超低渗透低压油藏水平井转变开发方式试验

鄂尔多斯盆地长X油藏压力系数低、储层物性差，前期采用超前注水七点井网长水平井开发，初期单井产能有所提高，但含水率上升快。为了避免人工裂缝与腰部水线窜通，压裂时往往会有约200 m水平段无改造而浪费。同时，因超前注水油井生产等停较长时间，影响了新井贡献时率。借鉴致密油的开发经验，采用逆势思维的方法，提出“停止超前注水、减少注水井数量、减少水平段长度、密切割压裂和体积压裂相结合”转变开发方式的思路，优化注水方式、开采井网、水平段长度和压裂工艺参数等，并开展现场试验。结果表明：形成的五点法短水平井密切割体积压裂开发技术效果较好，地层能量得到快速补充，含水率快速上升得到控制，缩短了油井因超前注水产生的等停时间，提高了新井贡献时率30%，减少的注水井数量和水平段长度使成本节约20%，每百米水平段产能较前期增加88%，该成果为同类超低渗致密储层高效开发提供了技术支撑。

Transformation of development model of horizontal wells in ultra-low permeability and low-pressure reservoirs

Chang X reservoir in Ordos Basin has low pressure coefficient and poor physical properties. Advanced water injection in seven-spot pattern and long horizontal well development can lead to sharp water cut increase and high single well production rate. what's more,fracturing in order to avoid the cross between artificial fracture and the waist-water-line will make about 200 m useless because of no stimulation. Meanwhile,long shut-in time needed for advanced water injection affects the contribution of production wells. To solve the problem, based on experience of tight oil reservoir development and opposite development theory,this paper proposed a new development concept of none advanced water injection,less injection wells, shorter horizontal length, combination of volume fracture technique and dense tube cut method. After field experiment as well as optimization and research of well pattern adaptability,energy supplement,horizontal length and fracturing parameters,it shows that the proposed theory in five-spot pattern can provide better development effect,taking advantage of quick energy supplement,efficient water cut control and longer oil wells production time by 30%.This development method can contribute 20% cost reduction and 88% increase of total oil production per hundred meter. The research can be further applied and provide technical guidance to the tight reservoir development.