The practice and knowledge of Maokou-Qixia Formation depth: Acid fracturing in the Hechuan Tongnan regione

Abstract

The Maokou Qixia Formation in the Hechuan Tongnan region is characterized by tight reservoirs, high pressure, high temperature, high sulfur content, multiple layers, and strong heterogeneity, Mainly using highly deviated wells in conjunction with general acidification to achieve production, although certain stimulation effects have been achieved, there are also problems such as uneven acid distribution, poor targeted acid fracturing technology, large production differences between wells, and rapid production decline. In order to improve the development effectiveness of the Hechuan Tongnan area, based on the physical characteristics of the Maokou Qixia Formation reservoir in the Hechuan Tongnan area, Combining the influencing factors and process research of deep acid fracturing transformation, through experimental evaluation of acid corrosion effect and crack simulation, a set of deep acid fracturing transformation process with alternating injection of “high and low viscosity gelling acid+turning acid” as the core has been explored and formed. This technological achievement has increased the volume of vertical and horizontal acid fracturing transformation, and has been applied in HS6 on-site for 5 levels, with a tested daily gas production of 118.2×104 m3, The production increase effect is significant, with 100% effective rate for deep acid fracturing transformation and 100% effective rate for production increase. This provides a theoretical basis and technical guidance for the deep acid fracturing transformation of the Maokou Qixia Formation in the Hechuan Tongnan region.