Modeling, Planning Allow Successful Implementation of South Texas U-Turn Lateral

Abstract

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208801, “Successful Planning and Implementation of First South Texas U-Turn Lateral,” by Riley Schultz and Joe Kiefner, Chesapeake Energy. The paper has not been peer reviewed. Legacy fields require innovative solutions for developing capitally efficient projects within highly developed acreage blocks. As another tool to improve well economics, a U-turn lateral strategy was implemented in the Eagle Ford Shale. This wellbore trajectory resulted in capturing a 9,200-ft equivalent lateral length well in a 5,000-ft-wide lease space. This successful U-turn trajectory test has created new economic project opportunities for the company and has increased optionality within challenged lease spaces across the field. Well Overview In a single U-turn well, the horizontal wellbore turns 180° to create two parallel laterals in a map-view U shape. The successful U-turn project detailed in the complete paper was the first drilled in south Texas (Fig. 1). This resulted in significantly improved economics by using a horizontal turn as a hydrocarbon pathway, rather than an additional vertical section from a new well to gain the equivalent treatable lateral length. This well followed operator standards for south Texas Eagle Ford two-casing-string well design. A 9⅝-in. casing was set to protect shallow water zones, and an 8¾-in. production section was drilled for the remainder of the well (using 5½-in. drillpipe). 5½-in. production casing was then run to total depth (TD). 8¼-in. centralizers were placed on each joint of the casing, freely floating between the collars. The production section was drilled with oil-based mud, and a standard cement job was pumped. Conventional directional tools were used for the entirety of the drilling phase. The decision was made early in the planning phase of the well to forgo fracturing the turn portion of the wellbore and instead drill into the adjacent unit to conduct the turn to maximize the amount of optimally oriented lateral footage in the unit to be produced.