江汉油田盐膏层套管损坏原因分析

江汉油田潜江组盐膏层比较发育,盐层在纵向上与泥岩组成的韵律层多达82个,存在多套压力层系,构成了潜江组复合盐膏层。由于盐膏层井径不规则,固井时水泥浆容易窜槽,导致固井质量差,油、水井套管较易损坏。为确保油田产量,每年需在同区块钻相应数量的调整并以补充因套管损坏等原因报废的井。针对套管损坏的状况,在广泛调查的基础上,运用地质力学的方法,从地质力学及岩石特征、盐膏层套管柱设计、注水泥质量因素等方面分析了套管损坏的原因及作用机理,提出了改进意见及采取相应的措施,为盐膏层蠕变评价和正确设计套管提供了理论依据。

Analysis of the Casing Damage Causes in the Evaporite Bed of Jianghan Oilfield

Large scale of evaporite bed exists in Jianghan oilfield, and as many as 82 rhythmites formed by the e-vaporite beds and shales stretch along the ordinate,while there are multiple pressure layers. During well cementing in this area, cement channeling usually occurs due to the non-regular hole diameter in the evaporite bed ,which results poor cementing quality and finally leads to serious casing damage. Adjustment wells have to be drilled to renew the abandoned because of casing damage in this area. The casing damage causes and their mechanisms is investigated and analyzed by the way of geomechanics, from such aspects as rock characteristics, casing string design in the evaporite bed,and cementing quality. Some recommendations and remedial measures are presented, and this provides a theoretical background for evaluation of evaporite bed creeping and accurate casing designing.