New Well Type of Shale Gas Development

Abstract:

China has large population with insufficient water and land and varied geomorphology, shale gas reservoir has the characteristics of deep burial, high dimension, low permeability and poor alterability. The application of horizontal well and multi-interval fracturing techniques have certain limitations in China, which are conventional techniques for shale gas development in America. For this reason, a new type of development well is proposed. Being different to traditional vertical, deviated or horizontal wells, it is formed with the main shaft and the surrounding auxiliary caves. The main shaft is designed for production, the auxiliary caves are for reservoir stimulation. The completion methods of main shaft can be vertical well or deviated well, the auxiliary caves are branch directional well or cluster wells and may be the combination of the two. For the reservoir stimulation, the cost-effective cumulative blasting technology is adopted in place of the high-cost of hydraulic fracturing; taking multi-cave in place of multi-stage fracturing and simultaneous fracturing in order to keep the continuity and effectiveness of reservoir fracture system, expand the effective drainage area and reduce the spacing density. To simulate the effect of reconstruction, an experiment was carried out on the hard concrete pavement, the result shows that by a number of caves and vibration, interconnected fissures can be produced to achieve the overall improvement of reservoir permeability.