Ultrasound-guided percutaneous microwave ablationfor small liver cancers adjacent to large vessels：long-term outcomes and strategies

Objective The aim of the study was to evaluate the long-term efficacy and safety of percutaneous microwave ablation(MWA) for small hepatic cancers adjacent to large vessels and to investigate the treatment strategies.Methods From March 2009 to July 2015,a total of 86 patients with 94 tumors underwent ultrasound(US)-guided percutaneous MWA,with pathologically proven or clinically diagnosed liver cancers measuring ≤ 3 cm in diameter and located ≤ 10 mm from a major vessel(n = 94).Regular follow-up after MWA was performed to assess treatment efficacy and perioperative complications.Results The complete ablation rate at 1 month after MWA was 93.3%(84/90).The 6-,9-,12-,24-,36-,48-,60-,72-,and 84-month local recurrence rates were 2.4%,2.4%,3.7%,6.6%,8.4%,8.4%,8.4%,8.4%,and 8.4%,respectively.There were no major complications.The perioperative special complication rate was 5.32%(5/94),including 3 cases of moderate liver function damage and 2 cases of limited sub-capsular hematoma.Conclusion Percutaneous MWA for small hepatic cancers adjacent to large vessels is feasible,effective,and safe with an acceptable rate of complications.The key point is to strictly follow operative indications and adopt proper treatment strategies.

Gas in place and its controlling factors of deep shale of the Wufeng–Longmaxi Formations in the Dingshan area, Sichuan Basin

Recently, deeply-buried shale (depth > 3500 m) has become an attractive target for shale gas exploration and development in China. Gas-in-place (GIP) is critical to shale gas evaluation, but the GIP content of deep shale and its controlling factors have rarely been investigated. To clarify this issue, an integrated investigation of deep gas shale (3740–3820 m depth) of the Lower Paleozoic Wufeng–Longmaxi Formations (WF–LMX) in the Dingshan area, Sichuan Basin had been carried out. Our results show that the GIP content of the studied WF–LMX shale in the Dingshan area ranges from 0.85 to 12.7 m^(3)/t, with an average of 3.5 m^(3)/t. Various types of pores, including organic matter (OM) pore and inorganic pore, are widely developed in the deep shale, with total porosity of 2.2 to 7.3% (average = 4.5%). The OM pore and clay-hosted pore are the dominant pore types of siliceous shale and clay-rich shale, respectively. Authigenic quartz plays a critical role in the protection of organic pores in organic-rich shales from compaction. The TOC content controls the porosity of shale samples, which is the major factor controlling the GIP content of the deep shale. Clay minerals generally play a negative role in the GIP content. In the Sichuan Basin, the deep and ultra-deep WF–LMX shales display the relatively high porosity and GIP contents probably due to the widespread of organic pores and better preservation, revealing great potentials of deep and ultra-deep shale gas. From the perspective of rock mechanical properties, deep shale is the favorable exploration target in the Sichuan Basin at present. However, ultra-deep shale is also a potential exploration target although there remain great challenges.