Multistage Hydraulic Fracturing in Horizontal Wells as a Method For the Effective Development of Gas-Condensate Fields in the Arctic Region

Abstract

Currently considerable part of new oil and gas fields put into production, features structurally complex low permeable reservoirs. Under complex Arctic climatic conditions, Yamal in particular, development of gas-condensate deposits seems to be especially difficult and capital intensive task. To increase projects commercial efficiency, productivity of each gas well needs to be maximized. Classic solution here is to drill vertical well (VW) with fracture. Under complicated conditions especially when developing offshore fields, where drilling unit costs are considerably higher than in already developed oil and gas bearing regions of Russia, horizontal or sub-horizontal wells (HW) with multiple fractures can be more efficient. To evaluate process efficiency under conditions of Urengoiskoe gas-condensate field, a high resolution sector reservoir model for a single well was built. The model was used to calculate production parameters for various bottomhole design variants: vertical well with fracture, horizontal well with several transverse or longitudinal fractures. In this sector model, each fracture was explicitly simulated, and in number of models minimum width of a cell containing fracture was 5 to 10 mm, which correlated with real fracture width. Analytical calculations and simulation results, considered in this paper, are indicative for a number of typical effects for gas-condensate wells, which should be given a notice: ▪Generation of condensate bank in bottomhole formation zone, leading to well productivity decline;▪Inertial effects in fracture (Forchheimer effect) caused by high gas filtration rate and also resulting in well productivity decline;▪"Straightening’ of relative permeability curves in the areas with high fluid velocity.

Gas Condensate Banking: A Review of the Phenomenon, Accumulation, Mitigation Methods, and New Breakthrough

“… Improve the well's productivity by creating conductive paths to increase the contact between the reservoir and the wellbore (10,11).  Limitation: temporary solution.…”

Mitigation of the Effects of Condensate Banking: A Critical Review

“…Longer propped-fracture half-lengths extended the production-rate plateau. Indriati et al (2002) proposed a model that predicts the performance of hydraulically fractured gas/condensate reservoirs and adjusts the fracture-treatment design. Indriati et al (2002) found that for every bottomhole flowing pressure, there is an optimum fracture geometry that maximizes the productivity of the well.…”

“…Indriati et al (2002) proposed a model that predicts the performance of hydraulically fractured gas/condensate reservoirs and adjusts the fracture-treatment design. Indriati et al (2002) found that for every bottomhole flowing pressure, there is an optimum fracture geometry that maximizes the productivity of the well. Orangi et al (2011) found that one of the key parameters that controls the performance of hydraulically fractured wells is the surface contact area between the fracture and the matrix.…”

Recent comprehensive review for extended finite element method (XFEM) based on hydraulic fracturing models for unconventional hydrocarbon reservoirs

“…The shale revolution is referred as the bloom of shale production due to the technological improvement of horizontal drilling and hydraulic fracturing. The improvements include hydraulic fracturing in horizontal well reduced from 200 m apart to 50 m while having over 60 stages per well (Aguilera and Ripple 2012;Ignatyev et al 2011) the USA is the world's largest dry natural gas producer because of the shale gas revolution. It contributes to 20% of the world consumption, in which 40% of the supply is from shale (Sieminski 2014).…”