大牛地气田产气剖面特征的认识及思考

Understanding and thinking of gas production profile characteristics in Daniudi gas field

大牛地气田属典型的低孔、特低渗致密砂岩气藏,自上而下发育七套气层,2012年以前采用直井开发,之后采用水平井开发.为进一步明确水平井不同阶段的各段产气特征,不断优化压裂工艺及合理生产制度,选取部分有代表性直井和水平井,开展产气剖面测试.结果 表明,气井生产是逐层段动用、接替开发的动态变化过程,其中多层合采的直井生产一定时间后,主力层会发生转变,渗透率、全烃含量和地质储量是影响转变的主要因素;水平井生产过程中,各段贡献率不一致,建议选取新投产水平井在投产90 d内、投产180~200 d各测试一次、之后每年测试一次,明确水平井全生命周期产出规律.

Daniudi gas field is a typical tight sandstone gas reservoir with low porosity and extra low permeability and seven sets of gas layers developed from top to bottom. Before 2012, the vertical well development was adopted and followed by the horizontal well development. In order to further define the gasproducing characteristics of each member in different stages of horizontal wells, the fracturing technology and reasonable production system were continuously optimized, some representative vertical wells and horizontal wells were selected to carry out gas-producing profile test. The results show that gas well production is a dynamic process of producing and developing successively. After a certain period of time, the main stratum will change, and permeability, total hydrocarbon content and geological reserves are the main factors affecting the change. In the horizontal well production process, the contribution rate of each member is inconsistent. It is suggested to select a new horizontal well within 90 d of production and 180 ~ 200 d of production, and then test it once a year, so as to clarify the production rule of the whole life cycle of horizontal wells.