Offshore of southeastern Vietnam, 16/20 HSP was used in “near-TSO” designs to maximize conductivity. Ramps to 10 lb/gal were executed, and well productivity increased 5-fold from initial rates, and over twice the acidized rate
The first hydraulic fracturing of wells in Vietnam were successfully performed Offshore in the Bach Ho (White Tiger) Oil Field. Near-tip-screenouts rather than tip-screenout treatments were performed. The goal of the project was to improve production from existing wells rather than drill new wells and reduce the cost per barrel produced. This case study involves wells with multiple perforated zones completed in the Oligocene sandstone. Zones were selectively fractured in order to optimize production. A detailed description candidate selection, design, execution and evaluation processes are presented.
The Bach Ho field has been producing for 8 years but not at its potential due to various reasons including drilling and completion fluid damage. Although acidizing was an option for damage removal, hydraulic fracturing was selected as a way to bypass near-wellbore damage and generate a negative skin. Production simulators were used to quantify postfrac production. Due to suspected high closure stress, high strength proppant was selected and ramped in a high temperature fracturing fluid. Calibration treatments were conducted on several wells to quantify fluid leak- off, fracture height and Young's modulus. Based on the results of the calibration treatment, fracture designs were modified. As predicted by computer simulation, near-tip-screenouts occurred as planned.
The treatments were performed using a work boat with skid pumping/blending equipment, a computer monitoring/operation center and a laboratory. Strict QC procedures were followed to ensure the quality of all products.
Postfrac well tests results and production data are presented. Overall, the fracturing campaign was very successful with wells showing negative skins and up to a five fold increase of production in agreement with systems analysis predictions.
Author(s): L.V. Hung, N.T. San, A.G. Shelomentsev, J.A. Tronov, D.D. Lam, VIETSOVPETRO; R.L. Thomas, T. Fox, C. Bisdikian, Schlumberger Dowell
Paper Number: SPE 29284