Understand the geological structure before drilling


Published:

2022-10-26

Hot Springs drilling is the process of drilling a cylindrical borehole with a certain depth into the ground using mechanical equipment. Before drilling a well, we must first understand the geology of the area to be drilled, such as the strength, hardness and drillability of the rock, in order to arrange the drilling operation in a scientific and reasonable manner.

  Hot Springs drilling is the process of drilling a cylindrical borehole with a certain depth into the ground using mechanical equipment. Before drilling a well, it is important to understand the geology of the area to be drilled, such as the strength, hardness, and drillability of the rock, so that drilling can be arranged in a scientific and reasonable manner.

  Influence of rock properties on drilling

  The influence of rock properties on the drilling of Sichuan water sources is mainly manifested in the influence of drilling speed and bit feed, which makes the drilling process complicated by well leakage, well blowout and stuck drilling.

  1、Clay rock formation. Mudstone and shale are generally soft and fast drilling speed, but they are easy to produce bit mud pack. Such formations are prone to absorbing free water in the drilling fluid and swelling, resulting in a shrinking well defile. With the extension of soaking time, the well wall will produce collapse and the well diameter will be enlarged.

  2、Sandstone formation. Sandstone is generally a better permeable layer, and it is easy to form thicker filter cake on the well wall, which can easily cause mud cake adhesion and jamming. In addition, the filter cake also has an impact on logging, so use drilling fluid.

  3、Conglomerate layer. Drilling in the conglomerate layer is prone to jump drilling, crappy drilling and well wall collapse.

  4、When the rock formation contains soluble salts, i.e., when drilling to gypsum layer and salt rock layer, attention should be paid to the effect on the performance of drilling fluid.