Facability Evaluation Of Shale Gas Reservoirs Based On Well Logging Data

Fracturing is an effective means to improve the permeability of shale gas reservoir.But not all the sections are fit for fracturing operation.Preliminary evaluation of the intervals,therefore,not only can have a more clear understanding on the available resources in the process of production,but also can make a reasonable choice for selecting fracturing zone,making fracturing to achieve the best effect.According to the current understanding,when fracturing,complicated fracture network rather than a single of wing-type fracture can be more effectively transform shale reservoir.When shale reservoir fracturing can form a complicated fracture network,certain brittleness,more development of the natural fracture system,a lower natural fracture open net pressure and favorable tendency Angle of facture is needed.In selecting fracturing zone,lower formation breakdown pressure and high gas content are also needed to consider.In addition,it is better that the height of the fracturing ican be controlled within the range of design.For the convenience of actual evaluation,the brittleness index,the formation breakdown pressure and the net opening pressure of natural fractures can be combined into fracturing index.The index comprehensive reflects the difficulty of shale reservoir forming complex fracturing network in a certain degree of nature facture development.Compared to rock testing experiment,well logging has the characteristics of large amount of data acquisition,more economic and can form the continuous profile.In this paper,using core testing experiment combined with 1og section,we evaluate the well.Jian 111,as an example,systematically.Well Jian 111 buried shallow and its mud shale section is thick.Although the upper also has good nature fracture development and brittle characteristics.But compared with the lower(610m-640m),the upper’s fracturing index is worse.The reason is that even though the lower’s brittleness is bad,but it has lower formation breakdown pressure and net opening pressure of natural fractures.And lower fracture and ground stress has a better match and also more likely to be opened in the fracturing.At the bottom,the gas content and physical characteristics,is also much better than the upper.