徐深气田火山岩气藏水平井优化设计

Horizontal Well Optimization Design for Volcano Rock Gas Reservoirs in Xushen Gas Field

徐深气田D区块属于深层大型低渗透火山岩气藏,岩性、岩相横向变化快,有利相带延伸范围有限,气藏底部普遍发育水层;储层物性差,单井产能低,气井以压裂投产为主,部分直井压裂后产较多的地层水。为了试验研究应用水平井技术控制底水、提高气藏单井产能的可行性,探讨这类气藏的有效开发模式,提高其储量动用程度和整体开发效益,在该区块开展了火山岩气藏水平井开发先导性试验,通过开展气藏精细描述、三维地质建模、储层地质条件适应性评价,地质、地震和气藏工程等多学科优化设计论证,优选有利区带,针对Ⅰ类火山岩储层部署1口水平井,完钻后采用筛管完井,测试求产,日产气达到55.5×104 m3,无阻流量高达165.9×104 m3/d,是区块内同层位直井无阻流量的5.0倍,取得了明显的增产效果。开发试验证实应用水平井技术开发Ⅰ类火山岩储层是可行的,可在Ⅰ类火山岩储层中推广应用水平井技术,同时可探索利用水平井开发Ⅱ、Ⅲ类火山岩储层。

D block in Xushen Gas Field belonged to a deep and large volcanic gas reservoir with low permeability,where lateral changes of lithology and lithofacies were fast,favorable facies belt extended in limited range,aquifer layers were generally developed on the bottom of the reservoir;reservoir physical property was poor with low productivity of a single well and fracturing production was dominated in the gas wells,In some of the straight wells after fracturing,more formation water was produced.In order to research the application of horizontal well to control bottom water in the gas reservoirs,improve the feasibility of productivity of single well,the effective development mode was studied for improving the producing degree of reserves and the whole development efficiency,a pilot test of horizontal well development for volcanic rock gas reservoirs was launched in the block,through the demonstration of fine gas reservoir description,3D geological modeling,the evaluation on geological conditions of reservoir adaptability,geological,seismic and gas reservoir engineering and other multi-disciplinary optimization design,the beneficial zones were optimized,according to Type I volcanic rock reservoir,1 horizontal well was deployed and drilled for screen pipe completion,testing and production,daily gas production was up to 55.5 × 104m3,open-flow capacity was up to165.9 × 104m3/d,it was the5 times of the straight well open-flow in the same block,obvious production increase was obtained.The development test proves that the application of horizontal well in the development of Type Ⅰvolcanic rock gas reservoirs is feasible and be introduced in TypeⅠvolcanic rock gas reservoirs,at the same time,the application of technology for the development of Type II and III reservoirs can be explored.