Deep Drilling Problems - Some Causes And A Possible Solution
Authors: O&apos;Brien T.B. 
Published: December 2007

Poor planning, wishful thinking, and lax or inept supervision combine to cause most oil field problems. Neglect or misinterpretation of available data and improper engineering evaluation of consequences of designs and techniques lead to often disastrous results. Inadequately trained, over-worked and occasionally lax supervisors fail to apply or misapply available technology.

Training at all levels suited to the level and applicable to current problems reiterated to the point performance becomes automatic is the first step in solving well problems. problems.

TEXT

During the last five years I have published several papers and magazine articles published several papers and magazine articles on the basic theme of poorly trained personnel and inadequate use of available personnel and inadequate use of available technology in the oil and gas drilling industry. After that period of time it appears that technology has advanced substantially and performance has advanced in some areas. The problem is wells are being drilled under more difficult conditions of environment, depth, pressure, corrosive well fluid and inflated cost. The net result is we are certainly not improving our relative position measurably. The industry seems to be content to operate at a fairly constant level of inefficiency.

As a part of my consulting work I am called upon to critique a number of drilling operations. These are generally wells that have been extremely costly, failed to reach their objective, blew out, had some catastrophic failure, or some combination of any or all of those. Every one violated several well known widely accepted engineering principles. In no case is there any indication that these violations are careless, negligent or derelict.

In many cases the desire to drill inexpensive wells tends to influence the designers estimate of the probability of encountering abnormal pressures and of getting those pressures on casing. In fact is appears that many pressures on casing. In fact is appears that many designers start by assuming the well will be dry and basing all their work on that premise. Although by no means restricted to the Oklahoma area this practice leads to a large number of the Morrow blowouts there. It is true that if every well were designed to accommodate Morrow pressure costs would be excessive and quite a pressure costs would be excessive and quite a few would be eliminated. There must be an answer that will allow drilling all reasonable prospects and yet minimize serious problems. A higher quality engineering evaluation of risks, probability and consequences of problems and quality probability and consequences of problems and quality supervision at critical times will do much to reach that goal.

Greater problems in this regard occur in deep high pressure wells and it is not confined to any area. Two problems both engineering related but one controlled by unqualified management and the other by established practice and poor engineering evaluation occur in all provinces.

In the past year wells have been drilled onshore and offshore in the Gulf Coast on which 5000 psi working pressure blowout preventers were used psi working pressure blowout preventers were used on protection strings where surface pressure could and did exceed 9000 psi. Fig. I.