常压页岩气水平井低成本高密度缝网压裂技术研究

Network fracturing technology with low cost and high density for normal pressure shale gas

随着能源需求量的不断增加,页岩气作为一种新型的非常规天然气资源,越来越受到关注。现阶段我国高压页岩气藏已成功实现了商业开发,但是深层页岩及常压页岩的高效开发技术仍处在探索阶段。我国的常压页岩储层主要位于盆外残留向斜,构造变形程度较强,地层压力系数为0.9~1.3,埋深普遍较浅,地层能量不足,单井压后日产量为(1~5)×10^4m^3,至今未形成商业突破。高压页岩气藏的压裂工艺措施在常压页岩改造过程中收效甚微,基于常压页岩气井改造中的难题,从射孔方式、人工裂缝控制及支撑技术、现场施工工艺及压裂材料等多方面进行优化,研究探索了配套的高密度缝网压裂工艺方案,初步实现了多簇裂缝均衡延展及多尺度人工裂缝网络。该方案在渝东南某页岩气区块一口常压页岩气井中进行了试验,压后取得了良好的改造效果。

With the increasing demand for energy, shale gas, as a new type of unconventional natural gas resource, has attracted more and more attention. At present, the commercial development of high pressure shale gas reservoir in China has been successfully realized, but the efficient development technology of shale in deep layer and normal pressure shale is still in the exploratory stage. The normal pressure shale reservoirs in China are mainly located in the residual syncline outside the basin. The deformation degree of structure is strong, the formation pressure coefficient is between 0.9 and 1.3, the buried depth is generally shallow, the formation energy is insufficient, and the daily production of single well after fracturing is(1~5)×10^4 m^3. All those problems result in the failure of commercial breakthrough so far. The fracturing technologies of high-pressure shale gas reservoirs have little effect in the process of normal-pressure shale reconstruction. Based on the difficult problems in the transformation of atmospheric shale gas wells, optimization has been carried out on many aspects such as the perforation mode, artificial fracture control and support technology, field construction technology and fracturing materials. The suitable network fracturing with high density is researched, and the multi- cluster fracture equilibrium extension and multi- scale artificial fracture network are preliminarily realized. The scheme has been tested in an normal pressure shale gas well of a certain shale gas block in southeast Chongqing, and good reconstruction effect has been obtained after fracturing.