a new method for determination of residual stresses in the bottom layers of laminated composites is developed. in this method the residual stresses are determined by performing a consecutive drilling of laminated composites in the center of the rosette and recording the strains after drilling each layer. the depth of the hole in each step is equal to the thickness of each layer and the maximum ...

The effect of the infiltration pressure on the birefringent properties of a side-hole fiber filled with indium was investigated by the fiber-optic Sagnac loop interferometry. The fiber was made at the various gas pressures during the metal infiltration process. It was found that the birefringence of the fiber strongly decreased from 5.55×10(-4) to 1.68×10(-4) with the increase of the pressure f...

Vibration drilling technology induced by hydraulic pulse can assist the bit in breaking rock at deep formation. Simultaneously, pulsed jet generated promotes removal of cuttings from bottom hole. Nowadays, mechanism is not clear, which causes to accumulate hole and increases risk repeated cutting. In this paper, a pressure-flow rate fluctuation model established analyze characteristics Based on...

[1] Subseafloor hydrologic observatories (CORKs) were installed in four boreholes in young seafloor on the eastern flank of the Juan de Fuca ridge to evaluate the hydrogeology of the upper oceanic crust. Two CORKs installed at Site 1301 were incompletely sealed, allowing cold bottom water to flow into basement at 2–5 L/s and causing a pressure perturbation in a preexisting sealed CORK at Site 1...

For complex drilling operations with narrow geo-pressure windows, it is not uncommon to have problems with formation fracturing, due to erroneous mud pump management. To assist the driller in managing the circulation, it is possible to limit both the acceleration of the mud pumps whilst changing the flow-rate as well as the actual flow-rate, to avoid generating downhole pressure above the fract...

Based on the tight oil reservoir conditions of Lucaogou Formation in Jimusar Sag, Xinjiang, this paper conducts a full-scale characterization experiment pore structure and designs optimization numerical simulation development scheme based geological model combination with fluid occurrence state. A comparative study methods reservoirs shows that enhanced recovery effect CO 2 flooding is obviousl...

Testing should never become a mindless exercise in which operations personnel blindly follow proceMany papers have been published extending the dures written by others. The people who are theoretical understanding of pressure transient implementing the test should be actively trying to analysis. Most of these papers have concentrated on achieve the test objectives. It is often difficult or anal...

Numerical simulation of fluid flow and transport processes in the subsurface must account for the presence of wells. The pressure at a gridblock that contains a well is different from the average pressure in that block and different from the flowing bottom hole pressure for the well [17]. Various finite difference well models have been developed to account for the difference. This paper present...

To ensure safe and stable drilling operation, bottom hole pressure (BHP) should be kept within some region. However measurement of the BHP is sometimes not available or reliable, especially when the circulation is low, e.g., during pipe connection procedures. This paper presents the application of a moving horizon estimation (MHE) method for online estimation of the BHP during petroleum drillin...