Minimising or eliminating completely the flaring of hydrocarbons during well clean-up and early production testing is an increasing challenge for the oil and gas industry and an important issue for Karachaganak Petroleum Operating b.v. (KPO).
KPO operates the giant Karachaganak gas-condensate carbonate reservoir located in north-western Kazakhstan. To improve reservoir management and field recovery, KPO drills long horizontal wells and then stimulates them with acid. KPO has used a variety of different acid stimulation techniques, progressing from simple acid washes to high rate matrix acid treatments and hydraulic fracturing with gelled acid. With the advent of mechanical downhole diversion equipment, KPO can now perform Multi-Stage Selective Acid Stimulation treatments. However, as the complexity of the stimulation techniques has increased, so has the volume of fluid injected into the wells, most of which is recovered to surface during the subsequent clean-up and well testing.
The processing facilities at Karachaganak are not designed to handle large quantities of water. A traditional approach to dealing with this problem would be to flare all the produced fluids from the wells until an acceptable water-cut of 1% is achieved. KPO recognised that it had to adopt a different methodology in order to reduce the volume of hydrocarbons flared during well clean-ups and testing. A new approach to well clean-ups was sought that would be capable of efficiently separating the fluids and measuring the flow-rates from high productivity wells and would:
Reduce or eliminate flaring.
Reduce the environmental impact of well clean-up operations.
Dispose of unwanted fluids in a safe and environmentally friendly manner.
Recover additional hydrocarbons that would otherwise be flared.
This paper describes the evolution and application of a new approach to performing well testing, clean-up and water separation and treatment in the Karachaganak field. It describes the methodology, challenges and strategies that were adopted to manage the liquids produced during the clean-up and early testing of new Karachaganak wells. It focuses on the value brought to both the environment and the field by the deployment of an advanced, integrated 3 Phase High Pressure Separator (3P-HPS) spread with associated water treatment concept.