Analysis of the Factors that Influence Diagenesis in the Terminal Fan Reservoir of Fuyu Oil Layer in the Southern Songliao Basin, Northeast China

The diagenesis mechanism and the physical properties of a terminal fan reservoir are determined by nuclear magnetic resonance (NMR), X-ray diffraction and scanning electron microscopy. The main provenance directions are NE and SE, and the two oppositely directed fans converge to form a small catchment basin. The mudstone color is red or purplish red, which accounts for 60% of the total rock. The sandstones are lithic-feldspar sandstones and feldspar-lithic sandstones, with a smaller quartz component relative to the adjacent sandstone formations. The reservoir mainly consists of intergranular pores (51%), intragranular pores (22%), corrosion pores (20%), micro-fractures (5%) and clay matrix pores (2%). The porosity of the reservoir is only 13%, and the throats are fine with high displacement pressure. The diagenetic processes included compaction, cementation, replacement, and dissolution, and the most influential factor on the reservoir porosity was compaction. The detrital rock cement mainly consists of clay minerals (48%), quartz (23%), carbonate (19%), feldspar (7%) and dawsonite (3%). Among them, the mixed I/S layer has the most content and the most important cementation. In addition, a small amount of dawsonite is found in the pores of the sandstone, which is a unique mineral that is related to the background of inorganic CO2. The main diagenesis factors that affected this sandstone’s porosity were compaction, early quartz overgrowth and calcite cementation, which reduced the porosity from 40% to approximately 8%. Although dissolution and fracture increased the porosity (from 8% to 26%), clay- and carbonate-mineral cementation during the late diagenesis period had a dramatic effect, forming a typical low-porosity and low-permeability reservoir.

Compensation of HVAC System Nonlinearities Using Cascaded Control Architecture

Research into heating, ventilation, and air conditioning systems has shown that coordinating building climate control leads to large energy savings. However, most analyses have assumed linear dynamics not reflective of actual systems. Using a cascaded control architecture, this linear behavior can be recovered, allowing for maximum energy savings to be realized. Case studies on variable air volume, hydronic radiator, and terminal fan controlled systems demonstrate the broad application and benefits of this approach. Also, because of the architectural simplicity and lack of required a priori knowledge of system performance or characteristics, the cascaded controller can be implemented immediately in the HVAC community.