Successful Stimulation of Dual-Lateral Producer in Ghawar Field

Abstract

This article, written by Assistant Technology Editor Karen Bybee, contains highlights of paper SPE 119675, "Case History: Successful Application of Combined Rotary-Jetting and MLT To Stimulate Dual-Lateral Producer in Ghawar Field," by Muhammad H. Al-Buali, SPE, Ibrahim H. Al-Arnaout, SPE, Ayed M. Al-Shehri, SPE, Surajit Haldar, SPE, and Saad M. Al-Driweesh, SPE, Saudi Aramco, originally prepared for the 2009 SPE Middle East Oil and Gas Show and Conference, Bahrain, 15-18 March. The paper has not been peer reviewed. Use of multilateral wells in Saudi Arabia and in the southern area of the Ghawar field 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. The full-length paper describes a unique use 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 the Ghawar field. Introduction Drilling strategy in Saudi Arabia has shifted dramatically from drilling vertical wells to drilling horizontal and multilateral wells. These wells enhance productivity by providing maximum reservoir contact. Although drilling practices and experience have progressed, there still are limitations on accessibility to the laterals for treatment or logging. Locating and accessing the individual laterals is not the end of the challenge because effective stimulation of these laterals also is challenging. Although water-based fluids are used in oil and gas fields during drilling, they still create mudcake that sometimes causes formation damage. Typical chemical-cleanup solutions for filter cake formed by water-based mud include acids, oxidizers, enzyme treatment, or a combination of these materials. Also, mechanical means such as the downhole rotary-jetting tool have been used to remove the filter cake in single horizontal wells. The advantage of rotary jetting is to eliminate the domination of the high-permeability zone on the treatment distribution by improved pinpoint jetting. The system also replaces traditional jetting and wash tools that do not have rotating capacity. For the first time in the Middle East, Saudi Aramco has successfully pilot tested a combined rotary-jetting tool and MLT. Well Completion and History Well A was a vertical oil producer drilled in the early 1990s. The well produced dry oil and started producing water after several years of production. This was followed by a decline in production, and the well eventually ceased flowing a few years later. Then, Well A was worked over for sidetracking as a dual-lateral horizontal open hole to have maximum reservoir contact and restore the well to production. The well was completed with two laterals across the pay zone. Lateral-1 was drilled to a total depth (TD) of 10,270 ft measured depth (MD), and Lateral-2 was branched out from 7,255 ft and drilled to a TD of 9,843 ft MD. The well potential was approximately 10,500 BOPD, but it was produced at a restricted rate of 7,000 BOPD of dry oil. Later, the well started producing a small amount of water, then it ceased to flow because of formation damage.