RIASSUNTO
Abstract
The Genesis project was ChevronTexaco's first Gulf of Mexico deepwaterdevelopment project and the first industry project to utilize spar technologyfor drilling, completion, and production operations. This paper discusses theunique results and lessons learned through the first four years of the Genesisproject in the areas of integrated teams, organizational learning, sparoperations, completion practices, well performance, and reservoirmanagement.
Introduction
The Genesis field is located in Green Canyon Blocks 160, 161, and 205 in theGulf of Mexico. The spar is located in Green Canyon Block 205 in 2590 feet ofwater. The Genesis project is a joint venture among three partners:ChevronTexaco (operator) with 56.67%, ExxonMobil with 38.38%, and BHP Billitonwith 4.95%.
The discovery well was drilled in 1988, and several delineation wellsfollowed in the early 1990's. Development funding was approved in 1996. Asemi-submersible rig was used to batch set 36, 26, and 20 inch casing stringson 19 wells. The seafloor well pattern includes locations for 20 wells and twoexport riser bases. Spacing between locations is 20 feet in a 140-foot diametercircle. The semi-submersible rig also drilled and cased the first twodevelopment wells.
The spar was installed in mid-1998 followed by topsides and riginstallation. Hook-up work commenced and the first rig operations, running theexport risers, began in November 1998. First production occurred in lateJanuary 1999.
Through the first four years of the project, fourteen producing wells havebeen drilled in the Genesis field. These fourteen wells include ten wells withsingle completions and four wells with stacked wireline selective completions.Major rig workovers to change producing zones have also been performed on twoof the initial fourteen wells.
Maximum daily production from the Genesis field was 61,130 bopd and 98,670mcfpd, achieved on July 4, 2001. Future plans for the field include numeroussidetracks and major rig workovers.
OTC paper 107971 published in 1999 titled ""Genesis Project:Development Well Planning"" discussed the development plan for the Genesis fieldas related to drilling and completion design and execution. This paper presentsa unique comparison between the planned and actual development program anddescribes results and lessons learned through the first four years of theGenesis project.
Geologic Overview
The producing reservoirs at Genesis are stacked Plio-Pleistocene turbiditesandstones.1,2 They lie on the eastern flank of a buried salt ridgeand dip to the ENE at 10° to 40°. Depths are between 11,000 and 16,000 feetsubsea. In general, seismic amplitude is an indicator of both fluid content andreservoir quality.
The Genesis reservoirs can be described as:
Laterally extensive, generally thick, thinly-bedded, low density turbidites(Lower Pleistocene N1)
Laterally extensive, generally thick, amalgamated turbidite channels (LowerPleistocene N3L)
More discontinuous, locally thick, amalgamated turbidite channels with someinterchannel facies (Lower Pleistocene N2 and Upper Pliocene 14,200' &14,800')
Isolated channels and ponded sands (Lower Pleistocene N4 & N5 and UpperPliocene TP & 14,500')
All are unconsolidated with varying amounts of silt and very fine to mediumgrained sand. Property ranges for commercially productive reservoirpenetrations are:
Gross thickness 20 to 130 feet
Net/gross ratio 0.7 to 1.0
Average porosity 0.23 to 0.32
Figure 1 is a Genesis type log.