新场气田易砂堵气藏加砂压裂技术

SAND FRACTURING TECHNOLOGY FOR GAS RESERVOIR WITH SAND PLUG IN XINCHANG GAS FIELD

川西新场气田中侏罗统沙溪庙组J2s21、J2s23气藏是典型的低渗透致密砂岩气藏,由于地层致密坚硬,施工中经常出现砂堵和泵压异常偏高的情况,导致加砂压裂施工失败。为此,从理论上分析了在该气藏进行低砂比压裂改造的可行性和低砂比压裂优化设计的原则,认为采用常规的压裂技术不能使地层对裂缝的供给能力与裂缝对井筒的供给能力相匹配,从而造成裂缝导流能力的浪费,而低砂比压裂工艺技术克服了常规压裂技术适应性差和施工容易砂堵等技术难题,取得了良好的增产效果和经济效益,在上述气藏的开发中具有良好的推广应用前景。

The gas reservoirs of Middle Jurassic Shaxi-miao group,J2s21 and Js23,in Xinchang gas field of west Sichuan is a typical low-permeability tight sandstone gas reservoir.Due to its tight and hard formation,sand plug and abnormal high pump pressure occur frequently and result in failure of sand fracturing operations.Therefore,based on theoretical analysis on the feasibility and optimization design of low proppant concentration fracturing,this paper thought that conventional fracturing technology will cause the great loss in flow conductivity of fractures because the supplying capacity of formation to fractures can not match with that of fractures to wellbore;while the fracturing with low proppant concentration has overcome bad adaptability and frequently-happened sand plug by conventional operations,increasing both the production and economic benefit.This paper recommends such this fracturing technology to be widely applied in gas reservoir development with bright prospect.