Low Porosity And Low Permeability Layer Composite Fracturing Technology

Hydraulic fracturing technology has been researched for a long time both in domestic and abroad and got a good result. Hydraulic fracturing technology is a combination production technique combined with the science of petroleum geology, fluid mechanics, solid mechanics and chemistry. Post fracturing deliverability modeling on hydraulic fracturing in fractures containing natural fractures has always been a difficulty of numerical modeling. The main cause is that fluid filtration in formations occured both in hydraulic fractures and natural ones and the permeability differed in fractures. This article no longer regards the formation permeability as a constant in post fracturing deliverability modeling, in which fluid and solid coupling and the affection of natural fractures to deliverability has also been considered. In consideration of the factors such as multi-phase fluid filtration, the presence of hydraulic fractures, injection and production well net, rock elastoplasticity deformation, porosity and permeability changes with stress field, the coupling of reservoir fluid filtration and fractures fluid filtration, the coupling of fluid filtration and rock filtration and so on, the basic theory of elasticity, plasto elasticity, lithomechanics and fluid mechanics in porous medium has been applied to establish various kinds of numeric model about fluid solid coupling filtration. Then mathmatics equations of fluid solid coupling were differed and computed and an example analisis was given. The result has demonstrated that the established model mentioned in this article can be used to analyse the rule of reservoir crustal stress, rock morphotropy, fluid pressure, porosity and permeability alternation with time and interspace and its effect to production. The improvement of fracturing stimulation mechanism has settled a more complete theory base for optimizing fracturing program.In order to enhance the reliability of fracturing selection of wells and formation, overcome the uncertainty and inaccuracy resulted from artificial factors, we have developed a set of artificial intelligence system of fracturing well and formation selection on the basis of fracturing wells' data in Zhong Yuan Oil Field over years. This system has applied two techniques of numeric statistics and neural net into fracturing selection of wells and formations according to the present fracturing data in target areas and established non-lineal multi parameter model building module of fracturing effectiveness and non-lineal multi parameter intelligence prediction module of fracturing effectiveness, a non-lineal multi parameter prediction model building and identification system aim at intelligence wells and formations selection. On the basis of stimulation mechanism and artificial intelligence wells and formations selection research, this article has also researched fracturing optimizing design and mating fracturing techniques. The optimizing fracturing design chiefly includes fractures parameter optimization of fracturing wells, the volume of pre-conditioning fluid and preflush, the optimization of pump parameter and program, the optimization of fracturing technology parameters (Optimizing various kinds of proppant, concentration, volume and program and the adding way to optimize the reasonable operation parameters so as to improve the fluid diversion in natural formation fractures and main fractures). A mating fracturing technology includes high proppant concentration fracturing, the annulus fracturing technique in small tubing, fractures height control technique and quick flowing technique of fractures forced closure. The wide application of a...