WellCAP’s built-in flexibility plays a key role in the safe execution of one of the fastest-paced drilling operations in the world, according to Rob Weakley, drilling manager for the Asia South Business Unit of Chevron Thailand Exploration & Production.
Mr Weakley provided the keynote address at this week’s IADC Well Control Asia Pacific 2009 Conference and Exhibition, held in Bangkok, Thailand. Chevron, which has adopted WellCAP as its internal training standard, was a platinum sponsor of the conference.
“Where does WellCAP fit in?” he asked. “WellCAP allows Chevron to add topics to our school for special operations. These include geothermal and steam floods, ballooning, and mudcap drilling.”
Other special situations included in the company’s WellCAP courses include slim-hole drilling and special monitoring, equipment and procedures for under rig floor logging (see article here).
Chevron Thailand’s operations are extremely fast-paced, requiring special focus on safety, well control and equipment maintenance procedures.
“On average, one rig in the Gulf of Thailand drills 12.5 rigs worth the footage of the average Chevron operation worldwide,” Mr Weakley said. “The efficiency of our operations depends on four key elements: planning, rigs, people and execution of the plan.”
In the first nine months of 2009, Chevron Thailand operated an average of 6.5 rigs that drilled 270 wells for a total footage of more than 2.4 million ft with 3.75 million ft of casing and tubing, Mr Weakley said. The average well took 6.6 days to drill, with an average total vertical depth of 9,304 ft and a measured depth of 12,430 ft. More than 20,000 ft of hole were perforated.
In the same period, well intervention operations included production logging on 181 wells, wireline operations on 2,549 wells and coiled tubing operations on 45 wells.
Mr Weakley estimated that Chevron Thailand encounters about 40 well control events a year that require circulating with the well shut in, which includes circulating bottoms up for trip gas, possible ballooning, and kicks. Almost all of these occur when making a connection or tripping due to loss of equivalent circulation density (ECD). Kicks can sometimes be confused with ballooning, and Chevron has developed special training and procedures to deal with this.
Mr Weakley said that Chevron’s focus on contractor safety has resulted in a noteworthy safety record, with more than 4.7 million manhours worked since the last lost-time incident in July 2008. He said a contributing element is an estimated 50 to 110 job safety analyses (JSAs) performed per well.
“There is no automated pipe handling equipment on these rigs,” Mr Weakley said, “only hydraulically operated slips and a Hawk Jaw on some rigs.”
Safety considerations include ensuring that safety devices are in place and functioning, following written procedures for high-risk or unusual situations and addressing abnormal conditions.
“It’s also important to involve the right people in decisions that affect procedure and equipment,” he said.
Natural gas produced by Chevron assets generates approximately one-third of Thailand’s electricity, Mr Weakley said.
Other conference sponsors included Petroleum Development Oman (PDO), Atwood Oceanics and GE Oil & Gas.