Repeated fracturing technology

Repeated failure of fracturing technology to transform the economy has been in production wells and production wells fractured below the line of effective measures. The United States repeated fracturing theory, technology and application of mine made  a lot of effective work. Such as the U.S. Rangely oilfield operations in 891 Inoue 1700 times, many well fracturing up to 4 times, repeated fracturing success rate of 70% to 80%. North westbark unit oilfield fracturing job in repeated use of advanced technology and forced closure End  frac sand  technology, and achieved good economic benefits. Repeated fracturing can be used to transform low, medium permeability formations; applied to conventional vertical wells, highly deviated and horizontal wells.
(A) well selection principles
According to well production history, formation evaluation findings and conduct a comprehensive analysis of the dynamic development of selected wells.
① wells must have sufficient remaining recoverable reserves and the formation energy;
② previous  Hydraulic fracturing  due to construction reasons resulting in the construction fails;
③ previous  Hydraulic fracturing  production in good condition, unable to handle the entire reservoir  Hydraulic fracturing , or size is not enough;
④ after  Hydraulic fracturing  previous good results, but not to the entire paragraph to provide effective support measures to take repeated rehabilitation measures, to improve the oil section.
(2) Process Technology
Repeated fracturing generally require a higher than the initial fracture conductivity.
① high  frac sand  ratio fracturing the formation of high conductivity fractures;
② using technology to transform segments forced closure maximum filling.
There are various types of fracturing fluid used (boron crosslinked HPC, guar gum, titanium HPC crosslinking, etc.), usually with diesel fuel (5% to 50%) or as a degradable polymer fluid-loss control agent,  Proppant  grains diameter from 20/40 mesh to 12/18 mesh range.