The implementation of multilateral wells in Saudi Aramco, and in the southern area of Ghawar field in particular, is being increased for production and cost optimization. Accessing and stimulating individual laterals is a challenge that requires an optimum design in terms of cost, application and efficiency.
This paper will describe a unique utilization of a combined high energy rotary-jetting tool with a multilateral tool (MLT) to access and treat a dual-lateral oil producer in the southern part of Ghawar field. The main purpose of utilizing this combined tool was to acid wash the Arab-D horizontal section of both laterals with nitrified hydrochloric acid using coiled tubing (CT). The objectives of the treatment were to increase flowing bottom-hole pressure (FBHP), remove formation damage and return the well to production. The rotary-jetting tool is a high energy jetting tool that maximizes performance of treatment fluids while minimizing the need for large acid volumes. It can be run with the MLT to enable accessing and stimulating both laterals in a single trip.
The implementation of the combined tool resulted in accessing and stimulating both laterals successfully. The well was returned to production at a rate of 11,000 barrels of oil per day (BOPD). The volume of acid was reduced due to utilizing the rotary-jetting tool, which maximized fluid treatment performance. This paper will cover the whole cycle of candidate selection, job design, execution, post job evaluation and conclusion.
Introduction
Oil drilling strategy in the world as a whole, and Saudi Arabia in particular, has shifted drastically from drilling vertical wells to drilling horizontal and multilateral wells. This increasing trend is a result of enhanced productivity provided by maximizing reservoir contact. These wells have proven successful and economical for field development in oil and gas fields. Although drilling practices and experiences have drastically progressed, there are still limitations on the accessibility of the laterals for treatment or logging. During the past few years, there was a considerable advance in rigless re-entry techniques. The well intervention work can now be conducted on an individual lateral as a result of utilizing the MLT re-entry tool with CT pipe1, 2 & 3.