Current Abstract
January 14th, 2025 Meeting Abstract
“Injection/production Behavior In Cyclic Steam Wells, And Their
Implications To Surface Expressions And The Kinematic Evolution Of The Diatomite Reservoir“
Presented by: Bill Bartling
Abstract:
Oil Production on the West side of the San Joaquin Basin in California includes contribution from Miocene/Pliocene formations dominated by diatomaceous sediments. Diatomite reservoirs are produced using Cyclic Steaming.
The wells are drilled in dense patterns as typically the fracturing and heating impacts of cyclic steaming are contained within 10’s of feet of the wellbore, and due to the high porosity and high oil saturations and thus very high oil in place, the recoverable volume of oil within this radius is sufficient to payout these shallow, inexpensive wells.
While in most cases the steam in the reservoir is controlled, there have been unexpected and uncontrolled high energy releases of steam, water and oil to the surface, known as surface expressions. These pose significant safety hazards to oilfield workers and in some cases, they release of large quantities of oil which causes sometimes significant environmental damage. Studies and oilfield remedial practices suggest that in most cases surface expressions are associated with or caused by damaged well bores or compromised cement in active, idle, and abandoned wells that provide a conduit for fluids and energy to near surface high permeability formations which can vent some distance from the leaking
well, or directly to the surface at the damaged well. However, the mechanisms of long distance fluid propagation in the subsurface between injectors and conduits to the surface are not fully understood.
This paper analyzes injection/production profiles and discusses surface expressions and potential causative mechanisms for subsurface fluid propagation to explain anomalies in these profiles, the distribution of surface expressions and a potential foundation for predicting and managing and thus avoiding future surface expressions. This study investigates the potential for kinematically induced fractures in the pre-
unconformity strata, and if those fractures exist, estimate their location, distribution, orientation, and potential impacts on the reservoir behavior. Typical forward modeling of kinematic induced strain is difficult as previously stated, as most of the mapping in these
fields was done on the post unconformity units and thus accurate cross sections and maps below the unconformity surface are generally unavailable except for work by Farley 2009 and others, and there were no detailed mapping studies identified specifically for the study
area.
The approach to the problem in this study is inverse from a typical kinematic analysis. That is, this study analyzes injection/production profiles to infer reservoir behavior at each well and from that, identifies populations of wells with similar behaviors
that may indicate differences in reservoir properties and then spatially map them. Once done, kinematic models are referenced to assist in interpreting these maps and the maps incorporate data from post unconformity structural maps, and borehole geophysical analysis that samples both pre and post unconformity strata. Naturally fractured rocks are expected to display higher permeability and show longer pressure and reservoir connectivity away from the well than would an unfractured rock. Also, the response of abnaturally fractured rock to cyclic steam stimulation, which in an unfractured rock creates smnall fractures near the well bore will be measurably different from that of an unfractured
rock and these differences in rock fabric will be expressed in injection and production flow and mass balance data.
The kinematic model employed as a foundation for this study predicts that naturally fractured and unfractured rocks will be spatially compartmentalized as a function of the rock’s location and deformational history relative to active and passive axial surfaces in
fault bend or fault propagation folds resultant from regional compression
Biography:
Bill Bartling is the retired Chief Deputy for CalGEM, formerly known as DOGGR, Co-Founder and Director of Regulatory Affairs for Geo2Watts, advisor for Lillianah Technologies and living in Prescott Arizona.
Prior to joining DOGGR in 2015 Bill was General Manager of Borehole Imaging for OptaSense Ltd, President and CEO of SR2020, Sr. Director of Market Strategy at Silicon Graphics Inc, CEO of SciFrame, Inc., Mgr. of Technical Computing at Occidental Petroleum, Sr. VP of Software Eng. at CogniSeis Development and Earth Scientist/Manager in exploration, production and research at Chevron.
Ongoing technical projects include energy transformation, carbon sequestration and management, subsurface/reservoir modeling and interpretation and medical imaging technologies along with tennis, hiking and mountain biking.
Bill has a BA in Biology from UCSB and MS in Geology from San Diego State, is VP of SEG Pac. Section, is on the Advisory Board of the SDSU Center for Computational Sciences and is a member of SPE, AAPG and SEG.