OPTIMIZATION AND DESIGN OF SEPARATE LAYER FRACTURING IN TIGHT LOW PERMEABILITY SANDSTONE GAS RESERVOIR: AN CASE STUDY

Tight sandstone reservoirs, widely distributed in the Sichuan Basin of China, are the significant gas exploration and exploitation area and have a profitable development prospect. Separate layer fracturing of vertical well is an indispensable technology to unlock the production potential and enable commercial productivity for tight reservoirs. This paper takes well X located in Zhongjiang County as an example to carry out separate layer fracturing design, aiming to provide an insight for efficient development of tight sandstone reservoirs. The results of laboratory experiments mainly achieved the following findings: 1. The average porosity and permeability of target formation are 4.6% and 0.2 mD. 2. Bedding fractures are locally developed, while overall structural fractures are underdeveloped. 3. The main mineral components are quartz, rock debris, a small amount of feldspar and carbonate cement. 4. Poisson's ratio and Young's modulus are 0.18 and 23 GPa, respectively. Moreover, the log interpretation analysis shows that the classification of geological and engineering sweet spots are III and II, respectively. The calculated breakdown pressure is mainly distributed at 107-120 mPa. Furthermore, numerical simulation shows that temporary plugging fracturing technology can achieve the uniform propagation of fractures in segment. The post-fracturing production of well X reaches 50,000 m(3)/d, marking a breakthrough in exploration for tight sandstone of Xujiahe Formation.