Technology Improvements in the Giant Manifa Field Maturation Project

Abstract

Abstract Several improvements were necessary in the Manifa giant oil field development to secure a superior or favorable business position through the deployment of value-adding technological solutions in rigless interventions. Developing a field is often like solving a typical problem of constrained optimization, in this case, to maximize field development outcomes from well intervention (leading to improved production) subject to certain constraints. The constraints in the giant Manifa field maturation project case include the state of technical knowledge to access its extended reach wells, allocated budget for intervention, or to protect the environment. Thus, the optimization problem is to determine the bundle of technologies which maximizes the field's well intervention strategy subject to technology, budget, or environmental constraints. The improvements are necessary to intervention outcomes dividends and to overcome several technical difficulties in the field. The scope of the paper is to examine technology improvements in coiled tubing (CT) reach and stimulation treatments specifically. CT reach technologies have improved to include elaborate physics or design aided simulations, which includes a consideration of friction coefficients, prediction or estimation of the lock-up points, selection of the amount, concentration, and volumes of friction reducers. The simulation offers guides to engineers with available methods for additional CT reach including the use of flowing fluid, downhole tractors and agitators, straightening, pipe size, and optimal taper of CT, drag/friction reducers, and buoyancy reduction. The advent of robust tractors that provide external pulling force on CT has increased CT reach especially on power water injectors. However, uncertainties remain in determining tractor performance, quantifying the tractor actual pulling force, fine-tuning friction coefficients, early detection of CT tags, and differentiating between CT tag and excessive drag. Stimulation treatments have improved from bull heading stimulation fluids into the wells with limited zone control. The use of CT for matrix stimulation treatments to optimize acid placements seemed to have helped to enhance diversion and acid placements through a combination of distributed temperature sensing, pressure, temperature, and casing collar locator real time measurements. Self-diverting viscoelastic diverting acid (VDA), designed to viscosify in situ as the fluid spends on the reacted formation for chemical diversion in carbonates have been optimized from 20 % HCl to 15 % HCl. Technologies which allow the measurement of bottom-hole parameters in real time enabled the conduct of deeper reach CT for enhanced stimulation practices. The improvements are significant because real-time capabilities can significantly improve the quality of well interventions and decision making in the field.