Tight sand gas development technology and practices in China

Abstract

Tight sand gas is the main type of unconventional natural gas. According to the geologic characteristics of large-scale tight sandstone gas reservoirs discovered in China in recent years, tight sand gas reservoirs can be classified into three main types, multi-layer lens overlaid tight sand gas reservoir, multilayered tight sandstone gas reservoir and massive tight sand gas reservoir. A series of development technologies for the first 2 types of reservoirs have been formed, focusing on improving individual well producing rate and reducing development cost. They drive the scale development of tight gas. As to multi-layer lens overlaid tight sand gas, the specific technologies include well location optimization, multi-stage sand fracturing, down hole choking and low-pressure surface gas gathering system. As to multilayered tight sand gas, the specific technologies include sweet-spot prediction and evaluation, integrated horizontal well development technique, and drainage gas recovery technique. There are still great challenges in tight gas development from several aspects, such as the enhancement of reserve deployment ratio and recovery ratio, the improvement of individual well producing rate, the development of new and difficult-to-produce reserves as well as the rate maintenance, and gas well management in its later stage of life cycle. Key words: tight sand gas, classification and evaluation, development technology series, technology challenges