement to the current casing program design. Meanwhile, the equivalent density of drilling fluid in wellbore annulus needs to consider the impact of back press...

The annular foam breaker is one which uses the vacuum and shear force generated by the Coanda effect to break foam. Its effectiveness in destroying drilling foam has been test in wellbore flow simulation loop experimental stand. Experimental results showed that the operating pressure of the annular foam breaker should be larger than 0.6MPa and the stabilizers concentration of the foam drilling ...