“Multi-Discipline Approach to Increasing Production in Organic Rich Shales”
Drilling horizontal wells is the common mode of operation for field development in permeability-challenged unconventional reservoirs such as organic shale. Assumptions are made regarding the homogeneity of the reservoir as wells are drilled away from the vertical pilot well. It is assumed that the reservoir characteristics remain uniform and also that the structure is known to remain in a constant orientation based on the dip information at the pilot wellbore. Experience tells us that these assumptions can lead to wells placed out of zone and in rocks with much different reservoir quality and stress magnitude, which can adversely affect the production potential of the well. With the high cost of drilling and completing these wells, it is generally economically beneficial to do some evaluation of the lateral to ensure proper placement of the well and also the optimal placement of completion zones along the lateral. Lateral measurements and petrophysical interpretations can be used to define variations in reservoir quality (RQ) and completion quality (CQ), which can then be used to optimally place perforation clusters in similar rock to increase production when compared to peer geometric wells. The integration and interpretation of pilot and lateral wellbores with a geological structure component is defined as geology quality (GQ). A methodology to integrate data from many sources enables a better understanding of the variability and structural challenges of these complex reservoirs. This integrated methodology has been refined using lessons learned from various case studies showing increased production when compared to geometric completions.