大港枣园油田高含水储层固井技术与应用

Cementing Technology of High Water-cut Reservoir in Zaoyuan Oilfield in Dagang and Its Application

针对大港枣园油田储层高含水这一特性以及现面临的固井技术难点,在完钻前循环洗井、提高井筒承压能力、钻井液性能调整、研发低温早强短候凝防窜水泥浆体系、倒浆柱结构设计等方面展开了技术研究:根据不同漏失岩性,选择不同堵漏措施;采用固井前钻井液调整技术,提高钻井液的pH,利用强碱性拆解井壁上钻井液化学结构;加入化学稀释剂,提高钻井液流变性(流型指数大于0.72),清除井壁虚泥饼;采用防窜性能好(静胶凝过渡时间12min)、失水量低(小于40mL)、候凝时间短(直角稠化)的低温早强短候凝防窜水泥浆体系;设计合理的浆柱结构,确保尾浆失重时井底当量密度高于钻井液密度0.05~0.1 g/cm^3;优化扶正器下入方式、采用复合排量顶替等配套施工措施。该固井工艺技术应用于枣园油田7口油井中,固井质量均为优质。

In view of the high water-cut characteristics of the reservoir in Zaoyuan Oilfield in Dagang and the existing cementing technical difficulties,the technical research was carried out on the aspects of circulating well washing,improving wellbore bearing capacity,drilling fluid performance adjustment,grouting column structure design,etc.before the completion of drilling,and the low-temperature,early-strength and short-waiting-on-cement anti-channeling cement slurry system was developed.According to different leakage lithologies,different plugging measures were selected;the drilling fluid adjustment technology before cementing was used to improve the pH value of the drilling fluid,and the chemical structure of the drilling fluid on the borehole wall was disassembled with strong alkali;the chemical diluent was added to improve the rheological property of the drilling fluid(The flow pattern index is greater than 0.72),and remove the false filter cake on the borehole;the low-temperature early-strength and short-waiting-on-cement anti-channeling cement slurry system with good anti-channeling performance(The transition time of static gelation was 12min),low water loss(less than 40mL),and short-waiting-on-cement(right-angle thickening)was adopted;a reasonable slurry structure was designed to ensure that the equivalent density of the bottom hole was 0.05~0.1g/cm 3 higher than that of the drilling fluid when the tail slurry was weightless;the running mode of centralizer was optimized and matching construction measures such as compound displacement replacement,etc.were adopted.The cementing technology has been applied to 7 oil wells in Zaoyuan oilfield,and the cementing quality is good.