This report specifies research progress of the first homemade Insert-journal Bearing Bit and drilling actual result by it, together with consideration thereof 8-5/8'' Insert-journal Bearing Bit “3 WS-K” gave a satisfactory result of drilling 102m depth of blackish brown hard mudstone in 80 hours and 40 minutes below depth 3, 200m.
The gas flow in pipe line under steady state has been described by various anthers. But when we draw up the plan of instantaneous flow control by process computer, the theory of gas flow under un-steady state should be needed. In this paper, the anther sets up a simultaneous partial differential equations of un-steady state gas flow in pipe line (Eq. 11 & 18), based on the equation of motion (Eq. 1) and the equation of continuity (Eq. 9). Subsequently, he expands these equation to simultaneous difference equations (Eq. 26 27), and simultates real gas flow. The simulator starts with random noise, caused by the changes of pressure or flow rate at either end point in pipe line (the unit), in which gas flow has been under steady state, and traces the changes of pressure and flow rate of any place in the unit with time. At the starting time, we can put any value of pressure and flow rate at any place in the unit, which is first condition of simultaneous difference equation (Eq. 26 & 27). But in the next time-step, the pressure or flow rate of end point in the unit, which is boundry condition of the simultaneous equation, can not be difined from solving the Eq. 26 & 27. The auther notices that if we select the point enough close by end point in the unit, the gas flow between them changes instantly to steady state. So he applies this conception to calculation of next time-step boundry condition in the unit, such as Eq. 30 & 31. Setting up data and giving selected noises to the simulator, sufficient results are obtained as shown Fig. 5-12.
As recently, deep oil and gas reservoirs have been exploited, so it has been created the need for more basical data about the effect of overburden pressure on physical properties of reservoir rocks in drilling and production problems. In this study, it has been discussed how varies were occured on the permeabilities of rocks under triaxial compressions. The samples used were less-permeable rocks (1.2 md and 1.4 md), more permeable one (240 md) and much permeable artificial sand-stone (660 md) in this experiment. In the results, it has been certain that the permeability essentialy depends on the differential pressure between the confining pressure and internal fluid pressure on less-permeable one. On the contrary, the effect of the differential pressure were not almost recognized but the slippage effects slightly appeared on every permeable rocks at each fluid pressure. On the directions of loads, the radial stress more affected than axial one on the permeability.