固井滑套分段压裂技术在大牛地气田的试验应用

APPLICATION OF CASING CEMENTING SLIDING SLEEVE STAGED FRACTURING TECHNOLOGY IN DANIUDI TIGHT GAS RESERVOIR

大牛地气田属典型的低孔、特低渗致密砂岩气藏,前期采用水平井裸眼封隔器分段压裂取得较好效果,但该工艺压裂裂缝起裂位置不明确,压后无法实现井筒全通径,为进一步提高压裂改造的针对性,试验了固井滑套分段压裂工艺。该工艺将专用固井压裂滑套与套管连接并按照气藏分析确定的压裂位置一趟管柱下入井内固井完井,并通过分级投球、液压或者机械等方式打开固井压裂滑套,进行分段压裂作业。该工艺具有固井完井分段压裂一体化管柱、压裂级数不受限制、压裂裂缝起裂位置明确、改造地层针对性强、作业速度快、压后井筒全通径等优点。A井应用表明,固井滑套分段压裂工艺1 d可完成10段压裂,压后井筒全通径,为大牛地致密低渗砂岩气田有效开发探索了一条新途径。

The Daniudi gas field,a tight sandstone gas reservoir with the characteristics of low porosity and special low permeability,got a good staged fracturing effect by using the horizontal well open hole packer,However,this technology has its own shortcomings,as the uncertain fracture initiation position and non-full bore hole. In order to improve the pertinence of hydraulic fracturing,the casing cementing sliding sleeve staged fracturing technology was tested,which makes a connection of cementing sleeve and casing,then being placed into the certain position by gas reservoir engineering analysis to realize cementing and completion. This casing cementing sliding sleeve staged fracturing technology has three methods to open the sliding sleeve,such as staged ball-throwing type,hydraulic type and mechanical type. Meanwhile,this technology has many advantages,such as an integrated pipe string for casing cementing staged fracturing,unlimited fracturing stages,definite fracture initiation position,high pertinence of hydraulic fracturing,rapid fracturing speed and full bore hole after fracturing. Field application in A well showed that this technology could complete 10-interval fracturing within one day under normal condition. Besides,it could provide a full bore hole after fracturing.