Examining the Impact of Hydrocarbon Drainage on Completion and In-Fill Drilling Strategies in Unconventional Reservoirs

摘要

Evaluating the effects of asymmetric stress distribution around a lateral can greatly help optimize completion techniques and overall production from in-fill horizontal wells in unconventional shale and tight reservoirs.Several factors affect long-term production from in-fill drilled wells including but not limited to pressure depletion from produced wells,change of effective stresses in the depleted formation and interference between hydraulic fractures when the new in-fill wells are drilled,stimulated and brought into production. The study addresses a variety of key challenges that the unconventional oil and gas industry is looking to understand.These include understanding: 1.How the presence of a depleted wellbore affects hydraulic fracture propagation from a nearby newly drilled well 2.How refracturing considerations in a producing well are affected by hydrocarbon drainage and modified stress contrasts 3.How fracturing/refracturing pumping designs and volumes should be optimized to address the challenges surrounding the wellbore Under circumstances mentioned above,pressure distribution around the wellbore from hydrocarbon drainage was estimated by history matching production data over a certain period of time.Then the impact of various types of fracturing treatments on pressure depletion profiles from offset wells was studied using a fully numerical fracture simulator that is capable of handling asymmetric stress distribution around the lateral.Fracture geometries from this study were either asymmetric due to depletion on only one side of the lateral or longer due to increased stress contrast.These fracture geometries were fed to a production model to forecast long-term production from in-fill wells and study drainage patterns over time. Understanding these challenges provided a sub-surface perspective of how completion techniques should be optimized to get maximum hydrocarbon recovery from reservoirs consisting of laterals that have already been on production.