Integrated Reservoir Management for the Long Term - The Carpinteria Offshore Field

Abstract The Carpinteria Offshore Field, Santa Barbara, California, has produced more than 100 million barrels of oil to date. This mature field has continued operations in an economically and politically challenging environment that finally resulted in the abandonment of the field's California State leases by the lease holder. The abandoned leases, together with adjoining federal leases are now operated by an independent producer. Los Alamos National Laboratory has joined with that independent operator, Pacific operators Offshore, and with the State Lands Commission of California and the Minerals Management Service, in a unique collaborative effort to redevelop the mature field. This project is a part of a larger umbrella project, the Advanced Reservoir Management Project (ARM), that is designed to demonstrate the worth of advanced computational tools and state of the art methods for independent oil and gas producers. The Carpinteria Reservoir Redevelopment project takes a long-term view of reservoir management - as a result, our management plan includes a continuing investment in time and technology in order to better understand the reservoir. In particular, we have completed an extensive reservoir characterization and geological modeling effort that has created a self-consistent model, satisfying geophysical, geological, and engineering data constraints. We have begun the engineering-intensive flow simulation phase of the project using the current geological description of the reservoir, and are confident that our careful efforts in geological modeling will result in a reasonable reservoir flow model. Dynamic documents exist that are used by participants to stay abreast of developments on the project. These WWW pages may be viewed at http://ees.lanl.gov/EES5/arm/pooi Other sites of interest, that describe the nature of the agencies and companies involved in the project are at http://ees.lanl.gov/EES5/, http://www.mms.gov/omm/pacific/index.html, http://www.slc.ca.gov, and http://www.pacops.com Introduction The Carpinteria Offshore Field (Santa Barbara, California, Figure 1) was discovered in 1964, and has been developed over three decades with deviated drilling from five platforms. The field has produced more than 100 million barrels of oil to date. This mature field is analogous to other nearby offshore fields, and efforts to redevelop it therefore have great implications for those fields. The three mile coastal waters boundary between Federal and State leases cuts through the Carpinteria field, so that of the five leases on the field, three belong to the State, and two are Federal. Over the years, various companies have operated the leases, a situation that has resulted in a disjointed production strategy for the reservoir as a whole. 29 productive intervals have been identified and mapped in the Carpinteria reservoir, and production from these intervals has been commingled to a large degree on individual leases throughout the history of the field. In recent years, increased water cuts and sand production from unconsolidated strata, accompanied by lower production, reduced the profitibility of the field, and contributed to a decision by the operator to abandon the California State leases. Two of the abandoned State leases, together with the adjoining federal lease are now operated by an independent producer, Pacific Operators Offshore, Inc. (POOI). In the course of abandonment by the previous operator in 1996, all wells on the two production platforms in the State leases were plugged and abandoned, and the platforms were removed. The State leases are thus unreachable by drilling, except from platforms in Federal leases. P. 269^