川西新场气田蓬莱镇组气藏老井挖潜选井原则

川西新场气田主力气藏已进入开发中—后期,挖潜增产是维持气田效益开发的重要手段。随着高品质气层动用程度增大,原有挖潜选井标准不再适用,亟需建立新的选井选层评价标准。为此,通过对新场气田蓬莱镇组气藏典型挖潜井开展挖潜效果评价,分析挖潜层段气层品质和储量动用程度,结合单井生产情况,建立了适用于研究区现今开发特征的挖潜选井原则。结果表明,需综合考量录井、测井、地震响应、邻井动用等多因素确定挖潜井及层段,降低挖潜失利风险;在同一有利区带或同一裂缝走向选取挖潜井时,邻井井距下限为350 m,相应井距下的邻井单层累计产气量上限为0.20×10⁸ m³;次级有利微相多层合采更适用于老区中—后期开发,可增大挖潜获产几率。

Candidate Well Selection Criteria for Potential Tapping of Existing Wells in Gas Reservoirs of Penglaizhen Formation in Xinchang Gas Field,Western Sichuan Basin

The main gas reservoirs in the Xinchang gas field in western Sichuan basin have entered the middle to late stage of development, and potential tapping of the existing wells is an important means to maintain the effective development of the gas field. As high-quality reservoirs are further recovered, the original criteria of candidate well selection for tapping potential are no longer applicable to the current development situation; instead, it is urgent to establish new criteria for well/layer selection aiming at recovering the hard-to-produce reserves. The potential tapping effect of typical wells in the Penglaizhen formation of Xinchang gas field was evaluated, and the reservoir quality and reserves recovery of the target interval were analyzed. Combining with the single-well production performance, the candidate well selection criteria suitable for the current development characteristics of the study area were established. The results show that the potential tapping effect is affected by multiple factors such as well logging, seismic response and adjacent well producing, which should be comprehensively considered to reduce the failure risk in potential tapping. When candidate wells are selected in the same favorable zone or the same fracture strike, the lower limit of well spacing to a neighbouring well is 350 m, and the upper limit of cumulative gas production from a single layer of a neighbouring well with the well spacing of 350 m is 0.20×10⁸ m³. Commingled production from multiple layers with secondary favorable microfacies is more applicable in the middle to late development stages, which is beneficial for the successful potential tapping.