Application of Pore Evolution and Fracture Development Coupled Models in the Prediction of Reservoir "Sweet Spots" in Tight Sandstones

The Chang-63 reservoir in the Huaqing area has widely developed tight sandstone ＂thick sand layers, but not reservoirs characterized by rich in oil＂, and it is thus necessary to further study its oil and gas enrichment law. This study builds porosity and fracture development and evolution models in different deposition environments, through core observation, casting thin section, SEM, porosity and permeability analysis, burial history analysis, and ＂four-property-relationships＂ analysis.

Downstream Development of Baroclinic Waves in the Midlatitude Jet Induced by Extratropical Transition: A Case Study

This study uses eddy kinetic energy analysis and a targeting method to investigate how an extratropical transition（ET）event induced downstream development（the modification of the midlatitude flow downstream of the ET system） in the midlatitude jet environment. The downstream development showed distinct characteristics of ＂coupling development＂ and being ＂boundary-trapped＂. Eddies（potential disturbances） first developed at the upper levels, and these triggered lower-level eddy development, with all eddies decaying away from the tropopause and the surface. Thereafter, a lower-level eddy caught up with the upper-level eddy ahead of it, and they coupled to form a cyclone extending through the whole troposphere. Vertical ageostrophic geopotential flux may be a crucial dynamic factor throughout the eddy＇s lower-level growth, boundary-trapping,and coupling development.Together with barotropic conversion, the ageostrophic geopotential fluxes that were transported from Hurricane Fabian（2003） to the midlatitudes by the outflow led to downstream ridge development in the upper-level jet. The strong downstream advection of eddy kinetic energy in the exit region of the jet streak triggered downstream trough development. The well-known ridge–trough couplet thus formed. The vertical ageostrophic fluxes that were transported downward from the developed upper-level systems converged near the surface and resulted in lower-level eddy growth. Baroclinic conversion was negligible near the boundaries, while it was the main source of eddy kinetic energy at mid-levels. In the upper-level jet, potential energy was converted to the mean kinetic energy of the jet, which in turn was converted to eddy kinetic energy through barotropic conversion.

The Development of Hi-Speed Punching System Using A Couple of Rotating Bodies

Punched steel sheets (metal sheets or foils) as thi n as 0.1mm are quite useful in the field of filters and various precision instrume nts. Thus, we have to develop more accurate and speedy techniques for punching t hin sheets. The traditional punching method uses an up-down pressing motion of a punch or a die on a strip of metal. The efficiency of this method is determine d by the speed of the motion. In the case of punching a sequence of tiny holes w ith a few millimeters’ interval, the speed of feeding a strip of metal to the p unching machine cannot exceed only a couple of meters per minute. We have de veloped a new technique for punching tiny holes with a pair of rotating bodies i n order to increase the feeding speed up to 100 meters per minute. Our proposed technique is shown in Fig.1 where the female tool has a round blade and the male tool has an M-shape boss. In addition, the setting of two tools i s alternating. The interference between them cannot occur because the clearance between the front and the back edge of the male tool and the female tool in the rotating direction becomes infinite in this configuration. An appropriate cleara nce is given for the thickness of the sheet between the side edge of the male to ol and the female tool. The punching itself is done by shearing. The side edge o f the male tool does contact with the female tool, but they cannot be interferin g. Our technique has another advantage to the traditional up-down pressing mach ine where the stamped out chips are hard to be discharged. It is quite easy in o ur proposed technique. Fig.2, 3 show a sample of punched material [TPP116A,+39mm88mm,Y,PZ#]Fig.1 The configuration of the punching parts using the sequential punching system.[TPP116B,+43mm155mm,X,BP#]Fig.2 A sample of punched material using the continuous punch ing lineFig.3 A exterior picture of a piece of punched steel foil(coi l) using the continuous punching For our developed high speed punching system, it is shown for (1) the configurat ion of punching tool and the punching mechanism, (2) the influence of male shape on punched hole quality, (3) the outline of continuous punching system, (4) the relation between punching speed and accuracy of hole pitch and hole dimensi on, (5) the mechanical property of punched metal sheet and (6) capability of hig her punching.