New Algorithm to Quantify Productivity of Fishbone Type Multilateral Gas Well

Abstract Due to the increase of global gas demand and the evolution of tight and shale gas development, thousands of multilateral gas wells have been drilled in the last decades. A multilateral well is defined, in general as a well with multiple branches in the lower borehole targeting oil and gas reserves in the same or different strata. These branches are called laterals. Multilateral wells with the laterals drilled out from the main horizontal wellbores at the same elevation are called fishbone wells. Multi branched wells are very effective in many different aspects such as reducing the development cost, improving sweep efficiency and maximizing recovery in oil and gas reservoirs. In this paper, a new empirical algorithm to quantify the productivity of fishbone type multilateral dry gas well is proposed. A reservoir commercial simulator was used to simulate the gas flow through a multilateral dry fishbone type gas well. Different well and reservoir parameters such as number of laterals, permeability ration (kh/kv), length of lateral sand lateral spacing have been changed and their effects on the well Inflow Performance Relationship (IPR) were evaluated and incorporated into the new IPR model. It was found that the IPR curves are strong function of the number of well laterals (n), the permeability variation and lateral length. Statistical software was used to perform nonlinear regression and generate a new empirical IPR correlation of Vogel-form to describe the productivity and well performance of a fishbone type multilateral dry gas well. Finally, detailed model verification was done through a comparison of data generated with the new empirical correlation and data generated from a commercial well performance software using real field data with acceptable match.