Fracturing sand geological factors

Geological factors refers to unconsolidated sandstone formations geological conditions , such as the content and distribution of cement , cement type , Diagenesis and geological proppants for hydraulic fracturing age and so on. Generally speaking , the later geological age , the less cemented mineral formations , sand cementation worse , the more uneven distribution of sand strata in the more serious exploitation ; different types of formations , formations cement cementing force of the fluid within the trap adhesion , friction and gravity stratigraphic formations bond strength of particulate matter formation between particles of the decision itself is different , smaller formations bond strength , sanding more serious. Depending on the size of the bond strength stratigraphic formations of sand divided into three types :
( 1 ) flow sand formations : the unconsolidated formations . No cement between the particles , the bond strength depends on only a small stratum of sand and ambient fluid adhesion strength trapping pressure , formation sand under certain conditions can flow.
When the event of such formations prone borehole collapse , causing sticking , buried underground drilling accident , proppant manufacturers openhole completions with conventional gravel pack method, prone to the phenomenon of formation sand spit , resulting in lower reservoir sand buried screens less than borehole bottom sand plug , gravel and sand strata intermixing , and even the formation sand into the cavity through a sieve slit screens , stuck pipe caused the accident . Therefore , the packer must grit , high density and thickening special technical measures completion completion fluid.
Immediately after the operation and continuous sand , sand wellhead relatively stable.
( 2 ) partially cemented strata : less cement content of such formations , formation sand partially cementation poor, low intensity . Such formations encountered while drilling , drilling fluids can be added in a suitable temporary blocking agent to stabilize the wall , to prevent formation collapse , avoiding the sharp drop in speed and downhole drilling accident, under certain conditions , you can use an openhole gravel pack completion method wells.
This formation wells through formations in the vicinity of borehole spalling in the mining process , the gradual development of the formation of caves. Flaking pieces easily fill the wellbore formation sand into the bottom pocket , plug tubing, buried reservoirs . After the oil sand production rule as shown in Figure 6-2 , the performance of the large amount of sand volatility changes . If we do not control them , then producing layer near mudstone, shale sandwich out of the hole increases due to peeling , causing the near-wellbore region of mudstone , shale and sandstone three kinds flaking material intermixing , permeability decreased production decline . If left unchecked, may cause formation collapse , drop cap , casing damage , serious consequences wells scrapped .