Research and Experiment on Differentiated Composite Transformation Technology in the Saline Water Spring Block of the Qaidam Basin

The Xianshuiquan block is located in the Qaidam Basin. The geological structure of this area is complex and diverse, influenced by multiple tectonic movements, forming a complex and unique structural morphology. The parameters such as porosity and permeability in the region vary greatly. Some areas have relatively high porosity in the reservoir but low permeability, showing obvious low-permeability characteristics. In contrast, in some areas with well-developed faults or more active structures, the permeability of the reservoir increases, but it is also accompanied by complex fluid migration channels. This non-uniformity of reservoir properties is one of the key technical challenges in oil and gas exploitation in this block. The current measures have a short effective period and are not very effective, which puts forward higher requirements for the production increase and efficiency improvement through fracturing. Combining successful cases of shale oil and complex reservoir fracturing at home and abroad and the experience of unconventional reservoir volume modification in the Qaidam Basin, the characteristics of the Xianshuiquan block reservoir and the history of measure modification were analyzed, and the difficulties of measure modification were evaluated. Through on-site construction, two composite fracturing modification measure schemes, namely “shale oil modification and low-permeability complex fracture network modification”, were optimized and formed, providing new ideas and methods for the modification of tight reservoirs under complex conditions.