利用VSP资料求地层破裂压力梯度

DETERMINATION OF PRESSURE GRADIENT OF FORMATIONAL FRACTURE BY VSP DATA

地质矿产部石油物探研究所

地层破裂压力梯度是钻井工程中的一个重要参数,它对于油气层水力压裂试验设计、钻井泥浆比重的合理选择和下套管程序以及固井质量控制等钻井工程都是有用的.为使VSP测井不仅能运用于物探,而且能运用于钻探,本文讨论了利用纵波震源的三分量VSP资料求取地层破裂压力梯度的方法.求出的破裂压力梯度曲线与测井曲线以及地层岩性之间有较好的一致性.本方法有可能成为求取破裂压力梯度既经济而又有效的方法.

Thr pressure gradient of formational fracture is considered as an important parameter which is of help to drilling engineering such as to deal with designing the hydraulic fracturing test of hydrocarbon-bearing formation; appropriate selection of mud weight density in drilling; casing procedure arrangement and quality control of cementing. For the purpose of not only making use of VSP well logging to serve geophysics but also enabling exploration drilling to find it applicable, the way to determine the pressure gradient of formational fracture by using 3-component VSP data of P-wave source is reviewed in the paper. There is a good coincidence between the determined pressure gradient of fracture, well logs and formational lithdogy.Possibly, the approach introduced in the paper could be a cos teffective way to determine the pressure gradient of fracture.