Experimental and Numerical Study of the Stability of Radially Jet Drilled Laterals in Chalk Reservoirs

One way of increasing hydrocarbon production is to extend the lateral reach of the wellbore by lateral holes. The approach bypasses the potentially damaged near-wellbore area, thus improving the productivity of the well and enhancing the swept area. This has become feasible by a new technology called Radial Jet Drilling (RJD) technology, in which, relatively long, small-diameter laterals can be jetted radially from the main wellbore. However, the success of this technology very much depends on the long-term stability of the laterals under dynamic reservoir conditions.

The objective of the present work is to evaluate which geometry of the lateral hole provides the most stable production as well as to define the limit of the rock material properties that withstands lateral hole collapse. To do so, a set of advanced laboratory experiments are performed on two distinct outcrop chalks from Austin (US) and Welton (UK) that are analogues to the reservoir chalk in the North Sea. Based on rock mechanics and jetting experiments, numerical modelling of jetted hole behaviour is implemented and analysed for the stability in the finite element (FE) software Abaqus.