A new first-stage fracturing process of horizontal well in unconventional oil and gas based on wetshoe cementing

In China, coiled tubing perforating, crawling device transmission perforating and toe sliding sleeve pressurization are generally adopted to establish the connection between wellbore and reservoir during the first-stage fracturing of horizontal-well staged fracturing of unconventional oil and gas. These three methods can basically meet the needs of the first-stage fracturing stimulation under the domestic current well depth conditions, but they have the problems of complex process, low efficiency, high operation cost and great construction risk. To this end, this paper put forward a new kind of first-stage fracturing process, which makes full use of the technical characteristics of wetshoe cementing. Through this process, no cement is left at the bottom of the hole by using the cementing tools such as high-performance float collar, float shoe and tailored rubber plug, and the connection between pipe shoe and reservoir is established while the wellbore safety is guaranteed, so that bridge plug and perforating gun can be pumped during the first-stage fracturing. Thus, consistent pumping in the whole borehole is realized, the fracturing construction efficiency is improve, and the costs are reduced. This process is widely applied in the unconventional oil and gas fields of the North America, which saves single-well cost by 300 thousand dollars, increases the success rate of first-stage fracturing up to over 98%, and improves the fracturing efficiency significantly.