New model for fracturing fluid leakoff in naturally fractured gas fields and its application;

The model is established that fracturing fluid leakoff in coal bed with/without the reopened natural fractures, and its analytical solution is present.

However, few relevant researches have been done for acid fracturing due to the complicated leakoff mechanisms.

Present computation model of filtration for horizontal fracture,established for homogeneous reservoir,could not be used for filtration calculation of fracturing fluid in naturally-fractured reservoir.

When acid flow along the fracture, the wormhole was developed because some of rock pore or nature fractures are denuded by the acid, thus the filtrateloss of the acid mostly occurs in wormhole.

Accurate understanding and calculating the total fracturing fluid leak-off coefficient is both key problem to the fracturing design and the important matter to the analysis after fracturing.

Therefore, it must be considered the effects of acidizing wormholes on acid leak-off in naturally-fractured reservoirs.

Two matter is often encountered in Carboniferous system layer when hydraulic fracturing: (1) unlocking of naturally fractures leads to the increasing of leak-off;(2) The producing of multi-fractures induces friction resistance to bring.

Numerical simulation of fracturing-fluid filtrate loss in natural fracture type reservoir;

Preparation and characterization of CTAB/polymer composite modification of montmorillonite as filtrate reducer;

A heat-resistant filtrate reducer was synthesized using 2-acrylamido-2-methylpropane sulfonic acid(AMPS),acrylamide(AM) and acrylic acid(AA) as raw materials and ammonium persulfate/sodium bisulfite as initiators by aqueous solution polymerization.

A zwitterionic polymer filtrate reducer PMADA were synthesized by copolymerizing in aqueous solution with DMDAAC,AMPS,MA,and AM as monomer and a redox initiator.