Innovative Use of Horizontal Wells in Mature Fields Boosts Production/Reserves

Abstract

Abstract Many Gulf of Suez fields operated by the Gulf of Suez Petroleum Co. (GUPCO) were discovered in the early 1970's and are in the mature stages of depletion, requiring application of advanced technology and multi-discipline focused teams to identify bypassed oil. These fields are structurally and geologically complex, with bypassed oil potentially underlying faults or gas caps in highly stratified reservoirs of varying rock properties. Significant vertical well development often precludes conventional application of horizontal well technology. Non-conventional application of horizontal drilling in the late stages of depletion has aided development of resources where vertical wells are not viable. Several field examples are discussed and illustrate the innovative use of horizontal wells to boost production and reserves. Horizontal wells are used to drill under faults to intersect multiple layers of thick reservoirs and to explore areal extension of reservoirs. Horizontal wells are also used to intersect appropriate reservoir layers in gravity drainage and gas cap reservoirs to improve rate and recovery. In each of these cases, multi-discipline teams identified the development potential, planned wells to meet objectives, and used real time data to ensure objectives were met. The concepts used in the these field cases are being applied to other GUPCO fields as multi-discipline teams are assigned to study them. Success in these applications of horizontal wells along with conventional application of horizontal wells is helping GUPCO to boost production and increase reserves from mature fields. Introduction Three field examples are presented where horizontal wells are used to boost production and increase recovery in mature fields where significant vertical well development has occurred. In each field, multi- discipline teams use geological modeling and mapping software, updated petrophysical and geological interpretations and apply reservoir simulators to determine the field structure and location of trapped oil. These examples include the July field where a 1200 foot horizontal well was successfully drilled to recover oil trapped under a low angle fault (85 degree) in high (42 degree) dipping beds. The use of structural computer mapping software resulted in drilling the well within 50 feet of a fault over the horizontal section and allowed well path modification based on real-time geological and drilling data. In the Badri Kareem field, reservoir simulation identified an area of recoverable oil underlying a gas cap, and a horizontal well crossing several geologic layers was drilled to recover reserves. Numerous vertical wells have been only marginally successful in draining the Badri Kareem reservoir due to gas coning, channeling and underrunning problems. The well was strategically placed in the geological layers to increase rate and recovery. In the Sidki field, a horizontal well was drilled to determine the northern field extension. P. 437