Abstract
In the past five years, shale gas development had made great progress in Longmaxi shale of Southwestern China. Different from the North American shale, the Chinese shale reservoir has the characteristics of deep and multi-stage tectonic movement, which presents a huge technical challenge for economic development. Especially, great horizontal stress difference resulted it was difficult to create complex fracture network during hydraulic fracturing. So it is vitally important to provide a workflow of geo-engineering integrated fracturing design for Chinese shale economic development.
In this paper, a workflow of geo-engineering integrated fracturing design is proposed to optimize fracturing parameters, which is based on geology modeling and formation quality evaluation. This workflow contains stress and natural fracture prediction and modeling, perforation sweet spot optimization, stimulated fracture network and productivity prediction, treatment parameters optimization, and fracturing design evaluation. In order to improve the use of convenient and complex data processing of fracturing engineers, the simulation system of shale stimulation (CQ-4S) is developed which is based on this workflow.
The applications of workflow and system during more than thirty shale gas wells in Southwestern China illustrated that the workflow and system could effective optimize design of shale stimulation, which contains some advice of perforation sweet spot, cluster spacing, treatment volume of fluid and proppant. The predicted fracture network had good agreement with microseismic data, and predict well performance also had good agreement with real-measured results. According to fracturing analysis and evaluation of more than thirty cases with this workflow and system, we also recognized that there were 13 geoengineering parameters which determined fracturing effectiveness of Chinese shale gas.
The results of this paper provide some guidelines for shale gas stimulation design and evaluation in Southwestern China, which is also can provide reference for other emerging shale gas development.